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RF_DIS_14_SUDHA
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K A/V4 /)AG A- A
Vector Surveillance
K A/GA AT4 A.4
Entomological & Vector Control Aspects
Division of Medical Entomology & Vector Control
National Institute of Communicable Diseases
22- Sham Nath Marg, Delhi - 110054
1
VECTOR SURVEILLANCE
The last 3 decades has witnessed the emergence , resurgence or
spread of vector-borne diseases like malaria, filariasis, Japanese
encephalitis, Dengue/DHF, Kala-azar, plague in various parts of the
country. Amongst the various reasons attributed contributing for the rising
trend of vector-borne diseases, the inadequacy or lack of entomological
surveillance is of paramount importance.
In view of the above it was thought worthwhile to gear up/strengthen
entomological surveillance activities at various levels viz. District, Zonal,
Regional, State and Central level to collect meaningful entomological data in
respect of existing vector-borne diseases prevalent in the district and about
the receptivity of the area for other vector-borne diseases. Some of the
important characteristics of the vectors of various vector-borne diseases,
sampling techniques, identification keys, techniques used for the
incriminatioin of vector species for pathogens/parasites, WHO techniques to
ascertain the insecticide susceptibility status of adults and immature stages
and vector control measures used viz. personal prophylactic, source
reduction, environmental management, biological control, chemical control
and integrated measures used for the prevention and control of vector-borne
diseases on long and short term basis are summarised below:
Entomological aspects
Most of vector-borne diseases prevalent in the country are transmitted
by animals from 3 Classes viz. Insecta, Crustacea and Arachnida belonging
to Phylum - Arthropoda (Arthros = Jointed, podos = legs). Members
belonging to these Classes can easily be differentiated on the basis of
following characters:
Class
Insecta
Crustacea
Arachnida
Body
Divisible into
head,thorax and
abdomen
Divisible into
cephalothorax
and abdomen
Undifferentiated
Legs
3 pairs
5 pairs
4 pairs
Antennae
1 pair
2 pairs
Absent
Wings
Present
Absent
Absent
2
c
1. Mosquitoes- Vectors of malaria, Dengue.
filariasis and J.E.
Mosquitoes are worldwide in distribution. There are ;
about 3450 species and
subspecies of mosquitoes belonging to 38 genera in
Family - Culicidae. In
India there are about 300 species of mosquitoes.
Mosquitoes may be easily differentiated from other insects of similar
shape and size on the basis of following characteristics:
*1 ,.Insects with a single pair of mesothoracic fore wings and
the hind pairs of wings are modified into halteres
ii)
r
Presence of forwardly projecting proboscis with piercing
and sucking types of mouth parts
iii)
Presence of scales on the thorax, abdomen, legs and wing
veins
iv)
Presence of fringe scales on the posterior margin of the
wings
*
V)
Characteristic wing venation i.e. wing vein 2nd, 4th and k
bifurcated
5"' !
I
Morphology of mosquito
lennh^J' Slender b°died ’ Sma" toSeCtS curing about 3-6 mm. in
length. However, some spp. may be as small as 2 mm, while others mav be
°hor°ie and
(roXOr^nchites>- Th' b°dy distinctly divided into head,
thorax and abdomen. Mosquitoes possess only one pair of functional
, f°reWmgS- The hind Pair of wings are represented by a pair of
small knob-ike structures, the halteres, which are the balancing organ
while mosquito is flying.
Mcucuiomg organ
. ..
head bears a Pair of large kidney-shaped compound eyes and a
pan- ol filamentous and segmented antennae. In females the antennae have
horls of short hairs (Pilose) whereas in males the antennae bear a whorl of
long hairs giving them .feathery appearance (Plumose). Just below the
-Z. ead bea7 pair °f
wh*h
be short o'r long
adults s o o” hT
a‘ thrr.tipS d'PendinS upon the sex and whetlj
adults are anophelmes or culicines. Arising between the palpi is a single
elongated structure, the proboscis, which contains the piercing and sucking
types of stylets or mouth parts. The largest component of the mouth parts
IaI
v
1£
" Shaped labium which terminates in a pair of
small lobe like structure called labella which are sensorv in nature The
heath
enC,rC1'
°ther n’0Uth parts and
- - proteolive
3
The upper most structure, the Lobrum is slender, pointed and grooved
a ong its ventral surface. In between the labrum and labium are five needle
like structures viz . a paii; of toothed maxillae, a pair of serrated mandibles,
a single hollow stylet, the hypopharynx.
At the time of taking blood meal, the tips of flashy labium are placed
on the skin and curves backwards. This allows the paired mandibles and
maxillae, labrum and hypopharynx to penetrate the host skin. Saliva is
pumped into the host body through the hypopharynx. Blood is ingested by
females mosquito through the pumping action of the pharynx.
The male mosquitoes are iincapable of taking blood meals as the
maxillae and mandibles are vestigeal and feed_l on plant saps or nectar.
The thorax is covered dorsally and laterally with scales which may be
duU or shiny, white, brown, black in colour. The arrangement of scales on
the dorsal surface of the thorax helps in the identification of some species of
mosquitoes (Aedes spp.)
The wings are long and relatively narrow, the number and
arrangements of the wing veins is almost the same in all mosquito spp.The
veins are covered with scales which are usually brown, black, white creamv
or yellow in colour. The shape of the scales and pattern of their
distribution varies in different genera and species of mosquitoes. While
sitting the wings of the mosquitoes are placed across each other over the
abdomen in the form of a closed scissor. There are three pairs of tiny
elongated legs which are covered with scales. The tarsus usually terminates
in a pair of toothed or simple claws. Some genera such as Culex have a pair
of small fleshy pulvilli at the end of tarsus.
The abdomen consists of 10 segments but only the first 7 or 8 are
visible.
In sub family Culicinae, the abdomen is usually covered dorsally and
ventrally with brown, black or white scales.
The last abdominal segment of the female mosquito terminates
in a pair of small finger like structure called cerci, whereas in males it
terminates in a pair of prominent clapers, which is a part of male
gentalia. ( Fig : 1)
4
c
Diagrammatic representation of a female adult mosquito
1.2 Anopheline Mosquitoes
Anopheles species are mainly responsible
for the transmission of malaria in various parts of the world. Out of 55
anopheline species prevalent in India , 9 are vectors of malaria viz.
Anopheles annularis, A* stephensi, A. Philippinensis, A. sundaicus, A.
minimus, A. vamna, A. culicifacies, A.fluviatilis and A. dims.
i) Habits • They are commonly found in large numbers in human
habitations, animal shelters or in mixed dwellings. Anopheline mosquitoes
have idso been fqund resting in outdoor situations on banks of stream ,
under culverts, and in thick shrub, forest etc.
ii) Breeding habits
The eggs are deposited singly and generally laid on
the surface of clean and unpolluted water such as pools, rice fields, slow
running streams, cisterns, overhead tanks, tree holes etc. Some species
prefer standing types of water like ponds, wells, irrigation cannals, pits and
also breed in various types of rain water collections.
Hi) Resting habits
Most of the anopheline mosquitoes are domesticated
and they are found in very large number in indoor situations; in cattlesheds
and human habitations. However some of the species like A. dims is an
outdoor rester (Exophilic). Males are usually found near the breeding
places.
iv) Biting and feeding habits
Male mosquitoes can not suck blood and
normally feed on nectar and plant juices. Female mosquitoes are able to
pierce the host skin and feed on blood. The great majority of species are
zoophagic i.e. they feed on the blood of mammals, reptiles, birds, and
5
amphibians but some of the species like A. fluviatilis and A. minimus have
got definite preference for human blood.
v) Elyfog habits:- Most domestic species of mosquitoes remain in close
vicinity of about 1 km. of human or cattles dwellings, however, creeping
movement of mosquitoes takes place on account of oviposition, feeding,
swarming, mating etc. (Fig : 2)_____________
. Aiicphdcs rctlins poiiiion
MA^rrA • '
riitophelci tnojquilo
MsImIi
1,3 Culicine Mosquitoes
The important human diseases transmitted
by culicine mosquitoes are Filariasis by Culex quinquefasciatus and
Mansonia species, Japanese encephalitis by Culex vishnui group and
Dengue/Dengue haemorrhagic fever by Aedes mosquitoes.
i) Habitat:C
Culicine mosquitoes prefer dark places and live in human
dwellings, cattlesheds and other such shelters^ They may also live in
outdoor situations in shrubs, grasses, forests etc.
HF Breeding habits:- Host
T'
of the culicine mosquitoes lay their eggs in
organically polluted water,. The eggs are also laid in unkept drains and
unused wells. Aedes mosquitoes generally prefer artificial breeding places
6
such as earthen pots, cement tanks, glass or plastic containers, tyres,
coolers, in small collections of water in man made containers. Mansonia
species breeds in water organically polluted and habouring aquatic plants
like Pistia spp., water hyacinth, lemna etc. The larvae and pupae of
Mansonia mosquitoes remain attached to the roots of these water plants
through their respiratory siphon to take oxygen. Eggs are laid on the under
surface of leaves of these plants.
iii) Resting habits:- Culex and Aedes are found in human dwellings or
cattlesheds.
Mansonia species mainly rest in cattlesheds and human
dwellings but may also rest outdoor.
iv) Biting and feeding habits:Culex mosquitoes are zoophagous and
anthropophagous . Mansonia species prefers human blood. Only Aedes
mosquitoes bite during day time and feed mainly on human,blood.
v) Flying habit:- Culex and Mansonia species of mosquitoes can fly upto a
long distance of 4 to 5 kms., while Aedes mosquitoes have very limited flight
range of about 100 meters and remain near the host.
( Fig : 3,4,5)
7
8
1I
I
Fig-4
Japanese encephalitis (Viral)
aJ.Principal vectors
Cxdritaenirohynchus, Cx.vishuni and
Cx.pseudovishntii
b) Suspected vectors
Cx.shitmorei,
Cx.epidesmus,
Cx.gelidus,
A.barbirostris,
A.hyrcanus, A.subpictus
9
"•‘•-■A.
/
/
S ■
\
.
--
'
Aedey mosquito resting position
Aedes aegypti
As. e^xjpjczus:
As.
Aedes aegypti
Dengue/DHF (viral)
Fig.- 5
1.4 Life cycle
There are four stages in the life cycle of mosquitoes viz. egg, larva,
pupa and adult, The first three stages are aquatic and adult stage is
aerial/terrestrial
i) Egg
Anophelines generally lay their eggs singly in clean, oxygenated
water. Each egg is boa^shaped in appearance and has distinct float on
either side. The number of eggs laid by a single female varies from 40-150.
Culex mosquito lay eggs in the form of egg raft. Each egg raft may
contain 150-400 eggs. C. quinquefasciatus, vector of filariasis lay eggs in
organically polluted water, whereas, Culex vishnui group of mosquitoes,
vectors of Japanese encephalitis lay egg rafts in the paddy fields, swampy
and marshy areas.
io
The Aedes mosquitoes lay eggs in artificial man made containers
containing fresh water. The eggs are laid singly and a female may lay 60150 eggs in one oviposition. The eggs of Aedes mosquito can withstand
ddssication upto 1 year ajid hatch when containers are inundated with rain
water.
The freshly laid eggs are white in colour but within half to one hour
of egg laying colour changes to black. The incubation period of egg stage is
about 2 days duration under favourable climatic conditions (Tem. 27 C and
R.H.- 75-80%) .
11) Larva
The larva feeds voraciously on minute algae and other plankton
present in the water and grows in size. As a result of feeding and growth,
the outer skin is shed and next larval stage comes out. There are four larval
stages in the life cycle and after third moulting, the larva changes into pupal
stage.
The larval period last for 6-8 days under favourable climatic
conditions.
Hi) Pupa
.
The pupa is coma-shaped in appearance. The head and thorax are
fused to form cephalothorax and the abdomen is curved. It is the resting
stage in the life cycle and does not take any food. The pupa is very active
and sensitive. It moves away, if disturbed. During this stage the future part
of the adult mosquito is formed inside the pupa.
The pupal period last for 2 days under favourable climatic conditions.
iv) Adult
The chitinous cuticle of cephalothorax of the pupa breaks in between
the respiratory trumphets and through this opening the adult mosquito
emerges out. On emergence, the adult mosquito sits on the empty pupal
skin or on adjoining vegetations for sometime to harden its body part after
which it flies away for mating, feeding and resting.
11
CHARACTERISTICS OF ANOPHELINES AND CULICINES
ANOPHELES
CULEX
I
••
I’M l, MI'illT
»»«* I».
Fig. - 6
12
1.6 Methods for estimating the adult and larval mosquito density
and for collecting information on other entomological
parameters
If
A.
Adult mosquito density
i)
Per Man Hour Density (PMHD)
10
ci/" 4-7 0
p'O
*
y-
No. of mosquitoes collected
r
No. of hours spent in search
li)
Total catch by pyrethrum space spray
Total catch by pyrethrum space spray in a unit area may be
undertaken by spraying 0.1-0.2% pyrethrum extract® 30-60 ml/ 1000 cubic
feet.
iii)
JMan-mosquito contact - Mosquito biting/landing rate on human or
animal bait may be determined by counting the number of mosquitoes
collected while landing or biting on human or animal bait per unit time or
per night.
iv)
Sporozoite rate in malaria vectors
No. of females anopheline species positive for sporozoites
±_____________________________
x 100
No. of mosquitoes dissected
v)
Vector susceptibility to insecticides
As per standard WHO technique (Details enclosed)
vi)
Parity rate
Simple detection of parous ( a female which has laid eggs) females on
the basis of tracheal skin or ovariole dilation.
No. of parous females encountered
x 100
No. of female mosquito dissected
13
Wall cage Test (Contact Bioassay test)
For studying the residual efficacy of residual insecticides under field
condition.
Percent mortality obtained after 24 hours amongst mosquitoes
exposed to insecticide sprayed surface for 15 minutes in plastic cones on
insecticide treated surface.
vHi) Collection of mosquitoes by using various traps viz.
window, light trap etc.
Magoon,
No. of mosquitoes collected species wise/ night/trap
ix)
Anthropophilic index
Percentage of mosquito blood meal found positive
for human blood
a) Collection of immature stages of mosquitoes
bor larval collections breeding habitats of the vector species may be
searched at any time during the day. Mosquito larvae are collected by the
following methods:
*)
pipping : Most frequently used method for collecting mosquito larvae
from edges of swamps, ditches, rice fields and other water bodies.
Equipments generally used are laddie, photo-tray, spoon etc. Larval density
is calculated in terms of average number of larvae collected per dip.
ii)
fletting :
Larvae can be collected from large water bodies or
streams by long handled larval net and from wells using well nets, Larval
density is calculated per net.
iii)
Pipetting : Small pipettes can be used to collect mosquito larvae
from shallow breeding places like hoof prints, plant axils, tree holes etc.
14
I
b) Larval Density per dip
(laddie, larval net, well net)
= No, of larvae collected
No. of dips taken
For Aedes cieqypti
i)
Container index
ii)
House index
No. of houses found positive
No. of houses searched
iii)
Breteau index
No. of containers found positive x 100
No. of houses searched
No. of containers found positive x 100
No. of containers examined
x 100
C.) Prpcauations to be taken while collecting mosquito larvae by dipper
1.
The enemel bowl, frying pan, ladle should be immersed in the
breeding places at an angle of 45°. The surface water will flow into the
cavity but care should be taken not to fill this completely as otherwise some
larvae will be washed out.
2.
When the surface of the water is covered with dense floating
vegetation or organic debris, the water surface should be agitated to cause
the larvae to sink, clear away the vegetation and then wait for 3-5 minutes
for larvae to come to the surface once more.
df Precautions to be taken while using larval net
Larvae may be collected from large stretches of water along the edge of
streams, wells and other situations using a larval net of 20-25 cms.
diameter. When collecting larvae, the net is held at an angle and skimmed
rapidly through the surface near emerging or floating vegetation or pushed
along very slowly allowing the surface water to float into the net.
Alternatively, the net may be used as a ladle, a series of quick dips being
made. The net is inverted and washed out in a bowl of water and the larvae
are collected with a pipette.
15
e) Precautions to be taken while using the well net
The well net is dipped slowly into the well keeping half the bor
above the water. After waiting 2-3 minutes to allow the disturbed lar/^r
return to the water surface, the net is dragged slowly and as quietly arpossible around the edge of the well keeping the net at the initial diy
When the net has been moved around the border of the well two or three
times it is withdrawn and inverted in a white enamel basin containing watr
Wait for 2-3 minutes then repeat. The larvae are collected with a pipette
w
c
fl Precautions to be taken while collecting adult mosquitoes in indoor
situations
Before collecting mosquitoes from human dwellings, cattle sheds,
mixed dwellings etc., one should thoroughly inspect the areas for the
presence of snakes, scorpions, centipedes etc. to prevent any mishappening
1.7 Susceptibililty status of vector Mosquitoes
i) Malaria vectors
An. culicifacies and An. stephensi, major vectors of malaria arc
resistant to DDT and HCH in most part of the country. In Maharashtra,
Gujarat and certain parts of Haryana triple resistance against DDT, HCH
and Malathion has been reported.
The other malaria vectors except An. annularis have been reported to
be susceptible to conventional insecticides used under NMEP.
ii) Dengue/DHF Vectors
Aedes aegypti mosquito is resistant to DDT and Dieldrin
susceptible to organophosphates and synthetic pyrethroids.
but
ilijJ.E, Vectors
The major J.E. vectors have developed resistance against
organochlorine insecticides (DDT, Dieldrin) but are reported to be
susceptible to organophosphates and synthetic pyrethroids.
iv) Filariasis Vectors
Ox. quirLquefciscia.tuSy vector of Bancroftian filariasis is resistant to
most of the organochlorine and organophosphate compounds but
susceptible to synthetic pyrethroids.
1*8
Determination of susceptibility test
A. Adults
Susceptibility tests of adult mosquitoes are carried out at six monthly
interval to ascertain the current susceptibility status of vectors against
various insecticides being used under public health programme so that
appropriate insecticide may be used for effective vector control.
Freshly fed female mosquitoes collected from the study area are kept
under laboratory conditions and the healthy mosquitoes are exposed for a
period of one hour and mortality count is made after 24 hrs. as per the WHO
method.
Equipments, material and method used to determine the insecticide
susceptibililty status of mosquitoes
Equippients/material required:
C
0
HCCDjjtq
fum
Winn*
1VBL
E^OyjAL
rut(
UPOSUfct
■wtPthC
(Fig:7)
19
(
Composition of WHO Test Kit :
(i)
20 plastic tubes - 125 mm length and 44 mm diameter.
8 tubes with red dot - exposure tube
2 tubes with green dot - control tube
10 tubes with green dot-holding tubes
(ii)
10 slide-units with a screw cap on either side
and provided with a 20 mm filling hole
(iii)
Insecticide impregnated papers
(iv)
Sheet of plain paper for lining of holding tubes
(v>
20 spring wire clips (8 copper clips for exposure tubes and
12 silver clips for holding and control tubes)
(vi)
Glass aspirator tube
(vii)
Adhesive tape, log probit paper
(viii
Impregnated papers Organochlorine /organphosphate /
carbamates /synthetic pyrethroid
Methodology
- Insert a piece of white paper in each holding tube and put a
silver spring wire clip to keep the paper in position.
- Now put 15-25 mosquitoes per tube in each holding tube with
the help of sucking tube through filling hole in sliding unit.
- Keep the holding tubes in upright position for 1 hour and
damaged mosquitoes should be removed
- In exposure tubes put insecticide impregnated papers of
different concentrations and one control paper impregnated
with oil (solvent). To keep the paper in position use copper
spring wire
clip.
- Now transfer mosquitoes in exposure tubes/control tube from
holding tubes with the help of sliding unit.
- Leave the exposure tubes standing upright with screen end
up for 1 hour
- At the end of exposure period, transfer the mosquitoes to
holding tubes. A small cotton pad soaked in glucose should
be kept at the top of screen.
20
- Keep the holding tubes for 24 hours in a place with diffuse
light, temperature , 25 + 5°C and R.H. 70-80%.
- Mortality counts are made after 24 hours. For each
concentration at least four replicates should be used
- If control mortality is between 5-20 per cent it can be
corrected by Abott’s formula. The tests with control mortality
more than 20 per cent are unsatisfactory and should be
repeated.
% test mortality - % control mortality
Abottp’s formula =
x 100
100 - % control mortality
Genend Remarks
1.
Each impregnated paper may be used upto 20 times and upto 3
weeks after removal from the packet
2.
After removal of impregnated paper, the packet should be
carefully with plastic tape
resealcd
Result / interpretation
1.
Percentage mortality obtained for each concentration can
be put in log-probit'graph paper.
2.
Regression line may be fitted by eyes and LC 50 and
LC 95 values can be read from graph.
21
hih cent
-rs- x
i-CZ
■sq|—r
I
carcin r haticm
I
:
2 OX
4-0 %
I
DDT •
•5 9-r |-/'; H ]0 0 J -h pcj n
...
[cxpcsvre
!
*?9 j-
• *.
__
^3
I
.... •
3fcr
/
... L
'T i
I
•__l_
1^
!
I
Ell
j
»
I
50
<1
<o
p-
Zt
I
JE
u
5
ro 5
i
I
—!
0-5
I
I
O-1 <-
1
J
I
(Fig. 8)
22
*
y
r
c
LARVAE
Susceptibility status of larval population of mosquitoes can be
determined by exposing late 3rd or early 4th instar larvae to various
insecticide concentration in 500 ml glass beaker for a period of 24 hrs. and
thereafter larval mortality is recorded as per the method recommended by
WHO using WHO test kit.
Based upon the larval mortality, the
susceptibility status of larvae against particular insecticide is ascertained.
As per the guide lines the following criteria is used for determining the
susceptible or resistant , tolerent status of adults and larvae.
Range of Mortality
Status
1.
2.
Between 98% - 100%
Between 80% - 98%
Susceptible
Tolerant
(Verification required)
3.
Below 80%
Resistance
23
Proforma of mosquito larval survey
Locality -
Date of collection -
PER DIP DENSITY IN + VE BREEDING PLACES
Sullage
water
drains
Septic
Tank
Cesspits
OHT
Cistern/
Barrel
Ornamental Tank
Wells
♦
ANOPHELINES
L-I-II
L-II
PUPA
CULICINES
L-I-II
L-III-IV
PUPA
AEDES
L-I-n
L-III-IV
PUPA
24
Irrgn.
Canal
Seepage
Water
Rice Field
Lake
Rain
Water
Colleta.
Rejected
Tyre
Utensil
Others
Proforma for Indoor Adult Mosquito Collection Record (MHD)
Distt.
Date
P.H.C.
Time
Method: Aspirator.
Village.
♦
♦
LastSpray on:
House/ Cattle shed
Weather: Clear/Cloudy/Rainy
S.No.
Mosquito Species
Houses
Abdominal Conditions
UF
1.
2.
3.
Anophelines
Culicines
Aedes
UF
Unfed
F= Fed
F
| SG
G
I Density
P.M.H.
(houses)
Total
F
SG = Semigavid
M
Time Spent
Cattle Shed
Total
Abdominal conditions
UF
G = Gravid
F
| SG
G
F
| M
I Density
P.M.H.
{Cattle Shed}
2.Vector Control
The major thrust for the control of vector-borne diseases has to be on
vector control, as the elimination of pathogens/parasites in human or
zoonotic reservoir of infection is not in the realm of practicability.
The main objectives of vector control is to keep the vector density at
low level to minimise vector-reservoir contact and to curtail the longevity of
vector species to interrupt disease transmission. Vector control measures
are undertaken where population aggregate for the sake of feeding, resting,
breeding etc. particularly Suring the high density period.
2.1
PERSONAL PROTECTION MEASURES
2.1.1 Anti- adult measures
Several personal protection measures are available for providing
protection against the mosquito bite. They can be used as supplementary
measures in remote and inaccessible areas or against exophilic and
endophagic vector species depending upon their feasibility, cost effectiveness
and sustainability.
i)
Physical methods
This include protective clothings,
windows/doors etc.
use of bednets, screening
of
Repellents - These are substances applied to the skin, clothings or
ii)
mbsquito net to repel the mosquitoes and prevent them from biting. The
most commonly used repellents are DMP ( Dimethyl phthalate) and DEET
(Diethyl toluamide). They provide protection for 3-4 hours.
iii)
impregnated bed nets
Pyrethroids are fast acting, broad spectrum insecticides with low
mammalian toxicity. Impregnation of bednet with synthetic pyrethroid
enhances its potential for reduction or interruption of disease transmission
against endophagic or exophagic species of mosquitoes. Impregnated bed
nets produce deterrent, repellent and killing action and help in reducing
man mosquito contact.
iv)
Coils- Mosquito coils containing natural pyrethrum and herbal
products are used in many countries for protection from mosquito bites.
Use of Tortoise, Rooster brand coils available in the market last 6-7 hours.
26
v)
Mats The mat is iimpregnated with synthetic pyrethroids viz.
Allethrin/bioallethrin and heated
—1 on a plate fitted in a small electric device.
Mosquitoes are either repelled or knocked down by the vapor action of the
pyrethroid. The mats provide protection from
--i mosquito bite for 10-12
hours.
vi)
Indoor residual insecticidal spray
Selective spraying is recommended against vector mosquito species
w ich predominently rest and feed in indoor situations. Depending upon
the susceptibility status of the vector mosquito species to various
organochloroine , organophosphate and
synthethic pyrethroids. The
insecticide is to be chosen to which the local vector is amenable to control
The details about the insecticide, dosage, the formulation and application
etc. are given in the Table- 1.
vii)
Space spraying by Mist, Thermal fogging or ULV spray
Space spraying has been successfully used to control outbreaks of
vector-borne diseases such as malaria, dengue, Japanese encephalitis
Western equine encephalitis etc. The space spray is usually undertaken to
control the resting population of mosquitoes either by using the natural
pyrethrum extract diluted in kerosene oil or malathion during outbreak
situations to interrupt the disease transmission by crisis. This is done in the
form of mist, thermal fogging or ULV spray . Insecticides formulation and
their dosages for space spray are given in Table- 2.
2.
Antilarval measures
Anti- larval measures are used as an adjunct to other methods of
control and are rarely used as main method of control except against
container breeding species or against those mosquito species which breed in
confined or specific small water bodies such as Aedes aegypti, An. stephensi
and An. sundaicus. Antilarval measures can also be tried in an area where
vector species are resistant to commonly used insecticide or exhibit exophily
and exophagy or under those situations where adulticide measures are not
cost effective or tend to endanger the environment.
Antilarval measures in tropical countries are mainly used in urban
or
pen urban areas. These measures can be used in ccertain specialised
situations like minning, irrigation wells, tanks etc. if they’ are operationally
feasible and cost effective. The basic idea of all antilarval measures is to
prevent, reduce or eliminate the breeding places, Certain commonly used
antilarval measures are briefly discussed below:
27
^OUMogfluito larvicidal oil) - Oiling is done in situations where
breeding is temporaiy and permanent measures may not be cost effective
t
SiteS kiH the larVSe by chokinS their sPiracles with oil
film & cutting the oxygen supply. It also deter the adult mosquitoes from
“)
gang-ggen (Copper aceto-arsenite) - It has been successfully used
in malaria control programme for the control of anopheline and culicinc
breeding. It is applied as dust or granular formulation.
M i
lTemePhosl and Baytex (Fenthion) - Widely used under urban
Malaria Scheme for the control of breeding of anopeheline and culicines
osqui oes .
arvicide formulations and their dosages are given in Table o.
2,3
Environmental management for vector control
WHO expert committee on Vector Biology and Control in 1979
deiined environmental management as follows:
“ The planning, organisation, carrying out and monitoring of activities for
modification and/or manipulation of environmental factors of their
interaction with man with a view to preventing or minimising vector
population and reducing man-vector pathogen control.”
This approach which should be carried out prudently and skillfully is
naturalistic and involves an <attempt to extend and intensify natural factors
which limit vector breeding, survival and contact with man. But these
measures nave many constraints and limitations viz.
*
i)
Selective appljcation,
ii)
Require high degree of inter-sectoral coordination,
iii)
Capital investment of some of the methods is high,
iv)
Maintenance is very essential and
v)
Active and sustained community involvement.
This is imost simple and dependable method of elimination or
prevention of mosquito breeding by" identifying
j the active and potential
breeding sites of mosquitoes. Environmental
management of vectors are
much suited for the vectors of urban malaria
and Dengue/DHF as their
vectors
. . mainly
. , breed. in overhead tanks,
---- > coolers and other man made
containers in domestic and peridomestic situations.
28
i)
Prainage
Different species of mosquitoes are known to be associated with
varied type of water bodies. It may be impounded rain water, seepage water,
natural water courses or man made water courses etc. These can be
eliminated by formulating an effective drainage system which will not permit
water stagnation and mosquito breeding.
>i)
Mosquito breeding associated with the construction of
I^oads/Railways
High mosquitogenic potential is generated during the construction of
roads and railways and most of these breeding places can be eliminated if
proper engineering methods are followed. The breeding places includes
burrow pits, culverts and quarry pits etc. Such breeding places need special
attention by Railway Health Authorities who may use a combination of
various vector control measures in an integrated way.
iii)
Irrigation and mosquito breeding
Engineers should incorporate various engineering devices in
consultation with public health experts to include
r
*
---------- an inbuilt system to drain
off the seepage water for its better utilization in agriculture.
2.4
Biological control -
The predators, pathogens or iparasites may be used for the control of
larval breeding. Some of the important biocontrol
- 1 agents are given below:
i)
Larvivorous fishes
Of several biological agents, larvivorous fishes are still considered Io
e the most potential and effective predators for the control of mosquito
breeding m unused wells, pools, ponds, lakes, fountains, paddy fields etc.
The Poeciha reticulata and Gambusia affinis are the two most important
larvivorous fishes used world over for the control of mosquito breeding
They were introduced in India in 1910 and 1928 respectively and have since
een acclimatized in vafious types of ecological conditions.
They arc
considered to be most important larvivorous fishes for field operation
because of their small size, voracious feeder on mosquito larvae, hardiness
agility and adaptability to variety of habitats.
The Poecilia reticulata
commonly known as guppy is a bottom feeder , can tolerate very high degree
of pollution. It may be used effectivity for the control of Culex breeding
whereas G. affims is a surface feeder and prefers to breed in clean
oxygenated water and is suitable for the control of anopheline breeding,
ishes can be easily cultured on large scale and require minimum efforts for
transportation to any distant place.
29
ii)
Biocides-The toxins of certain spore-forming bacteria viz. Bacillus
thhringiensis variety israelensis H14 strain and Bacillus sphaericus have
recently been shown to hold great promise as a microbial control agent for
mosquitoes. These bio-larvicides are host specific, safe to predators and
friendly to the environment. Of several indigenous ■ and imported
formulations of bio-larvicides, wettable powder formulations of B. sphaericus
(Spherix) and BTI-H-14 Bactoculicide formulations were found to be highly
effective in controlling the larval population of mosquitoes
2.5
Integrated vector control
The integrated vector control may be defined as the application of one
or more than one vector control method simultaneously or consequently in a
given area to control vector borne diseases. When available options arc
selected on the basis of epidemiological paradigms, vector behaviour,
human behaviour and environmental aspects, it becomes selective vector
control. This approach is quite appropriate but requires effective planning,
and judicious use of national resources.
This requires technical
competence, managerial skills and sound understanding of vector and its
environment.
Marsh alteration
(ditching, impoundment)
Others
Inundative releases of
natural enemies
\
Zooprophylaxis
Basic sanitary
/ measures
Introduction of exotic
natural enemies
o y
/
o /
Microbial
insecticides
Carrier
plantings
\
'Z-
O
Genetic
manipulations
INTEGRATED
CONTROL
CD
Filling, grading
& drainage
“ r-
V
House
screening,
bed nets
◄
Personal
protection
.
Others
C^EMtC^
Cbcmostcrilants
Others"
Developmental inhibitors
I
'Repellents
Attractants
Insecticides
Fig. 9
30
2.6
Public Health Education and Community participation in the
control of vector borne diseases
The role of public health education is vital for the effective
imlementation of vector control measures, in respect of vector-borne
diseases, as the problem mainly revolves around man and his environment.
The aim of the health education for the control of vector-borne diseases like
malaria, filariasis, Japanese encephalitis, Dengue/DHF and Kala-azar
should be to familiarise and motivate the people by highlighting the
following aspects of the disease :
Causation and mode of disease transmission
Awareness about the early signs and symptoms of the disease
Educating the masses to co-operate with the public health workers for
the early diagnosis of disease by clinical symptoms and laboratory
diagnostic tests
Usefulness of taking proper and adequate treatment of disease
Knowledge about the breeding, feeding and resting behaviour of vector
species
Usefulness of insecticidal spray for the control of mosquito/sand 11 y
borne diseases to *bring down vector density and to curtail their
longevity to interrupt disease transmission
To restrain local inhabitants from mud plastering of walls of houses,
cattlesheds etc. for a minimum period of two months after the sprliy to
retain the residual effect of insecticide for the effective control of
mosquitoes and sandflies
Personal prophylactic measures by using ordinary impregnated
bednets or repellents to prevent mosquito/sandfly bite
To educate masses to sleep on the cots/benches instead of on floor to
prevent sandfly or flea bite
To undertake bio-environment measures to reduce the
breeding,
resting and feeding places in and around human habitations,
cattlesheds etc.
Use of mass mediajike radio,television,cinema slides, newspapers,
posters and film showsetc. Involvement of Social workers, teachers,
school
children,
public
health workers Voluntary Health
Organisations/ Resident Welfare Associations should be involved for
31
f i
disseminating the above given information by holding group meetings
or by inter-personal, communication, Health exhibitions etc. to get rid
off/ reduce mosquito breeding.
COMMUNITY PARTICIPATION
WHO Alma Ata Declaration (1973) envisaged that community
participation should be considered as a crucial component of Primary Health
Care (PHC). The idea of community participation was developed with the
ond hope that it will make disease control programme more effective. The
integration of activities for the control of communicable diseases was
considered advantageous to improve the quality of preventive care reduce
morbidity and mortality due to communicable diseases and encourage the
participation of people. Involvement of community for the success of any
vector control programme assumed still greater significance as the problem
revolves mainly around man and his environment. The community will
perceive the impact of control measures which will stimulate their active
involvement in PHC socially, culturally and technically.
Consequent upon the resurgence of Kala -azar in Bihar in 1977 Plague
in Maharashtra and Gujarat in 1994 and Dengue/DHF in Delhi, Haryana
and Punjab during 1996, it was observed that the public health education
about vector-borne diseases is poor and community participation was
practically nil. It is felt that for the control of vector-borne^diseases
community may be motivated to co-operate and partcipate for the effective
implementation of vector control strategy. After motivation, the community
co-operation in getting their dwelling units
cattlesheds etc., sprayed-with insecticide and should restrain from mud
plastering the insecticide treated surface for a minimum period of two
months for the retention of residual effect of insecticide. Besides, the
community may be motivated to undertake bio-environmental measures like
removal of garbage from in and around the houses, pigsties, cattlesheds
filling of all cracks and crevices. The shelters should be made more’
ventilated and lighted to prevent the breeding, resting and feeding of vector
species.
b or the success of vector control programme, there has to be a
frequent interactions between the health workers and the people so that
they may accept the control programme as the “ People’s Programme” and
only this approach will be fruitful for the effective implementation of vector
control strategy vis a vis control of vector-borne diseases in various parts of
the country.
Activities to be undertaken by various agencies for the control of
vector-borne diseases are summarised below:
32
3.
Sandflies - vectors of Visceral and Cutaneous leishmaniasis
Sandflies are mainly involved in the transmission of visceral and
cutaneous leishmaniais in various parts of the country. Whereas, visceral
leishmaniasis or Kala-azar is transmitted by Phlebotomus argentipes, the
cutaneous leishmaniasis which is not a major problem in the country is
transmitted by Phlebotomus papatasi, P. salehi and P. sergenti.
P. argentipes is widely distributed species in India and found in
abundance where climate is warm and moist. P. argentipes can be identified
on the basis of silvery white legs.
P. papatasi is founcTmainly in plains where climate is hot and dry. Il
is yellowish brown in colour.
3.1 Morphology of sandfly
Adult sandfly is a small, delicate insect of about 2-3 mm. in length. It
is light yellowish to greyish brown in colour with large conspicous dark eyes.
The males and females can easily pass through ordinary mosquito net. The
body of sandfly is completly covered with long hairs, head bears piercing and
sucking type of mouth parts and only female sandfly can sucks the blood
whereas males feed on plant saps. They can be easily recognised in nature
by the presence of a pair of long and elongated wings which remain crrect
upward on the body and makes V’ shaped appearance while resting. The
males are identified on the basis of male genitalia at the terminal end of
abdomen and females by the presence of spermatheca.
Fig. 10
Life cycle
The life cycle of sandflies is comprised of four stages viz. egg, larva,
pupa and adult fig. 11.
33
i)
JPg£ - The eggs are laid in moist cracks and crevices containing
decaying organic matters. The female P. argentipes lay eggs ranging from 568 whereas P. papatasi, lays eggs ranging from 7-69.
The freshly laid eggs are creamy white in colour, however, their colour
changes from dark brown to black after laying. The eggs hatch in about 3-4
days under laboratory conditions at 28 + 2 C and 95% R.H.
Larva -The larva is creamy white in colour and possesses a number of
ii)
hairs on its body.. The body is divided into head, thorax and abdomen,
After emergence, ]larvae feed on decaying organic matters. Sandflies have
four larval stages, The total larval period of P. argentipes and P. papatasi
was recorded to be 11-29 days and 12-26 days respectively.
iii)
Pupa - Pupa is elognated and coma- shaped in appearance and is a
non-feeding stage. The pupal period varies from 6-10 days for P. argentipes
and 6-13 days for P. papatasi under optimum laboratory conditions.
iv)
Adult - The adult emerges through a longitudinal slit on the mid
dorsal part of cephalothorax of pupa. Mating in sandflies usually occur on
host while feeding but may also takes place after feeding.
Life cycle from egg to emergence of adult was found to be 20-36 days
for P. argentipes and 22-45 days for P. papatasi (Fig. 11).
Adult
Fig. 11
34
3.3 Habits and habitats^
1) Habits - Sandflies are active during night hours and during day time
they remain hidden in cracks, crevices in dark corners of houses and
cattlesheds. P. argentipes and P. papatasi are generally found in mud
plastered houses and adjoining cattlesheds.
il| Feeding habits - Female Phlebotomus feed on a varity of mammals al
night . P.argentipes mainly feed on bovine, whereas P. papatasi prefers lo
feed on human beings.
iii) Resting habits - P. argentipes and P. papatasi mainly rest in indoor
situations in houses, cattlesheds and mixed dwellings etc.
iv) Flight range and movement - Sandflies moves by hopping movements
and can not fly long distances. The flight range of P. argentipes has been
recorded to be 207-505 meters from their breeding places.
vf Longevity - The maximum longevity of P. argentipes has been reported
to be about 24 days.
vi) Breeding habit - P. argentipes lay eggs in the soil having lot of moisture*
and organic debris in and around cattlesheds and human dwellings.
3.4
Sampling Techniques
Sandflies can be collected by torch light and suction tube method
similar to that of mosquitoes. The density of sandflies is expressed in term
of Per Man Hour Density (PMHD) (Proforma enclosed)
Other methods of sandfly collections are:
3.5
>)
Sticky trap method
■i)
CDC light traps
iii)
Funnel traps *
iv)
Bait collection
Susceptibility status to insecticides
P. argentipes, vector of Kala-azar has been reported to be highly
susceptible to DDT. However, P. papatasi vector of cutaneous leishmaniasis
35
- (
is highly resistant
to DDT and Dieldrin but
other insecticides.
susceptible to Malathion and
3.6 ■Sgntrol of sandflieq -
i)
Prophylatic measures
- use of bed nets and
repellents to prevent
man/sandfly contact.
ii)
Environmental Pleasures - ThecA
These
control/eliminate -• —------i nese measures
by filling the cracks
are
Smc^ce.°f SandflieS ” and around
iii)
used to
houses
Chemical Control
P. argentips can
easily be controlled by
undertaking residual cspray of DDT.
Two
rounds
of indoor residual
spraying is undertaken^
- in endemic areas @ I gm per Sq meter upto <■>
leet height.
36
4. Rat fleas, vector of plague
count,
Distt. of Maharashti^
during 1994. This has
to detect
country to undertake timely intervention measure” ‘n ’“““s PartS <,r ,ln-
namely Xen^lta che^is'x ‘"astia andxT ’“V
SPeCi“ °r "c,,s
compressed insects and their body sire v '
sl,ensls- Fleas are laterally
divided in head, thorax and abd^mln “Tia0"1 ‘‘"a™' The bo">'
directed spines. It has three nair of
an)d1iS jCovered with backwardly
developed and modified for jumoina
PairS °f IegS arc Verv Wr|1
sucking type and both the sVxeXk' b.oSd™" PartS
Pi<!rem«
4.1_Ljfe cycle - There‘are four
stages in the life cycle of flea vi
viz. egg.
larva, pupa and adult, (fig. 13).
i)
Eggs - The eggs are laid in clusters in and around the nest of host
animals. It is small in size
shape and glistering white > i measuring 0.4 to 0.5 mm. in length, oval in
Velio, colour after
hours
37
300-400 eggs during its life time. The incubation period of egg is about 2-4
days
ii)
Larva - The 1st stage larva hatches out from the egg in 2-4 days.
Larvae are small, 13 segmented worm like creatures without leg'and its body
is.covered with hairs. It has chewing types of mouth parts and feed on all
types of organic debris. There are 3 larval stages which last for 14-16 days.
The 3rd stage larva when fully grown empties it’s alimentry canal and
pupates. The larva spins a loose meshed cocoon of thread around it to
which particles of debris adheres.
Hi) Pupa - Pupa is usually enclosed in a cocoon and emerges into adult
after 8-10 days under favourable climatic conditions ( Temp. 27C and
Relative humidity 80-90% ).
iv) Adult - After emergence adults usually
hours. Mating usually occurs on host.
takes blood meal after 24
4.2 Biology and ecology (*)
Habit and habitat - Fleas are ectoparasites of warm blooded animals
specially rodent species. They are generally found on host’s body while
taking blood or as free living and their immature stages are found inside the
rodent: burrows.
(>i)
Feeding habit - Both the sexes feeds on ia variety of' animals. The
female feed for the development of eggs and its survival. Flea species have
definite host preference but they can, also feed on other hosts also. X.
cheopis and X. ostia generally found on rodent species.
(*“)
Resting habit - After taking blood meal fleas rest in rodent burrows,
cracks and crevices having microclimatic condition favourable for the
maturation of their eggs.
(iv)
Dispersal/movement - Fleas move from one place to another by
jumping movement. Flea can jump 7 to 8 inches vertically and 14-10
inches horizontally. They can also disperse from one place to another with
their animal hosts.
4.3
Sampling Techniques -
Fleas can be collected from the rodents after trapping the rodents
using live traps (wire cages) in domestic, peridomestic and sylvatic
situations. Traps are laid in evening hours and retrieved in the morning.
The positive traps with rodents are to be transported in cloth bags to
laboratory and fleas can be collected by combing the rodents. Various
indices used for monitoring rodent and flea are given below:
38
Cl
Indices used to determine rodent/flea density
a) Trap positivity rate
_No. of Traps found +ve for rodents x 100
No. of traps laid
b) Total flea index
Total No, of fleas collected
Total No. of rodents examined
c)-Specific flea index
Total No. of fleas collected of a species
No. of rodents examined
d) cheopis index
Total No. of X.cheopis collected
N°. of rodents examined
The cheopis index must be kept below 1.0 in plague endemic areas m
prevent occurrence of the disease.
Proforma for monitoring rodent/flea population is enclosed.
,4. -g-resgrvatlon and mounting of fleas - The fleas retrieved from the
captuied rodents should be preserved in 70% alcohol containing a drop of
glycerine.• he tubes should be labelled properly giving the following details.
„
Name of the area Date of collection Name of host
i)
Mounting procedure
a)
Transfer the flea to water for one hour to get rid off 70% alcohol
b)
Keep flea material in 10% KOH solution at room temperature lor one
to two days till the specimen become yellowish transparent
c)
Keep material in water for few minutes
d)
Transfer to 5% aqueous solution of glacial acitic acid for 30 minutes
c)
Transfer to water for an hour with several changes
a)
Permanent mounting
(i)
After step (e) pass the fleas through CC%, ?w/
50%, 70% and 90% alcohol for
dehydration, thereafter, treat with absolute alcohol for
------------• one hour
39
(ii)
the speeimens i„ c,ove oil for few
(ii)
Keep the flea material in xylol for 10 minutes
(iv)
Mount Ilea specimen in Canada balsam
(b)
Temporary mounting
After step (e) fleas can be d’
directly mounted in
medium and
a drop of Hoyer’s
-1 can be dried < over hot plate
jipyer’s medium
Distilled water - 50 mi
Gum arabic
- 30 gms
Chloral hydrate - 200 gms
Glycerine
. 2o ml
4,5
^^^•^i*inination of *—
tests of fleas to various ,nsKtiddes 1S
suse^s:iit'tu^:rtakifg “ vector control measures
-as ar.
SXX iXXISX?
Le5Atandard WHO method
► are exposed to (he
a period of one
H~Pereent^
4-6 t^aLmsma^^
susceptibilit status of flp<!
•
Recent studies carried out nn u-.
cheopis from Distt. Beed( MaharashtraStatUS of ^nopsylla
shows that the species is hiehlv
’ Varanasi (Uttar Pradesh) and Delhi
Malathion and DeltameJ^m 7
tO DDT & HCH but susceptible to
4.7 Control of fleas
insecticide”^
“^m^Ues aPfP“Cati°n
burrows and run ways The housed
walls and the floor £r an
, oi
fl
appropriate
°f ^atment are rodem
rested with the dust formulation. Dust should al
°m Wal1 Should bc
the wall and along the rafters where rat runwav °
apphed on the top of
habitats such as piles of wood, debris woTdeZ t
PreSenL °ther rod<'”t
treated with the insecticide dust.
’
d structures etc. should also be
40
BHC the^ntlF *n V*eW tllat tlle vector flea
«nd Permethrin (0 5./I'd1"8,
Ma'athiOT U
■ nrniStant tO DDT """
(0.5
10-S %)
/«) dust can be used for th.
-re eo’nlrol'o™ feas" (°'T%)
Application
Por
application of" dust
'
- the
trie application
thr k
The rodent frequented sites shouW h u °perated Asters are
quite useful.
sites should be f
control fleas on whd rodents about'so Or°UBhl3'
dus,
about
30
sufficient for each burrow.
30 gms of ^e dust formulation To
is
41
■/
Annexurc -
Area visited Date of visit -
No. of Traps laid No. of traps +ve Traps positivity Total No. of rats trapped/Rodent species -
Total No. of Flea retrieved/ Flea index -
No. of sera samples collected No. of tissue smears of heart, lung, liver and
spleen collected -
No. of tissues taken for culture -
42
Proforma for Indoor Sand fly Collection
PHC___________ _
Date of Collection
Name of Distt.
Village
________ Sandfly Species Collected
Sergentomyia sp.
P.papatasi
S.No
P. argentipes
Time Habitat
Spent
M
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
F
T
DPMH
M
T
F
DPMH
♦
♦
43
M
F
T
DPMH
Insecticide
Spray Status
Remarks
(
Mosqui,to Control measures which may be undertaken by Individuals and Commnmty
Type of activity
Individual action
Community action
Reduction of
Man: Mosquito
contact
i) Screening of houses/bedrooms
ii) Use of protective clothings to
prevent mosquito bites
iii) Use of repellents to prevent
mosquito bites
iv) Use of ordinary or insecticide
impregnated mosquito nets
i) Site selection of houses in the villages
ii) Deforestation and clearance of vegetations near the dwellings (specific
to An., dims vector of malaria in North East India.
iii) Vector deviation by shifting of cattlesheds/ piggeries away from
human dwellings (specific to zoophilic anophelines/ culicines)
iv) Wire meshing of vent pipes of septic tanks to prevent emergence of
and oviposition by adults (specific to Cx. quinquefasciatus)
♦
i) Use of adulticides or aerosols
Destruction of
available in the market
adult mosquitoes
Destruction of
larvae
Source
reduction and
Source
alteration
c
i) Emptying water containers
periodically, scrubbing and cleaning
(specific to Ae. aegypti).
ii) Use of temephos sand granules for
water containers (specific to Ae.
aegypti} & A. stephensi
iii) Refrain from throwing garbage into
the drains and drain cleaning
(specific to Cx. quinquefasciatus)
i) Proper disposal of unused
containers, tyres etc.
ii) Covering water containers
iii) Filling up of breeding sites
i) Indoor residual spraying of chemical insecticides
ii) Thermal or cold fogging (ULV)
i) Larviciding
ii) Rearing and release of larvivorous fish viz. G.affinis & P. reticulata
iii) Flushing of drains and their periodic cleaning
iv) Removal of algae and other water plants from the ponds to prevent
breeding of vectors of malaria and Japanese encephalitis
i) Community cleaning-up campaign to remove trash and water-retaining
debris for Aedes control
ii) Installation of proper latrines, drainage and water supply to prevent
the breeding of C. quinquefasciatus
iii) Intermittent irrigation of rice-fields for J.E. vector control
iv) Filling up of low lying areas or pumping out of water for
malaria/filaria vector control
vj Reclamation of land
44
!i
Plan of action for control of DF/Dh£ vectors in urban and Rural areas
Control Methods
Expected
Agencies
Source reduction
methods for larval
control
Community
Ways and Means
Activities Expected
I) Remove/reduce non-essential
water containers conducive for
mosquito breeding
i) Health education
ii) Protect water containers from
larval breeding by providing lids
or cover
>
iii) School children/housewives health education
ii) Mass media (Radio, TV, Film shows, News papers etc.)
iv) Volunteers
v) PHC workers
vi) Community’ leaders
Government
I) To set up a core working committee for inter-and interasectoral coordination
1.Solid w’aste management to
prevent mosquito breeding
2. Provision for reliable piped
water
3. Legislative measures
4. Monitoring and assessment
45
\
_Di 5 i h- • x-
Prevention and
Control of
Outbreaks
OF
Meningococcal
Meningitis
NATIONAL INSTITUTE OF COMMUNICABLE DISEASES
(DIRECTORATE GENERAL OF HEALTH SERVICES)
GOVERNMENT OF INDIA
22 SHAMNATH MARG, DELHI 110054
AUGUST 1997
CONTENTS
Topics
1. Introduction
1
2. Indian situation
1
3. Causative agent
1
4. Source of infection & transmission
2
5. Incubation period
2
6. Pathogenesis
2
7. Risk factors
2
8. Clinical manifestations
3
9. Case fatality
3
10. Clinical laboratory findings
3
11. Differential diagnosis
4
12. Laboratory confirmation of diagnosis
4
13. Clinical management
6
14. Surveillance
7
15. Notification of disease
9
16. Actions during impending outbreak
9
17. Control of outbreak
10
18. Annex-I to Annex-VII
14-19
ABOUT THE DOCUMENT
Target audience:
This document has been developed primarily for the District level officers who
will be involved in National Disease Surveillance Programme. However, it can be of
good use to State level officers and PHC medical officers.
Objectives:
At the end of the session, the participants will,
•
•
•
•
•
•
have better understanding of the disease and its public health importance.
refresh knowledge about clinical presentations and treatment modalities.
get a clear view about the techniques and methods for diagnosis.
learn about the components involved in the surveillance.
appreciate the actions to be taken for prevention of impending outbreak.
acquire the knowledge of outbreak control methods.
Method of interaction:
Presentation followed by guided discussions with the help of facilitators.
Note for facilitators:
The document is designedfor a two (120 minutes) hours continuous session. First
30 minutes can be utilised to make a briefpresentation of the contents. Next 75 minutes
can be devoted to guided discussion giving particular emphasis on surveillance,
prevention and control aspects (including formats). The last 15 minutes can be used Jor
summing-up the document. All the participants should be provided with a copy of tr.e
document preferably one day before the session and instructed to take notes, if any, on it
only.
1. Introduction:
Meningitis means inflammation of meninges. It is a very serious disease and if not
properly treated in time, the patient may die. The disease is caused by a variety of
organisms including ^Uria^viruses^andJungi. Pyogenic meningitis is an acute
infection of meninges with bacteria. The common bacteria responsible for pyogenic
meningitis are Neisseria meningitidis. Haemophilus influenzae and Streptococcus
pneumonae. Among all these, meningococcal meningitis caused by N. meningitidis
(meningococci) is common in India and has^great epidemic potential.
2. Indian situation:
2.1. The disease is reported round the year from different parts of the country',
with peak incidence between January to March. Several outbreaks of meningococcal
meningitis have been reported from different parts of India in recent past and the disease
has continued to become endemic in the country. Names of the states and districts which
reported outbreaks are shown below.
States (and districts) of India, which have reported outbreaks of meningococcal
meningitis in recent past.
Name of state
Delhi___________
Gujarat__________
Madhya Pradesh
Orissa________
Bihar________
Andhra Pradesh
Rajasthan_____
Maharashtra
District reported outbreak
Delhi________ ____________ ______________________
Ahmedabad, Mehsana____________________ _____________
Sagar, Damoh, Jabalpur, Rewa, Bhopal, Gwalior, Indore,
Ujjain and Vidisha
_____________________
Kaiahandi, Phulbani and Koraput
__
Singhbhum, Gumla and Sahebganj
___
Vizag, Vizi anagram and Srika-kulam_____________________
Jhalawar ________________________________ _____
All the districts of the state
2.2. The epidemic of meningococcal meningitis usually comes after a gap of 1015 years, when the pool of susceptible population becomes large enough to trigger this
process. The epidemic takes about 4-5 years to subside.
3. Causative agent:
3.1. The disease is caused by bacteria, N. meningitidis,.
It is a Gram-negative
diplococcus, non-motile, usually encapsulated and may be intra or extra cellular. It is a
fragile organism, susceptible to cold and drying.
i
3.2. The capsular polysaccharides of the organism differentiate thirteen
serogroups. Among these serogroups of N. meningitidis, only serogroup "A" is reported
from India.
4. Source of infection and its transmission:
4.1. Primarily the “carriers” (humans, who carry the organism in nasopharynx
without getting the disease) are the source of infection. Sometimes, the patients of
meningococcal meningitis can also be the sourse of infection.
4.2. The infection is transmitted through droplets during sneezing, coughing and
direct contact with nasopharyngeal secretions. There is no extra-human reservoir of the
organism.
5. Incubation period:
The incubation period of the disease is between 2-10 days, commonly 3-4 days.
6. Pathogenesis:
As mentioned above, the organism is present in the nasopharynx of carriers.
Some of these carriers may develop mild upper respiratory infection only. After entry
into the nasopharynx of a host, the organism can adhere to and enter the nonciliated cells
of the nasopharyngeal mucosa. This colonisation is not sufficient for causing meningitis.
In some instances, the organisms transmigrate through these cells to the submucosal
space, where they have access to enter capillaries and arterioles and lead to a systemic
infection. In this whole process the antiphagocytic capsular and surface antigens play a
major role. This acute systemic infection can be manifested in three ways: meningitis
(most of the cases), meningococcemia without meningitis and meningitis with
meningococcemia.
7. Risk factors:
•
•
•
•
In endemic situation the attack rate is highest in children of 6 months to 1
year age group.
AbouTKO^per cent of cases occur in children below 5 years and 80-85 per
cent of total cases occur in less thai/25years age group.
Attending physicians, health personnel and household members cf patients
are at more risk of getting the disease.
Overcrowding, enclosed population (hostel, jail, remand home etc.) and low
socio-economic status can also increase the risk of disease spread.
2
8. Clinical manifestations:
8.1. Meningococcal meningitis is commonly presented with ^sudden onsetJeycr,
headache, vomiting, photophobia, altered consciousness and stiff neck. There may be
petechialr^£^stol[cjby
focal neurological signs and convulsions. In severe
case, patient' is usually comatose. In patient under one year, the disea^e^_ii^ually ?
presented with fever, irritability, lethargy, convulsion, bulging fontanelle, petechial rash, y
hypotonia, vomiting and neck rigidity..
The clinical presentations of meningococcal meningitis are
indistinguishable from other acute bacterial meningitis.
—
v,-
8.2. When the disease is manifested as Meningococcemia, bacteremia and sepsis
occur without meningitis. Three-fourth of such cases may develop characteristic
petechial rash in axillae, flanks, wrists and ankles. About 10-20 per cent of all
meningococcemia may lead to fulminating stage with vaso-motor collapse, shock and
high fatality rate. Both the types of the disease may co-exist in endemic and
epidemic situations.
9. Case fatality:
Injection with penicillin has been found to be most effective for successful
treatment of patients. However, case fatality rate (CFR) can be, as high as, 30 per cent
or more during epidemic mainly due to low public awareness, delay in hospitalisation
and improper management. With early diagnosis’, specific antibiotic therapy and other
supportive measures, CFR can be brought down to 5-10 per cent.
10. Clinical laboratory findings:
Apart from Gram staining of CSF, clinical laboratory studies are of little value in
establishing the diagnosis. In acute bacterial meningitis, which includes meningococcal
meningitis, the characteristic CSF findings are:
•
•
•
•
•
•
Turbid/Purulent
Increased
<50/cu.m.m.
200-3000/cu.m.m.
> 45 mg/dl.
-f—f
< 40 mg/dl.
—
Colour:
Pressure:
Mononuclear cells:
Polymorph cells:
Protein:
Sugar:
Cv
G
IS
e
■7
t.
7
7
r’c
c4-
cr
'
J
11. Differential diagnosis:
The common diseases, which have clinical features almost simiia
meningococcal meningitis are: other acute bacterial meningitis, cerebral mal
encephalitis, aseptic meningitis and brain abscess. A thorough history taking cl’
examination and laboratory investigations can help to establish the diagnosis.
to
12. Laboratory confirmation of diagnosis:
12.1. Culture of meningococci from CSF is “the confirmatory test”. Bui it is
very easy method. Moreover, the culture becomes difficult after the patients have t
antibiotics. Other methods (serologic) include Counter immuno-electrophoresis (C’J
and Latex agglutination tests. Like Gram staining, these tests are also performed on
CSF. The diagnostic rate is highest (70-80 per cent) with Gram staining ■:
agglutination. This can further be increased through combination of tests.
Techniques for Gram staining of CSF:
Atleast 20 drops (1 ml) of CSF should be collected in a sterile tube.
not refrigerate but hold at room temperature before staining. Processing !
should start immediately after collection.
• Centrifuge CSF at 2000 rpm for 10 minutes
• Draw off the supernatant and reserve for Latex agglutination test.
• Use a drop of sediment to make a smear on a glass slide. Air dry and i
fix gently by passing through flame.
• Flood the slide with ammonium oxalate-crystal violet solution and let J
stand for 1 minute.
• Rinse gently with tap water and drain off excess water.
• Flood smear with Gram’s iodine solution and let stand for 1 minute.
• Rinse with tap water as above.
• Decolourise with 95 % ethanol for 5-10 seconds.
• Counterstain with safranin for 20-30 seconds or carbol-fuchsin k
10-20 seconds.
• Rinse the slide with tap water and blot dry.
Results: Examine the smear under oil-immersion lens with bright field i
condenser. Meningococci appear intra- or extra-cellularly as Gram
negative coffee-bean shaped
— diplococci.
4
General method for performing Latex agglutination tests of CSF:
•
•
•
•
•
Take about 0.5 ml of supernatant of centrifuged CSF.
Shake the Latex suspension gently until homogenous.
Place one drop of specific latex suspension on a ringed glass slide or
disposable card.
Add 30-50 micro-litre of CSF to suspension.
Rotate by hand or by a rotator at 100 rpm for 2-10 minutes.
Results: Read under bright light without magnification.
Negative reaction: The suspension remains homogenous and slightly
milky in appearance.
Positive reaction: Within 10 minutes, agglutination (visible clumping) of
the latex particles occurs._________________
Demonstration of bacteria in tlie Gram stained smear made
from the centrifuged deposit of cerebro-spinal fluid (CSF)
is an easy and cost-effective method that can be used at
Primary Health Centre level. In field situation, Latex
agglutination test can be performed easily and satisfactorily.
12.2. When CSF samples are to be sent to laboratory, refrigeration should not
be done and the samples are to be sent at room temperature with in 2 hours of collection.
From each patient, about 3 ml of CSF should be drawn and collected in 4 small sterile
tubes in divided quantity for biochemical, culture, microscopy and serological tests. If
the quantity of CSF drawn/collected is less, then the person sending the sample
should decide upon which test(s) is to be done at laboratory. In such situation, jLf
depending upon the facilities available, serology and microscopy_are the best options in
- .
order of preference. Each sample should accompany detailed information as indicated
below,
1
• Sample identification No.:
• Name of patient:
• Age:
• Sex:
• Complete address:
• Presenting features with duration:
• Provisional diagnosis:
• Treatment given:
• Date of collection:
• Test (s) to be done:
5
13. Clinical management:
13.1. Patients with meningococcal meningitis require supportive treatment, as
well as, antimicrobial therapy. The primary areas of supportive treatment are:
•
•
•
•
•
•
•
Bed rest
Antipyretic
Sedative
Good nursing care
Maintenance of fluid and electrolytes balance
Prevention of respiratory complications in comatose patients
Use of anticonvulsants in patients with convulsions
13.2. For antimicrobial therapy, Crystalline benzyl penicillin is the drug of
choice.
•
300,000 to 400,000 units of penicillin/Kg body weight/day should
be given by I.V. drip or in divided doses 2-4 hours.
Alternatively, Chloramphenicol can be given.
•
The dose is 100 mg/Kg body weight/day intravenously in 6 hourly
divided doses.
This treatment can be given for a total duration of 7 days. Patients become noninfectious after 24 hours of starting specific antimicrobial therapy. Therefore, they
should be kept separately for 24 hours after the starting of antibiotic.
A four days course with penicillin has been
found to be as effective as any longer course
of antimicrobials.
This fact has special
relevance during outbreak situation.
In
large outbreak, even the great majority of
patients can be successfully treated with a
single dose of long acting oily preparation of
injectable chloramphenicol (100 mg/Kg;
maximum 3 gm. I.M) or long acting
penicillin.
6
J-
14. SURVEILLANCE:
14.1. Early warning signal: Like other epidemic prone diseases, surveillance is
the most effective tool for prevention and control of outbreaks of meningococcal
meningitis. If properly implemented, surveillance can generate early warning signal of an
impending outbreak by detecting sudden increase in nurriber oT casesTdeaths or its
clustering in time and space. This early warning should enable the health authorities in
confirming the diagnosis and controlling the outbreak at the earliest.
14.2. Case definitions: The prerequisite of a surveillance is identification of
patients (cases). The following case definitions
u----------- are
— to be used in the surveillance of
meningococcal meningitis.
Case definitions of Meningococcal meningitis
Suspect case: Sudden onset fever, severe headache and stiff neck with or without skin
under one year ofave, a suspect case occurs when fever is accompanied^
Cj
•
a bulging fontanelle...
Probable case: Suspect case with vomiting and positive neck rigidity with or without
positive Kernig’s and Brudzinski’s signs OR suspect case with either cloudy/purulent
CSF or petechial skin rash.
Confirmed case: Suspect or Probable case AND any one of the followings:
positive CSF for Gram-negative diplococci in direct examination, detection of
meningococcal antigen in CSF or positiw^cTilfivation of the organism from
CSF/blood/skin rashs.
_______
Kernig’s sign is tested by passively extending the patient’s knee when
his hip is fully flexed. This movement causes pain and spasm of the
hamstring group of muscles.
Brudzinski’s signs is tested by passively flexing the patient’s neck. This
movement causes an involuntary flexion of hip, knee and arm joints.
Both these signs become positive when meningeal irritation affects the
lower part of the spinal subarachnoid space.______________________
7
Use of case definitions at different levels
The peripheral health workers (MPWs) will use the “suspect”
case definition, while the Medical officers of PHC, CHC etc.
will use the “probable” one. The “confirmed” definition will
only be used by the hospitals where facilities for laboratory
confirmation arc available.
14.3. Type of surveillance: Two types of surveillance arc necessary in context of
meningococcal meningitis. Since clinical presentations of acute meningitis due to all
causative bacteria and some other diseases (see differential diagnosis) are
indistinguishable, PHCs (including sub-centres), CHCs, Taluk and Sub-Divisional
hospitals should use “suspect” and “probable” case definitions for passive surveillance
of acute meningitis. Whereas, all district hospitals and medical colleges should use
“confirmed” case definition for the sentinel surveillance of meningococcal meningitis.
•
•
PHC, CHC, Taluk &, Sub-Div. hospital: Passive
surveillance of acute Meningitis.
District hospital 8c Medical college: Sentinel
surveillance of meningococcal meningitis.
14.4. Identification of sentinel centres: The sentinel centres should include all
medical colleges and district hospitals of the state. In medical college, Head of PSM
Department can be the In-charge of the Centre. He has to act in close collaboration
with Medicine, Pediatric and Pathology / Microbiology Departments. For District
hospital, the Superintendent or his designated subordinate officer may be the In-charge
of the Centre.
14.5. Collection of Information: For passive surveillance of acute meningitis,
minimum information is to be collected. Information on name, age, sex, address and
date of onset will be sufficient to continue vigil on the disease situation. This
information should be compiled in a linelist manner. However, for sentinel centres, more
epidemiological and laboratory information is to be collected on each case as per format
in Annex-I.
14.6. Role of Medical college: Being sentinel centre having better facilities, the
medical colleges in addition to the above will also
•
Conduct antibiotic sensitivity/resistance and serogroup typing tests for the
Centre, as well as, of the samples sent from the districts hospitals.
•
•
Perform cross-checking of CSF samples ( both +ve and -ve ) sent from the
district hospitals.
Extend diagnostic support during epidemic situation.
8
14.7. Frequency of reporting: All the reporting centres should send monthly
report. Fonnats for passive and sentinel surveillance centres are in Annex-Il & Annexe
report.
HI. The regularity of complete reporting, including "Nil" report has to be ensured.
In the event of impending/coutinuing outbreak,
information should flow daily at all levels.
14.8. Flow of information: All the passive and sentinel centres should send
monthly report to the District Health Officer through FAX or by special messenger within
3rd day of next month. However, the sentinel centres should also send a copy of the
report to the state nodal officer through FAX/speedpost. The district health officer will
send consolidated monthly report of his district, as per format in Annex-IV, to the state
nodal officer within 7th day of next month by FAX/speedpost. The state nodal officer
will send the monthly report of his state to N1CD within 15th day of next month by FAX
with a copy to CBHI. Format to be used at state level is in Annex-Y. • With gradual
development of HMIS services, N1CNET will be used in near future. Flow chart of
information is in Annex-Vl. However, in case of emergency, FAX, telephone,
telegram should be used for sending daily reports at all levels.
14.9. Data utilisation & monitoring: The data generated / received at different
v 4 / levels are to be scrutinised and interpreted monthly for local utilisation. Comparison of
data should be made with that of previous month of the same year and same month of
the preceding years. Properly drawn charts and graphs can help in better understanding of
the situation. Special attention should be given to identify geographical clustering
of cases at the earliest.
14.10. Feedback: Regular feedback on the reports in form of acknowledgement,
discussion during monthly meeting, clarification, appreciation, advice etc. should flow
from higher to next lower level.
15. Notification of the disease:
15.1. Meningococcal meningitis is not a notifiable disease in India. Presently an
institution based passive monthly reporting of cases and deaths exists in the country.
These monthly reports from the States are compiled annually at Central level by CBHI
(Central Bureau of Health Intelligence). Besides being passive, the reporting is
sometimes irregular and incomplete. Thus, this system is ineffective to address the needs
of health administrators to look for the trend and foresee any impending outbreak.
15.2. If there is a sudden increase or clustering of cases or deaths due to acute
meningitis/meningococcal meningitis, information should be notified immediately (by
telephone or FAX) to the next higher level. The district/state health authorities will be
9
responsible to initiate investigation. If the outbreak is confirmed. National Institute of
Communicable Diseases (N1CD), Delhi, should be notified forthwith.
16. Actions to be taken in impending outbreak:
•
•
•
•
•
•
Immediate reporting of suspicion to the next higher health authority.
Immediate arrangements for laboratory confirmation of diagnosis.
Continued analysis and monitoring of information on cases and deaths on a
spot map.
Early institution of the specific treatment to patients.
Monitoring of number of cases and deaths graphically in time frame.
IEC regarding chemoprophylaxis of household contacts of patients.
17. Control of outbreak:
When an outbreak is reported, the Rapid Response Team should be activated and
mobilised by the district/state health authorities for taking up and helping in early
implementation of the following control measures.
17.1. Outbreak investigation:
With the first indication of an outbreak, a thorough investigation should be
carried out immediately to
•
•
•
•
confirm the outbreak
confirm the laboratory diagnosis
define the areas affected
assess the magnitude of problem (morbidity and mortality) in terms of
“Time”, “Place” and “Person”.
Appropriate and early recommendations to control the outbreak is the most
important objective of this investigation. Format for writing the outbreak investigation
report is in Annex-VII
In outbreak situation, laboratory confirmation
of each case is neither required nor possible.
17.2. Strengthening of surveillance:
•
Active surveillance of the cases and deaths should be started in the area by
health staff. For this “suspect” case definition can be used in community.
io
Daily reporting of cases and deaths should be started at all levels from
periphery to State Health Directorate.
•
17.3, Patient care;
Provision should be made to treat and follow-up all cases at hospital/CHC/PHC.
If the situation demands, “Camp hospitals” should be established in school buildings or
similar structures. Earliest institution of specific antibiotic can cut down mortality
sensitivity/resistance can give
drastically. Information already available on microbial
iright direction in this matter.
17,4, Health Education;
•
Vigorous IEC activity should be started to diffuse the fear and confusion, if
any, in the community.
•
Recognition of early features of the disease by the community members and
importance of earliest hospitalisation are two most important areas of IEC.
•
Household contacts, particularly those sleeping in the same room of patient,
should be warned about the need to obtain immediate medical attention at the
first sign of fever and/or headache.
17,5, Chemoprophylaxis;
Since all the contacts of patients are at a very high risk of getting the disease,
they should receive chemoprophylaxis for 2-4 days with Sulfadiazine tablet as per
following schedule:
•
•
•
Adults: 1 gm 12 hourly
School children: 500 mg 12 hourly
Pre-school children: 250 mg 12 hourly
If the organism is resistant to Sulfa, Rifampicin can be given orally. The
duration is 2 days. For adults 600 mg and for children 10 mg/Kg body weight to be given
12 hourly.
17.6, Immunisation;
The primary means of controlling epidemic of meningococcuL^eiiingLtis is
vaccination.
In India, bivalent vaccine (a«ainst 2erogroups/“A’’ & ‘‘c”)_ is
"p^ntkTmported from out side by the Central Govt, primarily for immunising
the Haj pilgrims.
/-) V C
11
Ideally, in an outbreak of meningococcal meningitis, whole of the community
should be vaccinated to cut down the transmission of the disease. One dose is
sufficient as it is considered a booster following wide spread mild and subclinical
upper respiratory infection due to N. meningitidid in the community.
About 7-10 days are required for the development of immunity
after vaccination, which is longer than the average incubation period
of the disease. Thus, vaccination can not prevent the secondary
cases. It also has no effect on established carriers.
In children below 2 years, the vaccine has poor immunogenic
response. But, as the outbreak takes years to subside, a second
dose after 3 months can be given to these children.
In a country like ours, it may not be feasible and economical to immunise the
whole population. But, immunisation if and when decided, should be targeted to the high
risk groups, who are to be identified at first. They include: clinicians, laboratory
officials, health staff and people staying in segregated places (jail, hostel, residential
school, barrack, camp, remand house etc.), as well as, in difficult terrain and remote
tribal areas. Once these groups are identified, their vaccination needs to be started as
rapidly as possible to achieve maximum benefit in terms of cases prevented. The period
of immunity varies from 1-3 years.
Dose & route of immunisation
The vaccine after reconstitution with the diluent
(supplied along with), should be used within 24
hours. The dose is 0.5 ml subcutaneously
irrespective of age.
17.7. Other measures:
•
Closure of schools and banning of large gatherings etc. have not been
shown to be effective in curtailing the spread of epidemics.
The information of the outbreak should
geographically contiguous districts/states.
12
be
provided
to
the
ANNEX-*
NATIONAL DISEASE SURVEILLANCE PROGRAMME
Meningococcal meningitis
(Format for collecting information on individual case in sentinel centres)
Name of the Centre:
District:
Patient’s name:
IPD Reg.No.:
Age:
Sex:
Complete residential address:
Address during last 10 days:
Chief complaints with duration: Fever:
Headache:
Nausea/vomiting:
Other (specify):
Date of onset:
Date of hospitalisation:
Clinical diagnosis:
Laboratory investigations & results:
Final diagnosis^:
Specific treatments given:
Out come: Cure & discharged/Died@/Absconded/LAMA :
Date of outcome:
Additional information in case of Medical college:
• Antibiogram:
• Serogroup:
# Level of information to count a ’’case”.
@ Level of information to count a "death”.
* LAMA: Left against medical advice
13
ANNEX-11
NATIONAL DISEASE SURVEILLANCE PROGRAMME
Meningococcal meningitis
(Format for sending report on Acute meningitis by PHC, CHC, and other Passive
reporting centres)
Name of Centre:
District:
Reporting month:
Year:
Date of reporting:
Number of deaths
Number of cases
* Cases include deaths also
Signature of in-charge
Date:
14
ANN EX-111,
NATIONAL DISEASE SURVEILLANCE PROGRAMME
Meningococcal meningitis
(Format for sending report on meningococcal meningitis by sentinel centres)
District:
Name of the centre:
Year:
Reporting month:
Date of reporting:
♦
Age group
(in years)
No, cases
Male
Female
No, deaths
Male
Female
Total
0-< 1
1 -<5
5- 9
10- 14
15 - 24
25 & above
* Cases include the deaths also.
Additional information in case of Medical college;
•
Antibiogram:
•
Serogroup:
Signature of In-charge
Date:
15
Total
NATIONAL DISEASE SURVEILLANCE PROGRAMME
Meningococcal meningitis
(Format for sending report by district health office)
Name of district:
Reporting month:
Date of reporting:
Number of cases
Acute meningitis________
Meningococcal meningitis
* Cases include deaths also
Signature of DHO
Date:
16
Number of death
ANNEX-V
NATIONAL DISEASE SURVEILLANCE PROGRAMME
Meningococcal meningitis
(Format for sending report by state nodal office)
Name of state:
I
Reporting month:
i
Date of reporting:
---------------------- - ----------------- —r
Number of cases
Number of deaths
Acute meningitis
Meningococcal meningitis
* Cases include deaths also
Signature of state nodal officer
Date:
17
ANNEX-VI
NATIONAL DISEASE SURVEILLANCE PROGRAMME
Meningococcal meningitis
Chart showing flow of information;
CBHI
N1CD
State Nodal Officer
//T jd'
/
I
I
I
District Health Officer
Passive reporting centres
PHC, CHC, Taluk hosp. etc.
Sentinel centres
Rapid Response Team
Sub-centres
Community
Direction of flow of report----------- >
Direction of flow of feedback ---------- >
Direction of action at community level p
18
ANNEX-VII
NATIONAL DISEASE SURVEILLANCE PROGRAMME
(OUTBREAK INVESTIGATION REPORT)
General information:
State
District
PHC/Town
Village/Ward :
Population
Background information:
Person reporting the outbreak
Date of report
Date investigation started
Person(s) investigating the outbreak :
Details of investigation:
Describe how cases were found (may include (a) house to house search in the affected
area; (b) visiting blocks adjacent to the affected area; (c) conducting records review at
local hospitals; (d) requesting health workers to report similar cases in their areas etc.).
19
Descriptive epidemiology;
•
•
•
Cases by time, place and person (attach summary tables and relevant graphs and
maps).
Age-specific attack rate and mortality rates.
High risk age group and geographical areas.
Description of control measures:
Description of measures for follow-up visits;
Brief description of problems encountered;
Factors which, in your opinion, contributed to the outbreak;
Conclusions and recommendations:
20
I
DlS
!
Ijl
.fl
INVESTIGATION
& ( CONTROL
OF
UTBREAKS
Cholera
NATIONAL INSTITUTE OF COMMUNICABLE DISEASES
(DIRECTORATE GENERAL OF HEALTH SERVICES)
22-SHAM NATH MARG, DELHI - 110 054
JULY 1997
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G)
Notification of cholera cases
1.
a
1.1. Cholera is endemic in India and several outbreaks of the disease
have been reported. Because cholera has the potential of rapid spread
leading to an acute public health problem, special attention is
required to be given to the surveillance and prompt follow up action
on reported cases of cholera.
1 2
A suspect case of cholera must be notified immediately by
messenger, telephone or fax to the local health office Weekly
notification of confirmed cholera cases is required to bet madt: by the
state health authorities to the Directorate General of Health Service
(Erector Central Bureau of Health Intelligence, Pushp Bhavan,
Madanri; Road, New Delhi - 110062) and endorsed to D.rector,
National Institute of Communicable Diseases, 22 Shamnath Marg,
Delhi 110054 (Phone:- 2521272, 2521060, 2913148; FAX. 29226/7;
Telegram: COMDIS, DELHI). The age, sex and address of the patient
should be included.
measures are taken, cholera remains a focal
1.3
If appropriate
limited habitation. Therefore^eporting. of
disease restricted to a
taluka and district help in
i identifying the affected area.
t.4.
The first suspect case of cholera m
Sdabey0bXed It the6 earnest —ni^^d^h^resuits
the earliest opportunity
intimated to local health office as soon as t.------
2.
2.1.
Clinical manifestation and case definition
in a majority of the cases
the° onse't
diarrhoea and vomiting, resuiting in loss of
large amounts of fluids and electrolytes.
CASE DEFINITION
P”SU?I'tSeeeere dehydration or death from acute watery diarrhoea in a
.
^umlWy^S^patiemAiears of age or older in
an area where an epidemic is occurring
^on, the .tool samples
C°°r“m,!W0„„
of any patient with diarrhoea------------------------------------------ -
1
2.2. The clinical features of moderate to severe cases of cholera are
the following:
acute onset
severe watery diarrhoea
vomiting
signs of dehydration and electrolyte imbalance
•
•
•
•
DEHYDRATION
•
•
•
•
increased
thirst
restlessness
irritability
decreased
skin turgor
dry mouth
t
HYPOKALEMIA
SEVERE
DEHYDRATION
• lethargic
• floppy
(hypotonia)
• unable to
drink
• decreased
urine
• fall in BP
• tachycardia
• unconscious
•
•
•
•
hypotonia
cardiac
arrhythmia
paralytic
ileus
cardio
respiratory
failure
Note:
Any two or more signs of dehydration in a patient with history of
acute watery diarrhoea and vomiting
Any one or more signs of severe dehydration or hypokalaemia in
a patient with history of acute watery diarrhoea and vomiting
2.3. The symptoms of mild cases of cholera
indistinguishable from non-specific acute diarrhoea.
90% of the cases, cholera is mild.
2.4
are clinically
In more than
It would also be useful to know if:
•
there are any other laboratory confirmed cases in area
OR
there is a clustering of cases clinically compatible with
cholera
Any one of the two above will support the presumptive diagnosis
of cholera.
It would also facilitate better understanding of the
epidemiology of disease and institution of appropriate control
measures.
)
<•
'I mi ••.HID !»<)«•
Causative agent
3.
3.1.,
3.1., There are more than 60 serogroups of Vibrio cholerae, but only
serogroup 01 and 0139 cause cholera.
3.2. V.cholerae 01 occurs as two biotypes - classical and El Tor.
Each biotype also occurs as two serotypes - Ogawa and Inaba.
3 3
Almost all the recent cholera outbreaks have been caused by
the El Tor biotype. Cases caused by the classical biotype have no
been reported in India since 1980. The El Tor biotype also causes a
higher proportion of asymptomatic infections than the classical
biotype and survives longer in the environment.
3 4 In late 1992, large scale epidemics occurred in India and
Bangladesh caused by a new serogroup - V.cholerae 0139.
Reservoir
4.
♦u
hn<?t
Patients remain infectious usually for a
amasses “
strain is susccpdblc, shorten the period of commun.cabthty.
making water an importanlreservoir for mfection.
5.
Mode of transmission
Infection usually spreads through contaminated water and lood
5.1.
The dose of V.cholerae required to produce illness depends on
5.2.
.... susceptibilitxjr.thtMMdual. h can. be affecte^ by hej^
the
;iorHnfectmn. in-eHdemic areas. Breast;
feeding protects infants and young children.
----------- ---------
COMMON SOURCES OF INFECTION
Food
Drinking water
• contaminated at its source
• contaminated during storage
. ice made from, contamlnatedwater
_
contaminated during or after preparabon
fruits and vegetables, ’freshened’ with
contaminated water and eatenjaw
• fruits and vegetables, grown at or near ground
level and fertilised with night soil or irrigated with
water contaminated with human waste, and
eaten raw
•
•
C: \.JS\CI IOLGUID.DOC
3
6.
Incubation period
6.1. Incubation period varies from a few hours to 5 days, usuall
days.
7.
Clinical management
7.1. Early treatment, in most cases by oral rchydration therapy, can
reduce the case fatality of cholera to less than 1%. If treatment is
delayed or inadequate, death from dehydration and circulatory
collapse may follow rapidly.
7.2. The clinical condition of the patient should be monitored during
and after rehydration until diarrhoea stops. Rapid loss of fluids and
salts can result in dehydration, acidosis and potassium depletion if
symptoms of diarrhoea and vomiting persist. Rehydration therapy
should continue to replace ongoing loss of fluids and salts. Young
and malnourished children need special attention.
ORAL REHYDRATION THERAPY
Recommended ORS solution
* WHO formula (see annex 5)
Unsuitable ORS
* ORS with high glucose content
* ORS with saccharine and colouring agents
7.3. Nearly 80 to 90% of the patients can usually be adequately
treated with oral rchydration salt (ORS) solution alone, without
intravenous therapy and antibiotics.
ORAL REHYDRATION THERAPY
•
•
•
give 100 ml/kg body weight of ORS solution in the first 3-6 hours
to correct dehydration
if the patient is tliirsty and wants to drink more, allow to drink
after rehydration has been achieved, continue giving ORS solution
for replacement of ongoing losses. Plain water and home available
fluids can be taken
____
_
7.4. In severely dehydrated patients ORS solution should be started
as :soon as the patients are able to drink, even before the initial
intravenous therapy has been completed. Patients can also be
permitted to drink plain water. For preparation of ORS at home, see
annex 6.
.1
( • \ I-" - l fr >! - • Ilf» I •< h •
______ Quantity______ _______ Infants_______
First 1 hour
30 ml / kg body wt
Next
5 hours________
70 ml / kg body wt
6 hours_______ _
100 ml / kg body wt
• assess for signs of
► reassess clinical
overload as patient
condition cvciy 1-2
recovers - evidence
hours; if hydration
of swelling,
is not improving
shortness of
give IV infusion
breath or puffiness
more rapidly
Older children/ Adults
First 30 min
Next 2'/2 hours
3 hours_________ __
• if patient can
drink, start ORS
solution along with
IV infusion. When
signs of severe
dehydration
disappear,
continue with ORS
7-5-
“by.hX of pabento wlU.
intravenous rehydration, b
<■
ineffective and should
unavailable. Plain glucgse^olutiorxs
are^
L—-- -------- - _„
glucose
/ not be used.
r
BTfluid THERAPY
•
•
Preferred
* Ringer’s lactate solution
Suitable
9
fdoesfiot^orrect base acidosis and potassium losses)
•
Unsuitable
.
* Plain glucose (dextrose) solution
acidosis
(is not effective for rehydratxon, correction of base actdos
or replacement of potassium losses^--------------------------------- -
should be monitored at
Patients on intravenous fluid thciapy
7.6.
; of improvement in the clinical
regular intervals to check for signs
must be taken to ensure that the
condition of the patient. Care i—
patient is not overloaded.
■
i reduce the volume and duration
7.7. In severe cases, antibiotics can
shorten the period during which the cholera
of diarrhoea and can Antibiotics can be given orally as.soon a
vibrios are excreted,
-^usually within 3-4 hours of starting rehy^ll°rle
vomiting stops,
advantage in giving injectable antibioUcs winch are
There is no <.--urnensive.
('.\js\f '.||()LGUH).l)OC
5
COMPLICATIONS OF IV FLUID THERAPY
Piilrnonctry oedema is caused when too much IV fluid is given, and
especially when metabolic acidosis has not been corrected. The latter
is most likely to occur when normal saline is used for IV rehydration
and ORS solution is not given at the same time. When the guidelines
for IV rehydration are followed, pulmonary oedema should not occur.
ORS solution never causes pulmonary oedema.
Renal failure may occur when too little IV fluid is given, when shock
is not rapidly corrected, or when shock is allowed to recur, especially
in persons above the age of 60. Renal failure is rare when severe
dehydration is rapidly corrected and normal hydration is maintained
according to the guidelines.
- Guidelines for Cholera Control, WHO 1993
7.8. Use of antibiotics for mild cases is not recommended. This
will hasten the development of antibiotic resistant strains as well as
exhaust supplies which may be needed for severe cases. Patients who
benefit most from antibiotic treatment are those with severe
dehydration.
7.9. The choice of antibiotics should take into account local patterns
of resistance to antibiotics. Knowledge of antibiotic sensitivity patterns
in the immediate or adjacent areas is important. Studies conducted at
NICD, Delhi; National Institute of Cholera and other Enteric Diseases
(N1CED), Calcutta and King Institute of Preventive Medicine, Chennai
have shown that Vibrio cholerae that are currently prevalent are
resistant to furazolidone, cotrimoxazole, ampicillin, nalidixic acid and
streptomycin. These continue to be sensitive to tetracycline and
norfloxacin.
No anti diarrhoeal, anti-emetic, antispasmodic, cardiotonic or
corticosteroid drugs should be used to treat cholera. Blood
transfusion and volume expanders are not necessary.
- Guidelines for Cholera Control, WHO 1993
7.10. Patients should be encouraged to take food, after severe
vomiting has stopped, usually within 3 to 4 hours after starting
rehydration. Breast-feeding of infants and young children should be
continued.
8.
Health education
8.1. Health education and public awareness and co-operation are
important to control an outbreak. If the community knows how the
outbreak spreads and what measures they can take in their own
families, the risks can be considerably reduced. It is also important
6
<:: \.JS\('! If )l: J JI().[)()«?
that the public should know that treatment is simple and efTectivc and
there should be no cause for panic. ORS packets should be widely
accessible. While the key messages will essentially remain the same
for all areas, the language and style may be adapted to local needs.
The Guidelines for Cholera Control, WHO 1993 have suggested
several messages. Some of these are given below:
KEY POINTS FOR PUBLIC EDUCATION
To prevent cholera
. drink water from a safe source or water that has been
disinfected (boiled or chlorinated)
. cook food or reheat it thoroughly and eat it while it is still hot
• avoid uncooked food unless it is peeled or shelled
. wash hands before preparing or eating food
. wash hands after using toilet or any contact with excreta
• dispose off human excreta promptly and safely
Reme. with proper treatment, cholera is not fatal
• take patients immediately to a health faci i y
. give increased fluids. If ORS packets are available, give ORS
solution as soon as diarrhoea starts
cholera vaccination is not recommended
.
THREE SIMPLE RULES FOR CHOLERA PREVENTION
.
.
•
Cook your food
Drink safe water (chlorinated or boiled)
Wash your hands ____ _______
—~—i^^RWEFsTOREDPROPERLY^^
...............
St.-JitixWW
.
Clean water can become contaminated again if it is not
.
wXshould be stored in a clean container with ar small
container to draw water—
■ > inform the public that most cases
8.2. It is particularly
important
to
bTtreatcd with simple measures and that vaecinal.an ,s
of cholera can L.. - not effective.
7
9.
Laboratory support
9.1.
Treatment of cholera docs not depend on the results of
laboratory examination.
However, laboratory examination of
specimens from the first few suspected cases is important to confirm
diagnosis and to determine the characteristics of the organism.
9.2. A sufficient number of stool specimens should be examined to
identify the causative organism and test its sensitivity to antibiotics.
Once the presence of cholera is confirmed, it is not necessary to
examine specimens from all cases or contacts. In fact, this should
be discouraged since it places an unnecessary burden on laboratory
facilities and is not required for effective treatment.
9.3. Stool specimens or rectal swabs should be sent to the laboratory
in a transport medium (e.g. Cary-Blair medium, VR medium, Alkaline
Peptone Water). If a transport medium is not available, cotton tipped
rectal swab soaked in the liquid stool should be placed in a sterile
plastic bag and tightly scaled. Specimens should be collected before
the patient has received any antibiotics.
9.4. Full particulars of the patient(s) from whom samples have been
collected must be sent along with the samples as many factors can
influence the results of the laboratory tests. The information that
should accompany each stool sample is given below:
•
•
•
•
•
•
name
name of mother or father
sex
date of onset of symptoms
provisional diagnosis
clinical outcome (recovered, under treatment, dead, not
known)
• antibiotic received prior to collection of sample - Y/N/not
known
• date sample collected
• full address
9.5. Apart from prior treatment with antimicrobials, the conditions
of collection and transportation of samples can influence laboratory
tests. The recommended practices and precautions to be taken to
minimise deterioration in the quality of the sample are giver in the
box.
9.6. Keep an inventory of all laboratories in the district w ach can
undertake culture and identification of VxfLolerae 01. The 5 ames of
these laboratories should be known to 'thernedical office!; of the
peripheral health facilities. Each laboratory must be well stocked with
■'Mil
Ill > I <f
tlic media and other reagents. The available stocks should be verified
well before the expected seasonal increase of cases of diarrhoeal
diseases.
9.7. In districts considered at high risk where outbreaks have been
reported in the past, orientation session of the paramedical personnel,
laboratory technicians and medical officers is recommended for
updating their knowledge and skills in the correct procedures for
collection, storage and transportation of laboratory samples.
9.8. The states could also identify a reference laboratory to perform
antibiotic sensitivity tests.
COLLECTION AND TRANSPORTATION OF STOOL SAMPLES
collect the stool sample before the patient receives an
antibiotic
• use a clean cotton tipped swab and introduce well into the
rectum. When this is done well, the swab will become moist
and may be faecally stained.
• alternatively, collect freshly passed liquid stool in a bottle or
a cotton tipped swab.
• send the sample to the laboratory in a tightly sealed[ screw
capped sterile bottle if the sample can reach the laboratory
within two hours.
. send the sample to the laboratory in a tightly sealed screw
capped sterile bottle with Cary-Blair transport medium (or
VR medium or Alkaline Peptone Water) if it will take more
than two hours to reach the laboratory.
• if transport medium is not available, soak strips of blotting
paper with liquid stool. Send these to the laboratory in
carefully sealed plastic bags to prevent drying.
• send the samples using a cold chain. If this is not possible
send at ambient temperatures.
• bottles or plastic bags should be placed in separate plastic
bags each to prevent leakage of the potentially contaminated
•
.
material.
.
each sample should be labelled. Detailed information as
_______ indicated at 9.4 should be sent for each sample.-------------- -
9 9
More complicated procedures such as phage typing and toxin
testing are undertaken by the national reference laboratory at the
National Institute of-Cholera and other Enteric Diseases (NICED),
33 CIT Road, Scheme XM, Beliaghata, Calcutta - 700 010, Phone:3504598, 3505533, 3504478, 3500448 FAX:-3505066.
9
10.
Prevention and control of an outbreak
10.1. The risk of an outbreak of cholera can be minimised and an
outbreak can be prevented from spreading further by taking measures
given below. There are no other alternatives for the control of an
outbreak of cholera.
•
•
•
•
provision of safe water
adopting safe practices in food handling
sanitary disposal of human waste
personal and domestic hygienic practices
10.2. The above steps are required both as long-term measures to
prevent cholera as well as measures to be taken in a focal area where
an outbreak is anticipated. Community participation is essential to
preempt an outbreak so that safe practices are followed for storing
water and for food handling.
10.3. When an outbreak occurs or when the risk of such outbreaks is
high, the co-operation of other government departments, non
governmental agencies and the community often becomes necessary.
Such help will be more forthcoming if mechanisms for interaction
have been developed before the onset of an outbreak. It might be
useful to convene a meeting of the concerned departments,
community representatives and the NGOs before the expected
seasonal increase of cases of diarrhoeal diseases. Some mechanism
for briefing the press should also be established. Some suggested
areas in which the government departments and NGOs can assist may
be seen at Annex 7.
10.4. According to WHO guidelines, chemoprophylaxis, vaccination
and travel & trade restrictions have been found to be ineffective and
arc not recommended for the control of an outbreak of cholera or for
the prevention of its spread to other areas.
INEFFECTIVE MEASURES
•
•
•
chemoprophylaxis
vaccination
travel and trade restrictions (cordon sanitaire)
10.5. Mass chemotherapy is not only ineffective in preventing the
spread of cholera, but it also diverts manpower and resources from
effective measures. In several countries, it has contributed to the
emergence of antibiotic resistance in the vibrio, depriving severely ill
patients from valuable treatment. The value of selective chemotherapy
of household contacts is also doubtful. It is not recommended as a
routine measure.
ic\r '| it ■!.< ;i III).I
■-'
10.6. Vaccines that arc currently available do not have high vaccine
efficacy rates. 2 doses arc required for primary immunization. In those
who arc immunised, protection lasts for 3-6 months only. Vaccination
does not reduce the incidence of asymptomatic infections or prevent
the spread of infection. Vaccination campaigns divert resources and
manpower from more useful control activities. Inadequately sterilised
needles and syringes may transmit the parenterally transmitted
infections such as HIV and Hepatitis B. No country requires
travellers to have a cholera vaccination certificate.
RISK OF CHOLERA TRANSMISSION THROUGH FOOD TRADE
Although
Although there
there is
is a theoretical risk of cholera transmission
associated with international food trade, the weight of evidence
suggests that this risk is small and can normally be dealt with
by means other than embargo on importation.
A large number of tests carried out on commercially imported
foods from affected countries (most recently from South
a America) have not detected Vibrio cholerae 01. Indeed although
^^indh/idual cases and clusters of cases have been reported, WHO
Z " documented a signincant outbreak of cholera result.ng
from commercially imported food.
_________________ . Guidelines for Cholera Control, WHO 1993 page 29.
10 7 Travel and trade restrictions between countries or different
control measures.
11.
Preparatory action in anticipation of an outbreak
11.1. Aiert health personne! and hospMs to
ing
clustering of cases of d.arrhOea_
cholera shouid be
diarrhoea is seen in childre
y
offjce immediately. All
suspected and notifijyd._ to... —.— —
should maintain
health facilities including t ose
Datients should be recorded
records of patients seen. Address of the P^ent^Sh°curs If there is a
and maintained locally for use ,n^Ta“ ^ area, Held
sudden ,ncrea® M b carried out and necessary corrective action
investigations should be car
provide an early warning
outbreaks of al! waterborne diseases, including cholera.
< W.ISX* '11( JlA'i* III) ()<)<■
11
Particular attention may be given in the pre-monsoon period
before the expected seasonal increase of water-borne diseases;
however, these measures are expected to be in place round the
year.
11.2. Ensure that the health personnel are adequately trained in oral
rehydration therapy and that the recommended guidelines arc
followed in the hospitals. If necessary, orientation sessions or
retraining may be organised. Early treatment can save many lives.
11.3. Arrange random checks for water quality for coliform organisms
(faecal contamination). Special attention may be given to high risk
pockets. In places where water is found to be of unsatisfactory quality
follow-up action may be taken with the concerned authorities for
water supply. If feasible, chlorination should be carried out to render
water safe for drinking (Annex 3).
11.4. Health educational activities should be carried out in the
community to promote safe practices especially before the monsoons
when the seasonal increase of cases of diarrhoeal diseases can be
expected.
11.5. Check that adequate stocks of essential supplies are available
and have been distributed to the peripheral health institutions well in
advance of the expected seasonal increase of cases of diarrhoeal
diseases. ORS packets should be available in all the health facilities.
It is recommended that adequate stocks of bleaching powder, chlorine
tablets, IV fluids and appropriate antibiotics are in stock in case of an
emergency.
11.6. A nodal officer should be identified at the state and district
levels with the responsibility of collecting and analysing relevant
surveillance reports and for ensuring that appropriate follow-up action
as required is taken up promptly. The name of the nodal officer should
be made widely known so that she/he could be contacted in case of
an emergency or if clarifications or additional information is required
by the medical and health personnel in the periphery.
12.
Investigation of an outbreak
12.1. Recognition of early warning signals, timely irvestigations and
the application of specific control measures can limit the spread of an
outbreak and prevent deaths. Control measures are most effective
when selective interventions are applied early.
12.2. When an increase in the number of cases of diirrhoeal diseases
is reported, the areas from where the cases arc reported should be
checked. Diagnosis should be confirmed of as many cases as possible
to check that it is clinically compatible with cholera.
•
*1 n »i.( ;i hi i Doi'
12.3. Stool samples from a few typical cases may be collected and
sent for laboratory examination (see 9)
12.4. Line listing of cases, including age, sex and address should be
made. Active search should be made for more cases.
12.5. Identify sources of drinking water. Check water quality for
bacteriological contamination. If piped water supply, check for
possible leakage. If a common source of water supply has been
identified, inform public not to use the water for drinking purposes or
for washing utensils etc.
12.6. Arrange alternate source for water, including tankers if possible.
If possible chlorinate water source. Distribute tablets for domestic
chlorination of water along with instructions for its proper use, i
necessary (Annexe 4). Contact concerned authorities for water supp y.
12 7 Alert health facilities and hospitals in the area. Make sure that
adequate supplies of ORS, IV fluids, appropriate antibiotics and other
essential supplies are available.
----- PRECAUTIONS AT TREATMENT CENTRES
. quarantine not necessary, although restricted contact between
patients and community may be encouraged
• strict infection control measures such as face mas , g ove or
special clothing for hospital staff and visiting family members is not
required
frequent hand-washing is recommended
safe disposal of excreta and vomit is necessary----------------- -------------
•
.
12 8 Arrange health educational activities in the community
recording personal and domestic hygiene, recommended sources of
safe water supply, oral rehydration therapy and health facilities where
patients can be taken for treatment (see 8).
12.9. Active case reporting should be continued for at least one week
after the last case.
r OTHER PRECAUTIONS AT HOME AMD IN THE COMMUNITY ,
. S clothing, mattresses can be disinfected by thorough
. Sunniest method for a family or a Smail rural health centre to
family or a
dispose of cholera stools is by putting them in a pit latrine or
. taS hospimls, Iktuid slools mid vomit cm. be disinfected before
liquid stools and vomit can l>
disposing lliese in the toilet by 4% hypochlorite. Sem.-sohd and
------------------------------------- -—
other waste can be incinerated.
I
13
12.10. On confirmation of a focal outbreak of cholera, take
precautionary measures as indicated in para 11 in other potentially
high risk pockets in the district.
12.11. Notify immediately to the concerned state officer as soon as a
clinically compatible case of cholera is reported.
12.12. The detailed procedures for conducting outbreak investigation,
data analysis and report writing are given in a separate document
(Outbreak Investigations - A Field Guide). A suggested format for
report writing may be seen at Annex 8.
ACKNOWLEDGEMENT
The manual has been edited by Dr Jotna Sokhey, Director NICD; Dr
Rajesh Bhatia, Consultant (Microbiology); Dr D.C.Jain, Joint Director
(Epidemiology) and Dr Jagvir Singh, Deputy Director.
(’ vis\<'l!( n.' UII) DOC
Annex 1
< SAFE WATER :
boiling for 1 minute will kill or inactivate V.cholerae and other
common organisms that cause diarrhoea. Boiling is, however,
expensive and not practical especially in. areas where outbreaks of
cholera and other diarrhoeal diseases are most likely to occur
because of fuel shortages
.
when surface water/ handpump water is contaminated, this source
should be closed for drinking water purposes. This information
should be prominently displayed indicating that the source o
water is not fit for use. In Delhi, shallow handpumps are painted
Zed Xnaie waler source shou.d be provided, includ.ng waler
tankers during the course of an outbreak
where it is feasible chlorination oC the waler source, such as a
draw-well should be immediately organised
urban
with the
co-ordination wan
should be organised
agency
,
in
.
chlorine releasing tablets may be used for domestic purposes in the
areas,
immediate
area of an outbreak
the family _______________
a
Annex 2
------------recommended MINIMUM chlorine levels
IN WATER DISTRIBUTING SYSTEMS
.
0.5 mg/litre - at all sampling points in a piped water system
.
•
1.0 mg/litre - at standpost
2.0 mg/litre - in tanker trucks at filling
<: \.is\' IIOIA'iUIU.DOC
15
Annex 3
CHLORINATION OF DRINKING WATER
PREPARATION OF STOCK SOLUTION
(1% solution in 1 litre of water)
Add Lo one litre of water any of tlie following:
•
calcium hypochlorite (70%)
15 gram
OR
•
•
bleaching powder or
chlorinated lime (30%)
33 grant
OR
•
sodium hypochlorite (5%)
250 ml
OR
•
sodium hypochlorite (10%)
110 ml
The stock solution should be used within one month. It should be
kept in a closed container in a cool place away from light
CHLORINATION OF WATER
(Add stock solution to water)
•
•
•
0.6 ml or 3 drops
6 ml
60 ml
1 litre of water
10 litres of water
100 litres of water
Allow water to stand for 30 minutes before using,
chlorine level should be 0.2 to 0.5 mg/litre
I
______________________________
_____________
The residual
e
Annex 4
DOMESTIC CHLORINATION OF DRINKING WATER
•
•
»
«
crush commercially available chlorine-releasing tablet
put in the water container with 20 litres of water
allow to stand for 30 minutes
use water within 24 hours
Containers with a narrow mouth are recommended for the storage
of drinking water.
Annex 5
Composition of ORS
(not weight = 27.9 gm)_________
Weight (gm)
Ingredient______
3.5
Sodium Chloride IP
1.5
Potassium chloride IP
_______ 2.9_______
Sodium citrate IP
20.0
Glucose anhydrous IP
itre
of
potable
water.
Notc:-To be used in one
Annex 6
HOW TO PREPARE ORS SOLUTION FROM A 1 LITRE PACKET
Mothers must be taught on how to measure one litre of water. It is
that a measure which is commonly available in the
important identified and mothers told the exact number of such :
homes is
.
measures that will make 1 litre.
boil water for preparing the ORS solution,
There is no need to
household normally uses for drinking
Clean water which the
purposes can be used.
•
•
making the ORS solution.
•
Hands must be washed before
.
Full packet of ORS must be used Gen^rally the mother will tend
it later. It is important
to save a part of the packet in order to use
to be- mixed in one litre of
to emphasise that the whole packet is t_
water.
CiYISWIK'UGUID.WC
17
Annex 7
INTER DEPATMENTAL COMMITTEE
SUGGESTED AREAS OF RESPONSIBILITY AHD ACTION
District administration
• mobilize resources by organizing meetings with
• concerned government departments
• non-governmental agencies
• community leaders
• ensure supplies of ORS packets and other essential items
• ensure adequate quality monitoring of water samples
• arrange safe water supply
• ensure adequate facilities for transportation of serious patients to
district hospital, if necessary
• provide relevant information to the press
• monitor status of control activities
• repair leakage in pipe water supply
District Health Office / Municipal Health Office
• alert health personnel to report cases and to monitor trends
• arrange active surveillant'e in affected area
• ensure that treatment guidelines are followed in hospitals and
other health facilities
• ensure availability of ORS packets and other essential items
• arrange health educational camps and distribution of health
educational material
• arrange chlorination of water sources if possible
• arrange water quality monitoring
• convene meeting under district administrator to seek co-operation
of other government departments and NGOs
Concerned Department (s) responsible for water supply
• repair leakage in pipe water supply
• arrange potable water supply, including water tankers if
necessary
• arrange chlorination of water
• ensure water quality monitoring
Other government departments such as social welfare, education,
tribal welfare and NGOs
J'
• dissemination of relevant information
• promotion of oral rehydration therapy
• reporting clustering of acute diarrhoea, jaundice (Pilia) cases
4 ><
Panchayat members, village pradhans, community leaders
• dissemination of relevant information
• promotion of oral rchydration therapy
• reporting cases of acute diarrhoea and jaundice (pilici)
• monitoring chlorination of water sources such as wells
• arranging transportation of serious cases to hospital
Annex 8
OUTBREAK INVESTIGATION REPORT
Cicncral Information
State
District
Town/PI IC
Ward/Village
Population
Background Information
Person reporting the outbreak :
Date of report
■-------
Date investigations started
:------
Person(s) investigating the outbreak
Details of Investigation
Describe how the cases were found (may include: (a) house-tohouse searches in the affected area; (b) visiting blocks adjacent to the
affected households; (c) conducting record reviews at local hospitals,
(d) requesting health workers to report similar cases in their areas,
etc.):
Descriptive Epidemiology
.
Cases by time, place and person (attach summary tables and
relevant graphs and maps).
• Age-specific attack rates and mortality rates
• High-risk age-groups and geographical areas.
Description of Control Measures Taken
l()
<• \.js\rii()i.r.tJii).()<><’-
Description of Measures for Follow-up Visits:
Brief Description of Problems Encountered
factors Which, in Your Opinion, Contributed to the Outbreak
Conclusions and Recommendations
Date
(Name and Designation)
i'
■
•f.
8i?
INVESTIGATION
& CONTROL
OF
Outbreaks
Japanese
Encephalitis
NATIONAL INSTITUTE OF COMMUNICABLE DISEASES
(DIRECTORATE GENERAL OF HEALTH SERVICES)
22-SHAM NATH MARG, DELHI - 1 10 054
AUGUST 1997
Contents
1. INTRODUCTION
1
2. NOTIFICATION OF CASES
1
3. CAUSATIVE AGENT
1
4. MODE OF TRANSMISSION
2
5. RESERVOIR OF INFECTION
2
6. VECTOR
2
INCUBATION PERIOD
3
8. CLINICAL MANIFESTATIONS
3
9. CASE FATALITY RATE AND SEQUELAE
5
IO. LABORATORY CONFIRMATION OF DIAGNOSIS
5
11. CLINICAL MANAGEMENT
6
12. PREVENTION AND CONTROL OF AN OUTBREAK
6
13. COMMUNITY PARTICIPATION
8
14. INVESTIGATION OF AN OUTBREAK
9
ANNEX 1 - CASE DEFINITION
10
ANNEX 2 - OUTBREAK INVESTIGATION REPORT PROFORMA
11
ANNEX 3 - FORMAT FOR MPW FOR REPORTING SUSPECTED JE CASE
13
ANNEX 4 - FORMAT FOR MEDICAL OFFICER FOR REPORTING JE CASE
14
ANNEX 5 - INTER-DEAPARTMENTAL COMMITTEE - RESPONSIBILITIES
15
7.
1.
Introduction
1.1. Japanese Encephalitis (JE) is a disease of public health
importance because of its epidemic potential and high case fatality
rate. In patients who survive, complications may lead to life long
sequelae.
^3
1.2. The first major outbreak of JE occurred in Bankura and
. Burdwan districts, West Bengal, in 1973 and since then has spread to
many states/UTs of country.
1.3. JE is a mosquito-borne zoonotic disease. The virus infects
mainly animals and birds. Man is an incidental host. The risks
increase in areas where ecological conditions facilitate transmission to
man.
1.4.
Though JE is primarily a disease of rural agricultural
areas, where vector mosquitoes proliferate in close association with
pigs and other animal reservoirs, its epidemics have also been
reported in peri-urban areas where similar conditions may exist.
2.
Notification of cases
2.1. If an outbreak of JE is suspected it must be reported
immediately to the district health office. The state health authorities
must be informed through the quickest mode of communication,
preferably through telephone, fax or e-mail of the details of the
outbreak including investigation and control measures initiated. The
National Institute of Communicable Diseases, 22-Sham Nath Marg,
Delhi - 110 054 (Phone:- 2521272, 2521060, 2913148; FAX:2922677; Telegaram:- COMD1S, DELHI) is expected to
be kept
informed of the action taken.
2.2. The total number of overt cases per village will be few and the
local health personnel must be alert about any casc(s) of
encephalopathy in their areas.
Active surveillance through key
individuals in the community should be encouraged in the high risk
pockets, for example, places where piggeries are commercially
established.
3.
Causative agent
3.1. JE is caused by a group B arbovirus (flavivirus). The virus is
antigenically related to other flaviviruses including dengue and yellow
fever viruses.
1
c \js\h-:guide txc
4.
Mode of transmission
4.1. The infection is transmitted through the bite of an infected
culicine mosquito. In human beings, viraemia is mild and lasts for a
short duration. Infection in man is the dead end of transmission.
Man to man transmission has not been documented.
4.2.
The transmission cycle is maintained in animals and birds.
5.
Reservoir of infection
5.1. JE virus has its natural cycle in wild or domestic vertebrates
and mosquitoes. The animal hosts include pigs, cattle and horses,
Water birds such :as pond herons, cattle egrets, poultry birds and
ducks play a significant role in the natural history of JE vi
virus.
5.2.
Pigs are the major vertebrate hosts. Although, infected pigs do
not manifest any overt symptoms of disease they develop tremendous
viraemia and can infect the mosquitoes The pigs are considered
as amplifying hosts.
5.3.
The currently available evidence does not indicate major role of
cattle in transmission of disease.
5.4. Horses develop active disease but viraemia is rarely present in
high titre or for long periods. Horses are unlikely source of mosquito
infection.
5.5
Infection in man appears to be correlated with living in close
proximity with animal reservoirs, especially pigs
6.
Vector
* 6.1. Mosquitoes belonging to the Culex vishnui group (Culex vislmui,
Culex pseudovishnui, Culex tritaeneorhynchus) are the most important
vector species in India. 11 more species of mosquito have been
incriminated as vectors of JE.
6.2. Culex mosquitoes generally breed in water bodies with luxuriant
vegetation.
Irrigated rice fields, shallow ditches and pools are
common breeding places.
6.3.
Culex mosquitoes are zoophilic, feeding primarily on animals
and wild birds. They rest outdoors in vegetation and other shaded
places but in summer may also rest indoors. The mosquitoes are
outdoor as well as indoor feeders.
2
6.4.
Epidemics usually coincide with the monsoons and post
monsoon period when the vector density is high.. However, in endemic
areas, sporadic cases may occur throughout the year.
6.5. Ecmalc mos([uitoes get infected alter feeding on a viraemic host.
1 hey can transmit the virus to other hosts after an extrinsic
incubation period of 9 to 12 days. The mosquitoes remain infected for
fife. The average life period of a mosquito is about 21 days. Culex
mosquitoes can fly for long distances (4-5 km).
7.
Incubation period
7.1. 'The incubation period in man, following mosquito bite probably
varies from 5 to 15 days.
8.
Clinical manifestations
8.1. The clinical features of JE are those of encephalopathy. The
patient will give a history of acute onset with fever and change in
behaviour or sensorium lasting for more than~~24“ hours.
Focal
neurological deficits may or may not be present. '
8.2.
Disturbances of sensorium are reflected as lethargy,
somnolence, irritability, apathy or loss of consciousness. The patient
may develop difficulty of speech and other neurological deficits like
ocular palsies, hemiplegia, tremor and ataxia. There may also be loss
of bladder and bowel control. The focal neurological signs may be
stationary or progressive.
CLINICAL LABORATORY FINDINGS IN ACUTE ENCEPHALITIC
STAGE
Blood: moderate to high polymorph leucocytosis (total count ranging
between 10,000 and 35,000 per cu.mm with neutrophils ranging
between 50 and 90%).
Cerebrospinal fluid (CSF): the cell count generally ranges between 10 to
1000 per cu.mm, with a predominance of lymphocytes. The protein may
be raised slightly to 60-100 mg percent and sugar may also be slightly
elevated.
8.3. In majority of the cases, however, the infection is mild with no
overt clinical symptoms or mild fever with headache. Individuals
develop immunity after infection.
In endemic areas cases are,
therefore, seen more often in children under 15 years of age as the
adult population is-already immune through natural infection. In
virgin areas, cases may be seen in all age groups.
3
<• 'JSMlUilJri)K ixk-
8.4. Meningitis should be excluded as a cause of the encephalitic
syndrome, so that specific treatment is started in time. Treatment of
JE, which is a viral infection, is symptomatic. Other causes of
encephalopathy include other viral infections, drugs and toxins. Some
of the causes are listed in the box.
8.5. One of the complications of malaria caused by P.falcipamm is
encephalopathy. Since malaria is relatively common, the diagnosis of
malaria should also be considered. The diagnosis is confirmed if field
investigations indicate malariogenic conditions, illness is clinically
compatible and anti-malaria treatment is effective. The facilities for
making blood slides and reading these slides should be available at
each__PHC.„
----------- —-----------------8.6. Typhoid fever is another important endemic disease which can
give rise to symptoms mimicking Japanese Encephalitis. It should be ■
excluded by careful history and physical examination and blood
culture for S.typhi, if necessary.
COMMON CAUSES OF ENCEPHALOPATHY
Infectious
• Vaccine Preventable Diseases Pertussis, measles
• Viral
Japanese encephalitis, mumps,
rubella, herpes simplex,
enteroviruses, cytomegalovirus,
Epstein Barr, rabies
Other
Enteric fever, malaria, tuberculosis,
toxoplasmosis, cryptococcal infection,
leptospirosis______
Non-infectious
• Fluid & electrolyte imbalance Hyper/hyponatremia
Alkalosis/acidosis
Metabolic
Thiamine deficiency, diabetic
acidosis, hypoxia, hypoglycaemia,
uraemia, hyperbilirubinemia
Toxic
Heavy metals (lead, mercury, arsenic)
Insecticides, Carbon - Monoxide
• Physical
Heat hyperpyrexia
« Tumours/Abscess
8.7. Epidemiological and entomological investigations are useful in
leading to a presumptive diagnosis of JE. The presence of risk factors
such as the vector and amplifying hosts supports the diagnosis of JE.
8.8.
The diagnosis of JE is confirmed by laboratory tests.
8.9.
Case definition may be seen at Annex 1.
4
C’jSUEC.UIDF. IXX-
9.
Case fatality rate and sequelae
9.1. Case fatality rate is high in severe cases. Case fatality rates of
20 to 40% have been recorded.
9.2. Patients who recover from the acute episode may have
neurological sequelae. These occur with variable frequency and
depend on age and severity of the illness. The commonly observed
sequelae are:
•
•
•
•
10.
mental impairment
severe emotional instability
personality changes
paralysis
Laboratory confirmation of diagnosis
10.1. The diagnosis of JE can be confirmed by serological tests. The
tests include detection of IgM antibodies which appear after the first
week of onset of symptoms and arc detectable for one to three months
after the acute episode.
A rising antibody titre of IgG antibody in paired sera taken at an
interval of 10 days or more is confirmatory.
10.2. IgG antibodies indicate previous infection and are useful for
conducting sero-epidemiological studies to determine the extent of
silent infection and immunity levels in the local population.
10.3. Antigen for conducting the tests is not yet commercially
available. Antigen for detection of IgG antibody is produced in limited
quantities for operational research and outbreak investigations at the
National Institute of Virology (20-A, Dr. Ambedkar Road, Pune - 411
001; Phone:-627301, 627302; FAX: 622669).
With the antigen
received from NIV, the National Institute of Communicable Diseases
(NICD) supports outbreak investigations on the request from the state
health authorities.
10.4. Isolation of virus from blood or CSI7 is not routinely done for
diagnostic purposes as viraemia is of short duration.
10.5. Blood for serological studies should be carefully collected taking
due universal precautions. Specimen containers should be clearly
labelled. Each specimen should be accompanied with the detailed
information about the case as given in the box so that the results
could be scientifically interpreted.
5
<• is jeci jiih'n ir
INFORMATION WHICH SHOULD ACCOMPANY EAclf SAMPLE
name of the patient
name of the mother/father
age
sex
complete residential address
name of the hospital/PHC sending the sample
registration number of the patient
date of onset of illness
date of hospitalisation
date of collection of sample
history of immunisation against JE
provisional diagnosis
brief clinical findings
results of clinical laboratory investigations
11.
Clinical management
11.1. There is no specific treatment of JE. However, supportive
treatment and good nursing care can significantly reduce case fatality
rate. It is, therefore, important that cases are referred to a hospital as
early as possible if encephalitis is suspected and treatment
commenced without waiting for serological laboratory results.
11.2. In the acute phase, clinical management is directed at
maintaining fluid and electrolyte balance. Keeping the airway open in
a comatose patient is important. Patients with hypoxia may reejuire
oxygen.
11.3. If the patient has convulsions, appropriate drugs are prescribed.
11.4. There is no evidence that gammaglobulins or corticosteroids
have a beneficial effect and these are not recommended.
11.5. Physio-therapy may be necessary in the convalescent stage.
11.6. Long-term neurological sequelae may require specialised care.
12.
Prevention and control of an outbreak
12.1. A surveillance system should be established so that any case of
encephalopathy is immediately reported to the local health
authorities. Necessary field investigations must be carried out in the
area of residence of the patient to check for amplifying host and
vector.
-————
6
|| < :i 'll ’I' I * X ■
12.2. The preventive measures are directed at reducing the vector
density and in taking personal protectionJx)^.prevent.Jthe bite of
mosquitoes. The isolation or destruction of the amplifying hosts
(usually pigs), which are the main source of infection, is not practical
as these animals do not show any overt signs of illness and it is not
possible to identify infected animals.
12.3. Immediate measures are called for to reduce the density of
mosquitoes by spray of insecticides. The public should also be
informed to take necessary precautions against mosquito bite such as
use of full sleeved clothes, mosquito nets at night and mosquito
repellent creams.
12.4. Long-term measures include the recommended steps for vector
control under the National Malaria Eradication Programme (NMEP).
12.5. Patients should be referred to the district hospital as the
peripheral health facilities may not have adequate resources to
manage serious cases.
12.6. Pockets of high risk should be identified so that these areas
could be given more attention with regard to control measures, health
educational activities and field supervision. Such areas would include
villages and peri-urban areas where pigs are reared, especially if these
are close to paddy fields which are rich breeding places for Culcx
mosquitoes.
12.7. Isolation of patients and disinfection of secretions and
excretions are not required as JE virus is not transmitted person to
person.
RECOMMENDED MEASURES FOR CONTROL OF JE OUTBREAK
•
•
•
•
Vector control
Prevention of man-mosquito contact
Prevention of animal reservoir-mosquito contact
Health education
i t
12.8. A killed JE vaccine is produced at the Central Research Institute
(CRI), Kasauli from the brain of suckling mice inoculated with the
Nakayama JE strain. The vaccine is not recommended for use for the
control of an outbreak. Two doses of 1 ml each (0.5 ml for children
under the age of 3 years) should be administered subcutaneously at
afrintervaTof 7-14 days- A booster injection of 1 ml should be given
after a few months (before 1 year) in order to develop full protection.
Re-vaccination may be given after 3 years. Since the risk of JE is not
universal and is limited to focal areas, JE vaccination is not included
in the national immunization programme in India.
"
7
C JS'Jr.GUIDE l)(X’
12.9. Arrange health educational activities in the community
regarding prevention of mosquito bites by use of mosquito nets and
mosquito repellent creams, avoiding sleeping in or near places where
pigs are housed, taking measures like mosquito proofing, residual
insecticide spray in piggeries and reporting suspected cases at the
health facilities early.
13.
Community Participation
13.1. Community participation is essential for the prevention and
control of an outbreak of JE. The community must be encouraged to
take steps to protect themselves from mosquitoes by using bed-nets.
The co-operation of the community is also important during the
periodic insecticide spray.
13.2. In pockets of high risk, active surveillance of JE should be
encouraged so that first case(s) are immediately reported to the local
health authorities.
13.3. Co-ordinated efforts by government departments'such as
agriculture,
animal husbandry, flood control,
irrigation and
industrial development are essential so that risk factors for mosquito
breeding could be reduced. 1In places where piggeries are being
established with government support, the concerned departments
must be aware about the potential risk of JE and must take necessary
precautionary measures for vector control in collaboration with the
local health authorities.
13.4. In an event of an outbreak,
the co-operation of other
government departments will help to bring it more effectively under
control. An inter-departmental committee for outbreak prevention
and control should be constituted which should meet periodically.
Panchayat members, key community representatives and NGOs
should be included as members of the committee. A meeting of the
committee should be convened before the expected seasonal increase
of water and vector borne diseases. In districts where risk factors of
JE exist, status of control measures for JE should also be assessed.
The suggested areas of responsibilities of the various departments is
given at Annex 5.
13.5. Press release and other mechanisms for briefing the press
should be considered to that the press has access to reliable
information.
RISK FACTORS FOR JE OUTBREAK
•
•
»
high density of Culcx mosquitoes
presence of amplifying hosts (pigs)
paddy cultivation
(' istll'dl 'll
I MW
14. Investigation of an outbreak
14.1. The investigation of an outbreak of JE is similar to the
investigation of other epidemic prone diseases. The first principle is to
receive early warning signals, confirm diagnosis and to take prompt
measures for control of the outbreak. Control measures are most
effective when selective measures are applied early.
14.2. Line list of cases, including age, sex and address should be
maintained. Active search should be made for more cases. Serum
samples should be collected for laboratory confirmation of diagnosis.
14.3. Vector surveillance should be immediately initiated and
should include collection of adult 'mosquitoes, identification of
mosquito species and density and assessment of susceptibility of
vectors to available insecticides.
14.4. On confirmation of an outbreak of JE, take precautionary
measures in other potentially high risk pockets in the district.
14.5. After the outbreak is over, a detailed report of the outbreak
must be written. Format for outbreak investigation report given at
Annex 2.
9
C 'SJir.t JIDE lx !(•
Annex 1
[
CASE DEFINITION
SUSPECT CASE
•
•
•
•
High grade fever of acute onset with at least two of the following:
Decrease in level of consciousness independent of convulsions
Significant change in mental status either in behaviour or
personality
Convulsions
PROBABLE CASE
•
•
•
•
Suspected case of Japanese Encephalitis, and
Usually not more than a few cases (1-2) in one village.
With or without signs of meningeal irritation and varying degree of
neurological deficits
Pleocytosis in CSF of more than 10 cells/mm3 in clinically
compatible illness.
CONFIRMED CASE
•
•
Serology for JE antibodies.
Demonstration/isolation of virus/antigen from CSF, brain tissue or
rarely blood.
10
c
Dor
Annex 2
OUTBREAK INVESTIGATION REPORT
General information
State
District
PHC/Town
Village/Ward
Population
Background Information
Person reporting the outbreak :
Date of report
Date investigations started
Person(s) investigating the outbreak :
Details of investigation
Describe how cases were found ( may include (a) house to house
search in the affected area; (b) visiting blocks adjacent to the affected
area; © conducting record reviews at local hospitals; (d) requesting
health workers to report similar cases in their areas etc.):
Descriptive epidemiology
Cases by time, place and person (attach summary tables and
relevant graphs and maps)
Age specific attack rates and rrortality rates
High risk age groups and geographical areas
Vaccination status of cases, unaffected population
11
<•
ix)c
Prevalence and density of JE vectors
Prevalence of reservoirs specially pigs
Description of control measures
Description of measures for follow-up visits:
Brief description of problems encountered:
Factors which ,in your opinion , contributed to the outbreak
Conclusions and recommendations
(Name and designation)
Date
12
)•: ii ci t|| ti- pi w
Annex 3
Format for MPWs for reporting
suspected JE case
Village.
District
Name
Age
Sex
Address
Fever
Yes/No
Date of onset
Headache Yes /No
Stiffness in Neck
Yes/No
Fits
Yes/No
Weakness of extremities
Yes/No
Vomiting Yes/No_
Unconsciousness
Yes/No_
Recovered/still suffering/death with date.
House :
Kacha/Pacca
Animals - Pigs/Cattlc/13ulfalo/Goat/Hcns/Ducks etc.
Sleeping habit - Outside/same room with animals/separate room
13
c i:;.ii ghii
!x><-
Annex 4
Format for medical officers for reporting JE case
District
House No.
Date of Survey.
Village
Head of Family.
Particulars of Patient:
Age(Years)
Name
Age(Years)Sex:
M/F
Father’s Name
Date of onset of illness
Recovered / Still suffering / Died on
Date of investigation.
Informant
Symptoms
Fever (more than 100 0 F):
Headache:
Neck rigidity :
Convulsions:
Unconsciousness :
Sequelae:
Some form of paralysis :
Involuntary movements:
Yes / No
Yes/ No
Yes / No
Yes/ No
Yes / No
Yes/ No
Yes / No
Similar illness in family/neighbourhood:
Name
Age
Sex
Date of onset
Clinical laboratory investigations
Samples sent for confirmation of diagnosis (and results, if available)
Diagnosis
(Signature A, Designation)
14
II t ;i I If >1 I )( u •
Annex 5
INTER-DEPARTMENTAL COMMITTEE
SUGGESTED AREAS OF RESPONSIBILITY AND ACTION
District administration
• mobilize resources by organizing meetings with
• concerned government departments
• non-governmental agencies
• community leaders
• ensure vector control measures
• ensure adequate facilities for transportation of serious patients to
district hospital, if necessary
• provide relevant information to the press
• monitor status of control activities
District Health Office / Municipal Health Office
• alert health personnel to report cases and to monitor trends
arrange active surveillance in affected area
• arrange health educational camps and distribution of health
educational materjal ,
• arrange vector control measures
• arrange drugs and fluids in nearest hospital in adequate quantity
• convene meeting under district administrator “to seek cooperation
of other government departments and NGOs
Concerned Department (s) responsible for agriculture and animal
husbandry
• ensure measures for reducing factors favouring the breeding of
mosquitoes
• support measures for vector control
• take precautionary measures where piggery development projects
are initiated
• report suspected cases of JE
Other government departments such as social welfare, education, tribal
welfare and NGOs, and Panchayat members, village pradhans and
community leaders
• ensure measures for reducing factors favouring the breeding of
mosquitoes
• support measures for vector control
• take precautionary measures where piggery development projects
are initiated
• report suspected cases of JE
• arrange transportation of serious cases to hospital
15
i:; ii < ;i 'll >l ixw
4r
Outbreak
Investigation & Control
A Field Guide
NATIONAL INSTITUTE OF COMMUNICABLE DISEASES
(DIRECTORATE GENERAL OF HEALTH SERVICES)
22-SHAM NATH MARG, DELHI - 110 054
AUGUST 1997
<
Jnthtc.ik firn-
CONTENTS
1. ROLE OF OUTBREAK INVESTIGATIONS
1
2. PREPAREDNESS FOR OUTBREAK INVESTIGATIONS
I
3. DISEASES COVERED IN THE FIELD GUIDE
4
4. DEFINITION OF AN OUTBREAK
5
5. TRIGGER EVENTS FOR OUTBREAK INVESTIGATIONS
5
6. FIELD INVESTIGATIONS AND ANALYSIS OF REPORTS
6
6.1 Verification of the Diagnosis
6
6.2 Epidemiological Features and Standard Case Definitions
7
6.3 Criteria for Investigating an Oih-break
7
6.4 Case-Finding Through Active Surveillance
K
6.5 Line-Listing, Defining and Counting of Cases
9
6.6 Descriptive Epidemiology........................................................................................................................ 9
6.7. Description of environmental conditions
io
6.8. Additional steps during investigation of outbreaks of vaccine preventable diseases
io
6.9. Laboratory investigations
II
6.10. Entomological investigations
12
6.11. Determining Who is at Risk of Disease
12
6.12. Follow-up Visits
12
6.13. Documentation
13
7. HEALTH EDUCATION
13
8. PREVENTION AND CONTROL OF AN OUTBREAK
14
8.1. Water borne outbreaks
8.2 Vector borne outbreaks
8.3 Food-borne diseases
8.4 PARENTER/XLLY transmitted infections
14
15
16
16
9. PRECAUTIONARY ACTION IN HIGH RISK POCKETS TO WHICH THE OU I BREAK
CAN POTENTIALLY SPREAD
. .............................
16
10. SYNDROMIC REPORTING OF OUTBREAKS
17
10.1. Common syndromes
10.2. Acute oxses of fever
10.3. Haemorrhagic fever
10.4. Fever with altered sensorium
10.5. Acute cases of diarrhoeal diseases
10.6 Acute Respiratory Infections (Acute pneumonias)
10.7. Jaundice
10.8. Acute Flaccid Paralysis...........................................
17
17
18
19
20
22
22
23
EXERCISE 1
25
EXERCISE 2
27
EXERCISE 3
31
EXERCISE 4
33
■ -.in
ANNEX - 1 CHECK LIST FOR MODEL DISTRICT LEVEL LABORATORY
36
ANNEX - 2 INTER-DEPARTMENTAL COMMITTEE - RESPONSIBILITIES
40
ANNEX - 3 SUGGESTED FORMAT FOR LINE LIST OF CASES
41
ANNEX - 4 OUTBREAK INVESTIGATION REPORT
42
■ II
Io.
1.
ROLE OF OUTBREAK INVESTIGATIONS
1.1. Many communicable diseases are endemic in India. An effective
surveillance system is essential for planning, implementation and
monitoring the disease control programmes. Many of these diseases have
seasonal patterns and cyclic trends which can be discerned through the
surveillance system. These diseases can also cause outbreaks with the
potential to spread rapidly and cause many deaths. Outbreaks of new
and reemerging infections may also occur.
1.2. Precautionary measures taken in anticipation of an outbreak can
prevent an acute public health emergency and save lives.
While
outbreaks cannot always be predicted or prevented, recognition of early
warning signals, timely investigations and application of specific control
measures can limit the spread of the outbreak and prevent deaths.
Control measures are most effective when selective interventions are
applied early.
1.3. The primary purpose of an outbreak investigation is to control the
outbreak, limit its spread to other areas and assess how prevention
strategies can be further strengthened to reduce or eliminate the risk of
such outbreaks in the future.
2.
PREPAREDNESS FOR OUTBREAK INVESTIGATIONS
2.1. The field guide has been designed to help in making decisions
regarding investigations, specific interventions and follow-up measures.
While adaptations may be necessary at local levels depending on the field
situations and available resources, it is important that preparatory action
is taken so that the district is able to meet the eventualities if an
outbreak occurs. Some of the recommended measures are given in the
Box.
•
•
•
•
•
•
•
•
•
•
RECOMMENDED PREPARATORY ACTION
Identify a nodal officer at the state and district levels.
Establish a routine surveillance system.
Constitute an inter-disciplinary team at state/district levels (rapid
response team).
Train medical and other health personnel.
List the laboratories at regional /state/district level.
List ‘high-risk’ pockets in the rural / urban area.
Establish a rapid communication network.
Undertake IEC activities for community participation.
Ensure that essential supplies are available at the peripheral health
facilities and buffer stocks are maintained at the district level.
Set-up an inter-departmental committee, including NGOs.
1
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2.2. The identification of a nodal officer at the state and district levels is
important for receiving information about unusual events and for
ensuring that necessary follow-up action is taken in a timely and effective
manner.
2.3. An inter-disciplinary expert team at state and district levels (rapid
response team) comprising of epidemiologist or public health specialist,
microbiologist, clinician(s), entomologist and concerned programme
. xC<-1 officer should be constituted and necessary administrative orders issued
authorising the team to move quickly to the site of the outbreak if such a
V request is made by the nodal officer. This is particularly important in the
event of an unusual outbreak for which the services of the expert team
may be required at short notice.
t
2.4. Concerned medical and health personnel should be trained in the
principles of outbreak investigations including recognition of early
warning signals, epidemiological and entomological parameters,
differential diagnosis, laboratory support and specific control
interventions.
2.5. Some laboratory tests are expected to be done at the PHC level,
others may be available only at the district level. For some laboratory'
tests, samples may need to be sent to the state, regional or national
levels. A list of the laboratories with full address, telephone and fax
numbers along with the type of tests conducted is recommended to be
maintained. The nodal officer should identify gaps in laboratory services
at each level that can be filled within the given resources. Special
emphasis must be placed on proper correction of clinical samples, their
storage and transportation. A suggested checklist of services at district
level is given at Annex 1.
2.6. An effective routine surveillance system must be established in
each district. Data should be regularly analysed as suggested in a
seperate module “Suveillance of Epidemic Prone Diseases” available
from National Institute of Communicable Diseases (NICD), 22-Shamnath
Marg, Delhi-110 054; Phone: 2521272, 2521060; FAX: 2922677; (E-mail:
jotna@del2.vsnl.net.in). Early warning signals will be missed in the
absence of a reliable surveillance system.
2.7. It is important that adequate facilities are established at the
district level for rapid and efficient analysis of the surveillance data. The
nodal officer and other key personnel should receive training in the use of
computers. Software such as EPI INFO are particularly useful in
maintaining and analysing line lists of cases of various diseases. Su0**
analysis provides valuable epidemiological information regarding high
risk groups, areas and factors.
2.8. In each district there are likely to be some areas which will be at a
higher risk of outbreaks because of inadequate facilities such as water
2
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supply, poor sanitation, or some areas may have poor transportation and
communication facilities which may impact negatively on early
notification of an outbreak and health seeking behaviour of the
community. Spot maps of these areas may be prepared so that special
attention could be given to the surveillance reports from these areas.
2.9. In the event of an outbreak, the state officer is required to be
notified immediately. The district officers may also need technical and
other support in the event of an unusual outbreak or if the diagnosis is
not confirmed. Since the National Institute of Communicable Diseases
(NICD) is the nodal office at the national level, it is expected that
notification of the outbreak would be made immediately to NICD, also
indicating if any technical support is required or not. It is obvious that
the communication network must be rapid in order to optimize its
effectiveness. Under the national disease surveillance programme, it is
expected that the district and state levels will be linked to NICD through
e-mail and fax. Telephone facilities are expected at the PHC level.
2.10. The prevention and control of outbreaks require the close and
active cooperation of the community. Community level 1EC activities
should be supported so that key messages regarding the control of the
diseases and prevention of outbreaks are known. Health education
material which has been prepared in advance and field tested will be
useful if there is an outbreak in the area because such material may be
required at short notice. The medical and health personnel should
establish contact with community leaders and other key personnel in
their areas which would be useful in receiving early warning signals and
in soliciting community support during an outbreak. Local private
practitioners could provide valuable support.
2.11. The nodal officer at the district level, in consultation with the
concerned programme officers, must ensure that essential supplies are in
place in the peripheral health facilities and that adequate buffer stocks
are maintained at the district level. Inventories should be checked before
the expected seasonal increase of cases. Some life saving medicines such
as ORS packets may also be kept at the village level especially in the high
risk pockets and areas which might become inaccessible during the
monsoons.
2.12. When an outbreak occurs or when the risk of such outbreaks is
high. the cooperation of other government departments, non
governmental agencies and the community often becomes necessary.
Such help will be more forthcoming if mechanisms for interaction have
been developed before the onset of an outbreak. It might be useful to
convene a meeting of the concerned departments, community
representatives and the NGOs before the expected seasonal increase m
cases of diseases. Some mechanism for briefing the press should also be
established. Some suggested areas in which the government departments
and NGOs can assist may be seen at Annex 2.
.
— >
3
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2.13 Detailed demographic, environmental and cultural profile of district
(including maps) should be available.
3.
DISEASES COVERED IN THE FIELD GUIDE
3.1. The diseases included in the field guide can broadly be classified
into the four following groups:
•
•
•
•
eridemic diseases with the potential of causing focal or large
outbreaks, e.g. malaria, cholera, measles, viral hepatitis,
meningococcal meningitis etc.
diseases for which eradication or elimination goals have been
set. A single case of such diseases should be treated as an
outbreak, e.g. poliomyelitis, guineaworm and yaws
rare but internationally important diseases with high case
fatality rates with the potential of importation due to conducive
epidemiological conditions, e.g. yellow fever
outbreaks of unknown aetiology
3.2. An attempt has been made to prepare a common methodology and
format for investigations to simplify its use.
3.3. First reports about an outbreak will be based on clinical syndrome
and diagnosis will be presumptive. Suggestions have been made for
clinical syndromes, outbreaks of which are more commonly reported.
Investigations must be made, including epidemiological, entomological
and laboratory, to rule out the more common causes first. A thorough
knowledge about clinical symptoms and epidemiological parameters is
important for outbreak investigations. In case of doubt, second opinion
should be taken. It may also be necessary to seek the help of the rapid
response team.
3.4. If the outbreak is unusual, case fatality rates are very high,
aetiology cannot be determined or if the clinical syndrome had not been
reported in the area before, the state officer and NICD would be expectecd
to assist the district authorities in investigations.
3.5. During the course of investigations, universal infection control
precautions are expected to be implemented. While investigating
outbreaks of haemorrhagic fever or if parenteral route of transmission is
suspected, protective gear such as gloves, masks etc. are expected to be
worn by health personnel treating or investigating patients. Procedures
that require the collection of blood and other clinical samples should be
undertaken carefully.
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4.
DEFINITION OF AN OUTBREAK
4.1. An outbreak or epidemic is defined as the occurrence in a
community of cases of an illness clearly in excess of expected
numbers. While an outbreak is usually limited to a small focal area, an
epidemic covers larger geographic areas and has more than one focal
point.
4.2. The number of cases which are needed to be called an outbreak
varies according to several factors. It depends on past historical patterns
of the disease, case fatality and complication rates, potential of spread to
other areas. For some diseases even a single case (acute poliomyelitis,
guinea worm, unusual acute severe episode of an illness of unknown
aetiology) constitutes an outbreak.
4.3. In places with established epidemic cycles, it may be worthwhile to
initiate necessary preventive measures and alert treatment centres in the
area in anticipation of a cyclic increase in cases. Similar precautionary
measures can be taken to minimize seasonal increase in cases.
4.4. States and districts should establish criteria on the number of
cases that constitute an epidemic based on their local situations.
4.5. Increase in the total number of cases does not, however,
necessarily indicate increase in the incidence of the disease. Variations in
the number of reporting sites, completeness of reporting, geographical
size of the catchment area and size of the population are factors that
must be taken into consideration while analysing reports.
5.
TRIGGER EVENTS FOR OUTBREAK INVESTIGATIONS
5.1. It is useful to have a short list of ‘warning signals’ which should
trigger an investigation. If personnel at the local levels are alert about
these signals and respond rapidly, it may be possible to arrest the
outbreak in the early stages when control measures are most effective
and can usually be undertaken within local resources.
5.2. It is important, however, that the list of such 'trigger events’ is kept
as short as possible so as not to divert resources from routine health care
services and control programmes. At the same time, an important
purpose of a surveillance system is to prevent outbreaks or detect them
in the early stage, and therefore the health personnel must be responsive
below in
to the warning signals. Some suggested trigger events are listed
1--------------
the Box.
5
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SUGGESTED TRIGGER EVENTS FOR OUTBREAK INVBSTIGATIONg^
clustering of cases/ deaths in time and space
unusual increase in cases or deaths
unusual increase in bacteriologically proved cases, even if total cases
are not increased
• patients older than 5 years of age with severe dehydration following
diarrhoea (usually accompanied with vomiting)
• acute febrile severe illness of unknown etiology
• acute haemorrhagic fever
• acute fever with altered sensorium
• acute flaccid paralysis in a child
• even one case of suspected plague
• even a single case of measles or any other epidemic prone disease
from a tribal or other poorly accessible area
• even one case of a disease which is not known to be present in an area
• shifting in age distribution of cases
• occurrence of two or more epidemiologically linked cases of meningitis
• unusual isolates
• high vector density
• disasters
_____
_
•
•
•
5.3. Intensified surveillance activities are recommended and health
personnel alerted in the event of the following:
•
•
disasters
high vector density detected by vector surveillance
unsatisfactory quality of water detected by water monitoring
unusual isolate detected by a laboratory from clinical/ environmental
sample
6.
FIELD INVESTIGATIONS AND ANALYSIS OF REPORTS
6.1
Verification of the Diagnosis
6.1.1. The first principle of outbreak investigation is to confirm the
diagnosis of as many reported cases as possible. Much time and effort
may be wasted due to misdiagnosis. The reported cases should be
investigated by a medical officer to confirm the diagnosis. The majority of
the cases are expected to fall within the standard case definitions. In
situations of doubt, whether an illness meets the case definition, a
second opinion may be sought.
6.1.2. Laboratory confirmation of clinically-diagnosed cases or
identification of the etiological agent may sometimes be necessary.
Under such a situation, samples should be collected carefully from a few
selected cases. It is not necessary to collect specimen from all cases
as it is not essential for the outcome of outbreak investigations and
control measures. Collection of unnecessary samples is discouraged as it
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places a heavy load on the laboratory and some tests are very expensive.
The types of tests, sample collection and transportation procedures have
been detailed in a separate module.
6.2
Epidemiological Features and Standard Case Definitions
6.2.1. It is necessary to know the clinical and epidemiological features of
the diseases to effectively investigate and control outbreaks. For easy
reference, the epidemiological parameters should be available in tabular
form.
6.2.2. Differential diagnosis of some of the important and common
clinical syndromes have been given in this document. Medical officers are
encouraged to expand the list and include other conditions prevalent in
their areas.
6.2.3. Standard case definitions are summarised in a separate module
“Case Definitions of Epidemic Prone Diseases” available from NICD.
6.3
Criteria for Investigating an Outbreak
6.3.1. After an outbreak has been confirmed, a decision must be made
and resources committed to investigate it, and to initiate follow-up
activities to limit its further spread. Specific interventions will depend on
the cause of the outbreak and mode of transmission. For example, if
dengue fever/ dengue haemorrhagic fever is suspected or confirmed,
vector surveillance and vector control activities should be taken up with
high priority. Vector surveillance* should be immediately undertaken in
some of the other high risk pockets even if no case has been reported
from the area. Similarly, if cholera is suspected, water quality monitoring
should be stepped up and the health facilities alerted. Specific
• suggestions have been discussed later in this module.
6.3.2. It is the responsibility of the local medical officer to arrange for the
treatment and follow-up of cases and contacts. It should be noted that
during an outbreak a higher percentage of more severe forms may occur.
Case fatality rate may increase due to ^litigating'factors such as high
malnutrition rates in young children or limited knowledge in the
community about the danger signs of severe illness. Precautionary
measures need to be taken and decide where and when to seek medical
help in a timely manner. For example, post measles pneumonia kills
many childrens. Mother must consult the health facilities whenever signs
and symptoms of pneumonia appear for proper treatment of cases. It will
only be possible if mothers know about signs and symptoms of
pneumonia i.e. increased respiratoiy rate and indrawing of ribs.
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6.4
Case-Finding Through Active Surveillance
6.4.1. After establishing the existence of an outbreak and verifying the
diagnosis, it becomes important to accurately define and count the cases.
During the period of the outbreak, all the cases of the disease under
consideration occurring in that area should be identified and listed.
6.4.2. Active surveillance refers to actively seeking out cases. This may
include visits or telephone calls to the medical facilities or private
practitioners that might expect to admit or attend cases of the disease.
Active surveillance through peripheral health personnel, personnel from
other government departments, NGOs and key community
representatives provides additional information about cases who may not
have been seen at government health facilities. Valuable information can
be obtained by contacting key community representatives, especially if
the outbreak is focal. Such information is useful in defining the extent of
the outbreak.
6.4.3. Suspect case definition may be used to identify cases. While it is
recognized that there may be some over-reporting of cases, it is
nonetheless important that no case is missed, especially if treatment is
available. Some of the epidemic prone diseases are amenable to simple
and cost effective treatment and case fatality rates are usually less than
1% if such treatment is applied early during the course of the illness (for
example, in cholera). In the absence of specific treatment, mortality rates
can be very high.
6.4.4. Depending on the disease and the resources available to
investigate the outbreak, it may even be desirable to conduct house-tohouse visits, especially in the homes of contacts of cases. In some
circumstances, community assistance may be enlisted for house-tohouse visits.
6 4.5. Completeness of reporting and relevant information on majority of
cases are important for determining high risk factors, complications an
mortality rates and health seeking behaviour as well as to further
understand the clinical pattern and epidemiology of the disease. The
information is also necessary to assess the quality of the national
programmes (if relevant).
6.4.6.
6.4.6. Active surveillance should be maintained until the outbreak is
' over. Developing a regular schedule of daily or weekly (depending on the
" urgency of the situation) visits or telephone calls to concerned
institutions or individuals will help maintain the flow of surveillance
information to those analysing the outbreak and directing control
activities.
8
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6.S
Line-Listing, Defining and Counting of Cases
6.5.1. It is important that information from surveillance be recorded in a
standardized manner. Persons who are ill and meet the case definition
for the outbreak disease should be entered onto what is called a "line
listing". This is a list of all reported cases with the relevant data on each
case which provides the basis for counting of cases. It is the data-base
on which the descriptive epidemiology of the outbreak can be made and it
can serve as the basis for other, more sophisticated, analytical
epidemiological studies, such as risk-factor analysis, vaccine efficacy, etc.
6.5.2.
6.6
The line list suggested for field use is shown in Annex-3.
Descriptive Epidemiology
In investigating an outbreak, it is necessary to provide a detailed
description in terms of time, place and person.
6.6.1. Cases by time
The onset of illness of the cases should be graphed by hours (for
example, in food poisoning), days, weeks or months, as appropriate. This
type of graph is commonly referred to as an epidemic curve. The epidemic
curve can be helpful in identifying the index (first) case or cases, and may
even suggest patterns or modes of transmission. During outbreaks,
analysis of cases by time will help to document the trend of the epidemic
and to monitor the effectiveness of the containment measures.
In case of endemic diseases, it is also useful to present previous
data on a line graph. Such graphs help to demonstrate the magnitude of
the outbreak compared to the previous reported incidence, rapidity of
spread of the disease and evaluation of control efforts.
6.6.2. Cases by place
A map of the area or even a rough sketch can be drawn showing
where each reported case resides to indicate geographical distribution of
cases and to identify high risk pockets. In some situations, serial spot
maps, by week or by month (or by disease generation) may provide
insight into the pattern of the spread of the disease over time.
Cases tend to cluster, and it may also be useful to mark affected
schools or other institutions on the map in addition to residential
locations. Such mappings may assist in identifying the sources of
infection.
Status of water supply, environmental and sanitary conditions, and
population density are important factors in the outcome of outbreak
investigations and control. These should be as descriptive as possible.
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6.6.3. Cases by person and population characteristics
Cases should be described in terms of age, sex, occupation, socio
economic parameters, migration, vaccination history and other relevant
characteristics.
It is usually sufficient to group cases by age-groups by 0-11
months, 1-4 years, 5-14 years, 15-45 years and > 45 years. However, in
the case of vaccine preventable disease outbreaks which usually affect
young children, grouping with smaller intervals will be needed such as
<1 year, 12-23 months, 24-59 months, 5-9 years, 10-14 years and > 15
years.
While preparing tables, the population characteristics should be
grouped accordingly. While calculating the age-specific attack,
complication or mortality rates, the proportion of the age group under
study to total population should be taken into account while calculating
rates.
6.7. Description of environmental conditions
The study of environmental conditions and the dynamics of its
interaction with the population and causative agents will help in the
formulation of hypothesis on genesis of the epidemic, which will make the
basis for the control measures to be taken. With respect to physical
environment, the data on rainfall, humidity and temperature are
available in the district meteorological centres. Information on natural
disasters like floods, cyclone, drought, earth quake etc., as available may
be utilised for the description of the epidemic. Man made situation like
developmental projects on irrigation and industries may create
environmental conditions conducive for disease transmission. Similarly
information on drinking water supply and environmental sanitation is
crucial for the investigation.
6.8. Additional steps during investigation of outbreaks of vaccine
preventable diseases
6.8.1. The determination of immunization coverage levels is crucial if the
outbreak is due to a vaccine preventable disease. The immunization
status in the community can be assessed through immunization
performance records available at the PHC. Percentage immunization
coverage is estimated by dividing the total number of doses (measles and
BCG) or third doses (OPV and DPT) of the vaccine administered to a
specific age-group by the total population of that age-group in the
affected village(s) or urban area. The data may be summarised for
example for OPV as shown below.
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Reported vaccination coverage for OPV
Year
Population
Estimated
No. of
infants
0 dose
Vaccination performance
1 dose 2 doses 3 doses
Booster
Percent
coverage*
* Percent coverage= No. given 3 doses x 100 / Estimated number of infants
6.8.2. The age-groups vaccinated should be fully assessed as inclusion of
older children may give a false sense of higher coverage. The
immunization activities, including periodicity of the immunization
sessions, quantities of vaccines received and cold chain system, should
be reviewed.
6.8.3. Information on immunization coverage may also be available
through past vaccination coverage evaluation surveys. If no such
coverage evaluation surveys have been performed recently, or if estimates
of immunization coverage by reports of doses administered are
unavailable or suspect, (a large number of vaccinations may be given by
the private sector and are not reported) then it may be useful to conduct
a coverage evaluation survey as a part of the outbreak investigation
which may also be used to estimate vaccine effectiveness.
6.8.4. Immunization status is an important descriptive as well as
analytical parameter. The immunization status of each case must be
carefully investigated to ascertain the number of doses of the vaccine
received by the patient. Immunization cards or immunization registers
should be checked to verify the immunization status. Verbal history
should be used only if such records cannot be obtained. Ideally, the place
of immunization should also be examined to assess quality of the cold
chain.
6.9. Laboratory investigations
6.9.1. The results of laboratory investigations should be listed in the
outbreak investigation report. Results of some tests can be obtained
locally and quickly. Such tests include water quality monitoring if a
water-borne disease is suspected.
6.9.2. Control activities and treatment of patients should not be delayed
pending laboratory confirmation of diagnosis. Action should be initiated
based on clinical, epidemiological and entomological findings.
6.9.3. Special emphasis must be placed
transportation and storage of clinical samples.
11
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proper collection,
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6.9.4. It is not necessary while submitting the preliminary report to wait
for the results of laboratory tests which have been sent to laboratories
outside the district and which may take sometime. The results can be
added in the final report.
6.10. Entomological investigations
6.10.1. Entomological investigations are an important aspect of field
investigations as a number of outbreaks are vector borne. Entomological
investigations are useful to confirm or rule out the probable cause of the
outbreak, especially if results of laboratoiy tests are not available.
6.10.2. High vector density is a warning signal as the risk of vector borne
outbreaks increases under such conditions. On the other hand, the risk
is low if the density is maintained below critical levels.
6.10.3. Vector control measures are expected to be applied under the
National Malaria Eradication Programme (NMEP). High vector density is a
reflection of the unsatisfactory field implementation and monitoring of
the above programme.
6.11. Determining Who is at Risk of Disease
6.11.1. The descriptive epidemiology will help to define the population
groups at high risk of disease in terms of age-groups, geographical
location, activity (school, mela, etc.), immunisation status and other
characteristics.
6.11.2. It is more appropriate to determine attack rates rather than
absolute numbers because rates take into account the variations in the
population size of different groups. Such rates are generally computed by
dividing the number of cases in a population group by the population size
of the same group.
Example: There are 45 cases of measles among 1100 children less than
5 years of age and 52! cases in 3400 children 5-14 years of age in the
affected town.
Attack rate =
45/1100 - 0.04 or 40 cases per 1 000 population less
than 5 years of age
Attack rate =
52/3400 = 0.015 or 15 cases per 1 000 population 5-14
years of age
6.12. Follow-up Visits
6.12.1. Follow-up visits after the outbreak has subsided are important
to make sure that late cases are not missed. Some of the diseases, such
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as measles, can lead to secondary infections in children. Post-measles
complications, most commonly diarrhoea and pneumonia, can occur at
any time up to six weeks after the onset of the illness. Prompt treatment
of these secondary infections can save lives.
6.12.2. The frequency and duration of follow-up visits will depend on
many factors and decisions will have to be taken at the local level. The
factors that will influence decision will be the severity of the disease, its
potential for spread to other areas, maximum incubation period and the
accessibility of the affected area to routine health services.
6.12.3. It is important to make follow-up visits to evaluate the control
strategy and to complete the documentation of the outbreak.
6.13. Documentation
6.13.1. Documentation of the epidemic is the last, but not the least step
in outbreak investigation. Important lessons can be learnt if the
documentation is complete and data properly analysed. The information
will be useful in drawing up long term strategies for reducing the risk of
the outbreaks in future and in more effective handling of the outbreak if
it were to occur. A suggested format for final report is given in at Annex4.
6.13.2. It is also important that the report is shared with the concerned
officers of other states and districts.
6.13.3. Publication of the report in a technical journal or newsletter will
ensure wider accessibility of the information to others who may be
interested.
6.13.4. The main findings of the outbreak should also be discussed with
the members of the rapid response team and the members of the inter
departmental committee.
7. HEALTH EDUCATION
7.1. Health education and public awareness and co-operation are
important to control an outbreak. If the community knows how the
outbreak spreads and what measures they can take in their own families,
the risks can be considerably reduced. It is also important that the public
should know if treatment is available and where to seek medical help. If
such information is available there is less likely to be panic and chaos.
Community support will also be more forthcoming. While the key
messages will essentially remain the same for all areas, the language and
style may need to be adapted to local needs.
7.2. It is suggested that action for preparation of health education
material and key messages is taken for epidemic prone diseases prior to
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an outbreak. This will allow enough time for the preparation and field
testing of the material. Some suggestions are given in the documents on
specific diseases.
7.3. It is particularly important to inform the public that most cases of
epidemic prone diseases can be treated with simple measures if
treatment is started in a timely manner.
\
+T-'
7.4. It is also important that the public and administrators are aware of
inappropriate measures so that much time and resources are not
diverted for measures which are ineffective. These include vaccination
and chemoprophylaxis for cholera and quarantine measures for most
infections.
8.
PREVENTION AND CONTROL OF AN OUTBREAK
8.1.
Water borne outbreaks
8.1.1. The risk of outbreaks of water-borne diseases such as cholera,
acute wateiy diarrhoea, viral hepatitis, shigellosis and typhoid fever can
be minimised and an outbreak can be prevented from spreading further
by taking measures for the following:
• provision of safe water
• adopting safe practices in food handling
• frequent handwashing
• sanitary disposal of human waste
8.1.2. The above steps are required both as long-term measures to
prevent cholera and other water borne diseases as well as measures to be
taken in a focal area where an outbreak is anticipated. Community
participation is essential to pre-empt an outbreak so that safe practices
are followed for storing water and for food handling.
SB SB:
t INEFFECTIVE MEASURES
_.
chemoprophylaxis
vaccination against cholera
travel and trade restrictions (cordon sanitaire)
8.1.3. Mass chemotherapy is not only ineffective in preventing the spread
of the disease, but it also diverts manpower and resources from effective
measures. In several countries, it has contributed to the emergence o
antibiotic resistance, depriving severely ill patients from a valuable
treatment. The value of selective chemotherapy of household contacts is
also doubtful. It is not recommended as a routine measure.
14
c- tJS\Outbreak.doc
8.1.4. Vaccines that are currently available against cholera do not have
high vaccine efficacy rates. In those who are immunised, protection lasts
for 3-6 months only.. Vaccination does not reduce the incidence of
asymptomatic infections or prevent the spread of infection. Vaccination
campaigns divert resources and manpower from more useful control
activities. No country requires travellers to have a cholera '
vaccination certificate.
‘
8.1.5. Travel and trade restrictions between countries or different areas
within a country do not prevent the spread of cholera. Majority of the
infected individuals have no symptoms. Setting up check-posts requires
massive inputs and diverts attention from other more useful control
measures.
8.1.6. An important objective of outbreak investigations is to reduce
mortality rates by early diagnosis and appropriate treatment. Case
fatality rates can be significantly reduced through effective therapy.
Specific treatment is not available for some diseases.
8.2
Vector borne outbreaks
8.2.1. Vector control measures should be applied as per the calendar of
activities to optimize impact. The control measures should be directed at
all stages of the life cycle of the vector.
8.2.2. The risk of vector borne diseases has increased in the urban and
peri-urban areas due to the changing life styles and industrial activities
which have made the surrounding environment more conducive for the
breeding of mosquitoes and other vectors.
8.2.3.The Aedes mosquito is a domestic breeder preferring clean water
containers. The cooperation of the community is imperative to control
mosquito breeding by taking simple precautionary measures. Regular
monitoring is essential to ensure that breeding sites are eliminated in a
timely manner.
8.2.4. The risk of some vector borne outbreaks increases in the presence
of animals or birds. For examples, pigs are considered to be amplifying
hosts of Japanese Encephalitis virus. Where piggeries have been
established, regular monitoring and periodic anti-vector measures are
indicated. The local pradhan and panchayat members should be aware
that if there is an acute case of fever with altered sensorium, the local
health authorities should be notified immediately.
8.2.5. Bubonic plague and visceral leishmaniasis are other important
vector borne diseases. In areas where leishmaniasis is prevalent or there
is a potential threat of leishmaniasis or plague, vector monitoring and
IEC activities are recommended.
15
C:\JS\Outbreak.doc
8.3
Food-bo me diseases
8.3.1 Food-bome diseases include food poisoning due to toxins produced
by micro-organisms (e.g. Staphylococcus aureus) and chemicals, as well
as food-bome infections (e.g. Salmonella infection). In fact, all the
waterborne infections (viral, bacterial and parasitic) can be transmitted
through contamination of food. Food-bome outbreaks are very common
in our country. Whereas in the past contaminated food processed in the
home exposed a few individuals, the food processed and distributed
extensively by the industry could result in the exposure of a large
number of people.
8.3.2 While investigating an outbreak of food-bome infection, efforts
should be made to interview all who are exposed for history of food
consumption and illness, if any. Rates of illness in those who did or did
not consume a specific food item are compared, and relative risk is
calculated for each food item. The implicated food would give the highest
attack rates, and/or the highest relative risk. In large outbreaks, a
sample of population may be interviewed, or the investigations may be by
case control studies. Food handlers and suspected food also need
attention during investigations.
8.4 Parenterally transmitted infections
8.4.1 Injections can transmit a variety of infections including HIV and
hepatitis B and C. Inadequately sterilized needles and syringes, sharp
instruments that penetrate the skin, and unscreened blood are common
source of parenterally transmitted infections. Appropriate sterilization of
needles (boiling for at least 20 minutes) and screening of all blood
donations for HBsAg, HIV, VDRL and malarial parasites will go a long
way in preventing these infections.
9.
PRECAUTIONARY ACTION IN HIGH RISK POCKETS TO WHICH
THE OUTBREAK CAN POTENTIALLY SPREAD
9.1. Alert health personnel and hospitals to report increase or
clustering of cases or deaths. All health facilities should maintain
records of patients seen, including OPD. Address of the patients should
be recorded. If there is a sudden increase in cases or clustering of cases
in an area, field investigations should be carried out and necessary
corrective action taken. An effective surveillance system can provide an
early warning signal and prevent outbreaks.
9.2. Ensure that the health personnel are adequately trained and that
the recommended guidelines are followed in the hospitals. If necessary,
orientation sessions or retraining may be organised. Early and
appropriate treatment can save many lives.
lv
C; \JS\Outbreak.doc
■
V
9.3. Arrange random checks for water quality for coliform organisms V p/V"
(faecal contamination). Special attention may be given to high risk
pockets. In places where water is found to be of unsatisfactory quality,
follow-up action may be taken with the concerned authorities for water a.*
supply. If feasible, chlorination should be carried out to render water 1
safe for drinking.
9.4. Health educational activities should be carried out in the
community to promote safe practices especially before the monsoons
when the seasonal increase of cases of water and vector borne diseases
can be expected.
9.5. Check that adequate stocks of essential supplies are available and
have been distributed to the peripheral health institutions well in
advance of the expected seasonal increase of cases, for example, ORS
packets should be available in all the health facilities. It is recommended
that adequate stocks of bleaching powder, chlorine tablets, IV fluids,
appropriate antibiotics and insecticides__£Lre in stock in case of an
emergency.
10.
SYNDROMIC REPORTING OF OUTBREAKS
10.1. Common syndromes
The monitoring of early warning signals and first reports will be
syndromic and diagnosis will be presumptive. These may include acute
cases of:
•
•
•
•
•
•
•
fever
haemorrhagic fever
fever with altered sensorium
diarrhoeal diseases
jaundice
flaccid paralysis
severe illness of unknown aetiology.
10.2. Acute cases offever
10.2.1. Clustering and sudden increase of acute cases of fever may be
due to malaria, dengue fever or other viral fevers. If the increase meets
the criteria of an outbreak, necessary clinical, epidemiological, laboratory
and entomological investigations must be conducted to confirm
diagnosis.
10.2.2. Fever with rash may be due to measles or chicken pox. Diagnosis
can be confirmed by typical clinical presentation, age group affected and
vaccination history (measles).
17
C;\JS\Ou (break, doc
10.2.3. Acute fever are caused by a variety of viruses. The type of virus
can be identified only by laboratory tests. However, the type of clinical
presentation and other epidemiological and entomological parameters
may help in presumptive diagnosis. Some of the diseases such as dengue
fever have a relatively small but distinctive form of severe forms such as
haemorrhagic fever and shock syndrome. The report of even a single case
of haemorrhagic fever from an area which has a reported increase of
acute fever cases compatible with dengue fever as well as a high density
of Aedes aegypti is a strong indication in favour of dengue fever.
10.2.4. Malaria is relatively common in our country. Any increase in
cases of acute fever from an area which has other conditions conducive
for the spread of malaria, requires that malaria is considered as the
cause of the outbreak.
10.2.5. Increase in the acute fever cases may be due to typhoid fever
which is also relatively common in many parts of the country. Patients
should be examined to see if the clinical presentation is compatible with
the case definition of typhoid fever.
10.3. Haemorrhagic fever
10.3.1 Cases of haemorrhagic fever are expected to be relatively rare and
few in number. It is therefore very important that notification by the
clinicians is made immediately by the fastest means of communications.
Investigation of the case of haemorrhagic fever may identify a dengue
fever outbreak. If a clustering of acute fever cases have been reported
and dengue fever is suspected on clinical grounds and entomological
investigations, a reported case of haemorrhagic fever from the area will
clinch diagnosis.
10.3.2. Haemorrhagic fever can also be caused by chikungunya virus.
The disease is clinically indistinguishable from dengue fever. However,
cases of shock syndrome have not been reported and case fatality rates
are low.
10.3.3. Severe forms of haemorrhagic fever with high case fatality rates
due to yellow fever and ebola fever have been reported from some
countries. There has been no report from India. However, epidemiological
conditions are conducive for the importation and spread of these
infections. Travel history or close contact with those who have recently
travelled abroad should be obtained if the above infections are suspected.
State and national authorities must be notified immediately by the fastest
routes of communication. Infection control precautions must be practiced
while investigating or treating patients, and handling infectious biological
material.
C:\cS‘.Qu tbrepk.doc
10.4. Fever with altered sensorium
10.4.1. Fever with altered sensorium (encephalopathy) may occur as a
result of complication of some diseases such as malaria, measles and
pertussis. Such complications occur in a relatively small proportion of
the cases. Even a single case of encephalopathy therefore reflects a
relatively large number of cases of the disease in the community. It is
probable that clustering of cases of acute fever have already been
documented through the routine surveillance system and report of a rare
but well recognized and documented complicated case further confirms
the cause of the outbreak. It is important that the clinicians are aware of
the need to report such cases immediately so that further field
investigations could be carried out.
10.4.2. One of the complications of malaria caused by P.falciparum is
encephalopathy. Since malaria is relatively common, the diagnosis of
malaria should be first considered. The diagnosis is confirmed if field
investigations indicate malariogenic conditions, illness is clinically
compatible and anti-malaria treatment is effective. The facilities for
making blood slides and examining them should be available at each
PHC.
10.4.3. A case of meningitis usually presents with sudden onset of high
grade fever, severe headache, stiff neck with or without altered
sensorium. Presence of nuchal rigidity and positive Kerning and
Brudzinski signs confirm the clinical diagnosis. Meningitis may occur
due to tubercular, viral or pyogenic organisms. A lumber puncture for
demonstration and/or isolation of organisms from CSF. A commercially
available latex agglutination test may provide the aetiology of some
agents of meningitis i.e. Streptococcus pneumoniae, Haemophilus
influenzae B, Meningococci A&C. It is noteworthy that meningococcal,
meningitis may occur in epidemic form.
10.4.4. Tuberculous meningitis is relatively common in many parts of our
country. Although large number of cases are reported, TB meningitis is
not expected to occur in the form of explosive outbreaks. Clinicians
must, however, keep in mind TB meningitis as a differential diagnosis,
especially if the patient is a young child.
10.4.5. Typhoid fever is usually characterized by gradual onset of
malaise, lethargy, headache, myalgia, loss of appetite and fever that
increases in stepwise fashion to reach 39-41° C in 5-7 days period. A
mental apathy and dullness is common and delirium may develop. At
this stage patient may present as fever with altered sensorium. Since
typhoid fever is very common in our country, it should always be
excluded by careful history, physical examination and blood culture for
S.typhi.
19
C:\JS\Outbreak.doc
10.4.6. JE infection is usually mild with no overt clinical symptoms or
mild fever with headache. However, the patient may present with signs
of encephalopathy. Usually not more than a few such cases (1-2) occur in
one village. These patients will give a history of acute onset with fever and
change in behaviour or sensorium lasting for more than 24 hours. Focal
neurological deficits may or may not be present. Disturbances of
sensorium are reflected as lethargy, somnolence, irritability, apathy or
loss of consciousness. The patient may develop difficulty of speech and
other neurological deficits like ocular palsies, hemiplegia, tremor and
ataxia. There may also be loss of bladder and bowel control. The focal
neurological signs may be stationary or progressive. In majority of the
cases, individuals develop immunity after infection. In endemic areas
cases are, therefore, seen more often in children under 15 years of age as
the adult population is already immune through natural infection. In
virgin areas, cases may be seen in all age groups. Patient should be
hospitalised immediately to reduce mortality rates. Cases are confirmed
by serology for JE antibodies and demonstration/isolation of
virus/antigen from CSF, brain tissue or rarely blood.
10.5. Acute cases of diarrhoeal diseases
10.5.1. Water borne and food borne diseases can present with a variety of
clinical symptoms. Acutcwatery diarrhoea in young children is the most
common problem. Cases occur throughout the year, with a seasonal'
increase in the monsoon and post-monsoon months. Focal outbreaks of
acute watery diarrhoea can occur. Such outbreaks have also been
reported following outbreaks of measles. Prompt action is important to
check the spread of the outbreak and to provide oral rehydration therapy
which is life saving. In the absence of ORT, high mortality rates have
been recorded. Death may occur within a few hours of severe episodes of
acute watery diarrhoea. The younger the age group, the more susceptible
they are to dehydration.
*
10.5.2. While diarrhoeal episodes may also occur in adults, these usually
do not result in severe dehydration or death. If cases of severe
dehydration or death following acute watery diarrhoea is reported in
patients older than 5 years of age, cholera should be suspected and
control measures at the field level should be initiated as per guidelines.
i
i
10.5.3. Outbreaks of dysentery can occur in children. Such outbreaks
have the potential of causing a large number of deaths unless specific
treatment is initiated in a timely manner. It is important that the
community and the peripheral health personnel are aware of the danger
sign of blood in the stools (bloody diarrhoea) so that medical help is
sought immediately.
20
\Oiilhie.ik.rlnr-
Acute fever
SYNt>RO«C«Ef»PRTWS‘OF OUTBREAKS
malaria
dengue fever
measles
influenza
other viral infections
plague
typhoid fever
Haemorrhagic Fever
dengue haemorrhagic fever
leptospirosis
chikungunya fever
yellow fever, ebola, hanta, lassa fever (potentially importable infections) **
Acute Fever with Altered Sensorium
falciparum malaria
apanese encephalitis
meningococcal meningitis
other meningitis (pyogenic, viral)
post measles encephalopathy *
pertussis encephalopathy *
Acute Diarrhoeal Diseases
acute watery diarrhoea in young children
acute watery diarrhoea in patients above 5 years of age with severe dehydration (suspected cholera)
dysentery (bloody dianhoea)
Acute Respiratory infections (Acute pneumonia)
influenza
leptospirosis
plague
anthrax
melioidosis
hanta virus
Jaundice
hepatitis E
hepatitis B & C (if focal with high case fatality rate) *
eptospirosis
yellow fever (potentially importable) **
Acute Flaccid Paralysis
poliomyelitis
i•
■J
Severe Illness of Unknown Aetiology_________
- relatively rare and cases may be few in number
** - not reported in India. If diagnosis is suspected, travel history and close contact with those who have recently
travelled abroad should be obtained.
21
C;\JS\Outbreak.doc
10.6 Acute Respiratory Infections (Acute pneumonias)
10.6.1. Acute respiratory infections leading to pneumonia are major
causes of morbidity and mortality in India, especially in early childhood.
They can be caused by a variety of microorganisms including bacteria,
viruses, fungi and parasites. Most of the pneumonias present as sporadic
cases.
10.6.2. Some diseases like plague, anthrax, leptospirosis, influenza,
melioidosis and hanta virus infection may result in severe outbreaks with
mainly pulmonary involvement. These may affect people from all age
groups. Even if a clustering of a few cases in older children and adults is
noticed, investigation should be initiated promptly for impending
outbreaks of these infections so that appropriate action for treatment of
cases and control of outbreak is promptly taken.
10.6.3. Patients with acute pneumonia usually present with acute fever,
chills, cough, chest pain, other non specific symptoms, varying degree of
respiratory insufficiency, and infiltrate on chest X-ray. In addition, there
may be haemoptysis and leukocytosis or leukopenia. Once pneumonia is
suspected, the specific etiologic diagnosis is necessary for proper
management to prevent mortality and reduce further transmission.
10.7. Jaundice
10.7.1. Although jaundice may occur due to many reasons, viral hepatitis
is responsible for the majority of cases with jaundice in our country. At
least 6 agents (HAV, HBV, HCV, HDV, HEV and HGV) can cause viral
hepatitis.
10.7.2. Feco-orally transmitted hepatitis E virus has been responsible for
virtually all the outbreaks of viral hepatitis in India. These outbreaks are
invariably linked to contamination of water supply. The expression of
icterus appears to increase with increasing age. There is no evidence of a
chronic form. A majority of Hepatitis E cases however, occur in young
adults. Secondary household cases during the outbreaks are uncommon.
The case fatality rate may reach up to 20% among those infected during
the 3rd trimester of pregnancy.
10.7.3. Recently, outbreaks of hepatitis B occurred in defined rural
communities of Gujarat, Haryana and Rajasthan states which were
epidemiologically linked to the use of unsafe injections by unqualified
medical practitioners. The outbreaks were marked by high case fatality
rates.
10.7.4. Acute viral hepatitis is such a sufficiently distinct clinical
syndrome that it usually poses no difficulty in diagnosis. Patient develops
nonspecific symptoms including malaise, weakness, anorexia, nausea,
vomiting, fever, and mild pain in abdomen. Soon, jaundice and dark
22
C:\JS\Outbreak.doc
urine follow. The duration of jaundice is variable, but usually lasts 1-3
weeks. These is dramatic elevation of ALT and AST (>8 times of normal),
and mild elevation of alkaline phosphatase (usually only 3 times of
normal). However, specific types of viral hepatitis in individual patients
can’t be distinguished on clinical grounds. The diagnosis is done by
serology.
10.7.5. Leptospirosis is emerging as an important cause of jaundice in
many parts of country. The disease is usually characterized by abrupt
onset of high grade fever, myalgia and conjuctivial suffusion. Rash is
occasionally present. If patient present with jaundice, renal involvement
and hemorrhage, leptospirosis should be strongly suspected. Meningitis,
pulmonary and cardiac involvement may also be present in some cases.
Unless treated promptly with antibiotics, it is marked by high case
fatality rates. The diagnosis is confirmed by demonstration of rising
antibodies, or isolation of leptospires from blood during acute illness and
from urine after the first week.
10.8. Acute Flaccid Paralysis
10.8.1. Poliovirus infection is the most important cause of acute flaccid
paralysis (AFP) in children. The possibility of polio should be considered
for any case of( AFP, even in areas with high OPV coverage levels and a
very low incidence of poliomyelitis. The diagnosis of paralytic
poliomyelitis should be discarded only after another diagnosis has been
established.
10.8.2. Acute paralytic poliomyelitis is characterised by fever followed by
abrupt onset of weakness or paralysis of limbs which does not progress
after first 3 days. Paralysis is not present at birth and is not associated
with serious injury or mental retardation. Typical findings on physical
examination include: acute flaccid paralysis, muscle tenderness, no
sensory loss, absent or depressed deep tendon reflexes, and
asymmetrical findings. Wasting of affected muscle is a late finding.
Residual paralysis after 60 days of onset of symptoms, or death or
unknown follow-up in an AFP case makes the presumptive diagnosis.
Isolation of wild poliovirus from AFP cases or contacts confirm the
diagnosis of acute poliomyelitis.
10.8.3. Paralytic poliomyelitis is most often confused with Guillain-Barre
syndrome (GBS), transverse myelitis, and traumatic paralysis due to
sciatic nerve injury. Traumatic paralysis due to sciatic nerve injury
following a misplaced gluteal injection can be differentiated by a careful
history and physical examination. Fever is usually absent in GBS and the
paralysis is symmetrical and distal. There are global hypotonia and global
absence of deep tendon reflexes. Cramps, tingling sensation, and hypo
anesthesia of palms and soles are usually present in GBS. Many cases of
polio have initially been diagnosed as GBS even by experts. Accordingly,
23
C:\JS\Outbreak.aoc
WHO recommends that stool specimens should be tested for poliovirus
on all cases of GBS less than 5 years of age.
Il '
c
A P ‘■ y
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C:\JS\Uutbreak.doc
Exercise 1
Koraput district was reported to be affected by an “outbreak” of acute
gastroenteritis (GE) in July-August, 1991. About 2270 cases and 413
deaths occurred during this period. Most of the cases had only diarrhoea
and vomiting.
Q.No.1.1.
How will you decide whether or not the district was in the
grip of an outbreak?
CA*—A’ ‘
{
b'
Table-1.1 describes the reported data on GE from the Koraput district
during 1988-1991.
Table 1.1
Cases and Deaths due to GE in district Koraput, 1988-91
(A
x,
______ Year_______
1988
1989
_______1990
1991 (upto August)
Q.No.1.2.
No. of cases
981 /
375 t 9 Ki
1387-| /
2380
No. of deaths
225
112
173
426
/%■
Now, will you consider it an outbreak of GE? If yes, why? If
not, why?
1
Analysis of the age distribution of 308 deaths revealed that about
9% of deaths occurred in children below five years of age and about 62%
of deaths occurred in adults above 20 years of age.
25
C:\JS\Outbreak.doc
Q.No.1.3.
Does it help you in suspecting cholera as the cause of this
outbreak?
Q.No.1.4.
What was the most disturbing features in this outbreak?
Was it preventable?
t x 7^'^
Rectal swabs from 59 cases were examined in the laboratories of
NICD, Delhi. 15 samples were positive for V.cholerae 01 biotype El Tor.
The isolates were sensitive to tetracycline, nalidixic acid, ampilcillin and
chloramphenicol, but resistant to furazolidone and streptomycin. The
other samples were found negative for any enteropathogens.
Q.No.1.5.
What are the possible reasons for 44 of 59 samples being
found negative for enteropathogens?
■■
,
,v_
z
■
-
L
Q. No. 1.6.
Assume yourself as the team leader for the investigation of
this outbreak, (i) How will you plan the investigations? (ii)
How will you control the outbreak?
0;
(■’
V-
tv)
C:\JS\Outbreak.doc
Exercise 2
W’Se19^ ‘r&S "c
epartment of PHC Galore, district Hamirpur, Himachal Pradesh Of
them, 101 were admitted in the PHC. Analysis of the data on clinical
features in the admitted patients revealed that they initially presented
with fever 100%), headache (74%), pain abdomen (18%), vomiting (17%)
li^X,15^o,/Onstipado2.(7%)> Palpable spleen (57.^ and palpable
liver (13 /o). Salmonella typhi was isolated in 10 of ~25 blood samples 6 c /
examined in the laboratories of Medical College, Shimlar "
' v
Q.No.2.1.
What makes this an ioutbreak
"
of typhoid fever? Comparable
data from previous years are not available?
Q.No.2.2.
If you want to organise a survey for active search of cases,
what case definition will you use?
be c (
^Cc cl
0
A line list of adrnitted cases was available in the primary health
centre Galore It provided information on name, age, sex, address and
date of onset of symptoms for all the 101 cases.
Q.No.2.3.
!l?Z_WiU y°U n113^86 1116 data? Prepare dummy graphs and
tables.
T7
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r
u
zf
. a ■
Co-'-v-,
A
4--
e
!
I
...
_______ ___ —-—
32X4..
, cx'/-
-rI . —
- ---------------------- —“
To /
IV
J "■
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i
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V"-
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---- P;
j 6 -/o
'JO^o /
po
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27
6. o
C:\JS\Outbreak.doc
Table 2.1 provides you data on admitted cases by date of onset of
symptoms.
c-
Table 2.1
Weekly distribution of admitted cases by week of onset of symptoms
Week ending
'
12.05.1991
2 18.05.1991
i,
25.05.1991
o 01.06.1991
08.06.1991
15.06.1991
upto 19.06.1991
Total
No. of Cases
0
4
16
41
25
12
3
101
*
J'V- Q.No.2.4.
Prepare epidemic curve using data given in Table 2.1
J
t
Q.No.2.5.
What type of epidemic curve have you got? How do you
interpret the epidemic curve?
[A
Tables 2.2 and 2.3 describe the cases by age, sex and village.
Table 2.2
Cases of typhoid fever by age and sex, PHC Galore
Age (years)
0-1
2-5
6-15
16-25
26-35
36-50
50 +
All ages
Male
0
2
25
18
2
5
0
52
Female
0
8
10
17
5
4
5
49
28
Total
0
10
35
35
7
9
5
101
C \JS\Outbreak.doc
Table 2.3
Cases of typhoid fever by sex and village, PHC Galore
Village
Lanjiana
Daswin
Pah al
Haiti
Ghirmani
5 other villages
Total
Q.No.2.6
Male
22
17
1
2
4
6
52
Female
31
1
2
3
0
12
49
Total
53
18
3
5
4
18
101
Using the data available in tables 2.2 and 2.3, can you
suggest a hypothesis for transmission of infection?
A marriage function was held in village Lanjiana on 16th May,
1991. The bridegroom belonged to village Daswin. Only males
accompanied the marriage party, whereas persons of both sexes
participated from bride’s side. During this function, water was used from
a Bawri fa local water body). Analysis of water from Bawri revealed very
high contamination; coliform count 1600/100 ml, faecal coli 275/100 ml
of water. Those who attended the function started becoming ill after
about 2 weeks. Contaminated water from Bawri was suspected as the
cause of this outbreak.
Q.No.2.7
Can you provide some alternative explaination for the
transmission of infection during the marriage function?
Table 2.4 describes the outbreaks investigated by NICD during 19701994. Most of the outbreaks were of GE/cholera and viral hepatitis.
Although typhoid fever is a major public health problem in India, only 2
outbreaks were due to typhoid fever.
29
C:\JS\Outbreak.doc
I
Table 2.4
Outbreaks investigated by NICD during 1970-94
No. of Outbreaks
41______
27______
13
_______ 9_______
_______ 8_______
6______
_______ 4_______
_______ 4______
Disease_________________
Cholera/GE_____________
Viral Hepatiits___________
Japanese Encephalitis
PUP___________________
Meningococcal meningitis
Malaria_________________
Polio___________________
Dengue fever____________
Smallpox_______________
Chickenpox_____________
Food poisoning
_______
Kala-azar_______________
Typhoid fever___________
Epidemic dropsy________
Vrial encephalitis________
Salmonellosis___________
Insecticide poisoning_____
Measles________________
Acute haemorrahagic fever
Plague_________ ________
Influenza_______________
Acute conjuctivitis_______
Herpes Zoster___________
Other/Unknown________
Total
Q.No.2.8
_______3______
_______3______
_______ 3______
_______ 3______
_______ 2
_______ 2______
_______ 2______
_______ 2______
_______ 2______
_______ 2
_______ 2______
_______ 2
_______ 2______
_______ 1______
_______ 1
7
151
Can you provide some explaination for a small number of
outbreaks of typhoid fever investigated by NICD?
r
I
<■
a
J
30
\JS\Outbreak.doc
t
Exercise 3
±0
j
Almost all the outbreaks of viral hepatitis in India are due to faecoorally transmitted hepatitis E. These outbreaks have been invariably
linked to contaminated water supply. An occassional outbreak may be
due to hepatitis A. Recently, a few outbeaks of hepatitis B
epidemiologically linked to unsafe injections have also been reported.
This exercise pertains to an outbreak of hepatitis E.
Residents of a locality in North West Delhi (SD Block, Pitampura :
population 1435) felt an unusal increase in the cases of jaundice in April,
1994. The block was inhabited by people belonging to middle or upper
socio-economic strata. All the residents had access to and used only
sanitary latrine. The Block had piped water supply. There was no other
source of water. The water supply was intermittent and did not fulfil the
requirements of people. The residents therefore, used on-line-booster
pumps to lift the water to their overhead tanks.
Q. No. 3.1.
How will you plan your investigation to (i) diagnose the
disease and (ii) select a suitable case definition to assess the
extent of outbreak?
(evx' U-d
^7 7v—-v1
r
Q.No.3.2.
<7
I
i
a.
^-7
A house to house survey revealed 27 cases of jaundice in
1435 population within a reference period of 3 months. The
attack rate of jaundice was found to be 1.9?/5-per ±009=population. Many outbreaks are on record where a varying
number of cases of jaundice (a few cases to many thousands)
occurred in a short period. 27 cases in SD Block were also
considered an outbreak. How could you have reached to this
conclusion?
*•
Q.No.3.3.
^0-9^AzC/
y
16 c c ■
> I
You found that most of the cases were due to hepatitis E
(laboratory findings). You suspect contaminated piped water
as the major factor in this outbreak. How will you
substantiate your suspicion?
Xc A
. Mt -31
J
C:\JS\Outbreak.doc
Q.No.3.4.
Were you dealing with an unusual clustering of hepatitis B
cases, how would you have planned to find out the mode of
transmission?
.1^
Q.No.3.5.
The outbreak in SD Block was due to hepatitis E. Using the
data already provided to you, can you speculate (i) why did
the outbreak occur at all? (ii) why was the outbreak not
explosive?
■
c‘
yz
-
\^
32
C: \ J \ r J ’ brea k. doc
Exercise 4
A patient from village Banyani (populatin 3403) came to the OPD of
PHC on 7.10.1991 with complaints of fever, headache, bodyaches and
chills. He also informed the medical officer about a large number of
cases having similar illness in the village, of whom many had died.
Q.No.4.1.
If you happened to be the incharge of PHC, what steps will
you take and why?
A team of doctors from the PHC surveyed the village on 8.10.1991.
They examined 756 persons. 696 (92%) of them were presently suffering
from fever usually accompanied with rigors and chills. None of them had
signs of meningitis. A medical specialist examined 63 patients of fever. 25
of them (40%) had spleen enlargement.
Q.No.4.2.
Will you consider this episode as an outbreak of febrile
illness? Do you need more information to reach at some
conclusion?
Q.No.4.3.
What was the most probable cause of this outbreak?
During the survey undertaken on 8.10.1991, 466 blood slides were
collected from fever cases. 81 slides were found positive for malarial
parasite (Plasmodium vivax 66, Plasmodium falciparum 15). The PHC
considered it an outbreak of falciparum malaria. District authorities were
33
\JS\Outbirak.doc
informed about the outbreak and a treatment centre was established at
village Banyani to treat the patients.
The state health authorities informed the National Instt. of
Communicable Diseases on 1.11.91 about the outbreak. The message
stated that a large number of fever cases and 21 deaths had occurred in
a village in district Farukhabad.
Q.No.4.4.
You do not have access to any other information except this
message. Will you include JE and/or dengue fever in
differential diagnosis? If yes, Why? If not, why?
NICD team visited the affected area during 1-3 November 1991.
The team collected the following data from the PHC.
(i)
2294 blood slides were collected in village Banyani upto 2.11.91.
325 were found positive for malarial parasite {P.faldparum 131,
/ •). P.vivax 194). About 40% of the positive slides were due to
P.falciparum.
(ii)
During the same period, 2184 slides were collected from other
villages of PHC within 5 kilometer of village Banyani. 208 were
found positive for malarial parasite (P.falciparum 36, P.vivax 172).
(iii)
Malaria situation in PHC in the last five years is shown in Table
4.1.
Table 4.1
Malaria situation in PHC Talgram, 1987-1991
Year
1987
1988
1989
1990
1991 (upto
September)
Slides positive for MP
Slides
collected
3170
5921
5822
7384
7233*
P.vivax
9
7
4
2
2
P. falciparum
0_
0_____
0_____
0_____
0 '
Total
9
7
4
2
2
* 948 slides still to be examined.
Note:- Population of the PHC about 2 lakhs.
34
C: \JS\Outbreak.doc
(iv)
19 persons
]
- ' due
'
died
to suspected malaria; 3 in August, 12 in
September and 4 in October.
Q.No.4.5
Why was this outbreak not detected in the "early rising
phase?
/
While going through the streets in village Banyani, it was observed
that a large number of residents were rolling bidies (local cigarette) in
front of their houses. On inquiry, it was found that bidi rolling and
agriculture were the main occupations in village Banyani and a few
surrounding villages. It provided the clue to the genesis of the outbreak
in the village Banyani.
Q.No.4.6.
Can you speculate on the gensis of outbreak of falciparum
malaria in village Banyani? It is noteworthy that District
Farukhabad did not report any case of falciparum malaria in
the last 3 years.
u
<
f , fr-
r '-
!
'-I''
rZ-—•
■
K"i-'
You have been given the responsibility to investigate and control
this outbreak.
Q.No.4.7.
How will you plan further investigations?
(Note:- See a related exercise in Module on Disease Surveillance)
35
C:\JS\Outbreak.doc
Annex 1
CHECK LIST FOR MODEL DISTRICT LEVEL LABORATORY FOR
DISEASE SURVEILLANCE
1.
The laboratory should be able to perform followings:
Microscopy:
diagnosis of
Rapid
presumptive Cholera
Tuberculosis
Diphtheria
Plague
Malaria
Filariasis
Meningitis
Bacteriological culture of
Stool especially for cholera
Bacteriological examination of
Water for coliform count
Rapid diagnostics for
AIDS
Meningitis due to meningococci,
pneumococci
H. influenzae
HBsAg (also for volunteer donors)
Syphilis
Typhoid fever
Non-ELISA based tests
2.
Laboratory should be equipped to collect, store and transport
specimens for following:
Stool, Blood/serum, CSF
Milk/food
vomtius
for various diseases including
arboviral diseases such as JE and
Dengue fever, Poliomyelitis, and
Measles
Samples from environment such as
soil
Laboratory should have the facilities to wash and sterilize
glassware etc. needed for collection and transportation of clinical and
environmental specimens as well as for separating serum from blood
samples.
3.
nV1'--'
36
C: \,1Su ibreak.doc
4.
Laboratory should have adequate inventory/or access to basic
material that may be needed for surveillance and investigation of
outbreak or to provide support in times of disasters.
5.
Standard operating procedural manual should be available with
the laboratory.
6.
Adequate staff members who are qualified and/or oriented/trained
for undertaking disease surveillance work.
7.
Sufficient stationery for maintaining the records and dispatching
the same to other centers.
8.
Laboratory should have access to electf-onic communication
network for rapid transmission of results and/or early warning signals.
i
cl
I
'I
i-
few—
•J
V >r'.t
37
C:\JS\Outbreak.doc
S.No,
I Activity
" -------------- ----------
1.
Yes/No
------ Sputum for tuberculosis bacilli
I
- -----------
CCir~---------
--
----- —Igggfgjgfepuium for piague bacilli
--------------- ----------------
2.
3.
----- smear for microfilaria^
"
‘
----- — tor meningitis organisms
—^°gilhe lab undertake bacterloli
logical examination of
—Faeces for cholera bacilli
~
——atQr samples for coliform count
_ _ nlv infection
__ Meningitis
_ "Syphilis
4.
5.
'
---------- ------------------ ------ -- -----------------------“
“——------------------ ------------------------------------------ -
_ .Australia antigen (HBsAgJ~
-------------- ------------------
_ Microscope
'
—------------------------- Centrifuge
~
____ ____ ________ ________
_ Refrigerator
--------------------------------Deep freezer (-20c)
----------------_ Balance
" - ---------- --------------------- --------pH meter
“— ----------------------------------Gas meter
------------------- --------Incubator
"
----------- -—---------- —________ _
Water bath
~——-------------- -Hot air oven
"
-------------- ----------- --------------I Does lab perform serological tests
------------------~_VDRL
Widal
Faso
6.
Any other
--------------
Jgchnicalstgff with qualification in lab medicina
T
_3_
Su| grtive staff with experience in lab
D
3.
38
C-'\JS\Outb—ak .doc
7.
8.
9.
10.
11.
12.
13.
14.
Does the lab has at any point of time followings
1.100 sterile glass syringes with needles___________
2.100 screw capped glass vials for blood collection
3.100 screw capped plastic vials for storage of serum
4.100 plastic/glass petri dishes_________________
5. Cary Blair transport medium (50 vials)___________
6.10 pairs of Gloves________________________
7._____________________________________
Are SOPMs available with the lab_______________
Does the lab has an access to NICNET/ERNET_____
Does the lab has a system of record storing which is:
Manual____________ _____________________
Computerised____________________________
Is there any periodic evaluation of working of lab
Is there a stand-by supply of electricity__________
If yes, what are the equipment which are on it
Does the lab has an inventory of regional and national reference labs
where samples can be sent:_________________________ ____
Does the lab participate in any external quality assurance scheme in
bacteriology/serology?
39
C:\JS\Outbrrak.doc
Annex 2
INTER-DEPARTMENTAL COMMITTEE
SUGGESTED AREAS OF RESPONSIBIUtY AND ACTION
District administration
•
mobilize resources by organizing meetings with
•
concerned government departments
•
non-governmental agencies
•
community leaders
•
ensure adequate quality monitoring of water samples
•
repair of leakage in water pipe lines
•
arrange safe water supply
•
ensure supplies of ORS packets and other essential items
•
ensure vector control measures
•
ensure adequate facilities for transportaion of serious patients to district hospital, if necessary
•
strengthening of existing provision under the Drug & Cosmatic Act to curtail over the counter sale of
parenteral dugs
•
provide relevant information to the press
•
monitor status of control activities
District Health Office I Municipal Health Office
•
arrange repair of leakage in water pipe lines
•
alert health personnel to report cases and to monitor trends
•
arrange active surveillance in affected area
•
ensure that treatment guidelines are followed in hospitals and other health facilities
•
ensure availability of ORS packets and other essential items
•
strengthening of existing provision under the Drug & Cosmatic Act to curtail over the counter sale of
parenteral drugs
•
ensure vector control measures
•
arrange health educational camps and distribution of health educational material
•
arrange chlorination of water sources if possible
•
arrange water quality monitoring
•
convene meeting under distrist adninistrator to seek cooperation of other government departments and
NGOs
•
check sterilisation practices of medical practitioners for syringes, needles and sharp instruments
Concerned Department (s) responsible for water suppy
•
repair of leakage in water pipe lines
•
arrange potable water supply, including water tankers if necessary
•
arrange chlorination of water
•
ensure water quality monitoring
Other government departments such as social welfare, education, tribal welfare and NGOs
•
dissemination of relevant information
•
promotion of oral rehyckation therapy
•
ensure vector control measures
•
check sterilisation practices of medical practitioners
•
reporting of cases
Panchayat members, village pradhans, community leaders
•
dissemination of relevant information
•
promotion of oral rehydration therapy
•
ensure vector control measures
•
check sterilisation practices of medical practitioners
•
reporting of cases
•
monitoring chlorination of water sources such as wells
•
arranging transportation of serious cases to hospital
40
C:\JS\Outbrcak.doc
Annex-3
SUGGESTED FORMAT FOR LINE LIST OF CASES
SI.
No.
Note:-
Name of Patient Father’s/
Husband’s Name
Address
Age
Sex
Date of
Symptoms
Onset of
symptoms
Outcome
of illness
(still ill/
recovered
/ died)
A column on immunisation status should be added for vaccine preventable diseases.
41
C:\JS\Ou (break.doc
Annex 4
OUTBREAK INVESTIGATION REPORT
General Information
State
District
Town/PHC
Ward/Village
Population
Background Information
Person reporting the outbreak
Date of report
Date investigations started
:
Person(s) investigating the outbreak
Details of Investigation
Describe how the cases were found (may include: (a) house-tohouse searches in the affected area; (b) visiting blocks adjacent to the
affected households; (c) conducting record reviews at local hospitals; (d)
requesting health workers to report similar cases in their areas, etc.):
Descriptive Epidemiology
•
•
•
Cases by time, place and person (attach summary tables and
relevant graphs and maps).
Age-specific attack rates and mortality rates
High-risk age-groups and geographical areas.
Descri-ption of Control Measures Taken
42
C:\.JS\Outbreak.doc
Description of Measures for Follow-up Visits:
Brief Description of Problems Encountered
Factors Which, in Your Opinion, Contributed to the Outbreak
Conclusions and Recommendations
(Name and Designation)
Date
4*3
C:\JS\Outbrrak.doc
_Dis Ut-.G
5
DISEASE SURVEILLANCE
AT DISTRICT LEVEL
A LABORATORY MANUAL
22 SHAM NATH MARG, DELHI - 110 054
|
f
&0ntents
1.
Role of Laboratory in Disease Surveillance
2.
Collection, Storage and Transportation of
Specimens
3.
Disinfection and Sterilization
4.
Microscopic Examination
a.
Serological Tests
6.
Bacteriological Analysis of Water
!
Laboratory Diagnosis of Cholera
8.
Safety Precautions in Laboratory
9.
Common Laboratory Equipment
I
CHAPTER- 1
1.
ROLE OF LABORATORY IN DISEASE SURVEILLANCE:
Epidemiological surveillance of a disease is tlie continuing scrutiny of all aspects of
the occurrence and spread of a disease that are pertinent to effective control. It is a dvnamic
process involving the infectious agent, host, reservoirs, vectors and the environment as well
as a complex mechanism concerned with the spread of infection and the extent to which
spread has occurred. Surveillance of any particular disease includes systematic collection
and evaluation of morbidity and mortality data, reports of investigation of epidemics,
laboratory investigations to find out the causative agent, use and untoward effects of
biologicals, insecticides and other materials used in control, assessment of immunitv status
of population and other relevant data for action. The introduction of laboratory techniques
in epidemiological services has revolutionised the concept as well as scope of disease
surveillance. Now a days laboratory support is considered an integral component of a
sensitive system of surveillance.
Role of Laboratory services in surveillance:
1.
Diagnosis of a syndrome
o
Encephalitis
o
Hepatitis^ . ■ ’
■
o
o
Pyrex^rMnknown origin
■,:Vt
2.
Tracing ffi^^^^SKihfection.
o
3.
4.
5.
Epidemiological markers
Detection of inapparent infections/carriers.
o
Japanese Encephalitis
o
Typhoid fever
o
Meningococcal meningitis
Early detection of outbreak:
o
Meningococcal meningitis
o
Hospital infections.
Retrospective diagnosis.
o
Rheumatic heart disease
o
Subacute sclerosing panencephalitis
o
Nephrotic Svndrome.
1
6.
7.
8.
9.
10.
11.
12.
Detection of New Disease Agents
o
HIV
o
Newer Enleropathogens ( V'. ('ItoJcnic )
Monitoring of treatment
o
Antibiogram
o
Sero-Therapy.
Quality Control of Biologicals
o
Vaccine potency testing,
o
Vaccine Safety studies
Prevalence studies
o
Sero-surveys
o
Immune status
Find out natural foci of infection
o
Plague
o
Leptospirosis
Controlled field trials.
o
Newer drugs/ vaccines
o
Newer regimens of drugs/ vaccines
. Key to successful laboratory based surveillaiice lies in :
i
1.
Right sample collection.
2.
'Right time to collect samples for disease surveillance.
3.
Right methodology to be followed for transpoi lalion of sample.
4.
Right laboratory to be chosen so as to get prompt
5.
Right interpretation of lab. Results.
and correct results
t'
Identify right patient
Order relevent tests
Collect appropriate specimens of good quality
Label appropriately
Transport to laboratory in unchanged state
Properly accession in laboratory
Perform accurate and precise analysis
Document and report
Interpret
Tlhiely ullIoh uh ngiiL puueii l
13.
Networking of laboratories
'ri
1i
Central or National Reference Laboratory
if
*
i
i
Regional Referral Labs
Regional Referral Labs
District Labs
District Labs
I
Regional Referral Labs
District Labs
__ ZJ__
Peripheral Lab
Peripheral Lab
l
Peripheral Lab
l: Networking of Inboralorics
‘•A
13
Proposed strengthening ol ilistrict level laboratories under NDSP
PERIPHERAL LABORATORY
These laboratories are located al the point of first contact of patients with the health
care service's. In most ol the' de'veloping, countries these are available only al primary health
centre or community health centre (upgj-aded primary health centres).
These laboratories
provide technical support for preventive, curative and promolive services for the individual
as well as the community.
S/H//
The staff in peripheral laboratories should include one technic ian and one laboratory
assistant/attendant.
Space
Space available in peripheral laboratories should include at least one laboratorv-cumoffice/record room (lo ft xlO ft) and one store-room combined with other services (16 ft xlO
ft).
Other facilities
Other necessary facilities include
a supply of safe water,
a reliable source of energy (battery, electricity, solar or
kerosene) and
sterilization facilities and waste deposit
There must also be transport and communication facilities between the peripheral and
intermediate laboratories for referral of samples and patients, procurement of supplies and
personal discussion.
Equipment and supplies.
Necessary equipment and supplies include: good microscopes,
centrifuges, transport media, glassware, sterile swabs, reagents for staining (eg. Gram,
Albert, Ziehl Neelsen, Romanowsky), kits and reagents for rapid diagnostic tests, sterilized
syringes and needles, micropipettes and tips as well as
sterile collection bottles for
blood/ serum and water analysis.
Tests to be performed
These laboratories are expected to undertake tests of public health
as well as clinical
relevance. Amongst the tests of public health relevance, diseases of greater epidemiological
importance should be accorded priority'. Testing of environment samples (especially water'
also falls into the priorities of public health relevance. Certain serological tests mav be of usin studying epidemiological pattern of the important diseases and the same can be
performed at peripheral laboratories (Table 1)
■j
I
Fable 1
Suggested microbiological tests at district laboratories
Procedure/Specimen
D i s ea s e/O rga n i s m
Microscopy for stained smears
(Gram, Albert,Ziehl Neelsen)
Nasopharynx and throat
Diphtheria, Vincent's angina
Sputum
Tuberculosis, pneumonia
CSF
Meningitis
(pvogeixic & tuberc’ilosis)
Urethra/vaginal discharge
Gonorrhoea
Stool
Cholria/dyscnleiy
Culture
Cholera
Serological tests
Enteric fever (Widal)
RPR/VDRL
Brucella (l ube agglutination)
Dipstick and Particle agglutination test
MBsAg, HIV
Bacteriological analysis of water
As far as possible, these tests should be reliable, sensitive, specific, rapid, easy to perform
and cost effective.
I
CHAPTER - 2
I
COLLECTION, STIORAGE AND
TRANSPORTATION OF SPECIMENS
CHAPTER- 2
2.
COLLECTION, STORAGE AND TRANSPORTATION OF SPECIMENS:
***[ Inventory of labs to be added ]
2.1
Effective diagnostic microbiology depends upon the correct collection and timing of
clinical specimens and their proper transport to the laborarcry under optimal conditions. It
has been observed that most important and frequent source affecting laboratory analysis is
collection and transportation of the specimen. The guidelines for it must be emphasized.
o
Specimen should be in adequate quantity.
o
Specimen must be collected before the
administration of antimicrobial agents.
2.2
o
Contamination of specimen with externally rrssent organisms or normal flora
of body must be prevented.
o
Specimen must be collected at appropriate szzre ?f the disease.
o
Specimen should not get contaminated durinz storage.
o
Specimen handling should not be risky to individual and/or community'.
Some of the essential precautions which need to be fzdiwed are as follows:
o
Apply strict aseptic techniques throughout th
o
WasKTiands^Before and after the collection.
o
Collect the specimen at the optimum time.
o
Make certain that the specimen is representazve ?f infectious process (e.g.
sputum is the specimen for pneumonias and r.:: saliva) and is adequate in
quantity for the desired tests to be performed.
o
Collect or place the specimen aseptically in ar. appropriate sterile container.
o
Ensure that outside of specimen container is :_z=n and uncontaminated.
o
Tightly close the container so that its contends i: not leak during
transportation.
o
Label and date the container, complete the reziisition form.
o
Arrange for immediate transportation of specnr.cn to laboratory.
rocedure.
1
I
2.3
Laboratory specimens required for tests for particukir causative agents:
I
Suspected agent/
Specimen
Test
Blood or brain (-70' C)
Isolation
Blood or serum (+4‘'C)
Serology
Rectal swabs or stool
Culture
disease
Arbovirus infection
Cholera
specimens in transport
medium, as recommended
by the laboratory.
Gastroenteritis
Stool
Culture, ELISA*
Viral Hepatitis
Serum (+4(’C)
ELISA*
Legionellosis
Blood, sputum, in
Culture/ FA**
enrichment broth.
Malaria
Blood (thick and thin smears)
Staining
Meningococcal meningitis
Spinal fluid, blood,
Latex agglutination test
Plague
Bubo fluid, blood
Staining, Culture/ FA**
(in broth or on slants)
Typhoid
Blood in enrichment broth
fever
(early in disease); serum
Dysentery
Faecal specimens
Cui tun'; serological test
Culture/ m ic rosco p \
or rectal swabs in
enrichment broth.
Syphilis
Blood/ serum
Enzyme linked immunosorbent assay
** Fluorescent antibody test.
VDRL/ RPR
Because of alterations in the specimen prior to measurement, the clinical state of the patient
will not be necessarily reflected by the result of the laboratory investigation despite the
correct laboratory performance. Some of the important specimens and their proper
collection and transportation methods are described here so as to ensure quality'.
2.4
Blood for serological testing:
Blood is the most important and frequently collected clinical specimen at district level.
Blood should be drawn using sterile (preferably disposable) syringes and needles. Quantity
of blood drawn should be minimum 4-5 ml. Vial in whrch blood is collected should be
preferably sterile, dry and properly labeled. The needle and syringe used, as also the vial,
should be completely DRY before collecting blood. After drawing blood, the needle should
be removed from the syringe before transferring blood from syringe to the vial. Do not
shake the blood that is collected in the vial. Let it stand undisturbed at room temperature
for 2-4 hours. After the blood has stood at room temperature for 4-6 hours, it should be
subjected to the process of serum-separation. If the facilities for separation of serum are not
available, then it should be refrigerated at 4L'C (NOT FROZEN).
Using a sterile Pasteur pipette, dislodge the retracted clot from the liquid portion of
blood, transfer the liquid portion into a clean sterile centrifuge tube having a rubber cork.
Centrifuge at 500g for 5 minutes. Transfer the supernatant!serum) using a sterile
Pasteur pipette kito ste'rile clean, dry plastic disposable screw capped vials. Label the vials.
2.4.1
Filter paper method of collection of blood:
Transportation of liquid specimens soaked on filter paper is a simple and safe
procedure. All kinds of body fluids can be absorbed onto filter paper strips (Whatman
No 1) Cards with incorporated filter paper strips having marked circle (usually 3 cm
diameter) are commercially available. The details of the patient are written on the card with
a ball-point pen. The blood is taken from the finger prick or heal prick of an infant. The site
is cleaned with 70% alcohol and wiped dry with sterile gauze. Puncture is made with a
sterile disposable lancet and the first drop of blood is wiped away with sterile dry gauze.
Filter paper (marked area ) is gently touched onto the second drop of blood and allow
the blood to soak till the premarked area is completelv filled. Punctured site should not be
squeezed to prevent any haemolysis, Blood is applied only on one side of filter paper and
once only.
The blood specimen is dried for 3 hours in the air in a horizontal position without
letting the specimen come in direct contact with any surface, direct heat or sunlight. These
samples should not be refrigerated.
The specimen is placed in a plastic bap, or an envelope along with few granules of a
desiccant and sealed hermetically before transpoi la I ion or mai’in-’. H stored in a cool and
dark place, such specimens give acceptable results even upto thT-.-. months.
( For collection of stool, CSF , .aspirates and water, see in ’
2.5
\ ant chapters )
Labeling of Specimens:
After collection of specimen, it should In' immediatelv lalx-txi and case investigation
form should be filled up and should accompany each specimen. 1 he specimen shoukl be
kept cool preferably at 2-8‘’C and sent to laboratory as early as }x>S'ibIc. in case of delav th^
sample should be stored at 2-8l’C before transporting to nearest labcratory.
Labels for specimen collection vial
Name.
Age.
Specimen No.
Specimen
Date
2.6
Fime
Storage and Transportation:
In general, infectious materils should be kept at a low ten'rerature during storage
and transport, except the CSF samples collected from cases of py 'genic meningitis which
should be maintained at room temperature. Fhe types of rcfrigcT2tion required to achieve
various temperatures are as follows:
Temperature (°C)
Type of refrigeration
(+)2-8
Domestic refrigerator
(+)4
Wet ice or frozen ice packs (cold bags)
(-)8
Freezer of domestic refrigerator
(-)20
Freezer cabinet
(-)70
Deep freezer or dry ice.
(-)160
Liquid nitrogen
The quantity of pathogens or antibody in original clinical samples can decline during
storage or transportation which seriously affects the diagnostic results. Hence special care
should be taken before or during transit of materials to laboratory to protect them from
heating or drying.
Precautions
o
Repeated thawing and freezing of specimens
should fe avoided.
o
Freeze the specimen only if transport to
District/National/Reference Laboratory is
assured at -20°C.
Recommendation - Store and transport all specimens at 2-8;C (Lower Compartment of
refrigerator) except CSF.
For Transportation of specimen
o
wet ice or ice pack should be used.
o
Specimen containers relating to single case investigation should be placed in
a plastic bag with an absorbent material surrounding the specimen so that
even if whole specimen leaks out, it will be absorbed.
o
The laboratory report form should be sealed within a separate plastic bag and
wrapped round the specimen or attached firmly to the box of specimens.
o
The material should be packed in an insulated carton/carrier to transport a
specimen to the laboratory.
o
All specimens should be considered as potentially pathogenic and
accordingly labeled with internationally accepted biohazard label.
Transportation of Virus Lsolatcs/Spcciinen to Reference Laboratory:
Specimen virus isolates to be sent to other laboratories require special attention for
packing of the material and strict guidelines for transportation ol samples should be
followed.
CHAPTER - 3
DISINFECTION AND STERILIZATION
•
'
I
CHAPTER- 3
3.
Disinfection and Sterilisation
Definition:
Sterilisation implies complete destruction of all living micro-organisms including spores.
Disinfection means destruction of vegetative forms of organisms which might cause disease
or spoilage of food etc. It does not necessarily kill spores. The two terms are not
synonymous.
3.1
Disinfection of used laboratory articles
Disinfection of both reusable and disposable glassware and articles contaminated
with morbid or culture material is of utmost importance in the laboratory. All the specimens
received in the laboratory should be considered as potentially pathogenic. Tire ideal method
of treating such materials is to incinerate all the disposables and decontaminate the reusable
articles by autoclaving. These facilities may not be available in every laboratory. For
purpose of disinfection, disposal and recycling, all the articles may be divided into three
categories.
3.2
o
Disposables.
o
Reusable articles contaminated with morbid material such as pipettes, slides,
test tubes etc.
o
Material containing or contaminated with
bacterial cultures.
Disposables:
Soak the material overnight in a strong solution of disinfectant before disposing alongrvitii
garbage; 1% sodium hypochlorite, 10% solution of formalin or 3% lysol may be used as
disinfectant.
3.0
Reusable articles contaminated with morbid material:
Discard the articles into a jar containing solution. Let them remain in this solution
overnight. Drain off the disinfectant. Transfer the material to a metal pot or tray with cover.
Pour water and boil for 15 minutes. Cool and drain off the ’.vater. Pass on the articles for
washing.
3.4
Glassware containing culture material
4
(
Discard all the articles containing or contaminated with culture material directly in a
metal box or a bucket. Place the box with material in the autoclave and decontaminate b\
autoclaving (see sterilisation).
i
Drain off culture medium and pass for washing.
i
3.5
1
Disinfection of rooms
Seal all the windows, ventilators and tin* plat vs with brow n paper and adhesive tape.
Pour 500 ml of formalin and 1000 ml of waler in a pan or tray and boil u ilh the help
of a spirit lamp or a bunsen burner. Spirit in the lamp should be just sufficient, to boil off the
formalin and the lamp extinguishes when there is a small quantity of liquid left in the pan.
i
Seal the door.
Open the door, next morning and spread a piece of lint soaked in ammonia on I
table. This will neutralise excess of formalin present in the room.
I
3.6
Washing of laboratory glasswares:
3.6.1
New glassware
Usually new glassware are slightly alakline.
neutralized. The method is as follows:
3.6.2
Before washing these have to be
o
Prepare a 2% solution of hydrochloric ar id in a big basin.
o
Soak the new glassware in this solulion lor one' day.
o
Rinse twice with clean water and once with demineralized water and dry.
Dirty glassware:
o
Rinse twice in lukewarm or cold water otherwise serum or blood may stick to
them and may not be washed.
o
Put the glassware in a bowl containing detergent solution and scrub the inside
with a brush. After scrubbing soak the glassware in this solution for 2-3
hours.
o
One by one, take out the arhi les and rinse under running. Lip w.iler. then put
all the glassware in a container containing lap water (no trace ot detergent
should be left otherwise this may lead to false results).
■««v-:.
3.6.3
3.6.4
3.7
o
Drain the water by putting each articles on a wall draining rack.
o
Place the articles in a wire basket and drv in a hot air oven at 6O0C.
o
Plug each article with non-absorbent cotton wool or aluminium foil and
store in a cupboard to avoid dust.
Pipettes:
o
Immediately rinse in running tap water to remove blood, urine, and serum
reagent, etc.
o
If the pipettes were used for infected materials, soak them in cylinder full of
disinfectant solution (2% dettol or 2% phenol) for 24 hours'otherwise place in
a large measuring cylinder full of water.
o
Soak in detergent and rinse as in case of dirtv glassware.
o
Incase the pipettes are blocked put them in dichromate solution for 24 hours.
Next day clean under running tap water, check individually, rinse for a
number of times.
Syringes and needles: '.
o
Immediately after use remove the plunger and rinse the barrel and plunger.
Syringe water through the needle forcefullv. Finailv remove the needle.
o
If the piston is blocked, either soak the syringe for 2 hours in hot water or
pipette with the syringe standing on its end. piston down. Alternativelv soak
the syringe in a container of 10 vol hydrogen peroxide.
o
In case of block needles use the stvlet to remove the bock.
Methods of sterilisation
The common methods of sterilisation used in a microbiology* laboratory* can be
broadly divided into three categories depending upon the materials to be sterilised.
o
Drv heat.
o
Moist heat.
J
o
3.7.1
Filtration.
Dry heat
The two commonly used methods of sterilisation by dry heat are:
(a) Red heat or flaming
(b) 1 lot air sterilisation.
3.7.1.a
Red heal or flaming
Instruments such as inoculating loops and searing irons are sterilised by this
technique. For sterilisation of inoculating loop, hold the loop vertically on the blue cone of
the flame for few seconds and slowly raise upwards till whole of the wire is red hot. Move
the loopholder rapidly downwards through the flame so that sevei il inches of the Io
holder is also heated-slightly.
3.7.1.13
1 lot air sterilisation
Items to be sterilised:
•3
Ibis is the best method for sterilisation of dry glasswares such as test tubes, flasks,
pipettes, pertidishes, assembled all glass syringes, throat swabs and other sealed materials
which can withstand hipji temperature and where penetration bv sleamis not possible.
Sterilisation by hot air can be conveniently carried out in an electrically heated oven.
A themostat is fitted to control the temperature. Larger units should be fitted with an air
circulating fan to ensure uniform temperature in the different parts of the oven.
(Add.: Preferable methods of sterilization)
CHAPTER - 4
MICROSCOPIC EXAMINATION
CHAPTER- 4
4.
MICROSCOPIC EXAMINATION:
In a peripheral laboratory, microscopic examination can provide rapid and
economical presumptive diagnosis which may have significant bearing upon control and
prevention strategies.
4.1
Cleaning and storage of Microscope Slides:
4.1.1
Cleaning of new slides
o
Soak the slides in a vessel containing soap water
olution for a few hours.
o
Place the slides either in running tap water or
several changes of clean water for few hours.
4.1.2
4.1.3
o
The slides should be wiped dry using a dryz clean, lint-free cloth.
o
Always handle the cleaned slides by the edges to avoid finger marks.
Cleaning of used slides:
o
Soak the slides for at least 60 minutes in 1-2% hvpo-chlorite solution.
o
Wash in hot soap water scrubbing both the sides with the brush, taking
particular care to wash only a few slides at a time to prevent scratching.
o
Clean the slides individually with gauze or cotton wool.
o
Transfer the slides to a fresh detergent solution.
o
’.Vash in running tap water or several changes of clean water.
o
Wipe drv with a clean lint free cotton cloth.
Storage of Slides
o
Initially, after washing and cleaning, the slides should be kept in a drv place
or a warm air cabinet.
o
Thereafter slides should be stored in packages of 10 which should be wrapped
in thick paper and secured with adhesive tape or rubber bands.
4.2
Microscopy for Pyogenic Meningitis:
Pyogenic meningitis is an acute bacterial infection of the meninges, commonlv caused
in epidemic form by
Neisseria
nieniii^ilidi^,
^Ireidm oet ns f’lieuinaiiiae and
I hieiiiophihis
influenzae.'
For the laboratory confirmation of the diagnosis, the following clinical specimen
should be collected.
4.2.1
Cerebrospinal I'kiicl (C SI')
CSF following lumbar puncture should be collected in 3 separate clean sterile
containers (Bijou bottles) for following investigations:
o
Biochemical analysis
o
Cytological examination
o
M icrobiologicaI tests
General guidelines for collecting CSF
o
CSF should be collected before the start of
chemotherapy.
4.2.2
o
Never refrigerate or expose it to sunlight, and transport immediately to the
laboratory.
o
In case of delay in transportation, keep CSF at 37'C.
o
Other clinical samples which can be collected are blood and petechial fluids.
Examination of CSF
(a)
Macroscopic:
I ,ook for the presence of turbidity, blood or coagiilum.
Cytologic examination to be done only when there is no coagulum in the C SF.
Material Required:
Neubauer's counting chamber, WBC diluting fluid, WBC pipette, compound
microscope.
The cell count should be done by the usual procedure of WBC count using a
Neubauer's chamber and count the number of leukocytes per cmm of fluid.
•
The normal CSF should be absolutely clear, free of any coaguium and should not
. contain more than 0-8 lymphocytic cells/cmm.
'
In pyogenic meningitis, appearance of CSF is turbid and contains more than 8-10
leukocytes/cmm, the cells being predominantly polymorphs in nature.
(b)
Microbiological examination:
* MiS&scopy
’
*
Microscopic examination is required to directlv visualise the causative organism in *■
the CSF. ’
Requirements:
■>r;-
O
Clean slides
'>r
SW-
o
Coverslips
o
Table top Centrifuge
o
Centrifuge tubes
o
Pasteur pipettes
o
Clean oglass vials
o
Reagents of Gram's staining.
o
Rubber teats
o
Discarding jar
o
Neubauer Counting chamber
o
WBC pipette.
-5f-
>
Procedure:
Transfer about 1-2 ml of CSF in a sterile Centrifuge
lube.
Centrifuge al 30()() rpm for 5 minules.
Keep the supernatant fluid for Latex Agglulination
test.
From the deposit, make smears on 3 ( lean glass slides and air dry.
In case of a clotted CSF, transfer 3 small pieces of clot on three different glass slides.
Tease the clots using needles or wooden sticks or the edge of the slide and after
spreading make the smears. Air dry.
In case of scanty CSF, several drops of CSF should be placed at one particular spot on
the slide, each being allowed to dry before the next is added. Air dry and heat fix
the smear.
Stain the smears by Gram's staining method as given in Annexure.
Examine under microscope under oil immersion.
Observations:
Presence of Gram negative bean shaped diplococci, both intracellularand
extracellular suggests the presence of Neisseria nieuiu^itidis (Meningococcus).
Other organisms which can be seen are Strcjdococciis luieiiuioutnc (Pneumococcus),
which appear as gram-ositive diplococci, Hacuio]ihilus influenzae which appear as
gram negative thin filaments rods.
Cram negative diplococi i
4.3
Diagnosis of Pulmonary tuberculosis by sputum examination:
o
Tuberculosis is a disease of great public health importance caused by A li/(vbiictcnmii
tuberculosis and some other species of Mycobacteria.
o
The diagnosis of pulmonary tuberculosis can be established bv demonstrating the
bacillus in the sputum of the patient by microscopv.
4.3.1
Sputum collection:
o
Collect the sample preferably early in the morning.
o
For optimum results, 3 consecutive days samples should
be tested.
o
In case sputum is scanty, a 24 hour collection may be examined.
o
A nebulized and heated hypertonic saline may be used to induce sputum production
in patients unable to bring out the sputum.
o
Sputum should be collected in a sterile wide mouthed container Avith a tight lid.
The sample should be delivered to the laboratory with minimum delav.
Specimen that cannot be delivered or processed immediatelv should be refrigerated
at 4-8°C for a maximum of 3-4 da vs.
Materials required for sputum microscopy:
o
Properiv collected specimen
o
Wooden sticks
o
Clean Mass slides
o
Spirit lamp/Bunsen Burner
o
Petri dish
o
Inoculation hood
o
Face masks
o
Reagents for Zeihl-Neelsen staining
o
Glass Rods, Plastic clay.
Procedure:
Preparation of the smear
o
In an inoculation hood or in an isolated room, wearing, a
portion of the sputum to a petri dish.
o
Using, a wooden slick, lease out a small portion of caseous, pm uh'nl or bloody
material and transfer it to a clean slide.
o
Using, the same wooden slick or an inoculing, win* loop, spread this material
uniformly over a large area, covering al least two thirds of the slide.
o
Air dry the slides and flame them immediately and stain
Neelsen staining method as given below:
4.3.2
Zichl Neelscn Stainin(Acid fast staining)
lace mask, h ansfer a
according to the Ziehl-
Requirements
o
Carbol fuchsin solution
o
20% sulfuric Acid
o
25% Alcohol
o
Loeffler's Methylene* blue'
o
Distilled waler
Staining Procedure:
o
Put the heat fixed smears onto a platform made using tw o parallel glass rods over a
wash basin.
o
Cover the slide with carbol fuchsin and heat the slide from below until steam uses.
o
Allow to stain for 5-8 minutes with intermittent heating, putting fresh carbol fuchsin
on the slide time to time.
o
Care should be taken not to allow the stain to drv oil the slide.
o
Wash the slide preferably using distilled water. (Do not use tap water)
o
Cover the slide with 20% Sulfuric Acid. Wash the slide with water after one minute.
Pour more acid and continue decolorisation till smear is just faint pink.
o
Wash tlie slide again with water.
o
Cover the slide with 25% Alcohol for 2 minutes.
o
Wash with water.
o
Counterstain with Loeffler’s methvlene blue for 30 seconds.
o
Wash the smear with tap water, air dry and examine under oil immersion.
Observations:
Mycobacteria appear as bright pink, slender, slightly curved rods, whereas the
background tissue, cells and other organisms are stained blue.
Note:
o
Staining jars should never be used as with a positive stained slide, the bacilli mav get
detached from the slide and float about in staining fluid later on sticking to the
negative slides and may give false positive results.
o
After examining a positive slide, take care to wipe the iens with a clean tissue
paper before examining the next slide.
O
Do not record the smear to be negative unless at least 200 microscopic fields have
been thoroughly examined under oil immersion objective.
4.4
Diagnosis of Plague
Plague is an ancient scourge of mankind, which is a bacterial disease caused bv
Yersinia yestis. It is endemic in rodents and fleas. Ln man, plague occurs mainlv in three
forms, bubonic, pneumonic and septicaemic.
The presumptive diagnosis of Plague can be established by microscopic examination.
Sample collection:
o
Bubo aspirate: in bubonic plague should be collected.
o
Under all safety precautions collect bubo aspirate by puncturing the bubo
with a sterile hypodermic svringe and exudate is withdrawn.
o
Sterilize the puncture site with tincture iodine.
4.4.1
o
10 ml or 20 ml syringe, armed with 18/19 guage needle and a few ml of sterile
saline drawn into the syringe, should be used for aspiration of bubo aspirate.
o
Bubo is then punctured and suction applied.
o
If aspiration does not produce fluid, then saline is injected into the bubo again
and aspirated again.
o
Transfer the exudate into a sterile container.
o
Label the container.
o
Transport to the laboratory at 2-8*'C.
Sputum Collection in Pneumonic Plague:
o
Collect the sputum sample in a sterile wide mouth screw capped container.
o
Label the specimen
o
1 ransporl the specimen to laboratory al 2 <S”C.
In the Laboratory:
4.4.2
o
Make three smears out of the same portion of exudale/spulum taking
precautions not to form aerosols.
o
Air dry the smear.
o
Stain smears either by Methylene blue/Gram staining/Wav^ons stain.
Gram Stain:
This is a routine laboratory procedure used lor examining speiimens suspected to
contain bacteriologic agents. Direct microscopic examination of specimen^ and cultures can
provide a rapid presumptive diagnosis. Gram stain results, the shape of cell (cocci, bacilli),
the type of cell arrangement (single, chained, clustered) visualized under ligjit microsCopv,
can provide a cjuic k assessment ol what lhe etiologic agent may bo.
Principle:
The Gram stain forms the cornerstone ot microscopic bacteriology. It was tlcscribed
by Hans Christian Gram over 100 years ago. Crystal violet (gentian violet) is the primary
stain that will bind to the peptidoglycan present in the cell walls of some bacterial cells.
Iodine is added as a mordant to fix the dye. If the cell wall does not contain peptidoglycan
then crystal violet is easily washed off with acid or alcohol (decolorizer). A secondary dve,
safranin (counterstain), is added after the decolorization step. If the primary did not bind
the cells will easily adsorb safranin. Thus gram-positive cellls are purple, while gram
negative cells are pink/ red.
Requirements:
Crystal violet (0.5%)
Gram's Iodine (1%)
Acetone (100%) or Ethanol (95%)
Safranine (0.5%)
Procedure:
o
o
Cover the slide with crystal violet solution and allow to act for about 30
seconds.
Pour off stain and holding the slide at an angle downwards pou on the iodine
solution so that it washes away the crystal violet; cover the slide with fresh
iodine solution and allow to act for 1 minute.
Wash off the iodine with ethanol and treat with fresh alcohol, tilt the slide
from side to side until colour ceases to come out of the preparation. This is
easily seen by holding the slide against a white background.
Or
Decolorize with 100% acetone. First, tip off the iodine and hold the slide at a
steep slope. Then pour acetone over the slide from its upper end , so as to
coyer its -whole surface. Decolorization is very rapid and is usually complete
in 2-3 decond. After this period of contact, wash thoroughly with water under
a running tap.
Apply the counterstain (0.5% safranine) for 30 seconds.
O
Wash with water and blot drv
o
o
When to use this procedure and what you expect to see
Y.pestis appears as a fat, short, gram-negative coccobacilli about 1 /um bv 0.5 /um.
Gram stains are Wpically done on cultures/subcultures, buboe aspirates, spleen, liver and
sputum smears.
Critical value/Action to be taken:
When gram stained material reveal small coccoid gram-negative bacilli. Material
should be further worked up with culture isolation and identification. No notification is
needed at this time.
Interpretation: Y. pestis appears as a fat short, gram negative coccobacilli about 1 um bv 0.5
/ um.
4.4.3
Wayson stain for visualizing Yersinia pestis:
Wayson slain is a polychromatic dilfeienlial slain used as a presumptive lest lor the
presence of Yersinia and I'asteurella spp.
Principle
Basic fuschin and methylene blue in the Wayson slain bind to bacterial cells which
appear morphologically under light microscope as bipolar, closed safelv pin-shaped cells.
The differential polychromatic mrophok^;y can be visualized with manv differenltvpes of
organisms therefore Wayson stain alone is not diagnostic for Y.i'esli^.
Critical values/ Action to be taken:
When stained unknown malerial has a charac (eristic "salelv pin" morphologx . it is
Wayson slain positive. Further work-up by culture isolation and idenlfiicalion must follow
No notification is needed unless submiltor specifically requests notification.
If Wayson bi-polar organisms known to have "safety pin" morphology cannot be
visualized after staining, check reagents and check for possible technical problems. Repeat
stain until characteristic morphological results are obtained with control cultures.
Materials needed for this test:
Wayson stain:
o
Dissolve 0.2 grams of basic fuchsin and 0.75 grams ot melh\ lene blue in 20 ml (4 05%
ethanol. Filter solution through Whatman # 1 paper (or equivalent).
o
Pour dissolved, filtered stain into 200 ml of 5% aqueous phenol. Store at room
temperature. Avoid exposure to light.
Procedure:
o
o
Prepare smear of tissue or culture on slide, air dry.
Float fix smear or fix in absolute methanol for 3 minutes,
fixation yields more
air dry slide. (Methanol
contrasting staining than heal fixation).
o
Flood smear with Wayson stain for 5-10 secoiuls.
o
Wash slide in tap water, blot gently or air dry.
o
I'.xamiiK* slide under lie,hl mk rosvope.
Interpretation:
Consistent, striking bipolar "safety pin" morphology of small, fat bacilli are
characteristic of the Yersinia and Pasteurella spp. Other bacteria mav exhibit bipolar
appearance as well, especially if the specimen is taken from areas with a wide variety of
normal flora (nasal, pharyngeal, and fecal).
"All Y.pestis are Wayson positive, but all Wayson positive stains are not Y.pestis '.
Quality control measures:
Test each lot of Wayson stain using known Yersinia/Pasteurella spp. (positive
control) and with Escherichia coli or other enteric bacteria as negative controls. When
examining tissue smears, controls slide prepared with plague bacilli infected and uninfected
tissue smears should also be examined.
4.4.4
Methylene Blue Staining;
Material required:
o
Air dried smear.
o
Methvlene blue stain.
Procedure:
o
Fix the smear by dipping the slides in a jar containing pure N lethanol for 5
minutes.
o
Cover the smear with methvlene blue stain.
o
Leave the stain for 3 minutes.
o
Wash with tap water. Air dry .
o
Observation:
Characteristic bluish bacilli showing bipolar staining. Suggests presence of Y.pestis
organisms.
4.5
Malaria
Malaria is a parasitic disease caused by Plasmodium species.
commonly caused by P.vivax and P.falciparum.
In India, the disease is
The laboratory diagnosis is ba^cd on
demonstration of different stages of the parasite in the peripheral blood film of the patient.
4.5.1
Collection of sample!
Peripheral blood smear:
Time for taking blood:
4.5.2
o
Collect blood either during or 2-3 hours after the peak of temperature.
o
Sample should bi' taken befort' administration of anlimala* ial drugs.
Preparation of blood smear:
Both thick and thin films should be made on the same slide.
Blood sample should be collected from the tip of the ring ling,er of the left hand.
However in small children, sample should be collected either from the heal or the tip of the
big toe of the foot taking all aseptic precautions using a sterile needle or a lancet ( see also
page.... under "Filter paper method").
Apply gentle pressure to the finger and collect a single small drop of blood on to the
mdidle of the slide. This is for the thin film. Apply further pressure to express more blood
and collect 2 or 3 large drops on the slide about 1 cm from the drop intended for the thin
film. Wipe the remaining blood away from the finger with cotton wool.
Thin film: Using another clean slide as a 'spreader' and with the slide with the Hood
drops resting on a flat firm surface, touch the small drop with the speader and allow the
blood to run along its edge. Firmly push the spreader alongwith the slide away from the
largest drop keeping the spreader at an angle at 45oC. Make sure the spreader is in even
contact with the surface of the slide all the time the blood is being spread.
Thick film: Always handle slides by the edges or by a coi ner to make the thick
film as follows:
Using the corner of the spreader, quickly join the larger drops of blood and
spread them to make an even thick film. The blood should not be excessively
stirred but can be spread in a ciix ular or rectangular form with 3 - 6
movements.
Allow the thick film to dry in a flat level position protected from flies, dust
and extreme heat. Label the dry film with a pen or marker pencil, bv writing
ross the thicker portion of die thin film the patient's name , or number and die
te. Do not use a ball pen to label the slide.
Wrap the dry slide in clean paper and despatch with the patient’s record form
the laboratory as soon as possible.
>
4.5.3
The slide used for spreading the blood films must be disinfected and could
en be used for the next patient, another clean slide from the pack being
used as a spreader.
Staining of Blood smears:
GEIMSA STAIN
Materials and Reagents:
I.
Geimsa stain powder/Ready Giemsa Stain solution.
Alcohol
3.
Methanol
4.
Marking pen
Staining jars
6.
Boric acid Borax buffer - pH 7.2.
Preparation:
o
Dissolve the stain powder in alcohol as per the manufacturer s instructions.
o
Prepare Borax Acid - Boric buffer as below:
a) Dissolve 12.4 gms of Boric Acid in 1 lit. of Distilled water
b) Dissolve 19.05 gm Borax in 1 lit of Distilled water
(I)
(II)
Take 50 ml of solution I and adjust the pH to 7.2 using appropriate volume of
solution II. Then make up the volume to 200 ml with distilled water.
Staining Technique:
4.5.4
o
Prepare thick and thin smear from malaria cast' on a glass slide.
o
Deaemoglobinize the thick smear by placing the film in a vertical position in a
ass Jarontaining distilled water for 5 minutes. When film becomes white, take
t and dry in upright position.
o
Fix the thin smear in methanol lor 15 minutes.
o
Dilute the Giemsa's stain solution, one part with 9 parts of Boric buffer pl I 7.2.
o
Immerse the smears in this stain for 1 hour.
o
Wash the smears in buffer solution.
o
Blot and dry.
o
Examine the slide under oil immersion of microscope.
J.S.B. Stain
Materials and Reagents Required:
o
Eosin yellow (waler soluble)
o
Methylene Blue
o
Potassium Dichromale
o
I )i sodium hydrogen phosphate (dihydiale)
o
I % sulphuric Acid.
o
Round bottom flask (2 lit.)
o
Healing mantle
o
Distilled water
o
Staining jars.
Preparation:
i/
j
J.S.B. II
Dissolve 2 gms Eosin Yellow in 1 lit. of distilled water and store in the dark for 4
weeks before use.
J.S.B.
Dissolve 1 gm of Methylene blue in 600 ml of
distilled water and mix well.
Add 1% sulphuric acid (6.0 ml) drop by drop and shake well.
Add 1 gm of potassium dichromate and shake well till precipitation occurs.
Dissolve the precipitate by adding 7 gms. of Di-sodium hydrogen phosphate dihvdrate.
Make up the volume to 1 lit.
Boil the stain in round bottom flask over a
heating mantle for one hour.
Cool the stain and re-adjust the volume to 1 lit by adding distilled water.
=> Store in dark for 4 w^eks before use.
■4
Staining technique: ...
•
=> Prepare thin and thick smears from malaria cases on micro slides.
De-haemoglobinise the thick smear.
=> Fix the thin smear in methanol for few minutes.
Take 3 staining jars for J.S.B. I, J.S.B.II and tap water.
Dip the smears in J.S.B. II for few seconds and immediatedly wash in water.
=> Drain the slides free of excess water.
Dip the smears in J.S.B.I for 30-40 seconds.
Wash well in water and drv.
Examine the smears under oil immersion.
4.5.5
Observation:
Examine' thin film lirsl.
II no parasite is loiind then only examine thick film.
Il
parasites are seen in the thick lihn but the identity is not clear, the thin Him shc^uld be
reexamined more' lheireiughly sei as te) determine' nature e>f inlectieni.
Thin film examination:
o
Area of the film examined should be along the upper and lower margins of tail end
f ilm as parasites are concentrated over there.
o
A minimum of 100 fields should be examined in about 8-10 minutes.
<0
The following stages of the parasite can be observed in a peripheral blood thin smear.
1. Ring, trophozoite, schizont and the gametocytes in case of Plusin nlium vivax.
2.The infected erythrocytes is usually enlarged in P.vivnx
infection.
3.However, in case of P.falciparum infection, it is mainly the ring stages which arc
een and occasionally schizonts and trophozoites. During the late stages of the disease
ven crescent shaped gametocytes can be seen in the peripheral blood.
Observation on thick smear:
o
Only elements seen are leucocytes andmalarial parasites.
O
Mrphology of malarial parasites is distorted.
o
secies of parasites cannot be identified.
Appearance in thick film
o
Trophozoites appear as streaks of blue cytoplasm with
detached nuclear dots. The ring forms rarely seen.
Schizonts and gametocytes, however, retain their normal appearances (although the
o
pigments are seen more clearly) are seen if present in smear.
4.6
Examination of blood for Microfilaria
Filariasis is a disc'ase of the l\ mphalit s caused mainlv by the nematode I \'ik hcrci in
bancrofli and rarely
imilm/i.
Laboratory diagnosis:
Is based on the demonstration of the larval stages of the parasite in the peripheral
blood of the cases.
4.6.1
Collection of blood:
The blood should be preferably collected between 10 PM and 2 AM specially in areas
where microfilaria shows nocturnal periodicity.
4.6.2
Examination of unstained preparation:
Take 2-3 drops of blood on a clean glass slide. Put a coverslip on it.
The rim is then smeared with vaseline to prevent drying up of the blood.
Examine the slides under low power microscope immediately or within 24 hours of
ollection of blood.
Wriggling microfilaria present in the blood can be seen.
4.0.3
Exammauon of stained smear:
Thick film:
J
Prepare a thick blood film as per the instruction given in tire Chapter on Malaria.
Dehemoglobinise the smear bv putting the slides in a iar containing water.
Air drv
i-
Fix the smear with methvl alcohol.
Stain with Geima’s stain as described earlier.
Examine the smear under the oil immersion of the microscope.
Tliin film:
o
Prepare as described for malaria.
o
Fix it with Methanol by dipping the smear in a jar containing methanol for 15
minutes.
o
Stain it with Giemsa stain as described earlier.
Observation:
Microfilaria of Wncheivria bmiciv/li are seen.
o
Size - 290 /u in length and 6-7/u in breadth.
o
It has blunt head and pointed tail and has smooth curve.
o
Structureless sack called I lyaline Sheath seen \\ here it projects beyond the exlremites
f embryo.
o
Somatic cells/nuclei seen as pjanules in (onlral axis from head to tail etui except the
erminal 5 percent area. At the anterior end there is a space devoid of granules called
ephalic space.
The granules are broken at definite space serving as the landmarks for identification
o
of the species.
Nerve ring, a oblique space.
Anlrrrior V spot, r(‘pres(‘nls the rudimenlai y rxcrolorv s\ stem
Posterior V spot or tail spot, represents the terminal part of the alimentary
canal.
Microfilaria of Bnigin nnilai.
o
Smaller then Wucheraria bancrofti (230 /u x 6 / urn)
o
Possess secondary Kinks instead of smooth curved.
o
Cephalic space is broader.
o
Tail lip is not free of nuclei and ntii lei air blurred.
o
It lies folded with head dose to tail.
CHAPTER - 5
SEROLOGICAL TESTS
CHAPTER- 5
5.
SEROLOGICAL TESTS:
5.1
LATEX AGGLUTINATION TEST FOR MENINGITIS
The ideal immunological test, which is also a rapid test and easy to perform in a
district laboratory, is the latex agglutination (LA) test, test is done to detect tire bacterial
antigen (Capsular polysaccharide) in CSF samples collected from patients.
The available comercial kits are designed to provide diagnosis for meningitis caused
by:o
N. meningitidis serogroup A
o
N. meningitidis serogroup C
o
Streptococcus pneumoniae
o
H. influenzae tvpe B
The general procedure for performance of the test is given below, however, the
laboratory personnel are advised to go through the instructions provided bv the kit
manufacturer, carefully, and strictly adhere to the same.
5.1.1
5.1.2
Equipments required: (bur not supplied with the kit)
o
Pasteur pipettes (sterile)
o
Rubber teats
o
Container with disinfectants (for discard)
Procedure
o
Systematically heat all CSF specimens for □ minutes at 80-100°C.
o
Centrifuge the CSF samples at 2000 rpm for 10 minutes, preserye the
supernatant for further use.
o
Shake each latex suspension well.
o
In tire corresponding fields of the slide, dispense one drop of each of the latex
suspension fllowed by one drop of the CSF supernatant.
5.1.3
o
Mix with a stirring stick; use separate stick for each combination of CSF and
latex suspension.
o
Rotate the slide, and read within 2 minutes.
Controls:
a)
Periodicailv check:
thatnone of the four latex reagents agglutinate in presence of 0.15
mol/1 N’aCl solution.
b)that each of the four latex reagents do agglutinate with positive control.
5.1.4
Reading:
o
Negative reaction: The CSF latex suspension mixture remains a
suspension'' (disregard any granules that may occur with S.pneinnonae .
o
miikv
Positive reaction: Distinct rapid agglutination occuring within 2 minutes
( normally 30 seconds).
5.1.5
Interpretation:
Agiutination with one of the latex reagents indicates presence of the corresponding antigen
5
in the CSF sample.
.Advantages of LA test:
o
Most sensitive method available
o
Rapid
o
Good field applicability
o
Can diagnose the disease even in antibiotic treated patients.
o
\’o special equipment/instrument required.
Disadvantages of LA test:
o
Commercial kits not produced in India; to be imported.
o
Expensive
<)
The test does not Yield any bacterial isolate; other prameters cannot be tested.
5.2
DIAGNOSIS OF HEPATITIS B VIRAL INFECTION:
Diagnosis of Hepatitis B viral infection is very important, not onlv in case of chronic
hepatitis and liver cirrhosis patients, but also in the screening of donor blood samples, to
ensure safe blood transfusion and to control or check the spread of hepatitis B infection
through unsafe bloodt ransfusion.This is achieved by detection/demonstration of HepatitisB surface Antigen" (HBsAg) or the 'Australia Antigen in the patient/donor blood samples.
A simple latex agglutination test for rapid detection of HBsAg, which is verv much
feasible in the district laboratories, is described below:
LATEX AGGLUTINATION TEST FOR RAPID DETECTION OF HBsAg
(AUSTRALIA ANTIGEN)
5.2.1
PRINCIPLE:
A distinct agglutination occurs, when serum sample containing HBsAg is mixed with
latex particles coated with purified and highly reactive anti-HBsAg antibodies: there would
be no agglutination when the serum sample does not contain HBsAg".
5.2.2
MATERIALS AND REAGENTS:
Commercial kits, for this test are available in India,
reagents and accessories.
Reagent 1:
HBsAg Latex Reagent
- 1 vial
Reagent 2:
Positive control serum
- 1 vial
Reagent 3:
Negative
control serum
o
- 1 vial
Accessories:
Disposable plastic slides
They contain the :ollc’.ving
Disposable applicator sticks
Disposable plastic droppers
Rubber teats.
All the reagents are stable and active, till the expirv date mentioned, provided they
are stored in a refrigerator at 2-8* C. Do not freeze the reagents.
5.2.3
SPECIMEN:
o
The test is performed on serum harvested from the patient's/donor’s blood.
o
Do not heat inactivate the :est or the control sera samples.
If delav in testing, store tes: sera samples in a refrigerator or deep freezer,
takingcare to avoid repeated freezing and thawing of the specimens.
o
TEST PROCEDURE
Allow the reagents to atcam room temperature, and shake the vials gently to
make sure that the latex reagent is comp.r:eiv in suspension.
o
Place one drop :'5O /ui) c; undiluted serum in one of the circles on the slide.
More circles to be filled if more than out rest sera samples are to be tested, Use separate
droppers for each specimen.
o
o
Add one drop ;'5O /ul) or .atex reagent on to each specimen drop m circles,
using a disposable dropper.
Mix the content of each cirtie, using separate disposable applicator sticks for
each circle, and spread the mixrure unircrmiy over the entire area of the circle.
o
o
Rock the slide gentlv, to and fro, tor 5 minutes, and watch for agglutination.
Precautions:
1.
To avoid contamination of reagents, make sure that the cap of each vial is properly
and promptly applied to the same vial. Interchanging of caps and droppers lead to
contamination and erroneous results.
Improper mixing and interchange of applicator sticks also lead to erroneous results.
3.
Vigourous rocking of slides may lead to impaired agglutination.
Use of Controls: Positive and negative controls are not always required, when reagents are
in continuous use. However, the performance of the kits needs checking, occasionally, using
the controls.
Interpretation:
o
Visible agglutination within 5 minutes
HBsAg Positive
o
No agglutination
HBsAg Negative
5.2.6
LIMITATIONS:
o
Probability of FALSE POSITIVITY - 1% of all samples, due to presence of
other antigens (RF).
o
FALSE NEGATIVE results may be encountered with specimens containing
very high titres of HBsAg (Prozone effect). In such cases the characteristic syndrome (severe
jaundice, GPT/GOT elevation) will be apparent. In that case repeat the test after diluting the
specimen 1:40, with normal saline.
5.3
VDRL SLIDE FLOCCULATION TEST FOR SYPHILIS:
This is a test with high sensitivity’ and specificity7 and can be used for rapid and exact
quantitative titration of the reactive sera samples.
5.3.1
PRINCIPLE:
The VDRL antigen particles, which are ’seen as small fusiform needles under the
microscope, floculate into clumps '.small, medium and large), when they comein contact with
a reactive (+ve) serum.
5.3.2
MATERIALS:
VDRL Antii?-,n:
It consists of a mixture f Cardioiinin, lecithin and cholesterol in definite proportions
and is commercially available. Each sealed glass ampoule contains 0.5 ml (with sufficient
excess for convenient '.vithdrawai:. Antigen amouples should be stored in a cool, dark place.
Ampoules showing precipitate mould be discarded.
Buffered Saline Solution:
10 ampoules containing s mi each are supplied with each package of VDRL antigen.
Buffered saline is required for preparing the antigen emulsion for the test.
SLIDES:
Glass slides, 2"x3", with 12 paraffin rings of 1.4 mm inner diameter are used for me
test. Slides of same size, with permanently fixed ceramic rings are also avaiiaoie
commercially and mav be used. The following points regarding the slides are to be noted.
')
New slides, as well as the used slides should be cleaned thoroughly.
<)
Slides should be handled by the edges only, to avoid anv greasy finger prints.
(1
Serum within the circles will spread evenly, within the rings, onl\’ if the slides
arc absolurtelv clean.
Parafin rings can bu maue on slides by transferring molten paraffin on tu slide
using a suitable mould or threaded wire rings.
□.j.
PROCEDURE:
A.
Preparation of serum:
< ■
inactivate serum by heating at 561 C for 30 minutes.
On removal from water bath, centrifuge the serum sample if it shows
particulate debris.
Test sera sample need to be reheated (at 5b°C for 10 min... if they are >-1 hr. old
since original inactivation.
c
0.0? ml of each sample is required for testing.
^REF.-.RATIOX OF AXTIGEX EMULSION:
Pipette out 0.4 ml of buffered saline on to the bottom or a 1 oz.reagenz bottle
with flat or concave inner bottom surface.
-xdd 0.? ml of VDRL antigen, drawn out from an ampoule, using a graduated
pipette, directiv on to saline in the reagent bottle, while rotating the bottle on a flat surface.
o
The antigen should be added drop by drop, but rapidly, so that it takes
o
approximately o seconds to complete the delivery of antigen.
Blow the last drop of the antigen and continue rotation of the hottie for 10
o
more seconds.
o
Add 4.1 ml. of buffered saline, using a graduated
o
Stopper the bottle and shake it vigorously for about 10 seconds.
5 ml. pipette.
Take care to see that the temperature of buffered saline solution and that of
o
VDRL antigen is maintained within the range of 23-29°C, during preparation of the antigen
emulsion.
o
Maturation of antigen is important for increased sensitivity’, maturation is
complete in 15-30 minutes, after preparation.
o
Store the antigen emulsion in a refrigerator, if necessary. It should be brought
to room temperature and shaken gently before use.
o
5.0 ml of antigen emulsion would suffice for 250 serum tests.
o
Each batch of antigen emulsion prepared must be pre-tested with known
ractive and non-reactive sera samples, in order to confirm that exact pattern of distribution of
antigen particles, typical of reactive and non-reactive sera samples, would result on testing.
5.3.4
TEST PROCEDURE:
o
Qualitative Test:
Pipette out 0.05ml of inactivated serum into one paraffin/ ceramic ring on the
glass slide; serum should spread.
★
Add one drop (1/ oO ml) of antigen emulsion on the serum within the ring.
Rotate the slide for 4 minutes, by hand on a flat surface (+ or -120 times per
minute covering circle of 2"dia.)
5.3.5
READING AND REPORTING OF RESULTS:
o
Read the test results immediatelv after rotation.
o
Observe the slide under micrscope, using low power objective
(100 ^magnification)
o
Antigen particles appear as small fusiform needles, they are more or less
evenly spread in case ota non-reactive serum sample, and aggregated
into
clumps
(flocculation) in the case of a reactive serum. Grade the observations as under:
No clumps or very slight roughness
NON-REACTIVE
Small clumps
WEAKLY REACTIVE (W)
Medium and large clumps
REACTIVE (R)
(N)
Zone reactions are possible; they are recognizable by irregular clumping. The clumps
are not compact and very small and large clumps may be seen within the same microscopic
field. In such cases, the results are reported on the basis of quantitative test done on the
same serum.
O
Quantitative test:
Quantitative test is performed on all positive (reactive) serum samples and on
samples which show weak(W) or ’ rough'' reaction in the qualitative tests.
Prepare successive two-fold dilution (1:1, 1:2, 1:4, 1:8, 1:16, 1:64 etc.) of serum sample
to be tested, using 0.9% saline.
r
Each serum dilution sample thus prepared is treated as an individual sample and
tested as described under ’ qualitative" test.
Results are read and graded under the microscope as before.
Reporting of results:
Results are reported in terms of the highest dilution of the serum that produces a
definite positive (or Reactive, R) reaction as below. Weakly reactive is not acceptable.
Serum
1:1
1:2
1:4
1:8
1:16
1:32
R
W
X
X
X
X
_ N
R1 dil
R
R
VV
X
X
X
X
R2 dils.
R
R
R
W
X
X
X
R4 dils.
W
W
R
R
W
X
X
R8 dils.
X
w
R
R
R
X
X
R16 dils.
W
X
X
X
X
X
X
WO dils.
w
w
N
X
X
X
X
R1 dils.
1:64 ■ Report
Dilution
5.4
RAPID PLASMA REAGIN (RPR) TEST FOR DIAGNOSIS OF SYPHILIS:
This test detects antibodies formed, in the blood of syphilitic patients, against
Cardiolipin. These antibodies are called Reagin". Two advantages of this test over the
previously described VDRL Slide flocculation test are - (a) It does not require a microscope to
read the test results; (b) The test sera/plasma sample need not be inactivated prior to testing.
5.4.1
PRINCIPLE:
"Reagin formed in the blood of syphilitic patients cause flocculation of tire antigen,
which co-agglutinates with the charcoal particles, giving small black clumps that are readilv
visible without a microscope".
Conunercial "Rapitest" kits, designed for carrying out 50 tests per kit, are available in
India.
5.4.2
REAGENTS AND MATERIALS:
a)
Provided in the Kit:
RPR Antigen
1 vial
Positive Control serum
1 vial
Negative control serum
1 vial
RPR Antigen'dropper
1
Specimen droppers (disposable)
Rubber Teats
Mixing sticks (disposable)
Plastic test cards
b)
9
Materials required, but not provided in the kit: •
Micropipette (capable of delivering 0.05 ml of test
sample)
Stop watch
Saline solution (0.9%) - Only for quantitative test.
Container with disinfectant (tor discard)
Storage:
The RPRantigen and control sera will remain stable and active, til. the expiry
date printed on the label, provided thev are stored in a refrigerator between 2-8*0. They
should not be freezed.
5.4.3
THE SPECIMENS:
a)
Serum:
o
Use fresh serum harvested from patient's biood sample.
If the test cannot be conducted immediately due to some reason, store the
o
serum sample between 2-8°C in a refrigerator, BUT NOT LONGER THAN 4*? hr., after
collection.
b)
Plasma:
o
Collect patient's blood into a tube/vial containing one of the anticoagulants
(EDTA, Heparin, Oxalate, Sodium Flounde etc.) Avoid excess of coagulant.
o
Centrifuge the blood sample, to separate the cells.
o
Use the plasma sample within 18 hr. of collection.
o
Inactivation of serum/plasma samples is not necessary.
PRECAUTIONS:
Blood samples should be collected from fasting patients, since ven- lipaemi
samples may give false +ve reactions.
o
o
Do not use grossly haemolysed samples.
o
Discard contaminated samples.
5.4.4
TEST PROCEDURE
A.
Qualitative test:
o
Allow all reagents to attain room temperature.
Place one drop of (0.05 ml) test serum or plasma, positive control and negative
o
control sera on to separate circles on the plastic test card, using disposable specimen
droppers provided.
o
Shake the RPR antigen suspension gently, to resuspend the particles.
o
Place one drop (0.015-1).02 ml) of the antigen suspension, on each of the circles
containing test samples and the positive and negative contiol sera drops, using the antigen
dropper provided.
o
Mix the contents of each circle, using the disposable mixing sticks provided,
and spreading the reagent mixture over the entire area of the circle.
Gently rock the card, to and fro, for o minutes, either manually or on a
mechanical shaker at 100 rpm, to ensure thorough mixing.
o
o
Read the results at the end of 6 minures, using a high intensity light source.
interpretation of Results:
POSITIVE (REACTIVE
NEGATIIVE
. NON-REACTIVE)
Development or clearly visible clumps of black
particles, within the test circles.
No development of clumps, the charcoal particles remain in a
HOMOGENEOUS GREY SUSPENSION.
A quantitative estimation is further recommended for all samples positive in the
•jualitative test.
j.
Quantitative test:
Dispense 0.05 ml (o0 ‘ uh of saline solution on to each of the circles (No.1-5)
on the test card, using a micropipette.
o
Dispense 0.05 ml (50 /ul) ci’ the specimen (test srum/plasma) onto circle 1
and mix the two (saline and test ‘''ample) thorouNaiv bv drawing the mixture into the
micropipette, up and down several times.
o
o
Transfer 0.05 ml (50/uh of the mixture m Circle-1, on to the drop of saline in
Circle-2. Repeat the mixing action, several times, as explained above.
o
Repeat transrerring and mixing actions from Circle-2, through circie-5.
o
Discard t>J)5 ml (50 / nil from Circie-r. arter mixing.
i>
Phu dilutions ot specimen obtained in airferent < ircles on the Lest are as under:
CIRCLE
1
SALIX'E (ml
0,05
specime:’
0.05
4
(.’.05
0.05
0.05
1<
1:8
1:1?
(Serum 'Plasma)
ml
MIX&
TRANSFER
0.05
DILUTION
1:2
o
Using the disposable mixing sticks, spread the specimen dilu: ?ns iii the
circles to cover the area of the circle. Start with circle 5 and end with Circle 1 Wire the
sticks clean between circles.
o
Gently shake the RPR antigen vial to resuspend the particles, and add one
drop (0.15-0.20 ml.) of antigen, on to each circle, using the antigen dropper.
o
Gently rock the card to and fro for 0 minutes (manuallv or on a mechanical
shaker), to ensure thorough mixing.
o
Read results at the end of o minutes, as described above under Qualitative
testing.
5.4.5
Interpretation:
The highest dilution of the sample, giving a definite positive reaction, is considered
as the titre of the specimen. In case the titre exceeds 1:32, continue with double dilutions
beyond that point,till the titre is obtained.
LIMITATIONS OF THE TESTS (RPR and VDRL Slide Flocculation):
Both these tests are considered as "non-treponemal antibodv tests”, which are prirnarilv
meant as screening tests. If the tests are positive when there is no clinical evidence of
syphilis, they must be repeated; if positivity persists, verifications bv more specific tesis (for
anti-Treponemal antibody) would be necessary to confirm syphilis. In RPR and VDRL slide
flocculation tests, false positive results may be obtained in diseases such as leprosv, malaria,
toxoplasmosis, infectious mononucleosis and lupus erythematosis, and also in specimens
having bacterial contamination.
WIDAL TEST FOR DIAGNOSIS OF ENTERIC FEVER:
(TA PHO ID AND PARATYPHOID)
Widai test is an agglutination test for detection of antibodies against Salmonella typhi
and Salmor.c'.'.a \iratupiii. the common causal agents of enteric fevers.
5.5. L
PRINCIPLE:
'When serum sample containing antibodies against S.hjphi and S.paratyphi
AB are mixed with respective antigens, agglutination will take place".
In S
important:
and ^.panm/piu AB, two types of antigens are recognised as diagnostically
•ai C anagen or 'Somatic'antigen.
•.b)
.‘.r.ngen or : Flagellar antigen.
O’ anneens of various species have components in common and hence only one
O antigen i.e. mat c-r S.typiii is employed: the H' antigens of Salmonella spp. are species
specific, and ?:ence the H' antigens of ail three, viz. S.impin. S.paratyphi A and S.paratyphi B,
are emicioved m the test.
Commercial test kits for WIDAL test are available in India, and using them both
quantitative and quantative tests can be put up on suspected sera samples.
MATERIALS AND REAGENTS:
mi
. r-st kit:
contains the following reagents and materials.
Reagent 1: S.hfpin i 'H')
5 mi
Reagent 2: S.Lupiii ('O')
5 mi
gent 3: S.pamh/piii A (’H:)
5 mi
Reagent 4: S.paratvphi B CH’)
5 mi
Reagent 5: Positive control
1 mi
Glass slide
1 No.
Product insert
(b)
1 No.
Materials required, but not supplied in the kit:
Small, drv and clean glass tubes
8 / specimen
(ror quantitative tube test)
Normal saline solution
Water bath
Micropipette/ dropper
5.5.3
SPECIMEN:
Fresh serum (patient) free from contamination should be useu. in CL'.*:-.
testing, store the sera samples at
C in a refrigerator.
Note:
: del.'
Specimen is used undiluted.
Do not use haemoiysed specimen.
Do not heat or inactivate the specimen.
TEST PROCEDURE
A.
Qualitative slide test for screening.
o
Clean the glass slide provided and wipe it drv.
o
Place a drop of undiluted serum sample to be tested in each of the first four
circles.
o
Add one drop of Reagent 1, Reagent-2, Reagent-3 and Reagent 4, on to the
specimen drop in Circles 1-4 respectivelv.
o
Mix the contents of each circle "with separate mixing sticks, and spread the
mixture to cover the whole circle.
o
Rock the slide gently tor 1 minute.
in
o
Read the results at the end of one minute.
Interpretation:
A positive reaction shows agglumrarion. visible to naked eve, in the respective circle.
Then proceed for quantitative slide test er quantitative tube test for the appropriate antigen.
B.
Quantitative slide test:
o
Clean the glass slide supplied in the kit and proceed as follows:
Serum
Appropriate
volume
antigen
0.08 mi
1 drop
1:20
0.04 mi
1 drop
1:40
0.02 mi
1 drop
1:80
0.01 ml
I drop
1:160
0.005 ml
1 drop
1:320
Titre
Mix the contents of each circle, starring with circle 5 and through Circle-1.
wiping the mixing stick clean between circles.
•>
Interpretation:
C.
Rotate the slide for one minute and observe for aggiunnadcn.
Titre of the serum is the highest dilution of the serum giving a
positive reaction.
(Quantitative tube test:
<>
Take a set of 8 clean glass rubes, per specimen, per antigen.
o
Prepare dilutions of serum specimen and add appropriate antigen as below:
i
1
TUBE
D
I
I 8
6
! 7
i Saline
i cor.trek
I
i!
i Serum
i dilution
1:20
1:40
1:80
i 1:160
1:320
l:M0
* 1:1280
Norma!
; saline
1,9ml
; l.Om.:
1.0ml
I
! 1.0ml
1.0ml
1 .Oml
1.0 ml
’ 1.0
Patient
scrum
0.1ml
1 ml
J 1 ml
' 1 mi
ii
1
i
1ml
T ransfer
; diluted
i scrum
1 ml
| 1 ml
. (discaro.
i mb
a
i
i
1
I
:---------------------i
i Aprropri 1 drop
iate antigen j
1 dror
2 drop
1 drop
1 drop
i 1 drop
j 1
!
drop
i dror
o
Mix well and incubate at 37oC for 16-20 hr. and observe for agglutination.
o
Repeat steps (iii and (iii) with all antigens which showed agglutination in the
screening test.
o
Note the highest dilution showing clearly visible agglutination with naked
eve.
'O' antigen shows granular agglutination.
'H' antigen shows flocular appearance.
o
Saline control should remain unchanged as it is a negative control.
mi :
5 !
Interpretation:
Agglutination titre of >1:80 is suggestive of infection.
Factors affecting WIDAL Test:
Effect of antibiotic administration:
There is evidence that early treatment with antibiotics suppresses the antiboduy response by suppressing
the multiplication of organisms. This may result in a low titre in WIDAL test.
Effect of past infection or typhoid vaccination:
. ,
It has been seen that th ‘H* antibodies persist for a long time upto many years after typhoid vaccination.
Also, many vears after recovering from enteric fever, any grave negative bacterial infection can trigger a
Salmonella ’H‘ antibody production, thereby giving a false positive result in WDAL test.
This is a verv inwortant parameter affecting the results of the WIDAL test. A single blood sample
collected durine the first week of the illness may give a negative WIDAL result, ■.vhereas in the same pattent, a
samnie collected durina the third week of illness may show a very high titre. Accordingly, paired samples should
be collected: the first sample being taken as early as possible and the second. 10-14 days later, for optimum
results.
CHAPTER - 6
BACTERIOLOGICAL ANALYSIS OF WATER
CHAPTER- 6
6.
BACTERIOLOGICAL ANALYSIS OF WATER:
Although it is not possible to lay down fixed standards, as various tvpes of water are
examined, from a public health point of view it is generally sufficient to sav that no faecal
contamination has occured. Coliform bacteria present in water mav not be harmful, but thev
indicate that water supply is contaminated with faecal matter and water is, therefore, liable
to contamination with more dangerous organisms. The coliform bacilli of human origin are
the most reliable indicators of faecal pollution.
The method of quantitative test for all coliform bacilli known as the presumptive
coliform count is described below'.
o.L
COLLECTION OF SPECIMENS:
Collect water m bottles of 230 ml capacity with ground glass stoppers, having an over
hanging rim. Sterilise the bottles by autoclaving.
Tap T.vater:
When -.vater is taken from tap, flame the mouth of the tap and allcw the water ro run
for five minutes before filling the bottle.
Stream, river and lake water:
Insert rhe bottle with its mouth closed with the stopper, a toot below the surrace of
. water and fill with water. Bring the bottle to the surface and replace the stopper. Avoid the
collection of surface water as it contains organic matter.
Precautions:
o
o
Test the water samples as soon as possible after collection. If delav is expected, pack
the water sample in ice for transport to laboratorv.
o
When sampling chlorinated water, add a quantity of sodium thiosulphate ro the
sample bottle before sterilising. This will neutralize the chlorine present in the water.
Presumptive Ceiitorm count:
Requirements:
Sample ot water
Sterilized test tubes.
Quarter strength Ringer solution.
1 ml and 50 ml pipettes.
Double strength MacConkev s fluid medium.
Single strength MacConkev s fluid medium.
Method:
o
invert the water sample 25 timeo to mix.
o
Flame the mouth of the bottle and discard 1 73 at the contents and mi:
thoroughly.
o
Using sterile graduated pipettes, the following amounts of water arOne 50 ml quantitv of water to 50 ml double strength MacConke;.
a flask.
Five 10 ml quantity each to 10 ml double strength MacConkev medium m tes
tubes.
Five 1 ml quantities each to 5 ml single strength MacConkev medium.
o
Incubate all tubes at 3/vC for 18-24 hours.
o
All tubes showing acid and gas are regarded as presumptive positives
Reincubate negatives for further 24 hrs.
o
Using McCradv s statistical tables the probable number of coliform organisms
present in 100 ml of sample can be calculated.
Interpretation:
Water samples are classified based on the presumptive count in the following wav:
Class
Preumptive coliform count 100 ml.
1. Excellent
0
2. Satisfactory’
1-3
3. Suspicious
4-10
4. Unsatisfactory
>10
Faeca 1 Coliform Count:
From the tubes showing acid and gas in presumptive coliform count, subculture into
fresh single strength MacConkey's broth or Incubate at 44 C in a water bath. Tubes showing
bcm acid and gas should be taken as positive for Faecal coliform. Using McCradys tables
commute the number of faecal coliform as in presumptive test. '.Vater showing even one
faecal coliform is unfit for human consumption.
Most Probable Number (MPN) values/100 ml of sample, for a set of tests of one 50 ml. five
10 mi. and five 1 ml volumes. (McCrady s Statistical Table)
\’o. Of tubes giving positive reactions
ml
0
5x10 mi
MPX/WOml
2\i mi
0
; <1
0
1
i
0
0
! U
1
i
1
•1
0
11
0
I2
0
0
ii
1
0
2
0
0
0
1
(i
4
I)
h
11
I
I
(I
0
1
I<.
11
!•'
I
(’
i 1
()
! 1
i 1
0
!1
I3
1
P
2
2
i ’1
1
, 1
I 9
i 4
h
i
9
|
p
. 1
: 1
5
i
' 9
2
i1
10
12
«*>
1°
8
1
1
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1
2
14
1
18
1
1
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21
1
4
0
13
a
4
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17
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—
4
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22
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4
35
i 4''
4
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35
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i cr
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i
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16:
1
3
>1S
6.1
FbS-Strip method:
In recent years a simple, reliable and easy-to-perform (bv even untrained nersonell),
'Yes-No' test for bacteriological quality of water has been devised. This test:, which is
currentlv under field evaluation and quality standardization is expected to be adopted as the
field test for water quality monitoring in the hands of peripheral nealth workers and
communit}’ participants.
Principle:
Presence of coliform bacteria in drinking water is associated with hvdrogen sumhide
(HzS)- producing organisms, and faecal pollution of water car. be established bv
demonstration of H2S production.
It has been claimed, by various workers, that the H2S-strip method shows 80%
agreement with the conventional MPN test described above.
Description of the test device (kith
It simply consists of a pre-calibrated 20 ml glass bottle (NlcCarmev bottle) with a
screw-cap lid, from which a strip of specially treated/coated tissue paper hangs down,
internally. Tire whole system is sterile and needs to be opened at the time oi water testing.
The paper strip inside the glass bottle (80 cm:,folded) is pro-soaked in a concentrated
medium containing peptone (20g), dipotassium hvdrogen phosphate (1.5g), ferric
ammonium citrate (0.75g), sodium thiosulphate (1g), Teepol (Iml; and water (50 ml): I ml of
the concentrated medium is absorbed on to the folded tissue paper strip and dried al 50
under sterile conditions. It is then introduced into the sterile bottle.
1 cst procedure:
Pour the water sample to r • tested for faecal pollution into the bottle, unto th-,
precalibrated level (2U ml
o
Incubate at 37‘“C or allow v stand at ambient temperature
C : ly ■
incubator is necessarv under field conditions, as the bottles can bt held m the
pockets and body tempera rare can be made use oi.
o
Faecal pollution is indicated if the- contents of the bottle turn black
Advantages of H2S-Strip Test:
o
No need to measure the volume of water to be tested:
o
No need to dechlorinate the water sample, since it instantaneous!'
dechlorinates thr sample:
o
The end point (reading) is \-ery clear, due to development of black colour:
o
No incubator is necessarv:
o
The test starts immediate!’.- on collection into the bottle, unlike other methods
which start after the sample is transported to the laboratory.
CHAPTER - 7
LABORATORY DIAGNOSIS OF CHOLERA
CHAPTER- 7
7.
LABORATORY DIAGNOSIS OF CHOLERA:
Cholera is characterized by sudden onset or effortless and profuse: waterv diarrhoea.
The watery stools with flakes of mucus and sweet fishy odour are characteristic ?f cholera.
These are also popularly known as rice water stool. Cholera is caused bv the ^nanism bv
the name of \'ibrio cholerae which are Gram negative usually curved bv shape of coma and
motile by a single polar flagellum. They are oxidase positive.
The laboratorv diagnosis is based on demonstration of '.'ibrio ^K-ierrte m the stool
specimen.
7.1
Collecdon of samples
Materials required:
o
Wide mouth container
o
Swabs sticks (sterile)
o
Cam’ blair transport medium
o
Case investigation form.
Stool:
(a i Voided stool:
o
* o
o
o
Most preferred specimen if available.
Should be collected before antibacterial therapy.
I
Should not be collected from bed pan r? as to avoid interference ::
bacteria or disinfectant used to clean bed pan.
i outside
Patient mav be instructed to void stocl :n wide mouth container e.p. ice cream
cup and transfer 3-5 gm. stool into a sterile screw cap pottle.
(B) Rectal swabs:
Whenever it is not possible to collect stool, a rc-c:al swab specimen mav c? collected.
It is a verv useful
and convenient sample under field condition anti m case- vr -oung
babies. Bv this methodology ().1-0.2 mi of liquid faeces can be collected.
o
Moisten the swab in sterile normal saime, it available.
o
Introduce the swab into 4 cm deep into rectum through anal sphancter.
Rotate by 9()oC and withdraw the swab.
o
Store the swab in stoppered container or in transport medium e.g. Carrv blair
so as to avoid drying.
Storage and Transportation:
o
Store the specimen at 2-8oC.
o
Transport to the laborator/ at the earliest and in case of delav use to Carv
Blair transport medium and send to the nearest laboratory.
Cary Blair transport medium:
It is a semi solid transport medium usually supplied in
small bijou hotties. It
should be stored in air tight container so as to avoid drying.
Inoculation of Cary Blair Transport Medium:
7.3
o
Insert one/two rectal swabs taken.from the same patient into the medium so
that the whole swab is dipped into the medium.
o
Break off the extra portion of sticks and replace the screw cap.
o
Label the bottles.
PROCESSING OF SAMPLES IN THE LABORATORY:
Microscopic examination and Culture:
i
Materials required:
o
Enrichment medium
- Alkaline peptone water.
o
Plating media
- Bile Salt agar
- Thiosulphate-citrate-
-Bile Salt-Sucrose (TCBS'I agar
- MacConkey Agar
o
Inoculating wireloop
o
Gas supply/burner
o
Incubator at 37°C.
o
Hand lens.
After the specimen arrives in the laboratory, it should be given laboratory code
number and entered in tire register before processing.
Demonstration of motility by direct microscopy:
It can he done using either the direct stool sample or using 4-6 hr. growth in alkaline
peptone water.
o
Prepare a hanging drop using culture growth in alkaline peptone water or
direct stool suspension.
o
Examine under the high power of a binocular microscope.
Obser-ation: A darting motility is suggestive of presence of Vilvio cholerae.
Culture:
o
Directly streak over BSA and TCBS media and also inoculate alkaline peptone
water (an enrichment medium).
o
Incubate overnight at 37° C in ordinary incubator.
o
examine the plates alter overnight incubation while APW is to be examined
after 4-6 hours.
Colony morphology on culture plates:
BSA (Bile Sait A.garh Small translucent raised flat colonies are characteristic of X'ibru) cholerae.
TCBS: Yellow, flat smooth colonies with pale yellow periphen’ are suggestive of Vibrio
cholerae.
APIV: Subculture growth in alkaline peptone water after 4-6 hour onto BSA/TCBS plates.
Incubate plates and APW overnight. Look for the characteristic colonies of V.cholerae as
described earlier.
Materials required:
o
Glass slides (clean)
o
Normal Saline
o
Platinum wire loop
o
Growth on BSA/TCBS
o
Discarding jars with disinfectant
o
Gas supply
o
V.cholerae 01 antisera.
Procedure:
o
Put a small drop of normal saline on a clean glass
o
Using a wire loop pick a colony from a culture plate.
o
Emulsify the growth in a drop of Normal saline using ^vire loop.
o
Add a loopful of cholera 01 non-differential antisera on to the suspension mix.
o
Look for agglutination (i.e. immediate clumping of organism within 30-60
seconds.
slide.
Observation: A positive agglutination is indicated by immediate clumping of organism and
suggests presence of Vilvio cholerae O1 and rest are labelled as non
agglutinating vibrios.
7.6
Stock culture and Referral to Reference Laboratory:
o
Make a stab into the nutrient agar slope, the cultures resembling 1 irrio
cholerae. (Agglutinating as well as non-agglutinating strains).
•
o
Transport the stab cultures to the reference laboratory for further testing.
4
Composition and source of culture media/reagents necessary for cholera labn
Bile Salt Agar (BSA)
Use:
Used for isolation and enumeraton of enteric bacilli.
Readvmade dehydrated media is available from Hi-Media Laboratories
Bombay.(Product code M-739 500 gms pack)
Pvt.
Directions for use:
o
Suspend 43 gms of media in 1000 ml of distilled water m a flask.
o
Plug flask with cotton.
o
Autoclave at 15 lbs pressure 121oC for 20 minutes.
o
Cool to 60-70eC.
o
Pour in sterilised Petridishes.
Remove air bubbles using flame.
Let it solidify
Store in refrigerator.
r.C.3.S. Medium:
■ : r.iosulphate Citrate Bile Salt Medium)
Usc:
Recommended for the selective isolation and culture ' r . ibnos causing cholera
vibrios which cause food poisoning.
Rc-acivmade dehydrated medium available rrom Hi-.Media .aboratories Pvt. Ltd.
(Product Code No. M-189).
Directions lor use:
Ltd.,
o
Suspend 89 gms of Media in 1000 ml of distilled water.
o
Boil to dissolve completely. Do not autoclave.
o
Cool at 50-C.
i>
Pour into sterilised petridishes
o
Allow to solidifv
o
Store in refrigerator.
Alkaline Peptone W'a
Use:
At pH 8.4 it is suitable for th- cultivation and enrichment of Vibric citoicn:. from
infected material.
Readvmade dehydrated medium available from Hi-Media Laboratories Pv;._td. Bomba”
(Product code i\o: M-C2;' - Peptone water).
Directions for use:
o
Suspend 15 gms in 1000 ml distilled water.
o
Mix well.
o
Adjust pH to 8.4 with NaOH.
o
Dispense 2-3 in test tubes.
o
Plug tubes, using cotton plugs.
o
Carv Blair Medium
(Transport Medium w o Charcoal)
Use:
Recommended for collection and shipment of clinical specimens.
Readvmade dehydrated medium available from Hi-Media Laboratories Pvt.Ltd., Bombay
(Product Code - M-202).
Directions for use:
o
Suspend 12.6 gms of media in 99% ml of distilled water.
o
Boil to dissolve completely.
o
Cool to 50°C.
o
Add aseptically 9 ml of 1% aqueous calcium chloride solution.
o
Adjust pH 8.4.
o
Distribute 5-7 ml in screw capped small bottles.
o
Steam bottles for 15 minutes.
o
Cool, allow to solidify.
o
Bottles are kept at room temperature.
—•xoi'Ar
- - -.
Nutrient Agar Stabs? y ''
Use:
A generaFculture medium.
Readvmade dehydrated media supplied by Hi-Media Laboratories Pvt.Ltd., Bombay
(Product Code M-012 Nutrient Agar W/1% peptone.-.
Directions for use:
o
Suspend 35 gms of media in 1000 mi of disnleid water.
o
Boil to dissolve medium completely.
o
Pour 2-3 ml in sugar tubes.
o
Plug tubes with cotton plugs.
o
Autoclave at 15 lbs pressure at 121 C.
o
Cool to solidifv.
CHAPTER - 8
SAFETY PRECAUTIONS IN THE LABORATORY *
CHAPTER- 8
£
8
?•
SAFETY PRECAUTIONS IN THE LABORATORY:
Biosafety in a microbiological laboratory is very essential and basically depends on
three components:
o
Basic standard of laboratory design, operation and equipment.
o
Selection and use of essential biosafety equipment.
o
Safe labooratory procedures.
I-.'
An exhaustive review of each component is beyond the scope of this manual but
practical and easily achievable safe laboratory rules are listed below:
i .•
=> Avoid mouth pipetting
Avoid eating, drinking, smoking and storing eatables in
the laboratory.
=> Decontaminate the working area at least once a day and more frequently after the
spillage of potentially infective material.
r
Wash your hands after handling the infectious material.
Wear laboratory coats/Gowns in the laboratory and these
outside.
should not be taken
Use gloves for all those procedures that may involve accidental, direct contact with
blood or infectious materials.
Decontaminate all liquid or solid waste before disposal.
Perform all technical procedures in a way that minimises the aerosol formation.
Provide adequate training to the staff in laboratory
safety procedures.
As far as possible actively immunize the workers against the diseases the materials of
which are handled by them.
I
I
-■
j. :■
aY-1
Employ only medically fit staff to work in clinical laboratories.
Rk
Report accident and illness promptly to the concerned officials.
r.;
Si
■
=> Provide ample space and illumination for safe conduction of laboratory rpocedures.
Design smooth easily cleanable walls, ceilings and
floors which should be
impermeable to liquids and resistant to chemicals and disinfectants.
Ensure a dependable and good quality water supply.
Make suitably equipped 'first aid' rooms readily accessible.
Provide the staff safe laboratory equipments e.g.pipetting aids, safety cabinets, screw
cap tubes and bottles, loop, incinerator if possible, and autoclaves, etc.
Carry out periodic health and medical surveillance of the workers to exclude the
highly susceptible individuals.
Provide safely systems covering lire and elecliica!
emergencies.
=> Control rodents and insects in the laboratory.
Don't permit the entry of the experimental animals
laboratory.
which are not to be used in the
Immunize your staff handling blood and blood products against Hepatitis B.
CHAPTER - 9
COMMON LABORATORY EQUIPMENTS
CHAPTER- 9
9.
COMMON LABORATORY EQUIPMENTS:
9.1
INCUBATOR:
Incubator is an apparatus having a desired temperature. The heating device used can
be gas, oil or electricity. Maintenance of uniform temperature within the incubator is
essential and is achieved by fan, blower or a waterjacket containing heated water.
Ideal temperature for most of the medically important bacteria is 35O+2°C. However
for some organisms different temperatures are necessary e.g. atypical mycobacteria (22oC45°C), fungi (22°C) etc. Some organisms may need extra gaseous element e.g. 5-10% CO2
incubator for Brucella. The size of the incubator may vary from a small table top to a large
walkin type rooms. A proper temperature recording thermometer and a small tray of water
inside the incubator to prevent excessive drying of air are the two other essential
requirements.
9.2
HOT AIR OVEN
It is used for sterilisation of the following materials:
Dry glass materials like test tubes, Petridishes, flasks, pipettes, svringes.
a)
b)
i InstrinrLents. like forceps, scalpels, throat swabs, etc.
c)
Seaied^materials which can stand heat and when penetration of steam is not
*
■
'
The imtrummrtr^tectrically operated and should be equipped with a fan to have
unfirom temperature inside, the required temperature for sterilisation is generally I6O0C for 1
hour.
Operation of Hot air Oven
o
Arrange the material to be sterilised loosely and evenly on the racks of the oven
allowing free circulation of air and thereby even heating of the load.
o
Air is poor conductor of heat so do not pack the load tightly.
o
Switch on the power supply and control the temperature of the oven by adjusting
thermostat. When the desired temperature is reached, note the time. Time taken for
the oven to reach the desired temperature is called 'heating up period'.
o
Hold the load in the oven at this temperature for a definite period of time. This
period known as 'holding up period1 is dependent upon the temperature employed.
At I6O0C the holding up period is 60 minutes, at 170oC for 18 minutes, at I8O0C 7.5
minutes and at 190oC it is 90 seconds.
o
The most common temperature for hot air sterilisation is I6O0C for one hour. When
the temperature is raised further, cotton plugs and paper wrappings get charred.
o
On the expiry of holding up period, switch off tire power supply and allow the load
to cool.
Open the oven door only when the temperature fall below 8O0C, otherwise it may
result in breaking up of glassware and also cause injuries to the operator.
o
o
Drv up the instruments before placing them in the hot air oven.
o
Do not place the heat sensitive materials inside.
9.3
- -Wg'"
■■■■■
WATER BATH.
Water bath is a water container having an electricallySoperated
electrically^.operated heating device to
provide a fixed and uniform temperature. A thermometer is inserted inside the water bath
for recording temperature. A mixer immersed inside water is also desired to maintain
uniform temperature throughout the water bath.
A few applications of water bath are:
9.4
37°C Water bath -
required during performance of WIDAL test;
44°C Water bath -
required in faecal coliform count (water bacteriology s test
56°C Water bath -
for inactivating complement in the serum.
CENTRIFUGE:
For an average laboratory a small table top centrifuge with a maximum revolutions
per minute of 6000 and capable of accommodating 10-12 tubes of 15 ml capacity is Sufficient.
The tubes should be placed exactly opposite to each other, should be of the same ^veight and
should contain same amount of fluid. The speed is adjusted by a rheostat and should be
allowed to rise slowly. A timer for fixed duration of centrifugation is preferred.
A few common uses are:
9.5
o
Sediment examination of urine - 1500 rpm for 5 minutes.
o
Separation of serum from clotted blood -1500 rpm for 15 minutes.
o
Concentration of microfilaria from blood - 2000 rpm for 2-5 minutes.
pH METER
A pH meter consists of an electrode pair which is sensitive to hydrogen ion
concentration due to tire development of an electrical gradient which is directly proportional
to the hydrogen ion concentration. The electrodes commonly used are one of glass for the
unknown and other of colomel to be used as a standard precautions while using pH meter
are:
o
The electrodes specially the glass ones should be handled carefully to prevent
breakage due to contact with hard surface.
o
Sufficient time should be given to warm up the instrument before use.
o
Frequent standardizations of the pH meter should be made using standard buffer
solution.
o
Electrodes are to be washed with a stream of distilled water between measuremer.zs.
o
The electrodes should never be removed from the solution when the measuring
circuit is closed. . m .
o
When not in"use,’ the electrodes must be kept immersed in water or electrode
solution.
9.6
REFRIGERATOR:
Refrigferators are essential for storage of degradable laboratory substances 'ike
media, reagents, antisera, antibiotic discs etc. Refrigerators can vary in their capacity
ranging from table top to a large walk-in-type. The usual temperature needed is 4o^2oC
which is maintained comfortably by household use refrigerators. Substances to be kep: at
frozen state like sera mav be kept in the freezer units of the same. Proper recording of -.he
temperature is verv important to avoid deterioration of biological materials.
9.7
MICROSCOPE:
o
Place a slide on the stage, specimen side up and the centre of the section to be
examined as accurately as possible over the hole in the centre of the stage.
o
Adjust the mirror until it reflects the maximum amount
of the light through the
specimen with the low objective in position, lower the body tube by means of
the
coarse adjustment until the objective is about 1/4" from the slide.
o
Look through the eve piece and slowly raise the objective with the coarse adjustment
until the specimen is in approximate focus. Never focus downward while looking
through the eye piece. Bring the specimen to sharp focus with the fine adjustment.
Adjust the iris diaphgram and substage. Condense until the light intensity’ is
optimum.
After examining the specimen with the low power objective^ shift to the high drv
o
objective by rotating the nose piece until the objective clicks i^^^ace.
o
Look through the eve piece and slowly raise the body tu^gwith the coarse
adjustment until the specimen comes into approximate'foctis. Then bring the image
into final accurate focus bv using the fine adjustment'the specimen is in
focus adjust the mirror and the iris diaphgram to givei^^lrarest possible image.
o
Focussing of the oil immersion objective:- First use the low power objective to locate
the portion of the specimen to be examined. Raise carefully the body tube, and then
rotate the nose piece until the oil immersion objective clicks into the position. Now
place a drop of immersion oil on the portion of the slide directly under the objective
watching the object from the side carefully lower it into the oil. Do not allow the
objective to touch the slide. Look through the occular and slowly focus upward
with the fine adjustment until the age appears. Once it appears do
the fine
adjustment and adjust the mirror and iris diaphragm to obtain optimum
illumination.
Maintenance:
o
Never touch the lenses if they become dirty, wipe them gently with lens paper.
o
Always remove oil from the oil immersion objective after its use. If by accident, oil
should get on either of the low power, wipe of the objective immediately with the
lens paper. If oil becomes dry or hardened on a lens, remove it with lens paper
lightlv moistened with xylol.
o
Keep the stage of the microscope clean and dry.
o
Do not tilt the microscope when working with the oil immersion system.
o
When the microscope is not in use, keep it covered in a microscope compartment.
Never apply force to the microscope. Never allow the objective lenses to touch the
cover
glass or the slide. Never lower the bodv tube with the coarse adjustment while looking
through the microscope. Never exchange the objective or occulars of different microscopes.
o
Store the microscope in its cabinet when not in use.
9.8
AUTOCLAVE
Principle
Water boils when its vapour pressure equals the pressure of surrounding
a tmosphere. The temperature at sea level is 100eC. When water is boiled within a closed
vessel at increased pressure, the boiling point of water is increased and so is the temperature
of steam produced. This principle is employed in sterilising material by steam ar
temperature higher than lOOoC and the process is called autoclaving.
For autoclaving in the laboratory, the most agreeable and commonlv used method is
to use steam at 121°C for 15 to 30 minutes depending upon the particular material to be
sterilised.
Items to be sterilised:
Autoclaving is most suitable for culture media, aqueous solutions, decontamination
of discarded cultures and specimens, rubber items such as gloves, stoppers with rubber
liner, glass ware with attached rubber tubings such as transfusion sets, glass metal svringes,
etc. Autoclaves designed for laboratory -work and capable of handling mixed loads should
be used.
9.8.1
Types of autoclave
Only autoclaves designed for laboratory work and capable of dealing with a 'mixed
load' should be used. 'Porous load1 and 'bottled fluid sterilizers’ are rarely satisfactorv for
laboratory work. There are two varieties of laboratorv autoclave:
o
Pressure cooker types; and
o
Gravity displacement models with automatic air and condensate discharge.
Pressure Cooker type Laboratory autoclaves:
The most common type is a device for boiling water under pressure. It has a vertical
metal chamber with a strong metal lid which can be fastened down and sealed with
a rubber gasket. An air and steam discharge tap, pressure gauge and safety valve are fitted
in the lid. Water in the bottom of the autoclave is heated by external gas burners, an electric
immersion heater or a steam coil.
Diagram
Operating Instructions:
There must be sufficient water inside the chamber. The autoclave is loaded and the
lid is fastened down with the discharge tap open. The safety valve is then adjusted to the
required temperature and the heat is turned on.
When the water boils, the steam will issue from tire discharge tap and cam the c
from the chamber with it. The steam and air should be allowed to escape freeiv undl all of
the air has been removed. This may be tested by attaching one end of a lengtr or rubber
tubing to the discharge tap and inserting the other end into a bucket or similar large
container of water. Steam condenses in the water and tire air rises as bubbles to the surface;
when all of the air has been removed from the chamber, bubbling in the bucket will cease.
When this stage has been reached, the air-steam discharge tap is closed and the rubber
tubing removed. The steam pressure then rises in the chamber until the desired rpessure,
usually 15 lb/in2, is reached and steam issues from the safety valve.
When the load has reached the required temperature the pressure is held for Io min.
At the end of the sterilizing period, the heater is turned off and the autoclave allowed
to cool.
The air and steam discahrge tap is opened very slowly after the pressure gauge lu.^
reached zero (atmospheric pressure). If the tap is opened too soon, while the autoclave is
still under pressure, any fluid inside (liquid media, etc.) will boil explosively and bottles
containing liquids may even burst. The contents are allowed to cool. Depending on tire
nature of the materials being sterilized, the cooling (or ’run-down1) period needed may be
several hours for large bottles of agar to cool to 8O0C, when they are safe to handle.
Autoclaves with air discharge by gravity displacement
These autoclaves are usually arranged horizontally and are rectangular in shape, thus
making the chamber more convenient for loading. A palette and trolley system can be used.
The jacket surrounding the Gravitv displacement autoclave consists oi an outer wall
enclosing a narrow space around tire chamber, which is filled with steam under pressure to
keep the chamber wall warm. Tire steam enters the jacket from the mains supply, which is at
high pressure, through a valve that reduces this pressure to the working level. The working
pressure is measured on a separate pressure gauge fitted to the jacket. This jacket also has a
separate drain for air and condensate to pass through.
The steam enters the chamber from the same source which supplies steam to the
jacket. It is introduced in such a way that it is deflected upwards and fills tlie chamber from
the top downwards, thus forcing the air and condensate to flow out of the drain at the base
of tlie chamber by gravity displacement. The drain is fitted with strainers to prevent
blockage by debris. The drain is usually fitted with a thermometer for registering die
temperature of the issuing steam. The temperature recorded by the drain thermometer is
often lower than that in the chamber. The difference should be found with thermocouple
tests. A 'near to steam' trap is also fitted.
The autmatic steam trap or 'near-to-stream' trap is designed to ensure that only saturated
steam is retained inside the chamber, and that air and condensate, which are at a lower
temperature than saturated steam, are automatically discharged. It is called a near-to-steam’
trap because it opens if the temperature fails to about 2oC below that of saturated steam and
closes within 2oC or near to the saturated steam temperature. The trap operates bv the
expansion and contraction of a metal bellows , which open and close a valve. Tire drain
discharges into a tundish in such a way that there is a complete airbreak between the drain
and the dish. This ensures that no contaminated water can flow back from the wasre-pipe
into tire chamber.
Operation of a gravity displacement autoclave:
If tlie autoclave "is jacketed, the jacket must first be brought to the operating
temperature. Tlie chamber is loaded, the door is closed and tlie steam-valve is c-oened,
allowing steam to enter the top of the chamber. Air and condensate flow out through the
drain at the bottom. When the drain thermometer reaches the‘required temperature a
further period must be allowed for the load to reach that temperature. This should.be
determined initially and periodically for each autoclave. Unless this is done the load is
unlikely to be sterilized. The autoclave cycle is then continued for the holding time. When it
is completed the steam valves are closed and the autoclave allowed to cool until the
temperature dial reads less than 8O0C. Not until then is the autoclave safe to open. It should
first be 'cracked' or opened very slightly and left in that position for several minutes to allow
steam to escape and the load to cool further.
9.9
BALANCE:
For measurement of mass, we employ an instrument known as balance. With this
instrument, we determine the mass in comparison with some standard weights. The
instrument primarily consists of the following parts. (Fig.)
Figures
A vertical pillar H is fixed on a base provided with levelling screws L, L Through
the vertical pillar passes a rod which can be raised or lowered by means of a key K at the
base. At the end of the vertical rod, there is a small piece of agate plate. On it rests an agate
or hard-steel knife-edge C, called the fulcrum, rigidly attached at the middle of a horizontal
beam AB of the balance. The beam is a light but rigid frame-work of thin metal rods. At the
two ends of the beam, there are two adjustable screw-weight.
L
f ■
I
r
CHAPTER- 9
9.
COMMON LABORATORY EQUIPMENTS:
9.1
INCUBATOR:
Incubator is an apparatus having a desired temperature. The heating device used can
be gas, oil or electricity. Maintenance of uniform temperature within the incubator is
essential and is achieved by fan, blower or a waterjacket containing heated water.
Ideal temperature for most of the medically important bacteria is 35O+2°C. However
for some organisms different temperatures are necessary e.g. atypical mycobacteria (22oC45°C), fungi (22°C) etc. Some organisms may need extra gaseous element e.g. 5-10% CO2
incubator for Brucella. The size of the incubator may vary from a small table top to a large
walkin type rooms. A proper temperature recording thermometer and a small tray of water
inside the incubator to prevent excessive drying of air are the two other essential
requirements.
9.2
HOT AIR OVEN
It is used for sterilisation of the following materials:
a)
Dry glass materials like test tubes, Petridishes, flasks, pipettes, syringes.
b)
Instruments like forceps, scalpels, throat swabs, etc.
c)
Sealedzmaterials which can stand heat and when penetration of steam is not
The instrument is electrically operated and should be equipped with a fan to have
untirom temperature inside, the required temperature for sterilisation is generallv I6O0C for 1
hour.
Operation of Hot air Oven
o
Arrange the material to be sterilised loosely and evenly on the racks of the oven
allowing free circulation of air and thereby even heating of the load.
o
Air is poor conductor of heat so do not pack the load tightly.
o
Switch on the power supply and control the temperature of the oven by adjusting
thermostat. When the desired temperature is reached, note the time. Time taken for
the oven to reach the desired temperature is called 'heating up period'.
o
Hold the load in the oven at this temperature for a definite period of time. This
period known as 'holding up period' is dependent upon the temperature employed.
At 160oC the holding up period is 60 minutes, at 170oC for 18 minutes, at ISOoC 7.5
minutes and at 190oC it is 90 seconds.
0
The most common temperature for hot air sterilisation is 160oC for one hour. When
the temperature is raised further, cotton plugs and paper wrappings get charred.
0
On the expiry of holding up period, switch off the power supply and allow the load
to cool.
Open the oven door only when the temperature fall below 80oC, otherwise it may
result in breaking up of glassware and also cause injuries to the operator.
0
o
Drv up the instruments before placing them in the hot air oven.
o
Do not place the heat sensitive materials inside.
9.3
WATER BATH:
Water bath is a water container having an electrically operated heating device to
provide a fixed and uniform temperature. A thermometer is inserted inside the water bath
for recording temperature. A mixer immersed inside water is also desired to maintain
uniform temperature throughout the water bath.
A few applications of water bath are:
9.4
37°C Water bath -
required during performance of WIDAL test;
44°C Water bath -
required in faecal coliform count (water bacteriology) test.
56°C Water bath -
for inactivating complement in tire serum.
CENTRIFUGE:
For an average laboratory’ a small table top centrifuge with a maximum revolutions
per minute of 6000 and capable of accommodating 10-12 tubes of 15 ml capacity is sufficient.
The tubes should be placed exactly opposite to each other, should be of the same weight and
should contain same amount of fluid. The speed is adjusted by a rheostat and should be
allowed to rise slowly. A timer for fixed duration of centrifugation is preferred.
A few common uses are:
When the microscope is not in use, keep it covered in a microscope compartment.
Xever apply force to the microscope. Never allow the objective lenses to touch the
cover
glass or the slide. Never lower the body tube with the coarse adjustment while looking
through the microscope. Never exchange the objective or occulars of different microscopes.
c
Store the microscope in its cabinet when not in use.
Q x
AUTOCLAVE
Principle
Water boils when its vapour pressure equals the pressure of surrounding
a losphere. The temperature at sea level is 100°C. When water is boiled within a closed
vessel at increased pressure, the boiling point of water is increased and so is the temperature
of steam produced. This principle is employed in sterilising material bv steam at
temperature higher than lOOoC and the process is called autoclaving.
For autoclaving in the laboratory, the most agreeable and commonly used method is
tc use steam at 12T’C for 15 to 30 minutes depending upon the particular material to be
sterilised.
■
Items to be sterilised:
Autoclaving is most suitable for culture media, aqueous solutions, decontamination
oi discarded cultures and specimens, rubber items such as gloves, stoppers with rubber
liner, glass ware with attached rubber tubings such as transfusion sets, glass metal svringes,
etc. Autoclaves designed for laboratory work and capable of handling mixed loads should
be used.
9.S.1
Types of autoclave
Only autoclaves designed for laboratory work and capable of dealing with a 'mixed
load' should be used. 'Porous load' and 'bottled fluid sterilizers' are rarelv satisfactory- for
laboratory work. There are two varieties of laboratory7 autoclave:
o
Pressure cooker types; and
o
Gravity displacement models with automatic air and condensate discharge.
Pressure Cooker type Laboratory autoclaves:
The most common type is a device for boiling water under pressure. It has a vertical
metal chamber with a strong metal lid which can be fastened down and sealed with
a rubber gasket. An air and steam discharge tap, pressure gauge and safety valve are fitted
in the lid. Water in the bottom of the autoclave is heated by external gas burners, an electric
immersion heater or a steam coil.
Diagram
Operating Instructions:
There must be sufficient water inside the chamber. The autoclave is loaded and the
lid is fastened down with the discharge tap open. The safety valve i- then adjusted to the
required temperature and the heat is turned on.
When the water boils, the steam will issue from the discharge tap and earn- the air
from the chamber with it. The steam and air should be allowed to escape freely until all of
the air has been removed. This may be tested by attaching one end of a icngm or rubber
tubing to the discharge tap and inserting the other end into a bucket nr similar large
container of water. Steam condenses in the water and tire air rises as bubbles to the surface;
when all of the air has been removed from the chamber, bubbling in the bucket will cease.
When this stage has been reached, the air-steam discharge tap is closed and the rubber
tubing removed. The steam pressure then rises in tire chamber until the desired rpessure,
usually 15 lb/in2, is reached and steam issues from the safety valve.
WHien the load has reached the required temperature the pressure is held for 15 min.
At the end of the sterilizing period, the heater is turned off and the autoclave allowed
to cool.
The air and steam discahrge tap is opened very slowly after the pressure gauge has
reached zero (atmospheric pressure). If the tap is opened too soon, while the autoclave is
still under pressure, anv fluid inside (liquid media, etc.) will boil explosively and bottles
containing liquids mav even burst. The contents are allowed to cool. Depending on the
nature of the materials being sterilized, the cooling (or 'run-down') period needed may be
several hours for large bottles of agar to cool to 8O0C, when they are safe to handle.
Autoclaves with air discharge by gravity displacement
These autoclaves are usuallv arranged horizontally and are rectangular in shape, thus
making tire chamber more convenient for loading. A palette and trolley system can be used.
The jacket surrounding the Gravity displacement autoclave consists of an outer wall
enclosing a narrow space around the chamber, which is filled with steam under pressure to
keep the chamber wall warm. The steam enters the jacket from the mains supply, which is at
>
high pressure, through a valve that reduces this pressure to the working level. The working
pressure is measured on a separate pressure gauge fitted to the jacket. This jacket also has a
separate drain for air and condensate to pass through.
The steam enters the chamber from the same source which supplies steam to the
jacket. It is introduced in such a way that it is deflected upwards and fills the chamber from
the top downwards, thus forcing the air and condensate to flow out of the drain at the base
of the chamber by gravity displacement. The drain is fitted with strainers to prevent
blockage by debris. The drain is usually fitted with a thermometer for registering the
temperature of the issuing steam. The temperature recorded by the drain thermometer is
often lower than that in the chamber. The difference should be found with thermocouple
tests. A 'near to steam1 trap is also fitted.
The autmatic steam trap or near-to-stream' trap is designed to ensure that only saturated
steam is retained inside the chamber, and that air and condensate, which are at a lower
temperature than saturated steam, are automaticallv discharged. It is called a !near-to-steam!
trap because it opens if the temperature falls to about 2oC below that of saturated steam and
closes within 2oC or near to the saturated steam temperature. The trap operates bv the
expansion and contraction of a metal bellows , which open and close a valve. The drain
discharges into a tundish in such a way that there is a complete airbreak between the drain
and the dish. This ensures that no contaminated water can flow back from the waste-pipe
into the chamber.
Operation of a gravity displacement autoclave:
If the autoclave is jacketed, the jacket must first be brought to the operating
temperamre. The chamber is loaded, the door is closed and the steam-valve is opened,
allowing steam to enter the top of the chamber. Air and condensate flow out through the
drain at the bottom. When the drain thermometer reaches the required temperature a
further period must be allowed for the load to reach that temperature. This should be
determined initially and periodically for each autoclave. Unless this is done the load is
unlikely to be sterilized. Tire autoclave cycle is then continued for the holding time. When it
is completed the steam valves are closed and the autoclave allowed to cool until the
temperature dial reads less than 8O0C. Not until then is the autoclave safe to open. It should
first be cracked' or opened very slightly and left in that position for several minutes to allow
steam to escape and the load to cool further.
9.9
BALANCE:
For measurement of mass, we emplov an instrument known as balance. With this
instrument, we determine the mass in comparison with some standard weights. The
instrument primarily consists of the following parts. (Fig.)
Figures
A vertical pillar H is fixed on a base provided with levelling screws L, L. Through
the vertical pillar passes a rod which can be raised or lowered by means of a key K at the
base. At the end of the vertical rod, there is a small piece of agate plate. On it rests an agate
or hard-steel knife-edge C, called the fulcrum, rigidly attached at the middle of a horizontal
beam AB of the balance. The beam is a light but rigid frame-work of thin metal rods . At the
two ends of the beam, there are two adjustable screw-weight.
ll
CASE DEFINITIONS
OF
EPIDEMIC PRONE DISEASES
NATIONAL INSTITUTE OF COMMUNICABLE DISEASES (
22-SHAM NATH MARG, DELHI - 110 054
1
S
- ■
I
s
. .....
initiated with high priority in known endemic areas. The help of the
community could be sought for this purpose.
5.
The guidelines include ‘trigger-events’ which should serve as early
warning signs or alarm signals warranting immediate invest igat ions.
All medical and health personnel should be aware of these (‘vents and
should report them to the nodal officer on telephone or lax will)
complete details. Name of the nodal officer, telephone, lax number
and address must be widely circulated.
6.
The trigger events include information about any acute in lections
severe illness requiring hospitalization of unknown etiology. Eac h
state and district should have a team of experts including an
epidemiologist/ public health specialist, microbiologist, entomologist
(for vector borne diseases) and clinician as a ‘Rapid Response 'ream’
for investigation of such reports. This will ensure ade(|uate follow-up
investigations, including collection of clinical samples for conlirmation
of diagnosis and avoid delay in initiating Held investigations and
outbreak containment measures where indicated. It will also ensure
that panic and chaos is avoided due to unsubstantiated rumours.
7.
If rare diseases, such as plague, are suspected, appropriale
investigations should be started on high priority. However, cases of
the following diseases will require laboratory confirmation and cannot
be diagnosed on the basis of clinical symptoms alone:
a.
b.
c.
d.
e.
f.
g-
Plague
Japanese encephalitis
Dengue fever
Leptospirosis
Cholera
Yellow fever
Typhoid fever
CASE DEFINTIONS OF
EPIDEMIC PRONE DISEASES
].
Chicken pox
2.
Cholera
3.
Dengue fever
4.
Diarrhoea, acute
5.
Diphtheria
6.
Dysentiy (Shigellosis)
7.
Food Poisoning
8.
Hepatitis, viral
9.
Japanese encephalitis
10.
Leptospirosis
11.
Malaria
12.
Measles
13.
Meningitis
14.
Pertussis (whooping cough)
15.
Plague
16.
Poliomyelitis
17.
Tetanus
18.
Tuberculosis
19.
Typhoid fever
20.
Visceral leishmaniasis (Kala azar)
1
rViinrrAdrziM ><:
Classification
Suspect -
Presumptive
Laboratory confirmed
Personnel
Lav public/MPWs
Medical officers
Medical officers
Method
History7,
History + Clinical
Investigations
Diagnostic Tests
Acute Diarrhoea
•
•
Three or more loose or watery
stools, OR Ay
Mother’s opinion during infancy
I
I
•
•
•
Acute watery diarrhoea in older
children (>5 years) and adults
leading to severe dehydration, OR
Profuse watery diarrhoea with or
without vomiting in an area
where outbreak is occurring
Cholera
•
•
•
•
Dysentery
•
•
Acute bloody diarrhoea
Fever and pain abdomen
Viral Hepatitis
•
Yellow colouring of the eyes and
skin (Pilia)
•
Three or more loose or watery
stools, OR
Change in consistency and
character of stools, OR
Mother’s opinion during infancy
None
Acute w’atery diarrhoea in older
children (>5 years) and adults
leading to severe dehydration, OR
Profuse watery diarrhoea with or
without vomiting in an area
where outbreak is occurring, OR
Other cases of similar illness
reported from the area, OR
Positive microscopic
immobilisation test for V.cholerae
in stool sample of patient having
clinically compatible illness
Note: Mild cases sire clinically
indistinguishable from non
specific acute diarrhoea
Isolation of V.cholerae 01 or
0139 from stool samples
Acute bloody diarrhoea
Isolation of Shigella sp. from stool
!
Acute onset
•
Hepatitis A - IgM HAV +ve
Jaundice
Malaise, anorexia,
•
Hepatitis B - IgM HBc with or
without HBsAg positive
Typhoid fever
Dengue Fever
(DF)
Dengue
haemorrhagic fever
(DHF)
•
Fever at present or preceding
jaundice
•
Hepatomegaly
•
Right upper quadrant abdominal
tenderness
•
ALT > 8 times of normal and
Serum Bilirubin > 2 mg% in
clinically compatible illness.
•
•
Suspected case, AND
With two or more of the
following:Toxic look
•
Coated tongue
•
•
Relative bradycardia
Splenic enlargement
•
Non productive cough
Sustained fever of more than one
week duration with gradual onset
with headache, malaise and loss
of appetite usually with
gastrointestinal symptoms
•
Hepatitis C - anti-HCV positive
•
Hepatitis D - HBsAg & anti HDV
+’ve
•
Hepatitis E - IgM HEV positive
•
Isolation of S.tuphi from blood,
stool or other clinical specimens.
•
Acute onset, and
•
High fever of less than 7 days
duration, and
Suspected case of dengue fever,
AND
•
•
4-fold rise of antibodies in paired
serum samples, OR
•
Severe headache, and
•
Joint and muscle pain and pain
behind eyes
Blood slide negative for malarial
parasite and patient does not
respond to anti-malarial drugs.
•
•
Serological test for IgM antibody
in single serum samples, OR
Isolation of virus from blood in
early phase
•
Outbreak of dengue fever in the
area
•
With or without rash
•
Suspected case of dengue fever ,
AND
•
Bleeding tendencies
•
\
*
Suspected case of DHF with .
bleeding tendencies evidenced bv
one or more of the following:Positive tourniquet test
♦
Petechiae. ecchvmoses or
•
3
above tests as in dengue rever
c:\JS\PS\CD2.DOC
I
*
*
♦
\
purpura
bleeding from the mucosa,
gastrointestinal tract, injection
sites or other locations
haematemesis or meiena
AND
Thromobocytopenia (100,000
cells per mm3 or less)
AND
• Evidence of plasma leakage due
to increased vascular
permeability-, manifested by one
or more of the following:
A rise in the haematocrit equal to
or greater than 20% above
average for age, sex and
population
ze> A drop in haematocrit following
volume replacement treatment
equal to or greater than 20% of
baseline
Signs of plasma leakage such as
pleural effusion, ascitis and
hyppproteinaemia*
Dengue shock
syndrome
•
(DSS)
Japanese
encephalitis
•
Suspected case of Dengue/DHF
with signs of shock including cold
clammy skin, restlessness or
sleepiness, excessive thrust
High grade fever of acute onset
with atleast two of the following:
•
Suspected case of Dengue shock
syndrome with
•
Low blood pressure
(Systolic less than 90 mm Hg)
•
Narrow pulse pressure (< 20 mm
ofHg.)_________________ __
Suspected case of Japanese
Encephalitis, and
•
4
As above.
•
Serology for JE antibodies.
c:\JS\PS\CI
Decrease in level of
consciousness independent of
convulsions
Significant change in mental
status either in behaviour or
personally
•
•
•
Pleocytosis in CSF of more than
10 cells/mm3 in clinically
compatible illness.
•
•
Suspected case of kala-azar
Progressinve weakness and
anemia
Splenomegaly, hepatomegaly,
lymphadenopathy
Convulsions
Visceral
leishmaniasis
•
(Kala-azar)
•
Persistant, irregular fever of more
than two weeks duration not
responding to anti malarial and
anti microbial.
Patient belonging to an area
known to be endemic for kalaazar or adjacent areas.
•
•
•
Diphtheria
•
•
•
Sore throat (with or without
difficulty in swallowing and/or
breathing)
Mild fever
Exposure to a case of diphtheria
in the previous 1 week or
epidemic of diphtheria in the area
Usually not more than a few
cases (1-2) in one village.
With or without signs of
meningeal irritation and varying
degree of neurological deficits
Clinically compatible illness in
endemic area with
thrombocytopenia and leukopenia
makes the presumptive diagnosis.
Direct agglutination test (DAT)
OR Postive aldehyde test in
clinically compatible case is also
highly suggestive of kala-azar.
Suspected case of diphtheria^
AND
Greyish-white membrane in
throat (with or without difficulty
in breathing),
AND
•
Demonstration/isolation of
virus/antigen from CSF, brain
tissue or rarely blood.
•
Demonstration of L-D bodies in
stained smears from bonemarrow, spleen, liver, lymphnode
or blood is highly suggestive but
not conclusive.
•
Presence of anti-leishmanial
antibody in significant titre as
detected by IFAT or ELISA.
Culture of the organism from a
biopsy material or aspirated
material confirms the diagnosis.
•
• • Positive culture of
Corynebacterium diphtheriae
(demonstration of toxin
production recommended but not
required)
Acute pharyngitis, naso
pharyngitis or laryngitis,
OR
Myocarditis or neuritis (paralysis)
one to six weeks after onset of
5
c:\JS\PS\CD2.DOC
symptoms
I________
Measles
•
•
•
Generalised blotchy rash lasting
3 or more days
'
Fever
At least one of: Cough, runny
nose or red eyes
•
Staining of throat swabs by
Albert stain showing organism
resembling C.diDhtheriae in a
clinically compatible case is also
sufficient to make presumptive
diagnosis.
•
Generalised maculopapular rash
lasting 3 or more days, and
Fever 38°C. (10IT) or more, and
At least one of: Cough, coryza,
conjunctivitis.
•
•
•
Positive serology (4 fold or greater
rise in serum antibody titre).
Laboratory confirmation is not
required at present.
Koplik’s spots in a clinically
compatible illness confirm the
diagnosis.
Note: A child may come with post
measles complications like
pneumonia and diarrhoea.
Mother should be interviewed for
any past history of measles.
Neonatal tetanus
Poliomvelitits
•
Normal suck or cry for first 2
days, and
•
A suspected case of neonatal
tetanus, and
•
Onset between 3-28 days of birth,
and
•
Trismus often leading to death
•
Inability to suck, followed by
stiffness or convulsions
•
Fever
•
•
Abrupt onset of weakness or
paralysis of the leg(s) or arm(s)
A suspected case of poliomyelitis,
and
•
Flaccid paralysis
•
No sensory loss
•
Muscle tenderness
•
Absent or depressed deep tendon
reflexes
•
No progression of paralysis after
first three days
•
Paralysis not present at birth or
associated with serious injury or
6
None
•
Isolation of wild polio virus from
cases or contacts of AFP.
c:\JS\PS\CD2.DOC
mental retardation
Tetanus
Tuberculosis
(childhood)
Whooping
(Pertussisi
•
Histoiy of Injury, ear infection or
child birth or abortion,
AND
•
Difficulty
and/or
•
Acute stiffness or convulsion
in
opening
•
Asymmetrical findings
•
Wasting of affected muscles (late
findings)
•
Residual paralysis 60 days after
onset of illness makes the
presumptive diagnosis.
•
Death or unknown follow-up in
AFP cases also makes the
presumptive diagnosis.
•
•
A suspected case of tetanus
Trismus
•
Tubercular meningitis - Any case
of meningitis not responding to
conventional
treatment
but
responding to anti TB drugs.
•
Microscopy or culture of tubercle
bacilli,
identified
as
Mycobacterium
1tuberculosis,
'
'
from secretions or tissues
•
Tubercular
lymphadenitis
lymphadenitis in a clinically
compatible
or
radiologically
suggestive case not responding to
conventional
treatment
but
responding to anti T'B drugs.
•
Suggestive histological findings in
biopsy material
•
Prolonged coughing followed by
apnoea, cyanosis or vomiting
Typical whoop
mouth,
Fever or swelling neck/axilla/
groin with history of tuberculosis
in the family
cough
None
•
Cough persisting 2 weeks or
more, and one oi the loilowing;
•
Fits of coughing which may be
followed by vomiting
•
Subconjunctival
7
of
Culture
nasopharyngeal
secretions for Bordeteila oerrussis
bacteria.
haemorrhages
c:\JS\PS\CD2.DOC
Chicken pox
Food poisoning
Meningitis
Typical whoop
Exposure to a case in previous 2
weeks or epidemic of whooping
cough in the area
may or may not be present
White blood cell count with
15000 lymphocytes/cu mm or
more in a clinically compatible
illness is suggestive of whooping
cough.
Acute onset of fever and
generalised vasico-pustular
eruptions on trunk and face but
less on limbs.
Fever, bod vac he
Rash from 3rd-4rd day
Occurrence of diarrhoea and/or
vomiting within a short but
variable period of time, and
Consumption of food from a
common source.
Sudden onset of high grade fever
Severe headache with or without
altered conciousness
Not required.
Rash on trunk and face, less on
limbs
Lesions have irregualr oval
shape, are not homogenous and
are generally unilocular. Never
indented
Crops of spots appear so that
lesions are at different stages.
A clinically compatible case
epidemiologically linked to
another probable case confirms
the diagnosis.
Suspected case of food poisoning,
and
2 or more persons experience a
similar illness after ingestion of a
common food and the
epidemiological analysis indicates
the food as the source of illness.
(Exception: botulism or chemical
poisoning may affect only one
person).
A suspected case of meningitis
Nuchal rigidlity
Kerning and Brudzinski sign +ve
Stiff neck
8
Isolation and/or identification of
causative organisms and/or
toxins from the clincal samples
(faeces or vomitus) and
incriminated food.
Latex agglutination kits can
detect meningococci,
pneumococci and H.influenzae in
CSF in field conditions.
c:\JS\PS\CD2.DOC
•
•
Leptospirosis
•
•
Plague
•
•
•
Contact with a confirmed case of
Plague or presence of plague
outbeak in the area. AND
Bubonic plague: Sudden high
fever , chills and painful lymph
node swellings in the groin or
underarm region. Patient looks
extremely ill. OR
Pneumonic plague: Sudden high
fever, chills, cough, chest pain
with or without haemoptysis
(blood in sputum). Patient looks
extremelv ill.
•
•
Staining of CSF may reveal
organisms; Meningococci are
Gram negative diplococci which
may be intracellular also.
Biochemical features
An illness charaterised by fever,
headache chills, myalgia
conjunctival suffusion, and less
frequently meningitis, rash,
jaundice or renal insufficiency.
Symptoms may be biphasic. AND
Supportive serologic findings i.e.,
a leptospira agglutination titer of
>200 in one or more serum
specimens.
A clinically compatible illness,
and contact with a confirmed
case of plague or presence of
plague outbeak in the area
should be taken as a suspect
case.
Clinically compatible illness with
identification of a Y.pestis like
organism by light microscopy in
the clinical material should be
taken as a probable case.
Culture for isolation and
confirmation of pathogens.
•
•
Isolation of leptospira from
clinical specimen
4 fold or greater increase in
agglutination antibody titre in
paired samples obtained > 2
weeks apart.
•
Demonstration of leptospira in a
clinical specimen by
immunofluorescence.
•
Isolation of Yersinia pestis from
bubo aspirate or sputum.
4 fold rise in specific Fl antibody
titre by PHA test in paired serum
samples.
•
•
Clinically compatible illness with
one serum specimen tested by
PHA test for Fl antigen giving
titre >1:8 also gives presumptive
diagnosis.
Clinically compatible illness and
demonstration of Y.pestis like
organism with fluorescent
microscopy gives presumptive
: : . diagnosis.
•
9
c:\JS\PS\CD2.DOC
Di
Surveillance
OF
Epidemic Prone
Diseases
NATIONAL INSTITUTE OF COMMUNICABLE DISEASES
(DIRECTORATE GENERAL OF HEALTH SERVICES)
22-SHAM NATH MARG, DELHI - 1 10 054
AUGUST 1997
•8
CONTENTS
1. Introduction
1
2. Surveillance
2
3. Prioritisation of diseases for surveillance
3
4. Prerequisites for effective surveillance
4.1 Regularity of reports
4.2 Frequency of reporting
3
4
4
5. Methods of data collection
5.1 Routine reporting (institutional based or passive reporting)
5.2 Sentinel surveillance
5.3 Active surveillance
5.4 Vector surveillance..*.
5.5 Laboratory surveillance
5.6 Sample surveys
.
5.7 Outbreak investigations
5.8 Special studies
.5
.6
.7
.8
.9
.9
10
10
6. Data to collect
6.1 Age
6.2 Sex
6.3 Date of onset of symptoms
6.4 Outcome
6.5 Immunization status
6.6 Residential address
10
1 1
7. Compilation of Data
7.1 Tabulation
7.2 Drawing
13
13
8. Analyse Data
8.1 Increasing Completeness of Reports
20
27
9. Summary
30
10. Conduct Investigation
30
11. Action
3I
12. Feedback
31
Exercise 1 ..
Exercise 2 ..
Exercise 3 ..
Exercise 4..
Exercise 5 ..
Exercise 6 ..
Exercise 7..
Exercise 8 ..
Exercise 9 ..
Exercise 10
Exercise 1 1
Exercise 12
Exercise 13
lb
19
20
21
22
22
23
23
23
1 I
I I
12
12
12
14
25
26
27
32
i
b’<i (i
1.
Introduction
Surveillance of diseases is the continuing scrutiny of all
aspects of the occurrence and spread of a disease that air
pertinent to effective control. Communicable diseases constitute
a significant disease burden and are major causes of nioibidity,
mortality and long-term severe mental and physical disabilities.
Many of the diseases are epidemic prone.
■X
x
V-'
<^c
The vulnerability of an area to an outbreak increases with
increase in population density and high migratory habits of the
population. The receptivity of an area to outbreaks is related to
inadequate drinking water facilities, poor sanitaiy conditions
and adverse environmental events conducive for increase in
vector density and natural disasters such as earthquakes,
floods etc. Developmental activities such as large constructions,
irrigation, industries can also increase the risks of epidemics
unless adequate preventive and precautionary measures arc
J-- inbuilt in the planning and implementation stages.
Epidemics are public health emergencies. Epidemics
disrupt routine health services and are a major drain on
resources. Besides direct costs in outbreak control measures
and treatment of patients, the indirect costs due to negative
impact on domestic and international tourism and trade can be
significant. The avoidable human misery resulting from illness
and death cannot be quantified in economic terms.
Not all outbreaks can be predicted or pi evented.
However, precautionary measures can be taken within the
existing health infrastructure to reduce risks of outbreaks and
to minimize the scale of the outbreak if it occurs. The
effectiveness with which national programmes are implemented
and monitored, the alertness for identification of early warning
signals and the capacity for initiating recommended specific
interventions in a timely manner are important to achieve the
above objectives.
The course of an epidemic is dependant on how early the
outbreak is identified and how effectively specific control
measures are applied. The epidemiological impact of the
outbreak control measures can be expected to be significant
only if these measures are applied in time. Scarce resources are
often wasted in undertaking such measures after the outbreak
has already peaked and the outcome of such measures in
limiting the spread of the outbreak, and in reducing the minibei
of cases and deaths, is negligible.
1
C:\.IS\Slll ■ <"'l ■ln<-
When outbreaks occur or when the risk of such outbreaks
is high, the co-operation of other government departments, non
governmental agencies and the community often beeomejj
necessary. Such help will be more forthcoming if mechanisms
; for interaction have been developed before the onset of an
outbreak.
The frequency of the occurrence of the epidemic s is an
indication of the inadequacy of the surveillance system and
preparedness of the district to identify and control outbreaks in
a timely manner.
The purpose of the training programme is for capacity
building at district level to detect the outbreak in its early rising
phase and to respond effectively to control its further spread.
2.
Surveillance
Surveillance is data collection for action.- Surveillance
data are required for planning disease control activities and for
evaluating impact. Disease surveillance data are also required
to ^lontify_high__risk_.areas or high_risk agejspecific and other
groups who require special attention. -Early warning signals will
be missed in the absence of an effective suivcIITancc system.
To plan any disease control programme and to identify
and control outbreaks, it is important to know the following:
•
•
•
•
•
who get the diseases
how many get them
where they get them
when they get them
why they get them
There are five steps in the surveillance procedure which
must be carried out at each level, starting from the PHC. Each
level must have the capacity for analysing and using
surveillance data for it to be effective for outbreak prevention
and control. The live recommended steps arc:
•
•
•
•
•
collection of data
compilation of data
analysis and interpretation
follow up action
feedback
2
(• \.IM\Hhi f■>•• I .1
Prioritisation of diseases for surveillance
3.
\
-
- p'"
There are many communicable diseases which are
widespread and are the major causes of morbidity and
mortality. Many of these diseases also have the potential of
causing large outbreaks. Most of the diseases with an epidemic
potential are either water-borne, vector borne or are transmitted
Uirough contact.
Besides the epidemic prone diseases, the surveillance
system must also include diseases which are covered under the
national programmes. These diseases account for a significant
disease burden, lead to lifelong severe mental and physical
disabilities and are usually amenable to control through cost
effective means.
4
The existing health infrastructure can be effectively used
to introduce a system of early warning signals or 'trigger eventsj,
to detect an outbreak in the early rising phase aridl^ccmtrol it
effectively. Orientation of the medical officers and the O
paramedical personnel will be needed to make the programme a (
success.
4.
Prerequisites for effective surveillance
The manual includes diseases and formats which arc
already in use. Some districts may have special problems or
needs. Additional information may be collected if necessary.
However, all information collected at PHC or district is not
required to be transmitted to the state or central levels unless a
special request is received. Only data that is used should be
collected otherwise it will clutter and overburden the system.
Irrespective of what data is collected, the basic principals of
surveillance would remain the same:
•
use stnndard cnsc definitions
•
•
maintain regularity of the reports
take action on the reports
For developing an effective disease surveillance system,
the district health officcr/PIIC medical officer must also he clear
about:
•
•
•
•
•
what information to gather
how often to comi
an(3 analyse the data
how often and to whom to report
what proforma or formats to use
what action to take
3
1 he data collected should be uniform, regular and timel\ .
Standard case definitions are important to ensure uniformity in
reporting so that all reporting units use the same criteria for
reporting cases. It is also important to have a list of all reporting
units so that the regularity and timeliness of the rcpoits is
checked. If no cases are seen, a nil report should be submitted.
All levels in the system must:
•
•
•
•
have the standard case definitions
have a list of all reporting units
monitor receipt of reports in time
monitor completeness of reports
I he standard case definition of diseases is given in a
separate manual. The cases have been classified as:
4.1
•
lay (suspect) - diagnosis made on the basis of history
by paramedical personnel and members of the
community
•
presumptive - diagnosis made on typical histoi y and
clinical examination by a medical oiliccr
•
confirmed - clinical diagnosis by a medical officer
and/or positive laboratory identification
Regularity of reports
Monitoring the regularity of surveillance reports is an
important function of the surveillance system.
A list of all
reporting units in the area must be kept. The Chief Medical
Officer of Health of the district must identify the reporting units.
Besides the PHCs and CHCs, hospitals, large dispensaries and
clinics should be included as reporting units.
4.2
Frequency of reporting
4.2.1 A system of monthly reporting of disease and progi amine
specific data already exists in the districts. The lotilitie
reporting of cases and deaths should continue.
Many epidemic prone communicable diseases have short
incubation period. If a review of the data is made only on
a monthly basis, it might delay the timely identifieaiion of
an outbreak in the early rising phase. Reporting units
may consider the weekly^plotting of cases seen in their
institutions in the simple format. If the number ol < ases
4
•J- i
is (Io1JbjJ.wcoi)secuIivc weeks, it should serve ns n
warning signal for investigations. The area of residence of
the patients should be checked and if these' rn-rs me
clustered with respect to time and place, an immediate
ficld_ visit is indicated._ An epidemic can be avciied by
taking ^"appropriate control measures in time*. It an
outbreak is suspected or identified, the next level should
be notified immediately.
4.2.2 Daily reports arc necessary once an outbreak has been
identified so that the situation^ can be nionitorcd.
Neighbouring areas would need to step up surveillance
activities also to rule out the spread of the outbrrak.
After the outbreak has subsided to prcLiQUtbreak levels,
weekly reports should be continued for at least double the
inaximum incubation periods of the disease.
5.
Methods of data collection
Several methods can be used for collecting data. While
routine reporting (passive surveillance) is universalised, other
methods are need and area specific. These include:
•
•
•
•
•
•
•
5.1
sentinel surveillance
active surveillance (active search for cases)
vector surveillance
laboratory surveillance
sample surveys
outbreak investigations
special studies
Routine reporting (institutional based or passive reporting)
All the national health programmes require that the cases
and deaths recorded in the out-patient or in-patient
departments of hospitals, dispensaries, community health
centres, primary health centres and other health facilities
manned by a medical officer, report these cases to lIn’ local
health authority on a monthlyjpasis. The consolidated h port of
the district is forwarded to the state health officer, f or some
national programmes, a copy of the district report is also
forwarded to the concerned officer at the central level.
At each level in the system, the report is recjuiicd to be
analysed and appropriate action taken as indicated. The reports
should be checked for completeness and regularity ns llu'sc
factors can influence the analysis of the reports.
5
i >i'..
Each reporting unit must have the following, details
available in their records for each case. The details of th-- - ascs
are essential for outbreak investigations. Each reporting, unit is
advised to 'spot-map’ cases at least for a few select dis- *.'r;rs su
that high-risk pockets could be identified. The line listing is,
however, required to be submitted on a regular basis only Im a
few select diseases for which goals for eradication have h----n •;r|.
•
•
•
name of the patient
name of the mother or father
full postal address of the residence (the address must
be complete to facilitate home visit, if reqiiin d. Il
might be helpful to record the name of the m-mesl
sub-centre and PHC, for example, if the pali< nt can
provide this information)
•
•
•
sex
date of onset
immunization status (if child under five years of age
and vaccine is available for public health use)
out come
date of collection of clinical sample (if any) ami lab.
result
•
•
5.2
Sentinel surveillance
A sentinel surveillance system is developed to obtain more
reliable and extensive disease information than is available from
the routine reporting centres. A hospital, health <(mtie,
laboratory or a rehabilitation centre which attend to a relatively
large number of cases of the disease can be considered as a
sentinel centre. A sentinel centre can provide information on
one or more diseases.
Since the sentinel centres are carefully selected and
because the number of the reporting units is much smallci, it is
easier to maintain the quality and regularity of the reports.
There should be a close liaison between the
incl
centre and the local health office. The sentinel centre coti help
in providing:
•
•
line lists of selected diseases which is esscnli;il for
epidemiological analysis
early warning signals which should trigger action foi
outbreak investigations
(j
M
■
The sentinel centre data will not include all coses in the
area. However, If one or more senlinel centres ha\e been
carefully selected, it will include sufficiently large iniinlicr o!
cases for epidemiological analysis and for reliably deteimining
trends in the incidence of the reported disease.
The district hospital, infectious diseases hospital, medical
college hospital (if located in the district) and other large
hospitals or laboratory should be included as scritinc£< enlres
and reports liduTthese centres should be analysed sepaiately.
These centres would also be submitting the routine monthly
report under the passive surveillance system.
5.3
Active surveillance
However good the routine reporting system there will si ill
be cases that will not be recorded under this system as palienls
with mild or moderate severity may not seek treatment. Some
may go to private practitioners. It is also possible that patients
in severe condition arc taken directly to a large hospital in
another district for specialized care. Some cases may die within
a short period of onset of symptoms without receiving cate at a
health facility such as cases of mtonatal tetanus.
Active surveillance or active search for cases is lesource
intensive. The decision to start active surveillance depends on
many factors and ground situations. Active search may be
called for under the following circumstances:
•
during outbreaks to determine the extent of the ontbical;
and keep mortality rates low by initiating early tiealmenl.
Active surveillance is carried out to know the magnitude of
the problem which will help in planning logistics for control.
In addition it will give baseline data to evaluate control
strategy. It also helps in understanding the genesis of the
outbreaks—
as the number of cases of a disease decline to negligible
levels and it becomes important to receive infoi inal ion on
every single case as quickly as possible so that further
transmission is interrupted by initiating outbreak control
measures. For example, active surveillance is recommended
for acute flaccid paralysis (AFP) and guinea worm disease.
•
trace-cases and contactsjjver a limite.d_period_()f time for
selective interventions to interrupt transmission This
strategy is recommended in the yaws, affected dish ids. In
selected districts, similar strategies arc being tiiod for
filariasis and leprosy control
7
-\
\
\
•
to confirm the absence of even a single case. 'I bis i . d-aJo
dining the pre-ccrtification phase for disease ei;i<li> :11i<>ii ,-v;
^zero
zero ’hl£i<l51tice
incidence has to be maintained for
lor a pciiod
period <•! Ihl ( r
years. Special measures, such as annoimcemciTt
,y£2£S,
announcement -,T c ;r.li
awards arc also introduced at this time, 'the last ' sc (l|
guinea worm disease was reported in July 1996. II the Z(‘l (»
status is maintained, eradication of guinea worm f I iso;isc*
will be certilied in India in 1999.
During field visits by the supervisors, absence ol (I i sms'’
can be confhmed by contacting few key persons sinh as
sphool teacher, gram pradhan, anganwadi worker and oiin-i s.
Since active surveillance is usually recommended 'Alien it
is important that not even a single case is missed, follow up on
the report of"a case must be prompt, preferably not lai< i than
.48 hours.
The health personnel, outreach personnel ol other
government departments, non-governmental organizations and
the members of the community must be encouraged to rcpoii
cases. The lay case definition of the disease should be widely
circulated for this purpose. The health personnel should not
be punished or <"
discouraged in any way from reporting cases
as this will lead to suppression of vital information.
5.4
Vector surveillance
Vector surveillance is important to identify the < isiine,
vectors in the area. Increase in the density of tlie vcctois is a
high risk factor for vector borne outbreaks.
District health officer should have linkage with the Zonal
entomologist of his district.
Data on entomological survey
carried out in the past should be fully utilised for planning of
anti-vector measures, If no entomological studies have |)rrn
carried out, these can be planned in consultation with ih<
sj zonal/ state entomologist.
c <5:
T
cr
Depending on the resources available, survcillan-ol
vector density and their bionomics should be done in sclrded
epidemic prone pockets such as areas with seepage iiom
'riiggligp canals, dam projects, flood prone areas arul~<rrTwi~; go
that, anti-vector
anti-vector m
measures
that
easures can be initiated as a precauii<.nm\
■J measure to prevent an outbreak.
8
r:\.IS\S
Sample checks will also document (he inipai I <>l Ihr
routine measures for vector control under the National Malari
ii in
Eradication Programme (NMEP).
5.5
/c
Laboratory surveillance
Testing water samples for coliform organisms is ;i
measure to determfne the risk of water borne outbreak';, Writer
quality monitoring is recommended in vulnerable po< I rts and
from sources supplying drinking water to a large populalton?
4^
JZ
Checking the chlorination levels of the water is also
important, especially during the monsoon and post monsoon
periods. These measures by the health department a i e
precautionary measures in addition to the mandatory
requirements of the concerned departments.
Laboratory surveillance must be stepped up in
anticipation or in the event of an outbreak. Serologic al and
other laboratory based- surveys are sometimes eondm led ;is
research projects to collect baseline, prevalence rates or i<l('Dt ily
high risk factors, age-groups or population sub-groups.
The identification of new agents and changes in the
behaviour of micro-organisms especially in’ t elation Io
susceptibility to anti-microbial arc also important components
of laboratory surveillance.
Laboratory also plays a very important role in sin veillmiee
of certain diseases like dengue fever (monitoring of fever cases
for antibodies against dengue), cholera (isolation of V.eholeKie
from stool sample of acute diarrhoea leading to dchydirition in
persons five year and older) and poliomyelitis (isolation of virus
from stool samples of AFP cases).
Clinical samples should be collected and transported
properly to the identified laboratories for appropriate Icsts. The
samples should be labelled properly and accompanied with
requisite epidemiological information.
5.6
Sample surveys
Surveys give reliable epidemiological information. I hese
are particularly useful to collect baseline data prior to the
launch of a large control programme, especially if such data are
lacking through other sources.
Surveys are, however, difficult to conduct and me
relatively expensive. The sample size, sampling pio<<-< line,
9
• i. -I
methodology, questionnaires and forms must be well d< -.ipm-d
to avoid bias and misinterpretation of data. Morrom, the
results of the surveys are area and time specific. The u suits
of the surveys are relevant only to the area in which th(-s<- v.e-rr
conducted and the period when these were conducted.
Not all surveys are, however, difficult and standard
guidelines are available. These surveys can be conducted aftei
a period of 3 to 5 years or more to document impact. Such
surveys include multi-indicator studies on ORT and API in
children. Stool surveys of school children for assessing iIn
prevalence of helminthic infestation can also be organiz(‘d
It is expected that if a survey is conducted in a distii' il
will be in collaboration with the state and central hr;dth
authorities. Since this activity is not recommended as a rouiinc,
further information on the subject can be obtained horn ihr
concerned state officer directly.
5.7
Outbreak investigations
Outbreaks investigations provide a rich smirr of
epidemiological information. The outbreaks should be
investigated to understand why they occurred and Io identify
high risk areas and groups. The data collected as a icsiili of
outbreak investigations must be utilised for impioving
programme activities and the surveillance system as well as foil
filling gaps identified as a result of these investigations.
The results should he shared with other district olli< fi s
and other states so that the experience gained could be
effectively used for preventing such outbreaks in these air as.
5.8
Special studies
Special studies are sometimes required to study piohh-ms
that are not addressed through the methods of data <mllcction
listed above. Some districts, for example, may have a high
prevalence of cases linked to or suspected to be due Io
environmental pollution; other districts may have pi obh inS
related to multi-drug resistant micro-organisms.
6.
Data to collect
Usually only the number of cases and deaths an* rcpor'rd
under the routine reporting system. If the number of <
<4 n
disease is large, it is neither practical nor necessary to *
detailed information on each case. However, as nvmiioocd
earlier, each treatment centre must, keep a record of all
10
e:\.IS\t-iu
Relevant information may be obtained for selected epidemic
prone diseases from selected centres (sentinel hospitals) so that
high risk areas and groups (for example related to age and
immunization status) can be identified. Besides the name of the
patient and name of father or mother so that she/ he could be
traced for further investigations if necessary, the following
information is required for making policy decisions and to
evaluate impact:
•
•
•
•
•
•
•
6.1
age
sex
date of onset of symptoms
outcome
immunizalion status (lor vaccine preventable diseases
in children under five years of age)
residential address
date of collection of sample and lab. report (if any)
Age
Age is important to identify age-groups at highest risk.
This information is important in understanding disease
dynamics and formulation of control strategies. Data on age of
cases for vaccine preventable diseases helps to determine the
immunization schedule and to have cut-off age limits during
outbreaks which can be controlled by vaccination. Some
diseases are more severe in the higher age-groups.
Some
diseases are seen more in one age-group than another and this
might help in differential diagnosis. Age, for example, is one of
the criteria in the differential diagnosis of acute flaccid paralysis
in children.
6.2
Sex
Gender is recorded to determine the sex differential
which is common in some diseases with either males or females
being more prone depending on the risk factors.
Hospital
records may however also reflect the medical attention given to
male members of the family as compared to the females. Tor
example, while almost all cases of neonatal tetanus admitted in
hospitals are males, this is due to the fact that the female child
is not brought for treatment.
6.3
Date of onset of syini>lorns
The date • of onset of symptoms is important for
determining the course of the outbreak and to undertake
epidemiological investigations. Information regarding the onset
11
(Kl <I<H-
Of symptoms is also necessary for interpretation of laboratory
55 L S>.
6.4
Outcome
One of major objectives of the national programmes and
outbreak control measures is to minimize niortaiity and case
fatality rates. Recording the outcome of the diseases in terms of
whether the patient recovered fully or has long-term
complications as a result of the disease or died.
Recording the outcome and case fatality rates will also
indirectly give information on the quality of the management of
cases if there are wide variations in the clinical outcome in
different hospitals.
High case fatality rates may trigger lurthcr investigations
and identify other underlying cause (s) in the area.
6.5
Immunization status
Immunization is one of the most cost effective public
health programmes and no child should be denied its benefits'
Contacts with the health care delivery system should be used
to check the immunization status of all children under live
years of age so that they could be immunized as appropriate for
the age. Recording the immunization status is particularly
important if the case is of a vaccine preventable disease.
Occasionally a child who is fully vaccinated at the correct
age with potent vaccine may get the disease. This is because the
vaccine efficacy is usually less than 100%. Even if a potent
vaccine is used at the right age in the right dose, some children
will not be fully protected. If a large proportion of cases occur in
fully vaccinated children, it should be investigated.
While the immunization status of a child may not have a
direct relevance for diseases other than the vaccine preventable,
high immunization coverage would indicate a healthy public
health system with a good outreach and 1EC efforts. (Jn the
other hand, if a large number of children are non-immunized, it
reflects poor contact with the health system or other problems
of access to health care.
6.6
Residential address
Residential address of the patients helps in identifying
high risk area.
It is not only essential to apply control
measures in the affected areas, but is also useful to understand
12
(’:\.IS\Siii Mt./I (loc
the natural history of disease's. Some disease's an* more
prevalent in rural areas (for example, JE, neonatal tetanus)
whereas the others affect mainly urban population (Dengue
fever). Diseases like kala-azar are confined to certain
geographical area (Bihar, some districts in West Bengal and
U.P.).
7.
Compilation of Data
Data should be compiled to describe the diseases in terms
of time, place and person. There are two methods of compiling
data.
1.
2.
7.1
Tabulation
Drawing
a) Graphs
b) Diagrams
Tabulation
Usually the data collected is large in amount and
therefore, should be classified and presented in the form of
frequency distribution table. This is very important step before
statistical analysis of data. It groups large number of
observations and presents the data very concisely giving all
information at a glance.
Example 1:
Table 1 shows the geographic distribution of
laboratory confirmed cholera cases in Delhi during
1988.
Table 1
Laboratory confirmed cholera cases in Delhi by Zone, 1988
Zone_____________
) CITY ZONE
2JS.P. ZONE
KAROL BAGH
WEST ZONE
CIVIL LINES
NARELA
NAJAFGARH
q SOUTH ZONE
Cases
10
45
43
50
508
48
79
69
s0N.D.
26
SHAHDARA
583
V
NDMC
15
^CANTONMENT
1 1
ZONE UNKNOWN____ 49
Total______________
1536
Note: 1 13 cases were from outside Delhi.
Records were not available for 59 cases.
13
Percent
0.7
2.9
2.8
3.3
33.1
3.1
5.1
4.5
1.7
38.0
1.0
0.7
___ 3.2_
100.0
('.:\.IS\Snt M < ><i < i< i<*
.V
It is evident from Table 1 that most of the cholera cases
occurred in Shahdara (38%) and Civil Lines (33.1%) zones.
Example 2:
Table 2 describes the vaccination status of measles
cases which occurred in 7 districts of Uttar J’ladesh
during the epidemic of 1996.
Table 2
Immunization status of measles cases in
Uttar Pradesh, 1996 *
District
No. of measles
No.
cases
immunized
examined
Bareilly
173
5
Baharaich
_______ 41______
2
Hamirpur
______ 108______
6
Maharajganj
______ 3(>3______ _6d
Kheri_______
315
66
Lucknow
102
24
Alniora_____
31
__ 9
All__________
1133
175
* More than 9 months of age.
immunized
_3.()
4.8
5.6
.
J.Z(’
20.9 "
23.5
29.()
”
15.4 '
It is clear from Table 2 that almost 85% of the cases had
not been vaccinated against measles.
7.2
Drawing
After
group-wise
tabulation,
the
frequencies
of
characteristics can be presented by graphs and diagrams. They
are useful for quick eye reading of data.
Line graph, bar diagram, pie diagram and map diagram
are used frequently in disease surveillance. For example, in
order to monitor the incidence i.e. number of new cases in a
defined population during a specified period of time, it is
necessary to maintain diagram (charts) or graphs. These charts
and graphs show the number of cases of the diseases for each
reporting period. With charts and graphs it is easy to visualise
the number of cases which occurred in each reporting period.
14
M...I
7.2.1 Disease Diagrams
Figure 1
Seasonality of cholera in Delhi, 1996
(Bar Diagram)
□ No. of Cases
250
200
150
100
50
, n
0
Jan
Example 3
Feb
Mar
Apr
I n
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Figure 1 is a sample bar diagram for the number of
laboratory confirmed cases of cholera in Delhi in
1996.
By looking at the chart it is easy to determine how many
bactcriologically proved cases of cholera occurred each month in
Delhi. For example, most of the cases occurred from May to
September, while Dec-Feb were completely free from the
disease.
7.2.2 Line Graphs
In order to maintain a disease graph, perform
following tasks:
the
On the first day of each reporting period, count the
number of cases of disease diagnosed during the previous
reporting period.
Place a dot on the graph directly above the mark for that
reporting period.
Draw a line from the previous dot to the new one, so that
you will have a clear picture of the trend in the incidence of
disease. If the line goes down from left to right, the number of
cases is decreasing. If the line goes up from left to right, the
number of cases is increasing.
IS
M-h| <1
Figure 2
Seasonality of cholera in Delhi, 1996
(Line Graph)
250
[ -"♦—No. of Cases]
200
150
100
-
50
o ♦Jan
Feb
Example 4:
Mar
Apr
—i—
—i—
May
Jun
-♦
Jul
Aug
Sep
Oct
Nov
Dec
Fig 2 drawn from the same data as in Fig I. You
can see that cholera (appearcd in March, had peaks
in July-August and almost disappeared in
November-December.
During ongoing disease surveillance of epidemic' prone
diseases, compile the data weekly rather than monthly (Table 3).
Exercise 1
Table 3
Weekly distribution of cases of epidemic-prone diseases
attending a health institution
Diseases
1
2
3
4
Weeks
5
6
7
8
52
Diarrhoea
Jaundice
Malaria
Measles
16
C:\.IS\Siii ’ i- i -I -
•
Draw Bar diagram and line graph using data in table No.4.
Ir
t----- r
T
L
------ r
i
•>i‘r
J
r.. ~
fT
t
i
i
T
I
i
—
i
I
vd----I
f
i-
T
T
u-i-----
t
i
A ,
T
T H= 1=1
aCj......
I-
•4
!
r—......
:-------Co !--------
£ o !"-......
I
t7~-
qc:
i
I ' u4
■
_________ »■
1
9.
8
.
0\A
V',
9
10
'AkVt.
11
12
13
14
15
16
17
18
19
20
21
22
23
Week
17
C:\JS\Sur-Mod.doc
24
i
Table 4
Week-wise reported cases of Measles in
District Maharajganj, Uttar Pradesh, 1996
Period
ending week
1
2
3
_____ 4_______
5
6
7_
8
9
____ 10_______
11__
12
No. of cases
0
£
6
^8
£
£
0
£
2
Period
endiiig week
13
____ 14_______
____ 15_______
____ 16_______
17
____ 18_______
____ 19
20
No. of cases
_()
__5 i
0
()
_()
_()
_ ()
_0
__ 22_____
0
____ 22_______
23_______
24
£
9
i
15
21T
7.2.3 Map Diagram
A map is commonly used to monitor the location ol
diseases during investigation. You can tell exactly where acute
diarrhoea cases are occurring by just looking at. the map. The
map will also help you in determining how serious the disease
situation is in different reporting units.
Place pins or draw dots on the map to indicate the areas
where cases of target disease are recorded.
You can monitor locations of many diseases by using
different coloured pins or dots, Each colour represents a
different disease.
If the number of cases of a disease reported in an aira is
very large, you can use a pin or dot to represent more th an one
case. However, be sure to place the pins at the area where the
cases occurred (and not where the cases were diagnosed).
If you have a computer, EPI.MAP can be used.
18
<-:\.is\Siii f.h I '
Exercise 2
•
Draw the map diagram using data in Table 1. Map of Delhi is
being provided.
7
'-Vll
I u
13
V .x
/lV\ \\ 012. O;
0© \
kW9
1%
.0
OnO •0
&
No. Name of Zone
1. City Zone
2. S P Zone
3. Karol Bagh Zone
4. West Zone
5. Civil Lines Zone
6&7. Narela Zone
8. Najafgarh Zone
9. South Zone
10. New Delhi
11&12. Shahdara
13. NDMC
14. Cantonment
r-’ pC.4c-'
10 - k I
ll;r
19
(::\.IS\Snr-M<><l.cl<><-
8.
ANALYSE DATA
After the data have been compiled, it needs to be analysed
and interpreted to find out useful information. For proper
analysis of data, compare the morbidity or mortality in two
different areas or in the same area over a period of time. Data
should be compared in different groups also which relate to the
characteristics of the host viz age, sex, immunization status etc.
Rates rather than absolute numbers should be used to
solve the problem of change in population. Cases should be
analysed by age, sex and residence status. The problem of
completeness of reports can be solved by utilization of sentinel
sites.
For comparing the data in the same area over a period of
time, the number of cases reported during the period under
review should be compared with the data reported during the
previous week/month and with corresponding period of
previous years. Is the number higher, lower or nearly same?
Whatever the answer the analysis is not complete until you have
explained the most probable reason for it.
Exercise 3
Table 1 shows the cases of cholera in Delhi by zone in 1988.
•
Name the zone that suffered most in 1988 epidemic of
cholera.
Do you want more information ?
If yes
What information ?
The best way to define the extent of problem in an area is
by rate rather than absolute number of cases. Rates take the
denominator (population) in account.
Table 5 gives the incidence of cholera per 100,000
population. Now it is clear that the rate was maximum in Civil
20
(':\JS\Siir-Mo(l.(l<jr
line Zone rather than Shahdara Zone. Therefore, when you are
comparing the morbidity or mortality in two different an as or
in the same area over a period of time, the attack rate lather
than absolute number should be taken into account.
Table 5
Zone-wise incidence of cholera in Delhi, 1988
Zone
Cases
Percentage
City Zone_____
S.P.Zone
Karol Bagh
West Zone
Civil Lines____
N are la________
Najafgarh_____
South Zone
N.D.
Shahdara_____
NDMC________
Cantonment
Zone Unknown
10
45
43
50
508
48
79
_69
0.7
2.9
2.8
3.3
33.1
3.1
5.1
4.5
1.7
38.0
1.0
0.7
3.2
26
583
15
11
49
Incidence pel
100,000
population
_______ 1.9
8.7
5 .(>
_______ 5.2
_____ 85.(/
______ 16.9
______ 14.0
-___ 10.8
_______ 5.3
55.5
1.5
9' 1
However, when the denominator is not likely to change
much during a period under examination, even the absolute
numbers can be compared. For example, examine the data
shown in Table 4.
Exercise 4
•
What inference you draw from Tabic 4.
•
What more information, if available, can make the data more
meaningful?
QI
.1,
21
r, ■'
C:\.IS\Sni Mod 'l'»<
Exercise 5
How the information available in
Fig- 1 or 2 are usclul to you
as a programme manager?
•
g ,4^ ~
____
r
r-
Table 6
Reported cases of Gastro enteritis
in some districts of UP, 1982-89
District
1982
Agra
192
Alligarh
Mathura
2
Jhansi
2
Etwah
Rai Bareilly Sitapur
73
Saharanpur
Ballia
1983
202
1984
395
1985
139
io
73
75
44
98
177
5
121
157
166
13
6
1986
119
1987
5Sr
112
184
78
2jl
15
96
131
84
3__
2£_
44
11
79
5_
26
17
1988
23
J39___
105
264_
i i_
Examine table 6 carefully and answer the following queslions.
4
V
•
Do you think that the reported incidence is correct?
rv
y If yes: Substantiate your answer with arguments.
01 .
V
A ■
A '
22
~To
7
24___ 39__
128
88
ZAP
1084' 216
Exercise 6
2'
1989
5
M. I .1,,.
If no : Are the incidence overestimated or underestimated?
Exercise 7
•
Enumerate the possible reasons of underestimation of acute
diarrhoea, measles and malaria in a district?
<
______________ f
*____________________
J.
(
■e
- ■ -•
rV q0
___
I
4__ p
\
Oc J
Exercise 8
•
How can you solve the problem of under-reporting of disease
morbidity and mortality.
f!
___________iD
('‘ fy
rp"' r
'.a
e
Exercise 9
Despite limitations of the data reported through routine
surveillance system, useful information can be drawn if the
data is compiled properly and interpreted cautiously.
While investigating an outbreak of Malaria in PIIC
Taigram of district Farrukhabad, UP in October 1991, an
epidemiologist visited the adjoining PHO Jalalabad which was
not reported to be affected during the current outbreak. Table
7 shows data on Malaria from PHC Jalalabad during 1
January 1987-October 1991.
23
(::\.IS\Siii M-xl <I'H
e-c
Table 7
Malaria situation in PHC Jalalabad, Farrukliabad, 1987-19fU
Year
Months
4,
J;ui
___Feb.
M ar.
Apr.
May.
Jun.
Jul.
__ A ug.
Sep.
__ Oct,
__ Nov.
Dec.
Total
1987__
___ 1988
1989
___ 1990
199 I
Slidas
coltacted
Slides
Positive
Slides
collected
Slides
Positive
Slides
collected
Slides
Positive
Slides
collected
Slides
Positive
109
_1
1
1
0
2
0
3
_3
11
4
0
_0
26
_4_14
_337
278
_334
_293
211
326
J009
830
650
_438
353
5473
o
o
o
276
287
263
_^08
283
324
345
J602
1492
862
333
279
6754
_2
_2Z'2
0
0
0
4
0
1
8
1
0
0
0
15
_348
_34J_
_252
_J29
323
__550
1440
941
497
_28<2
295
5778
_O
_O
_0
_0
_0
0
__0
_5
_9
_0
_0
_0
14
187
203
254
200
170
267
_292
418
301
287
230
2918
2
o
o
0
20
22
0
_0
f
45
r "':ir fa d
Po': • - a
.'».7
?i
.•’> i
o
o
o
()
i 13
1f
_3 72
’33
1S
i< 1
8KJ9
13U
Do you agree with the local health officials that PI IC
Jalalabad was not affected during the current outbreak af
Malaria?
If yes: Substantiate your answer with arguments.
If no : why the area was not considered to be affected by l he
outbreak?
•
Calculate the SPR for each year. Do you still feel that PHC
Jalalabad did not register unusual increase in cases dining
October 1991?
r a
I^.UIMQ ■
________
r
^.2.______
r. ■ x-c,______
1^1 \
a
i
24
0
I an j
*1227 slides were still to be examined.
•
■)
xplv/
M-
If no: Why were the local health authorities not aware of tlaincrease in cases in October 1991?
The Medical Officer 1/C of the PHC was not aware of the
unusual increase in the Malaria cases because the data was not
compiled properly. You could appreciate the increase in
incidence because the data has been compiled properly for you.
This example highlights the importance of compiling the data
properly before analysis and interpretation.
Exercise 10
Table 8
Typhoid fever in PHC Galore, district Hamirpur, Himachal
Pradesh, June 1991: Distribution of cases by sex and village
Female
Total
s
22
Lanjiana______
31____
53
17
Daswin________
1
18
2
3
Pahal_________
2
Haiti__________
3
5
4
4
Ghirmani_____
0
12
5 other villages
18
6
52
49
101
Total__________
Note: All the villages had almost equal population.
Village
Males
Provide comments on the data shown in Table 8.
•
Were male and females affected differently? Substantiate
your answer with arguments.
25
C:\.IS\Sm M'"l 'I
•
$
You must have appreciated that cases were more in two
villages (Lanjiana and Daswin) than other villages. C;in you
provide some explanation for such geographic
styx
distribution of typhoid fever in this PHC?
A marriage function was held in village Lanjiana in May,
1991. The bridegroom belonged to village Daswin and only
males accompanied the marriage party. The cases started
coming two weeks after this function. In fact, the outbreak
occurred due to consumption of contaminated water Irom a
local water body.
Exercise 11
Screening method for estimating vaccine effectiveness is a
simple, rapid and cheap surveillance tool. It requires data on
proportion vaccinated among the cases and population, which
may be available in many circumstances. For example, 2() of
136 (19:1%) cases of acute poliomyelitis in Delhi in 1()(H (ag(*
group of 12-23 months) were found having received 3 doses of
oral polio vaccine. Immunization coverage, surveys in J.J.
colonies and resettlement colonies of Delhi which contributed
most of the polio myelitis cases in Delhi revealed vaccine
coverage of three doses of OPV as 64.5%. Using the c urve's
shown in figure 3, the vaccine effectiveness was calculated as
around 90%.
AAU - AAV
26
r:\.IS\:-
• h. 1.1...
Percentage of Cases Vaccinated (PCV) per
Percentage of Population Vaccinated (PPV),
for 7 Values of Vaccine Efficacy (VE)
JOO
100
90 ■
PCV -
PPV-(PPV x VE)
IHPPV X VE)
fl
90 -
90
///F90
70
60
- GO
O 50 -
- -50
40 -
- -40
30
-30
20 --
-20
10 -
-10
o
<
Ll_
o
10 20
V s•
>
0'^
30
40. 50
60
70
80
3
--J 0
100
PPV
Figure - 3
'Q
□ ■
•
Assuming that measles vaccine is 85% effective when
administered at 9 months of age, calculate the measles
vaccine coverage in UP using the data from Table- 2. •
Exercise 12
8.1
Increasing Completeness of Reports
One method to overcome incompleteness of reporting from
multiple sites is to chose what is known as a sentinel site - an
institution that consistently and completely reports for all cases
of the diseases under study. At first glance, Hospital A in Table9 would seem to fit that criteria.
27
( . x
«»\S 111 M« »I < h i< •
Table 9
Case of viral hepatitis reported by different hospitals in a
Geographical area
Hospital A
Hospital B
Hospital C
Hospital D
Hospital E
Total Cases
1990
100
1991
110
25
1992
120
30
15
1993
130
25
_20
15
1_994
i -io
_ 30
_2()
'30
100
135
165
190
240
But, once again, it is important to look beneath the
surface of yearly compilation of reports. For example*, it is
possible that the hospital has not completely reported for each
month of the year. Again, if only the yearly surnmaiy of total
cases are plotted, the artefact of increased complctcne'ss of
reporting in evident. The following data illustrateThis point.
Table 10
Cases of Viral hepatitis reported by Hospital A
January
February
March
April_____
May______
June_____
July
August
September
October
November
December
TOTAL
CAS ICS
8.1.1
1990
5
1991
10
1992
15
10
25
25
30
20
30
30
10
20
15
15
20
25
100
10
15
10
20
20
10
J.5
15
1 10
1993
10
15
15
120
130
_10^
_15^
_J5_
10
15~
_5_
_J_5_
_J0_
_20_
J0
_L(2
M(i
Increasing Number of Non-Residents
Now consider the situation of a sentinel hospital
that consistently and completely reports all cases of viral
hepatitis. It is still possible that data on cast's of Viral
hepatitis are confounded. Consider the situation when'
improved standards of living and transportation innke il
possible for increasing numbers of persons residing from
28
e:\.is\!’in M- I H.u
outside of the normal catchment area of the hospital Io
now have access to the referral hospital. The ntimher of
cases of Viral hepatitis may be artificially higher due to
the increasing number of non-residents. If only the yem ly
summary of total cases is considered, the artefact of
increasing numbers of non-residents is seen, 'flic
following data demonstrate this possibility:
Table 11
Increased Non-Residents, Sentinel Hospital
Residents___
Non-residents
TOTAL CASES
8.1.2
1990
90
__ 10
100
1991
90
__ 20
110
1992
_ 95
_ 25
120
1993
95
35
130
1994
J00
’4 6
140
Increasing Size of Population in Catchment Area
A final consideration of possible confounding of the
true trend of Viral hepatitis in the community is a
changing population base in the community. This may be
especially important if there is large migration of persons
into the area. The best way to compensate for a changing
population in the hospital’s catchment area is to convert
the absolute number of cases into rates. Rates take the
changing population denominator into account and
correct for changes in the population over time. The
following data illustrate this point and now it is finally
possible to demonstrate an impact of the control
programme for Viral hepatitis through incidence falling
rates.
Table 12
Increased Population in Viral Hepatitis in
Catchment Area under Hospital A
1990
1991
1992
1993
1994
Resident Cases
Catchment Popu.
90
10000
90
12000
95
14000
95
16000
100
18000
Rate in Residents
9
7.50
6.79
5.94
5.56
29
(•.:\.IS\Sill Mo.l .b«-
SUMMARY
9.
The discussion so far demonstrates the concept of di u-iric
surveillance, the methods commonly used, the changim1. ii<-e<h;
of surveillance in different stages of programme devclopiii<-ii!
and some of the problems in intei prctalion of data.
The problems of changing population can be sol1 < d bv
using rates rather than absolute numbers. The problem'; ol
increasing referrals from outside the usual catchment an a ( an
be solved by keeping information on the residency status at
cases. The problems of completeness of reporting can be salved
by utilisation of sentinel sites. Further analysis may be danc bv
analysing the age-specific incidence rates.
P
\ >
? (
10.
The important point to realize is that surveillance
rc([uirc thoughtful analysis and simply adding up ab'-.o lnlr
numbers of cases reported from various institutions in tin* at ca
Jmay
. not give a true picture of disease trends in the community.
Conduct Investigation
There arc various situations requiring investigations such as:
1.
2.
3.
4.
5.
6.
8.
9.
10.
-*■ X
-L
1 1.
12.
13.
Clustering of cases/deaths in time and/or space.
Unusual increase in cases or deaths.
Unusual increase in bacteriologically proved cases even
if total cases are not increased.
Unusual decrease in cases.
Even one case of AFP, plague, DI IF.
Even one case of a disease which is not known to be
present in an area.
Cases of measles from remote areas.
Shifting in age distribution of cases.
Patients older than 5 years of age with scx-eic
dehydration from acute diarrhoea with or without
vomiting.
Occurrence of two or more epidemiologically linked < uses
of meningitis.
T
Unusual isolates.
v
High vector density.
Disasters.
First try to confirm the diagnosis of cases. Visit the' mens
from which the cases are being reported. During the visit see as
many cases as possible and involve laboratory to the maximum
possible extent.
30
e:\.IS\Stn M
I. ..
11.
ACTION
Action has to be taken to correct any problem uncovered
during routine reporting or epidemiological investigation or a
survey. If increased rates of morbidity or mortality are
documented, you have the responsibility for determining the
methods and feasibility required to control the situation. The
purpose of investigations and analysis is thus not only to
determine what happened, but also to decide how to control
current outbreaks and how to prevent further attacks in the
future. Action, where possible and feasible, is the logical follow
up of every investigation and analysis.
12.
FEEDBACK
To ensure that the reporting units at the various levels
remain motivated and involved in the surveillance process, there
must be regular communication back from higher levcds of
programme managements to lower levels. This can be done
through communication in staff meeting and publication of
news letters. The list of various reporting units would show how
many regular reports have been received. The number of cases
reported during a particular reporting period may be compared
with data of the corresponding period of previous years. 1 he
feed-back should include comments on the performance in
recording and reporting of cases and suggestions in solving
problems in collection of data. The feed back will keep the staff
motivated by helping them to understand that the information
they collect is important.
The news letter should be sent not only to reporting units
but also to all involved in the programme.
Other method of feed-back can be discussion of reports
during routine visits to the health centres.
31
M<-l <l-»r
I
Exercise 13
•
I
Now you have understood all the steps to surveillance. Can
you design an ideal surveillance system for viral hepatitis in
your district?
•Y
v J
• .
■
fl.
»
\
X
•
Under what circumstances you will like to get the assistance
from other agencies for investigation of an epidemic.
1
32
C:\JS\Snr Mod.dor
l
Investigation & (Control
OUTBREAKS
IRAL JuiEPATITIS
nattonal institute of communicable diseases
(DIRECTORATE GENERAL OF HEALTH SERVICES)
22-SHAM NATH MARG, DELHI - 110 054
JULY 1997
CONTENTS
Page
1.
NOTIFICATION OF CASES
1
2.
CAUSATIVE AGENT
1
3. RESERVOIR
1
4. MODE OF TRANSMISSION
2
5. INCUBATION PERIOD
2
6.
CLINICAL MANIFESTATION AND CASE DEFINITION
4
7.
LABORATORY CONFIRMATION OF DIAGNOSIS
6
8. CLINICAL MANAGEMENT
8
9. HEALTH EDUCATION
8
10. PREVENTION AND CONTROL OF AN OUTBREAK
9
11. PREPARATORY ACTION IN ANTICIPATION OF AN OUTBREAK
11
12. INVESTIGATION OF AN OUTBREAK
12
ANNEX 1 - INTER DEPARTMENTAL COMMITTEE - RESPONSIBILITIES
14
ANNEX 2 - HEALTH EDUCATION MESSAGES
15
ANNEX 3 - OUTBREAK INVESTIGATION REPORT
17
ANNEX 4 - PROFORMA FOR SURVEY FOR JAUNDICE CASES
19
ANNEX 5 - PROFORMA FOR JAUNDICE CASES
20
I
C:\.IS\::H()I.GU!D.DOC
1.
Notification of cases
1.1.
Hepatitis is an acute infection of the liver caused by hepatitis
virus. There are six types of hepatitis virus - A, B, C, D, E and
G. Although clinical picture is similar and the type of virus can
only be confirmed by laboratory tests, there are differences in
modes
of transmission,
incubation
period,
long-term
complications and mortality rates.
1.2.
Based on clinical diagnosis, around 100,000 cases of viral
hepatitis are reported annually. The numbers reported is a gross
under-estimate of the actual annual incidence of the disease. It
is important that the surveillance system is improved as this is
necessary for early identification of an outbreak (viral hepatitis
E) or potential high risk areas, groups, behaviour and practices
such as use of unsterile syringes and needles (hepatitis B & C).
1.3.
Cases of viral hepatitis must be reported monthly to the Central
Bureau of Health Intelligence through the concerned state
health officer. A report may be endorsed to the Director,..
National Institute of Communicable Diseases (NICD), 22
Shamnath Marg, Delhi - 110 054 (Phone:-2521272, 2521060,
2913148; FAX:-2922677; Telegram:- COMDIS, DELHI).
1.4.
If there is a sudden increase or clustering of cases or deaths due
to viral hepatitis, information must be notified immediately
(particularly by telephone or fax) to the next higher level. The
district officer must similarly inform the concerned state officer
immediately. If an outbreak is confirmed, NICD should be
notified.
2.
Causative agent
There are six viruses which are hepatogenic and lead to a
similar clinical syndrome of hepatitis.
These viruses are
hepatitis virus A, B, C, D, E and G.
3.
Reservoir
Man seems to be the only natural host for HAV to HDV.
However, these viruses can be transmitted experimentally to
chimpanzees. Reservoirs of HEV and HGV are unknown.
Humans as well as nonhuman animals are possible reservoirs
for HEV; HEV is transmissible to chimpanzees, pigs, tamarins
and cynomolgus macaques.
Chronic carriers are absent in hepatitis A and Hepatitis E.
Hepatitis B, C, D, and G can lead to persistent infections
1
< ’:\.IS\| Irpnuide.doc
(chronic carriers). These chronic carriers can transmit the
disease to others.
4.
Mode of Transmission
HAV and HEV are transmitted by faeco-oral route through
contamination of water and food. Important mechanisms of
transmission of HBV are mother to infant in perinatal period,
parenteral (through infected needles and syringes, blood
y ’ transfusion),, and sexual routes. Intimate physical ^c
contact
ontact
OO nlon
r-» 4- nr\!
especially in infants and children has
also been "postulated'
to
usually
cause transmission of HBV infection. HCV ""is^usually
transmitted by parenteral route; the risk of transmission by
household contact and sexual activity appears to be very low.
HDV which needs the presence of HBV for its multiplication is
transmitted like HBV. Only limited information is available for
OCVy this virus can certainly be transmitted by parenteral
route.
,
/
MODE OF TRANSMISSION
Hepatitis A & E
Faecal-oral
Hepatitis B
•
•
•
•
•
contaminated blood and bloodproducts
contaminated (unsterile) syringes and needles
unsafe sex
/
perinatal
intimate physical contact between children or mother
& child
Hepatitis C, D & G
•
•
•
5.
contaminated blood and blood products
contaminated (unsterile) syringes and needles ’
?
Incubation period
Agent
HAV
HBV
HCV
HDV
HEV
Range_____
15-50 days
15-180 days
15-180 days
20-140 days
15-65 days
2
Average_________
28-30 days
60-90 days
45-60 days
15-60 days-y^
25-45 days
C: \ .J > \l
CHARACTERISTICS OF DIFFERENT TYPES OF VIRAL HEPATITIS
VIRUS
HAV
HBV
HCV
HDV
HEV
Transmission
Faecal-oral
Parenteral
Parenteral
Parenteral
Faecal-oral
Average Incubation Period
(days)
28-30
60-90
45-60
15-60
25-45
Epidemics
Occasional
No
No
Yes
Homologous immunity
Yes
Recently
documented
Yes
?
Yes
Chronic carrier
No
Yes
Yes
Yes
No
Chronic hepatitis
No
Yes
Yes
Yes
No
Liver Cirrhosis
No
Yes
Yes
Yes
No
Liver Cancer
No
Yes
Yes
3
No
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6.1.
In majority of the cases, especially in young children, the
infection is mild with no overt signs or only mild jaundice. In
moderate to severe cases, the onset is usually acute with fever,
loss of appetite, feeling of general ill-health and abdominal
discomfort, followed within a few days by jaundice. Fever is
present or precedes jaundice. Right upper quadrant abdominal
tenderness and hepatomegaly arc important findings. Liver
function tests include a raise in ALT to 8 times or more than
normal levels and serum bilirubin to more than 2mg%.
V
ud
d'jfi-ition
6.2.
Hepatitis B, C and D can lead to persistent infection (chronic
carriers). The sequelae of persistent infection include chronic
active hepatitis, liver cirrhosis and liver carcinoma. Around 3 to
5% of our population are estimated to be chronic carrier of
hepatitis B. This data is mainly based on institutional studies.
6.3.
The public and the paramedical personnel can assist in
reporting ca.ses whom they can recognise by the yellow
colouring of the eyes and skin (pilia). Active case finding is
particularly important during the investigation of an outbreak.
6.4.
Definitive diagnosis by type of hepatitis virus can be made only
by laboratory tests.
USPECT
o
yeli'jw colouring of the skin and eyes [pilia]
PRES UM PTIV E / C 0 N FI R MED
«!•
<5
e
o
e
acute onset
jaundice
fe^er usually precedes jaundice. May be present
when jaundice appears
malaise, anorexia
hepatomegaly and abdominal tenderness in the
right upper quadrant
increase of ALT >8 times and serum bilirubin
>2mg% in clinically compatible illness
epidemiological link or outbreak in the area of
residence of case
Serological teel are necessary for confirmaiton of types,.of viral
hepatitis viz. A J?. C‘,P,E & G.
' •S\HrTTt>i<!r.<|or
6.5.
It would also be useful to know if:
©
there are any other laboratory confirmed cases in area
OR ’
there is a clustering of cases clinically compatible with
viral hepalitis
Any one of the two above will support the presumptive diagnosis
of viral hepatitis and type of virus. It would also facilitate better
understanding of the epidemiology of disease and institution of
appropriate control measures.
6.6
Clinical features in specific types of viral hepatitis
6.6.1 (Hcpatitis^Xs usually mild in children, but can be very severe in
adults. However, almost all the children in India develop
immunity following sub clinical repeated exposure to this virus
before 10 years of age. The disease is hence rare in adults.
Hepatitis A characteristically has an acute, sudden, influenza
like onset with a prominence of myalgia, headache, fever, and
malaise. This type of onset is less common with other forms of
viral hepatitis, which tend to have a more gradual, insidious
onset. Hepatitis A usually is not as severe or as long lasting as
type B hepatitis. Hepatitis A docs not lead to a chronic hepatitis
or a carrier state; chronic hepatitis with persistence of HAV
infection for more than 12 months has not been observed.
Morbidity from Hepatitis A is not higher in pregnant women
than in non-pregnant women of the same age, nor is the course
of Hepatitis A during pregnancy usually different, and -foetal
malformations due to Hepatitis A have not been reported.
6.6.2 Onset of hepatitis B is usually insidious with anorexia, vague
abdominal discomfort, nausea and vomiting, sometimes
arthralgias and rash, often progressing to jaundice. Fever may
be absent or mild. Hepatitis B has a more prolonged course
than HA. Chronic liver disease due to HBV (chronic hepatitis,
liver cirrhosis, and liver carcinoma) occur only in persons who
become chronic HBsAg carriers. Protective immunity follows the
infection if antibody to HBsAg (anti-HBs) develops and HBsAg
becomes negative.
6.6.3 Hepatitis C clinically resembles hepatitis B. However, it tends to
be milder during the acute phase and tends to progress to
chronicity much more frequently than hepatitis B. Subclinical
HCV infections predominates. There is usually episodic
fluctuation of ALT.
6.6.4 Clinically HDV infection, whether acute or chronic, tends to be a
'■■e'.’ere illness. Although only some of HBV infections cause
5
' ' ' 'S\ I !<•’
icterus, most of the HDV infections (co-infection or super
infection) cause an episode of clinical acute hepatitis with
jaundice. The risk of fulminant disease may reach 10% for
clinical
HDV-HBV
coinfections
and
20%
in
HDV
superinfcctious.
6.6.5 The clinical course of Hepatitis E is similar to that of Hepatitis
2i. More than 50% cf HEV infections may remain anicteric. The
expression cf icterus appears to increase with increasing age.
There is no evidence of a chronic form. A majority of Hepatitis E
cases occur in young adults. Secondary household cases during
the outbreaks are uncommon. The case fatality rate is also
similar to that of HA, except in pregnant women where the CFR V
may reach 20% among those infected during the 3rd trimester
of pregnancy.
6.6.6 HGV has been recently discovered. Its circulation in India has
been demonstrated. HGV has been linked to acute and chronic
hepatitis. The majority of individuals infected with HGV do not
have clinical evidence of liver disease.
6.7.
Case fatality rates for hepatitis A and E infections are generally
low. Viral hepatitis may cause serious illness in pregnant
women. High CFR (un to 20%) has been seen in pregnant
women having hepatitis due to HEV. Case fatality rate for
hepa.titis B infection for hospitalised cases is around 1%; higher
in those over 40 years of age. The case fatality rate increases if
there is concurrent infection of hepatitis B and D viruses.
7.
Laboratory corwrniatf -a of diagnosis
7.1.
Acute viral hepatitis is such a sufficiently distinct clinical
syndrome that it usually poses no difficulty in 'diagnosis.
Clinical diagnosis is supported by:
(i)
Elevation of ALT and AST (>8 times of normal), and mild
elevation of alkaline phosphatase (usually only 3 times of
normal).
(ii)
Exclusion of nonviral causes of acute hepatitis (e.g. Ba.cteriuLeptospirosis; Drugs- Anti-tubercular drugs, acetaminophen;
Toxins and Non-specific Injury).
7 2.
The type cf virus causing hepatitis can be identified by
laboratory tests only.
LABORATORY DIAGNOSIS.O.F SPECIFIC TYPES OF
\ lHAL, II[■PATH IS BY SEROLOGY
Acute Hepatitis A virus infection - IgM HAV positive
Acute Hepatitis B virus infection - IgM HBc and HBsAg
positive
Chronic hepatitis B virus infection (chronic carrier) HBsAg alone positive
Acute Hepatitis E virus infection - IgM HEV positive
Acute or chronic Hepatitis C virus infection - Anti HCV
positive
7.3
Most of the diagnostic kits are imported, expensive and require
an ELISA reader. The cost of some of the kits (especially for
hepatitis C, hepatitis D and hepatitis E) is around Rs 30,000
and unit cost of each test may vary from Rs 200 to 600. Carrier
rates for hepatitis B can be determined by testing the blood
using a similar technique and the reagents are less costly. Unit
cost varies from Rs 15 to Rs 35.
7.4.
Treatment of viral hepatitis does not depend on the results of
laboratory examination. However, laboratory analysis of
specimens from the first few suspected cases during the
outbreak is important to confirm diagnosis and to determine the
characteristics of the organism. Once the hepatitis virus is
confirmed, it is not necessary to examine specimens from
all cases or contacts. In fact, this should be discouraged since
it places an unnecessary burden on laboratory facilities and is
is
not required for effective treatment.
7.5.
Serum specimens should be sent to the laboratory as early as
possible, preferably in cold chain. If delay is inevitable in
transporitng the samples to laboratory, they should be stored at
+2 to +8° C. Specimens should be stored and transported in
sterile screw capped vials.
7.6.
Full particulars of the patient(s) from whom samples have been
collected must be sent along with the samples as many factors
can influence the results of the laboratory tests. The information
that should accompany each serum sample is given below:
•
•
•
•
•
•
•
•
name
name of mother or father
sex
date of onset of symptoms
provisional diagnosis
clinical outcome (recovered, under treatment, dead, not known)
date sample collected
full address
7
'\JS\HepRuicle.doc
7.7.
The conditions of collection and transportation of samples can
influence laboratory tests. The recommended practices and
precautions to be taken to minimise deterioration in the quality
of the sample is given in the box.
7.8.
Keep an inventory of the referral laboratories which can
undertake laboratory tests for all mar kers of viral hepatitis.
COLLECTION AND TRANSPORTATION OF SAMPLES_______
Sr
collect the blood sample from a few patients with
clinical/frank jaundice
use a sterile syringe and needle for drawing blood.
Practise universal infection control safety precautions.
Separate serum and keep in a sterile screw capped vial.
Serum specimens should be sent to the laboratory as
early as possible, preferably in cold chain. If delay is
inevitable in transporitng the samples to laboratory, they
should be stored at +2 to +8° C. Specimens should be
stored and transported in sterile screw capped vials.
bottles should be placed in separate plastic bags each to
prevent leakage of the
potentially contaminated
material.
each sample should be labelled. Detailed information as
indicated at 7.6 should be sent for each sample.
7.9.
The National Institute of Communicable Diseases (NICD), Delhi
has the facilities for testing all markers of viral hepatitis. This
support is available for investigation of outbreaks provided
samples are accompanied by comprehensive details of outbreak
and information indicated at 7.6.
8.
Clinical Management
There is no specific treatment. Patient requires only
supportive and symptomatic management.
Ensure nutritious diet and adequate rest. However, strict
bed rest is not required unless patient is acutely ill.
Corticosteroids are not indicated.
9.
Health Education
Outbreaks of viral hepatitis are usually caused by hepatitis E
virus which spreads through contaminated water and food
products. Outbreaks of hepatitis A are not frequent because
HAV causes very mild or sub-clinical infection in children, and
8
i \.JS\I lepnuide doc
most of the persons in our country are exposed to this virus
during childhood. However, we may see such outbreaks in
future as many people may escape exposure during childhood
due to improvement in hygiene and sanitation. The risk of
outbreaks due to HEV is higher in the summer, monsoon and
post-monsoon periods.
Since transmission of hepatitis A and E is faecal-oral, measures
of personal hygiene and environmental sanitation that apply to
control of other enteric infections are the basis for their control
in any settings. There is no vaccine available for hepatitis E.
Vaccine available against hepatitis A is not cost-effective due to
epidemiological considerations and very high costs.
Hepatitis B, C and D viruses spread through body fluids of
patients or carriers. General measures to prevent hepatitis B,
C, D, and G include sterilisation of needles and instruments
that penetrate the skin, screening of blood for hepatitis B and
hepatitis C markers ■ and promotion of safe sex behaviour.
Vaccine is available against hepatitis B only.
Health education and public awareness and co-operation are
important to prevent and control viral hepatitis. If the
community knows how the disease spreads and what measures
they can take in their own families, the risk can be considerably
reduced. While the key messages will essentially remain the
same for all areas, the language and style may be adapted to
local needs. Suggested material or health education messages
which can be adapted for local use is given at Annex 2.
10.
Prevention, and control of an outbreak
10.1. Almost all outbreaks of viral hepatitis in India are due to faecoorally transmitted hepatitis E. An occasional outbreak of
hepatitis A has also been reported. Although an unusual
increase in viral hepatitis cases due to hepatitis B have been
recognised in hospital setting, it had not been documented as
the cause of an outbreak in community setting. However the
NICD investigated 3 outbreaks of hepatitis B in 1997 which
occurred due to the use of inadequately sterilised needles and
syringes by^unqualiried)medical practitioners in the concerned
areas.
10.2 Outbreaks of hepatitis E are due to contamination of water
supply. Measures to prevent and control these outbreaks should
be directed towards ensuring safe water supply.
10.3. Majority of the outbreaks have occurred due to contamination of
Dipe.water supply. Clustering of cases in some area linked to a
<)
common water supply will help in identifying the points where
the contamination is taking place. Repair of water pipe lines at
these points will prevent the further spread of Hepatitis E.
10.4 Alternate arrangement for safe water supply should ideally be
made during the outbreak. Simultaneously, source of
contamination should be removed on priority. If the local water
sources are still used, the community should be advised to boil
pV \
water. Hepatitis E virus is not destroyed by chlorination
\ /'J VyC
usual doses; the virus is killed by boiling. Hepatitis A
Is however, destroyed by chlorination.
v
•10.5 All human excreta should be disposed of promptly and safely.
10.6 Whether the outbreak is due to hepatitis A or E, the measures
for prevention and control are similar. These measures should
be applied immediately.
10.7. If an outbreak of hepatitis B occurs, identification and removal
of risk factor/s will control the outbreak.
10.8. Ensuring safe injections and screening of all blood donations for
hepatitis B (and if possible ^FiepatiTisC^ will largely prevent all
the parenterally transmitted inlcction^including hepatitis B, C,
D and G. National AIDS Control Programme takes measures to
promote safe sex behaviour to prevent HIV infection. These
measures will also contribute towards the prevention of
hepatitis B and other parenterally transmitted viral hepatitis.
ACTION TAKEN FOR PREVENTION OF HEPATITIS B INFECTION
•
mandatory testing of blood in all blood banks
•
promotion of safe sex behaviour under the National AIDS
control programme
•
health awareness campaigns regarding the dangers of
using unsterile syringes and needles under the
immunisation programme and National AIDS Control
Programme
•
guidelines have been issued to the state health
authorities for the use of a separate sterile syringe and
needles for each injection
•
immunization of health personnel in hospitals against
hepatitis B
PREVENT WATER-BORNE DISEASES BY
provision of safe water
adopting safe practices in food handling
sanitary disposal of human waste
10
C: \.
1; uHirlc.ckx*
10.9 Hepatitis B vaccine
There are two types of hepatitis B vaccines available - the
recombinant DNA vaccine and the plasma derived. Both are safe
and effective. They should be administrered as per
recommendations by manufacturers. These vaccines are
available in single and multi-dose vials.
10.10 When an outbreak occurs or when the risk of such outbreaks is
high, the cooperation of other government departments, non
governmental agencies and the community often becomes
necessary. Such help will be more forthcoming if mechanisms
for interaction have been developed before the onset of an
outbreak. It might be useful to convene a meeting of the
concerned departments, community representatives and the
NGOs before the expected seasonal increase of cases qf
diarrhoeal diseases. Some mechanism for briefing the .press'
should also be established. Some suggested areas in which4hey Levy
government departments and NGOs can assist may be seen at
Annex 1.
11.
Preparatory action in anticipation of an outbreak
11.1
Maintain surveillance for acute diarrhoea, typhoid fever, and
jaundice cases. Viral hepatitis E has a long incubation period of
usually 1-2 months (not less than 15 days). There are other
diseases which have shorter incubation period and are also
transmitted by faeco-oral route. They are acute watery diarrhoea
(incubation period: a few days and typhoid fever (incubation
period: 1-3 weeks). By analogy, viral hepatitis E is likely to
follow an increase in acute diarrhoea or typhoid fever following
water contamination.
Describe cases by time, person and place to identify any
clustering of cases in an area or group.
11.2. (Kegulan, monitoring of water quality by examination of water
samples for residual chlorine and/or coliform organisms on a
random basis.
11.3 An increase in the incidence of diarrhoea and/or typhoid fever,
and poor water quality indicate impending epidemic of viral
hepatitis. Manage the existing increase in diarrhoea and/or
typhoid fever cases, and take corrective measures to prevent the
impending outbreak of viral hepatitis.
11.4. Periodic sanitary surveys should be undertaken, especially
before monsoon, for sewer overflow, and leakage in water
supply system. If any leakage is found, it should be attended to
11
' ‘ \.IS\Hrpumtlr <I<m
on priority. In areas where water supply is intermittent, on-line
booster pumps can create negative pressure in the pipeline
leading to suction of sewage into the water pipeline.
11.5. Prepare/update inventory of existing and required resources if
outbreak strikes.
11.6. 1EC activities for minimising the risk of faeco-orally transmitted
diseases should be undertaken in the community.
11.7 To prevent faeco-oral transmission, supply of sale water,
environmental sanitation, and personal and domestic hygienic
practices should be applied.
12.
Investigation of an outbreak
12.1
Establish the existence of an outbreak:
Surveillance for jaundice cases (institutional surveillancesupported by surveys if necessary) to find out the existence of
outbreak - rule out any seasonal increase.
12.2 Confirmation of diagnosis:
Acute viral hepatitis is such a sufficiently distinct clinical
syndrome that it usually poses no difficulty in diagnosis.
However, specific blood tests are needed to diagnose different
types of viral hepatitis. See Box at page 8.
Collect and transport the blood samples as given in the box
under-7.
12.3 Characterise the outbreak in terms of time, person and place.
Geographical distribution-Identify the area or group affected by
the outbreak-attack rates in different areas will indicate the
points where contamination is occurring.
12.4 Carry out a sanitation survey-find out the leakage points.
12.5 Institute the control measures
(i)
Repair of the water and sewer lines - close co-ordination
with public health engineering department - safe disposal
of human excreta.
(ii)
Disinfection of water - boiling (chlorination does not
inactivate HEV). Chlorination of water sources to-prevent
12
<\.JS\I IcpKuitlr.tlfx’
the transmission of agents of acute diarrhoeal and
typhoid fever. Frequent water quality monitoring.
(iii)
IEC to prevent the spread of infection.
(iv)
Standard measures to prevent faeco-oral transmission.
(v)
Arrangement for management of the existing cases.
(vi)
Supply of ORS for acute diarrhoea, and antibiotics for
typhoid fever.
12.6 In case the CFR is very high hepatitis B should also be
suspected. Data should be analysed for the risk factors of viral
hepatitis B. All the 3 outbreaks of hepatitis B investigated by
the NICD during the first half of 1997 were due to the use of
unsafe injections by unqualified medical practitioners. Removal
of the risk factor/s will prevent the further spread of the
infection.
12.7 Notify the state nodal officer about the outbreak.
12.8 Write outbreak investigation and action taken report. Send a
copy to the concerned state authorities as well as to NICD.
ACKNOWLEDGEMENT
The manual has been edited by Dr. Jotna Sokhey, Director
NICD; Dr. Rajesh Bhatia, Consultant (Microbiology); and
Dr.Jagvir Singh, Deputy Director (Epidemiology).
13
Annex 1
INTER-DEPARTMENTAL COMMITTEE
SUGGESTED AREAS OF RESPONSIBILITY AND ACTION
District administration
•
mobilize resources by organizing meetings with
•
concerned government departments
•
non-governmental agencies
•
community leaders
•
ensure adequate quality monitoring of water samples
•
repair of leakage in water pipe lines
•
arrange safe water supply
•
ensure supplies of ORS packets and other essential items
•
ensure adequate facilities for transportaion of serious patients to district hospital, if necessary
•
strengthening of existing provision under the Drug & Cosmatic Act to curtail over the counter sale
of parenteral drugs
•
provide relevant information to the press
•
monitor status of control activities
District Health Office I Municipal Health Office
•
arrange repair of leakage in water pipe lines
•
alert health personnel to report cases and to monitor trends
•
arrange active surveillance in affected area
•
ensure that treatment guidelines are followed in hospitals and other health facilities
•
ensure availability of ORS packets and other essential items
•
strengthening of existing provision under the Drug & Cosmatic Act to curtail over the counter sale
of parenteral drugs
•
arrange health educational camps and distribution of health educational material
•
arrange chlorination of water sources if possible
•
arrange water quality monitoring
•
convene meeting under distrist administrator to seek cooperation of other government
departments and NGOs
•
check sterilisation practices of medical practitioners for syringes, needles and sharp instruments
Concerned Department (s) responsible for water suppy
•
repair of leakage in water pipe lines
•
arrange potable water supply, including water tankers if necessary
•
arrange chlorination of water
•
ensure water quality monitoring
Other government departments such as social welfare, education, tribal welfare and NGOs
•
dissemination of relevant information
•
promotion of oral rehydration therapy
•
check sterilisation practices of medical practitioners
•
reporting cases of jaundice (pil/a)
Panchayat members, village pradhans, community leaders
•
dissemination of relevant information
•
promotion of oral rehydration therapy
•
check sterilisation practices of medical practitioners
•
reporting cases of pilia
•
monitoring chlornniir > of water sources such as wells
•
arranging transportation of serious cases to hospital
14
C:\.JS\HepRuicle.doc
Annex 2
PROTECT YOURSELF FROM VIRAL HEPATITIS BY
•
•
•
•
•
•
•
•
•
drinking water from a safe source
not eating cut fruit and vegetables from the market
cleaning thoroughly fruits and vegetables which are eaten
raw
storing drinking water in a clean, covered and narrow
mouthed container
eating cooked food while it is still hot
washing hands before eating and after using the toilet
avoiding use of on-line-booster pumps which can suck
sewage in water line
reporting to municipal authorities broken water pipes
reporting cases(s) of JAUNDICE (PILIA) to the nearest
health centre or local health officer
HOW CAN YOU PROTECT YOURSELF FROM HEPATITIS B
AVOID
unsterile syringes and needles
other unsterile sharp instruments
transfusion with unscreened blood
unsafe sex
PROTECT YOURSELF FROM PARENTERALLY
TRANSMITTED VIRAL HEPATITIS BY
•
•
•
•
•
•
ensuring that a separate sterile syringe and needle is used
for each injection. Insist that a glass syringe and needle are
boiled for 20 minutes before reuse OR a sealed disposable
syringe and needle is used
taking injections only when medically indicated. Take
treatment from qualified personnel only
using condoms. Avoid unsafe sex and extra-marital sexual
contacts
getting blood from a registered blood bank. Promote
voluntary blood donation and donate blood
reporting JAUNDICE (PILIA} case (s) to the nearest health
centre or local health officer
hepatitis B vaccine is available in the market. Contact your
physician for further guidance.
15
1 * ' JS\Ih,|5’iii<lr.floc
PROTECT YOURSELF FROM UNSAFE INJECTIONS BY
•
•
•
ensure that a separate sterile syringe and needle is used
for each injection. Insist that a glass syringe and needle
are boiled for 20 minutes before reuse OR a sealed
disposable syringe and needle is used
take injections only when medically indicated
take treatment from qualified personnel pnly
f)
yt
Your life is precious. Say No to ^Injections
16
<> \.JS\HepKinrle.doc
Annex - 3
OUTBREAK INVESTIGATION REPORT
General Information
State
District
Town/PHC
Ward/Village
Population
Background Information
Person reporting the outbreak :
Date of report
Date investigations started
Person(s) investigating the outbreak
Details of Investigation
Describe how the cases were found (may include: (a) house-tohouse searches in the affected area; (b) visiting blocks adjacent to the
affected households; (c) conducting record reviews at local hospitals;
(d) requesting health workers to report similar cases in their areas,
etc.):
Descriptive Epidemiology
•
•
•
Cases by time, place and person (attach summary tables and
relevant graphs and maps).
Age-specific attack rates and mortality rates
High-risk age-groups and geographical areas.
Description of Control Measures Taken
17
' ’ \.IS\I |f|>K'ii<k'.rlix-
Description of Measures for Follow-up Visits:
Brief Description of Problems Encountered
Factors Which, in Your Opinion, Contributed to the Outbreak
Conclusions and Recommendations
Date
(Name and Designation)
18
C \v'S\Hept;uide.(Joc
Annex 4
PROFORMA FOR SURVEY FOR JAUNDICE CASES
Name of Surveyor
Date of Survey.
City/Village.
House
No.
Name of persons
Street/Mohalla
Age/Sex
History of
jaundice in
past 6
months
Yes/No
Currently
having
jaundice
Case No. for
jaundice cases
Yes/No
I
I
19
<\JS\ Hepgu ide.doc
X
-A
Annex 5
PROFORMA FOR JAUNDICE CASES
Surveyor’s NameDate of SurveyName of caseFather*s/Husband’s Name
_____
Age of Patient (in complete Years)
Ward NoA/illage.
Address^
____ ___________________________
If female, history of pregnancy when she had jaundice:
If case is a child <15 Years then ask :
Education of Mother
Occupation of Mother
Case No.
Sex: M/F
Yes/No/do not know
Education of Father
Occupation of Father
Information about Family for all Jaundice cases :
No. of Family Members
No. of members had jaundice in past 6 months (excluding index case)
Source of drinking water
Tap/Hand pump/Well/other (specify)
Storage of drinking water
Bucket/Pitcher/Surahi/Vessel with Tap/other
Method of drawing drinking water
Tap/Ladle/other
Type of Latrine:
Open field/Service/Sanitary/Community latrines
Hand washing after defecation:
Soap/Ash/Earth/Water alone/did not wash
Hand washing before meals:
Soap/Ash/Earth/Water alone/did not wash
Information about Illness for all Jaundice cases:
Date of Onset of Jaundice
Outcome: Still Ill/Recovered/Died
Symptoms Present (circle): Dark Urine, Yellow Eyes, Anorexia, Nausea, Vomiting, Pain abdomen, Fever, Clay
coloured stool, Malaise, Itching, Others (Specify)
Liver palpable:
Yes/No/not examined
Any Treatment taken for Jaundice:
Yes/No
If Yes, the type of treatment:
Allopath/Ayurved/Homeopath/Other (specify)
Past history of jaundice before this episode :
Yes/No
History within 6 months but 15 days prior to onset of jaundice for the following points:
Hospital Admission due to any cause: Yes/No
Multiple Injections:
Yes/No
Surgical Operation:
Yes/No
Dental Surgery:
Yes/No
Blood Transfusion:
Yes/No
Dialysis:
Yes/No
Intravenous Drip:
Yes/No
Blood Donation:
Yes/No
Vaccination (Specify):
Yes/No
Tattooing:
Yes/No
Nose/ear pricking:
Yes/No
Shave from a barber
Yes/No
Drug addiction:
Yes/No
Alcoholism:
Yes/No
Extramarital sexual contact (adult):
Yes/No
Movement outside the village:
Yes/No
Contact with a case in the family:
Yes/No
Contact with a case in the Community: Yes/No
Contact with a case outside the village: Yes/No
Any chronic illness
Drug history
Diagnosis by a Doctor
Investiaqtions already done:
S.bilirubin
SCOT
SGPT
Urine
HbsAg.
Blood Sample collected:
Yes/No
(Collect Blood Sample if the patient had jaundice in the last 3 months)
Blood sample No.
Remarks
20
C:\.JS\I
i<Ic.doc
/H-. 10
Investigation & Control
OF
Outbreaks
Dengue & Dengue
Haemorrhagic
Fever
NATIONAL INSTITUTE OF COMMUNICABLE DISEASES
(DIRECTORATE GENERAL OF HEALTH SERVICES)
22-SHAM NATH MARG, DELHI - 1 10 054
JULY 1997
CONTENTES
1. INTRODUCTION
i
2. NOTIFICATION OF CASES
1
3. CAUSATIVE AGENT
1
4. INCUBATION PERIOD
1
5. MODE OF TRANSMISSION
2
6. VECTOR OF TRANSMISSION
2
7. HIGH RISK AREAS
3
8. CLINICAL MANIFESTATIONS AND CASE DEFINITIONS
3
8.1 Dengue fever (DF).................................
8.2 Dengue Haemorrhagic Fever (DHF)
3
4
9. DIFFERENTIAL DIAGNOSIS OF DHF/DSS
6
10. LABORATORY CONFIRMATION OF DIAGNOSIS
6
11. CLINICAL MANAGEMENT
7
11.1 Management of Dengue fever
11.2 Management of DHF..................
.7
.7
12. PATHOGENESIS AND PATHOPHYSIOLOGY
8
13. IMMUNITY
9
14. SURVEILLANCE IN DF/DHF
9
14.1 Epidemiological surveillance
14.2 Vector surveillance................
9
9
15. INVESTIGATION OF AN OUTBREAK
10
16. PREVENTION AND CONTROL OF AN OUTBREAK
11
17. COMMUNITY PARTICIPATION
12
ANNEX 1 - FORMAT FOR MPW FOR REPORTING SUSPECTED DHF CASE
14
ANNEX 2 - FORMAT FOR MEDICAL OFFICERS FOR REPORTING DHF CASE. 15
ANNEX 3 - OUTBREAK INVESTIGATION REPORT
16
ANNEX 4 - INTER-DEPARTMENTAL COMMITEE - RESPONSIBILITIES
18
|\J cO -
(’:\JS\l)ciiRiiiilc.ctoc
'
1.
.
•
A
./
/^, .'XX.S
Introduction
1.1. Dengue virus infections are significant causes of morbidity and
mortality in many parts of the world, including India. The dengue
virus is believed to cause two forms of clinical syndrome, namely,
classical dengue fever (DF) and dengue hemorrgahic fever/dengue
shock syndrome (DHF/DSS).
- ------------ ----1.2. Dengue fever is a self - limiting disease and represents the
majority of cases of dengue infection. In some situations, it manifests
in severe forms as haemorrhagic (DHF) and shock syndrome (DSS).
1.3. In India, dengue infection is known to exists in endemic
proportions for a very long time. The first major outbreak of dengue
fever accompanied by dengue haemorrhagic fever was reported in
Calcutta in 1963. About sixty outbreaks have been reported during
the period 1956 to 1996. Because dengue infections have the potential
of rapid spread leading to an acute public health problem, special
attention is required to be paid for its surveillance, prevention and
control.
2.
Notification of cases
2.1. Cases of DF/DHF must be reported monthly to Directorate of
National Malaria Eradication Programme (NMEP) through the
concerned state nodal officer. A report may be endorsed to the
Director, National Institute of Communicable Diseases (NICD), 22Shamnath Marg, Delhi 110054; Phone:-2521060, 2521272, 2913148;
FAX: 2922677; Telegram: COMDIS, DELHI.
2.2 If there is a sudden increase or clustering of cases or deaths due
to DF/DHF, it must be reported immediately to the district health
office. The district health office must simikuly inform the concerned
health officer by the quickest mode of communication, preferably
through telephone, Fax or e-mail with details of the outbreak
including investigation and control measures initiated. The National
Institute of Communicable Diseases is expected to be kept informed of
the action taken.
3.
Causative agent
DF/DHF is caused by a group 13 arbovirus (Flavivirus) and include
serotypes 1,2,3 and 4 (Den-1, Den-2, Den-3 and Den-4).
4.
Incubation period
The incubation period is usually 5-6 days but may vaiy from 3 to 10
days.
1
C:\..JS\Dcngiiicle.doc
5. -
Mode of transmission
5.1 The infection is transmitted by the bite of an infected female
mosquito- Aedes aegypti. The mosquito usually bites during day time.
The mosquito becomes infected by biting a patient with dengue
infection. Once the mosquito becomes infected, it remains so for life.
The female mosquitoes can survive upto 3 weeks under normal
temperature and humidity.
------- - ------- - —
5.2 Female mosquitoes get infected after feeding on a viraemic host.
They can transmit the virus to human host after an extrinsic period of
8-10 days. The ambient temperature range for dengue transmission is
16°C to 40°C. Below 16°C Aedes aegypti ceases to bite.
6.
6.1 Aedes aegypti is the main vector of dengue transmission in India.
Dengue outbreaks have also been attributed to Aedes albopictus.
However, Aedes polynesiensis and species of Aedes scutelloris complex
have also been incriminated as vector in other South East Asian
countries.
6.2 lhe mosquito has characteristic white strips on the back and legs.
It is also known as Tiger mosquito (figure).
Figure. Aedes aegyptii
2
C:\JS\Dciiguiclc.doc
6.3 lhe mosquito rests__indnors.-. in closets and other dark places.
Outside, they rest where it is cool and shady. The female mosquito
lays eggs in clean water containers in and around homes, schools and
work places. The larvae hatch from the mosqdito eggs, and live in the
water for about a week; they then change into a round pupal stage for
one or two days after which the adult mosquito emerges, ready to bite.
6.4 The mosquito is a domestic breeder. It breeds in any water
catching or water storage container in shady or sunny places. The
water coolers and overhead water tanks are major places of breeding
of this mosquito. The mosquito can also breed in any container which
has water for several days such as unused tyres, broken plastic
containers and discarded cups, glasses and other utensils, flower
vases etc.
6.5 Aecles mosquito can lly upto a limited distance of 400 meters^
6.6 The outbreaks of dengue fever/DHF are most likely to occur in the
post-monsoon period when the breeding of the mosquitoes is highest.
7.
High risk areas
7.1 Usually, urban areas, having high population density, poor
sanitation and large number of desert coolers, overhead tanks,
discarded buckets, tyres, utensils etc. which promote mosquito
breeding, are at high risk.
7.2 Dengue fever /DHF can also occur in rural areas where the
environment is friendly for mosquito breeding. Mosquito breeding can
occur, for example, in large containers used for collecting rain water,
which are not emptied and cleaned periodically.
8.
Clinical manifestations and case definitions
8.1
Dengue fever (DF)
The symptoms of dengue fever are similar to acute fevers of viral
origin. These are sudden onset of fever, headache, bodyache, joint
pains and retro-orbital pain. Other common symptoms include
anorexia, altered taste sensation, constipation, colicky pain,
abdominal tenderness, dragging pains in the inguinal region, sore
throat and general depression.
Patient may or may not have rash. Some of the patients may also
show signs of bleeding from the gum, nose etc.
3
(':\.IS\I )cngiii(lc.cloc
of dengue fever
SUSPECT CASE
Acute onset
High fever of less than seven days duration
Severe headache, backache
Joint and muscle pain and pain behind eyes
With or without rash
•
•
•
•
•
PROBABLE CASE
•
•
•
•
Suspect case of DF
High vector density
Presence of confirmed case in the area
Blood slide -ve for malarial parasite & patient does
not respond to anti-malarial drugs
CONFIRMED CASE
•
•
8.2
Isolation of virus from blood in early phase
Serological test for IgM antibody in single serum
samples, or 4 fold rise of antibodies in paired
serum samples
--------------- *
Dengue Haemorrhagic Fever (DHF)
131 IF is a severe form of dengue lever. Typically, it begins abruptly with
high fever accompanied by headache, anorexia, vomiting and
abdominal pain. During the first few days, the illness resembles
classical dengue fever, but a maculopapular rash is less common.
There are signs of haemorrhage (bleeding), such as easy bruising and
bleeding at the venepuncture sites.
The liver is usually enlarged, soft and tender. Approximately 50% of
patients have generalized lymphadenopathy.
The critical stage is reached after 2-7 days, when the fever subsides.
Accompanying or shortly after a rapid drop in body temperature,
varying degree of circulatory disturbances occur. The patient is
usually restless and has cold extremities. Sometimes there may be
sweating.
4
C: \. IS \ I )ci ignidc.doc
9
CASE DEFINITION OF DHF
•
•
•
•
•
SUSPECT CASE
Acute onset
High fever of less than 7 days duration
Severe headache, backache
Joint and muscle pain and pain behind eyes
Bleeding tendencies
•
•
PROBABLE CASE
Suspect case of DHF
Positive tourniquet test
•
•
•
O c c
■?
CONFIRMED CASE
Probable case
Thrombocytopenias 1,00,000/mm.3
Heamoconcentration (haematocrit increased by > 20% or evidence
of increased capillary permeability(e.g. pleural effusion in X-ray
chest).
DHF is clinically confirmed by the positive tourniquet test (a blood
pressure cuff is used to impede venous flow. A test is considered
positive if there are >20 petcchiae/square inch).
STAIWARD TOURNIQUET TEST
•
•
•
•
Apply sphygmomanometer cuff to the arm and take Blood
pressure.
Inflate cuff so that it registers a pressure midway between that of
systolic and diastolic blood pressure.
Hold it for five minutes.
Examine the cubital fossa for petechiae if >20 petechiae in 3 cm
diameter circles, the test is positive, if >20 petechiae in 2.5 cm
square, the test is positive.
Haematocrit increase by 20% or more of the baseline value
Thrombocytopenia and haemoconcentration are constant findings in
DHF. Hacmoconcentration- indicating plasma leakage- is always
present.
CLINICAL LABORATORY FINDINGS
•
•
A platelet count of 1,00,000/mm3 or less between the third
and eighth day of illness
Haematocrit increase by 20% or more of the baseline value
5
C:\JS\I Jcngiiidc.doc:
severe cascs, shock ensues and the patient may die within
12-24 hours. Prolonged shock is often complicated by metabolic
acidosis and severe bleeding, which indicate a poor prognosis. If the
patient is appropriately treated before the irreversible shock has
developed, rapid recovery is the rule.
A major cause of deaths due to DHF is leakage of plasma in the
Detmli^t- abdTTd Cavitics Ieadin8 to hypovolaemic shock.
Determination
z
I
of
haematocrit
and
platelet
is
for
essential
h*Tgn°S1Vnr nCaSe managemeilt- The time course relationship
aor^m-s
Platekt C°Unt
a rise in hematocrit levJl
appears to be unique to DHF. These changes occur before the
subsidence of fever and before the onset of shock and are correlated
with the disease severity.
cuuuaieu
Encephalitic signs associated with intracranial haemorrhage
metabolic and electrolyte disturbances, and hepatic failure (a forn^of
XosYs
°rae) may °CCUr- They are
but carry1 a°grave
9.
Differential diagnosis of DHF/DSS
Early in febrile illness, the diflerential diagnosis includes
a wide
spectrum of viral and bacterial infections.
hypopioteinacmia may indicate plasma leakage.
10.
9
'
Laboratory confirmation of diagnosis
10.1i The
diagnosis of
iv.
ine uiagnosis
oi DF/DHF
DF/DHF can be confirmed by serological tests
end of incIude detection of JgM antibodies which appear around the
mntthV a
°f °nSet °f symPtoms and are detectable for 1-3
months after the acute episode.
10.2 A rising titre of IgG antibody in paired sera taken at an interval of
ten -days_or more is-confirmatoiy.
X Xi
silent infection and immunity levels in the local population.
10.4 Antigen is produced in limited quantities for operational research
and outbieak investigations at the National Institute of Virology (NIV)
Pune. With the antigen received from NIV, the National Institute of
6
\. JS\| )rn|’iii(le.(loc
Communicable Diseases (N1CD) supports outbreak investigations on
the request from the state health authorities. The antigen is also
commercially available.
10.5 Blood for serological studies should be carefully collected taking
due-universal precautions from suspected DF/DHF cases (a) as soon
as possible after hospital admission or attendance at the clinic (S-l)
(b) shortly before discharge from the hospital (S-2) and (c) if possible,
14-21 days after disease onset (S-3). Failure to leave an interval of 1014 days between collection of S-l and S-2 samples may prevent the
serological diagnosis of primary dengue infection. Specimen
containers should be clearly labelled.
10.6 Each specimen should be accompanied with the detailed
information about the case as given in the box so that the results
could be scientifically interpreted.
INFORMATION WHICH SHOULD ACCOMPANY EACH SAMPLE
name of the patient
name of the mother / father
age
sex
complete residential address
name of the hospital / PHC sending the sample
registration number of the patient
date of onset of illness
date of hospitalisation
date of collection of sample
provisional diagnosis
brief clinical findings
results of clinical laboratory investigations
11.
Clinical management
11.1 Management of Dengue fever
The management of Dengue fever is symptomatic and supportive and
comprises of:
•
•
•
Bed rest is advisable during the acute febrile phase
Antipyretics or sponging are required to keep body
temperature below 39°C. Salicylates should be avoided.
Paracetamol may be prescribed.
Analgesics or a mild sedative may be required for those with
severe pain
7
(\JS\I Ictigiiidc.doc
Home available fluids and OKS solution are recommended
for patients with excessive sweating, nausea, vomiting or
diarrhoea to prevent dehydration.
11.2 Management of DHF
•
•
•
•
•
•
•
Management during febrile phase is similar to that of DF
Antipyretics may be indicated but salicylates should be avoided.
Increased fluid intake
Fluid and electrolyte replacement by IV fluids, isotonics etc.
Plasma expanders, if clinically indicated
Fresh frozen plasma may be indicated in some cases
Blood transfusion
As thrombocytopenia and concurrent haemoconcentration usually
occurs well before the onset of shock, the use of these criteria can
enable the clinician to make early diagnosis at the time the plasma
leakage starts and hence early fluid replacement for plasma loss can
be administered and disease severity can be modified. Prolonged
shock is often complicated by severe massive bleeding and grave
prognosis.
Judicious volume replacement is mandatory as the rate of plasma loss
is short for 24 to 48 hours and is more rapid around the time of
defei'vescence and /or shock. Haematocrit determination is essential
for monitoring the rate of IV fluid infusion and to check overload
(which has been recognised as a common problem).
Isotonic solution (0.9% sodium chloride, also known as normal saline)
or a compound solution of sodium lactate is preferred. Saline with or
without glucose can be used depending upon availability. Glucose
solution without saline do not provide the salt required to restore
electrolyte balance.
Transfusion of platelets does not change the course of the illness and
is not recommended. Blood transfusion may be indicated in patients
with severe shock, massive bleeding and DIG.
Amount of fluid given should be constantly monitored, Any
evidence
of
swelling,
shortness
of
breath
or
puffiness
may
indicate fluid overload.
12.
Pathogenesis and pathophysiology
The pathogenic mechanism of DHF is not clear, but two main
pathophysiologic changes occur:
8
(’. SIS\I
(a) vascular permeability increases which results in plasma
leakage, leading to hypovolaemia and shock
(b)
abnormal
haemostasis,
due
thrombocytopenia and coagulopathy,
haemorrhagic manifestations.
to
vasculopathy,
leading to various
The severity of DHF as compared with dengue fever may be explained
by the enhancement of virus multiplication in macrophages by
heterotypic antibodies resulting from a previous dengue infection.
There are evidences suggesting that cell mediated immune response
may also be involved in the pathogenesis of DHF.
13.
Immunity
Infection with one serotype provides life-long homologus immunity but
does not provide protection against other serotypes, and instead may
exacerbate subsequent infection.
14. Surveillance in DF/DHF
Surveillance is prerequisite for monitoring the dengue situation in the
area and should be carried out regularly for early detection of an
impending outbreak and to initiate timely preventive and control
measures. Surveillance should include epidemiological, entomological
and laboratory parameters.
14.1 Epidemiological surveillance
The epidemiological surveillance should include the following:
Fever surveillance
•
Diagnosis based on standard case definition
•
Reporting of DE/DI IF cases to state health authorities
•
During an outbreak situation, samples of about 5% of
clinically diagnosed cases should be tested for confirmation
of diagnosis by the laboratory.
The peripheral health staff should be alerted to report increase or
clustering of acute febrile illness compatible with the case definition of
DF/DHF. Such increase of cases should be investigated locally,
including entomological investigation to check for vector density in the
area.
9
(IS\I Jr.iiguide.dcic
14,2 Vector surveillance
A number of indices have been described and are currently used to
monitor the vector population in a defined area:
1. House index- Percentage of houses positive for larvae of Aedes
aegypti.
2. Breteau index- Number of positive containers for Aedes aegypti per
J-'l 100 houses.
■
3. Container index- Percentage of containers positive for Aedes
breeding.
Epideiniological interpretation of various entomological indices
Entomological
Loiv risk of
High risk of
indices_______
transmission
transmission
Breteau index
>50__________
<5___________
House index
>10%
<1%
Container index :Container index mostly utilised for drawing vector
control strategy.
In areas where Aedes aegypti is absent or very scarce and dengue
outbreaks occur, a special effort should be made to identify the local
vector(s) to develop vector surveillance accordingly.
15.
Investigation of an outbreak
15.1 The investigation of an outbreak of DF/DHF is similar to the
investigation of other epidemic prone diseases. The first principle is to
receive early signals, confirm diagnosis and to take prompt measures
for control of the outbreak. Control measures arc most effective when
selective measures are applied early.
Factors Increasing the risk of DF/DHF outbreaks
•
•
•
•
Increasing urban population
Expanding mosquito breeding due to:
• shortage of water supply,
• traditional water storage,
• poor garbage collection,
(create more mosquito breeding places)
Changing life style ( use of water coolers etc.)
Rapid transportation
15.2 Line list of cases, including age, sex and address and other
details should be maintained and also reported to district health office
10
C:\JS\I )ciigni(lc.doc
(Annexure 1&2). Active search should be made for more cases. Serum
samples should be collected for laboratory confirmation of diagnosis.
15.3 Vector surveillance should be immediately initiated and should
include collection of adult mosquitoes, identification of mosquito
species and density, assessment of susceptibility of vectors to
available insecticides.
15.4 Arrange health educational activities in the community regarding
prevention of mosquito bites by use of mosquito nets and mosquito
repellent creams, mosquito breeding by drying out water containers at
least once a week, residual insecticide spray, wearing of protective
clothing and reporting suspected cases at the health facilities early.
15.5 On confirmation of an outbreak of DF/DHF, take precautionary
measures in other neighbouring high risk areas.
15.6 After the outbreak is over, a detailed report must be written.
Format for outbreak investigation is given at annexure 3.
16.
Prevention and control of an outbreak
PREVENTION AND CONTROL OF DF/DHF OUTBREAK
•
•
•
•
•
Initiate vector surveillance and control measures
Conduct IEC
Community participation
Assess facilities for case management of patients with
haemorrhagic shock
Alert health personnel to report increase/clustcring of cases
16.1 A surveillance system should be established so that DHF is
immediately reported to the local health authorities. Necessary field
investigations must be carried out in the area of residence of the
patient to check for vector.
16.2 The preventive measures are directed at reducing the vector
density and in taking personal protection to prevent the bite of
mosquitoes.
PREVENTION OF MOSQUITO BITES
•
•
•
•
Wear cloths that cover arms and legs during outbreak situations
Use mosquito nets or insect repellents while sleeping at night to
keep away mosquitoes
Children should preferably not wear shorts and half sleeved cloths
Keep patients protected from mosquito bite in acute phase
11
C:\JS\I )cngi tide.doc
16.3 Immediate measures are called for to reduce the density of
mosquitoes by use of insecticides. The public should also be infoimed
to take necessary precautions against mosquito bite such as use of
full sleeved clothes, mosquito nets al night and mosquito repellent
creams, if necessary.
ELIMINATION OF MOSQUITO BREEDING PLACES
•
•
•
•
Empty water containers at least once a week
Cover and seal septic tanks and soak-away pits
Removal of rubbish
Remove water from coolers and other places where water has
remained stagnant
16.4 Long term measures include the recommended steps lor vector
control under the National Malaria Eradication Programme(NMEP).
16.5 Pockets of high risk should be identified so that these areas
could be given more attention with regard to control measures, health
educational activities and field supervision.
16.6 Isolation of patients and disinfection of secretions and excretions
are not required as DF /DHF virus is not transmitted from person to
person.
16.7 Patients should be treated in nearby health centre/ hospital
where the facilities for platelet count and haematocrit value estimation
are available. These parameters are essential to monitor clinical status
of the patients. Haematocrit levels are required to know the degree of
plasma leakage and determine the impact of fluid replacement to
avoid fluid overload.
17.
Community participation
17.1 Community participation is essential for the prevention and
control of an outbreak of DF/DHF. The community must be
encouraged to take steps to protect themselves from mosquitoes by
eliminating mosquito breeding sites and taking personal measures
such as use of bed nets, mosquito repellents etc. The co-operation of
the community is also important during the periodic insecticide spray.
17.2 In pockets of high risk, active surveillance of DF/DHF should be
encouraged so that first case(s) is (are) immediately reported to the
local health authorities.
12
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17.3 Co-ordinated efforts by government departments such as
sanitation, urban development, education etc are essential so that risk
factors for mosquito breeding can be reduced and other control
measures taken up effectively.
17.4 In an event of an outbreak, the co-operation of other government
departments will help to bring it more effectively under control. An
inter-departmental committee for outbreak prevention and control
should be constituted which should meet more periodically.
Panchayat members, key community representatives and NGOs
should be included as members of the committee. A meeting of the
committee should be convened before the expected seasonal increase
of water and vector borne diseases. In districts where risk factors
exist, status of control measures for DF/DHF should also be assessed.
The suggested areas of responsibilities of the various departments is
given in Annexure 4.
13
C:\.JS\l)engui(lc. ’oc
Annex 1
Format for MPWs for reporting suspected DHF case
Village.
District
Name.
Age.
Sex
Address
Fever
Yes/No
Date of onset
Headache Ycs/No
Bleeding
Yes/No
Cold extremities
Yes/No
Unconsciousness
Yes/No
Recovered/still suffering/death with date.
House :
Kacha/Pacca
Mosquito breeding : Desert coolers/Over head tanks/discarded
tyres/Buckets/Others
Signature
(Name and designation)
Dale:
14
Annex 2
FORMAT FOR MEDICAL OFFICERS FOR REPORTING DHF CASE
District
House No.
Date of Survey.
Village
Head ol Family.
Particulars of Patient:
Name
Age(Years)
Age(Years)Sex:
M/F
Father’s Name
Date of onset of illness
Recovered / Still suffering / Died on
Date of investigation Informant
Symptoms
Fever (more than 100 0 F):
Yes / No
Headache :
Yes/ No
Haemorrhagic manifestations Yes/No
-Petechiae. Purpura, Ecchymosis
-Epistaxis, Gum bleeding
-Haematemasis and or melena
Tourniquet test: Positive/Negative
Enlarged liver: Yes / No
Shock: Yes / No
Other signs:
Similar illness in family/neighbourhood:
Name
Age
Sex
Date of onset
Clinical laboratory investigations
Haematocrit (%)
Platelet count
Samples sent for confirmation of diagnosis and result if available
Acute sera sent:
Yes/No,
Date of collection:
Convalescent sera sent:
Yes/No
Signature
(Name and designation)
Date:
Name of Pl-IC / Hospital
15
C:\JS\ Dei igt iidc.doc
Annex 3
OUTBREAK INVESTIGATION REPORT
General inloriimtioii
Stale
District
PI IC/Town
Villagc/Ward
Population
Background Information
Person reporting the outbreak :
Date of report
Date investigations started
Person(s) investigating the outbreak :
Details of investigation
Describe how cases were found ( may include (a) house to house
search in the affected area; (b) visiting blocks adjacent to the affected
area; © conducting record reviews at local hospitals; (d) requesting
health workers to report similar cases in their areas etc.):
Descriptive epidemiology
Cases by time, place and person (attach summary tables
relevant graphs and maps)
and
Age specific attack rates and mortality rates
High risk age groups and geographical areas
Prevalence and density of dengue vectors
16
(L \JS\Deiigi lido.doc
Description pF control mcasures
Description of measures for Follow-up visits:
Brief description of problems encountered:
Factors which ,in your opinion , contributed to the outbreak
Conclusions and recommendations
Date:
(Name and designation)
17
C:\JS\I Jciignidc.caoc
Annex 4
INTER-DEPARTMENTAL COMMITTEE
SUGGESTED AREAS OF RESPONSIBILITY AND ACTION
District Administration
•
y
•
•
•
•
•
mobilse resources by organising meetings with
• concerned government department
• non-governmental agencies
• community leaders
ensure vector control measures
ensure adequate facilities for transportation o.’ serious patients to
district
hospital if necessary
ensure adequate supply of drugs and insccticii ■ s
provide relevant information to the press
monitor status of control activities
District Health Oflice/Municipal health office
•
•
•
•
•
•
alert health personnel to report cases and to monitor trer.da
arrange active surveillance in affected area
arrange health educational camps and distribution jf hcalih
educational material
arrange vector control measures
convene meeting under district administratror to se
co-operati .
of other
government departments and NGOs
alert hospitals for prompt management of cases
Concerned department (s) responsible for agriculture and sanitation
ensure measures for reducing factors favouring the breeding of
mosquitoes
suppport measures for vector control
report suspected cases of DI7/DBF
Other government departments such as social welfare, education and
NGOs, and Panchayat members, village pradhans, community leaders
•
•
•
•
•
ensure measures foe reducing factors favouring the breeding of
mosquitoes
support measures for vector control
report suspected cases of DF/DHF
arrange transportation of serious cases to hospital
ensure community participation
18
(\.IS\| Jcngiiidc.doc
National Institute of Communicable Diseases
22 Sham Nath Marg, Delhi- 110 054
Line List of Suspected Dengue Cases
()3-Feb-97
Name
Pat_ID Hosp_ID Hosp_N
Onset AdmitDa Tour
Age Sex Locality /J(/
Plat_co MP_ Type
Died
82288
Priyanka Shar
12
F
Malviya Nagar Q
22-Aug-96 (Yes
es Z Yes
No
DSS
Yes
471440
Bhura Singh
53
M
Sadiq Nagar
01-Sep-96
No
Yes
No
DHF
No
471866
Tina
F
Vinay Nagar tj
05-Sep-96
No
No
No
CHF
No
4 AllMS
471879
Sachin
9
17
M
Pitampura
05-Sep-96
No
No
No
DHF
Yes
5 AllMS
472402
Sanjay
12
M
Dakshinpuri
No
472458
Urvashi
11
F
Malviya NagarCj
Aparajita Khosl
11
F
Narela C
Galib Samuel
9
M
Ashram
3
10
1 AllMS
2 AllMS
3 AllMS
6 AllMS
7 AllMS
472424
8 AllMS
472605
9 AllMS
10 AllMS
.
120742
472606
Sannah
Rakesh Kumar
r
10-Sep-96 No
11-Sep-96 <Yes>
11- Sep-96 ^N<
to
No
No
DHF
Yes
No
DHF
No
No
No
DSS
Yes
12- Sep-96
No
No
No
DHF
No
F
Lajpat Nagar
Io
12-Sep-96
No
No
No
DHF
No
M
Ansari Nagar j
12-Sep-96
No
No
No
DHF
No
21-Sep-96
No
No
No
DHF
No
No
]o
7
12 SJH
94553
Arun Kumar
24
M
Mehrauli
15 SJH
146461
Resham Bhadu
30
M
M
Greater Kailash Q
21-Sep-96
No
No
No
DHF
Inderpuri 3
21-Sep-96
No
Yes
No
CHF
No
21-Sep-96
No
Yes
No
DHF
No
21-Sep-96
No
No
No
DHF
No
No
DHF
No
DHF
No
16 SJH
146715
Bhog Singh
45
17 SJH
146749
Lalita
13
M
Pragati Vihar f %
18 SJH
61522
Shagwani
14
F
Hasanpur ►—
19 SJH
9673
RamKishore
18
M
BadarpuijfJ
21-Sep-96
No
No
146947
Neeta
20
F
Sadiq Nagar 7
21-Sep-96
No
No
No
21 SJH
145985
Vikas Verma
20
M
Palam Colony g
21-Sep-96
No
No
No
22 SJH
• 146829
Pinki
28
F
Najafgarh g,
21-Sep-96
No
No
No
23 SJH
146977
Somesh
20
M
Saraswati Vihar'y
21-Sep-96
No
No
No
24 SJH
147058
Vijay Kumar
22
M
Vasant Vihar
No
No
25 SJH
147114
Babu lai
36
M
Delhi Cantt. /
21-Sep-96
No
21-Sep-96 (Yes>
No
No
147118
Suresh Kumar
30
M
Mayur Vihar
147121
Harbeshan
25
M
61615
Sarvesh Kumar
17
20 SJH
26 SJH
27 SJH
28 SJH
29 SJH
30 SJH
31 SJH
32 SJH
33 SJH
35 SJH
36 SJH
147164
147177
147193
147196
60812
61015
66913
Reena Gupta
Subha
Guddy
Guddu
Neeraj
Rehmat
Atul
21-Sep-96
No
No
No
Mehrauli <7
21-Sep-96
No
No
No
M
Bareilly I S'
21-Sep-96
No
No
No
21
F
Pushp Vihar
21-Sep-96
No
No
No
20
F
21-Sep-96
No
No
No
2-
21-Sep-96
No
Yes
No
farukabad U.P
Kidwai Nagar 3
21-Sep-96
No
No
No
21-Sep-96
No
No
No
New Delhi /O
21-Sep-96
No
Yes
No
20
22
22
22
F
M
M
M
Pahar Ganj
J 3.
j
20
M
Uttam Nagar
21-Sep-96
No
No
No
Gautam Nagar 7
21-Sep-96
No
No
No
37 SJH
61025
Raj Kumar
25
M
38 SJH
61040
S.M. Yadav
42
M
Soami Nagar
21-Sep-96
No
No
No
39 SJH
60974
Rajinder
20
M
Aliganj
21-Sep-96
No
No
No
40 SJH
61024
Afttabuddin
12
M
Garhi /q
21-Sep-96
No
No
No
41 SJH
60975
Ram Wati
45
F
Govindpuri Io
21-Sep-96
No
No
No
C/145499
Rajeev
15
M
Hauz Khas 7
21-Sep-96
No
No
No
21
40
M
Okhla Estate/O
21-Sep-96
No
No
No
M
Sarojini Nagar/3
21-Sep-96
No
No
No
F
Sangam Vihar io
21-Sep-96
No
No
No
F
Lado Sarai 7
21-Sep-96
No
No
No
18
F
Old Faridabad /£
21-Sep-96
No
No
No
Minucharan
25
M
Sangam Vihar Io
21-Sep-96
No
No
No
C/1452500 Tulocharan
40
M
Sangam Vihar IO
21-Sep-96
No
No
No
65
F
Mohd.pur
21-Sep-96
No
No
No
42 SJH
43 SJH
44 SJH
45 SJH
46 SJH
47 SJH
48 SJH
49 SJH
67800
6099-
61910
61022
60824
C/145032
Kudan
Satnam
Sebawati
Kalawati
Beddgiri
31
28
/q
50 SJH
61011
Laxmi
51 SJH
61026
Naresh
23
21- Sep-96
No
No
No
61648
14
M
M
Shahpur 7
Gopal
Gautam Nagar 7
22- Sep-96
No
No
No
40
M
Neb Sarai
22-Sep-96
No
' No
No
52 SJH
147269
Ved Raj
^55 SJH
147318
Jai Kishan
24
M
Sewa Nagar jJJ
22-Sep-96
No
No
No
56 SJH
146365
Anesh
20
M
Gautam Nagar 7
22-Sep-96
No
No
No
147415
Narender
14
M
Masjid Moth
22-Sep-96
No
No
No
53 SJH
57 SJH
)
No
CHF
DHF
DHF
DHF
DHF
DHF
DHF
DHF
DHF
DHF
DHF
CH!
DHF
DHF
DHF
DHF
DHF
DHF
DHF
DHF
DHF
DHF
DHF
CHF
DHF
DHF
DHF
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
Yes
DHF
DHF
DHF
CHF
CHF
D-F
No
No
No
No
No
No
/
Pat_ID Hosp_ID Hosp_N
Name
Age Sex Locality
147413
147414
147952
95003
147647
C/147799
C/47839
C/143855
C/14785
C/147879
C/147866
C/147893
C/147959
61081
61150
145815
61148
C/145913
61258
146014
•J 46213
146275
61322
67035
473350
473566
473503
476492
473456
121264
473991
473187
473981
473976
473975
473915
473967
473866
471231
Kavita
- 26
58 SJH
59 SJH
60 SJH
61 SJH
62 SJH
63 SJH
64 SJH
65 SJH
66
67 SJH
68 SJH
69 SJH
70 SJH
71 SJH
72 SJH
73 SJH
74 SJH
75 SJH
76 SJH
77 SJH
78 SJH
79 SJH
80 SJH
81 SJH
82 AllMS
83 AllMS
84 AllMS
85 AllMS
86 AllMS
87 AllMS
88 AllMS
89 AllMS
90 AllMS
91 AllMS
92 AllMS
93 AllMS
94 AllMS
95 AllMS
96 AllMS
97 AllMS
98 AllMS
99 AllMS
100 DDU
101 AllMS
102 AllMS
103 AllMS
104 AllMS
105 GANGA
106 GANGA
107 GANGA
108 GANGA
109 GANGA
110 AllMS
111 AllMS
112 AllMS
113 AllMS
114 AllMS
121170
473312
31303
473308
473219
473214
473232
29838
30019
29834
29532
29801
473660
473610
473605
16
Sunita
Sanjay
I 26
27
Rakesh
22
Surender
22
Ram Bahudar
V.K. Upadhaya 25
13
Qayam
25
Narean Singh
25
Rajvir
22
Ravi
42
K.C.Barge
20
Daya Kishan
18
Kali Parsad
0
Mahavir
30
Arun
25
Madhu
0
Ram Parsad
0
Dayaram
15
Pravesh
45
Batul
24
Brij Mohan
25
Ashok Dass
10
Nadeem
20
Gunjari
8
Prapti
3
Gaurav
8
Rinku
2
Baby Arushi
3
Shahid
24
Vishvanath
Chandan Wadh 14
19
Manisha Rajan
7
Reetu
7
Shital Kumar
26
Felix Thomas
19
Waqi Khan
15
Jyoti
Onset AdmitDa Tour Plat_co MP_ Type
F
R.K.Puram
F
Masjid Moth 9
M
KaleKhan
M
M
Sadiq Nagar
Dakshinpuri
M
Chirag Delhi Io
M
M
Malviya Nagar
M
Hauz Khas
M
/o
M
Ashram
M
East Kidwai Nag
M
M
New Mubarakpuy jD
Sarojini Nagar 9
M
M
F
Faridabad
M
Lajpat Nagar 1°
M
Nehru Place
M
Gandhi Nagar 12
F
M
M
M
F
Prem Nagar 3
Ghaziabad I
F
Ansari Nagar 9
F
M
F
Kotla Mubarakp /o
Trilokpuri /X
Mehrauli 9
Hauz Khas
Okhla Estate Io
Savitri Nagar
Jaipur IJT
M
A.V. Nagar
Sangam Vihar Io
M
C.R.Park
M
Malviya Nagar
F
Masjid Moth
F
Masjid Moth
F
2
F
Ansari Nagar
Bara Tuti 2.
Jose
‘
1
M
F
M
Saumya
’
4
F
Pahar Ganj 2.
F
Laxmi Nagar IP
F
Nehru Place
M
Bankanar Vill.
Subji Mandi 2
Subha
Sapna
Harish
Umesh Kumar
Roop Kishore
Poonam
Dr. Nisha
Bushra
Kapiko A. Mahr■
Jai Veer Khura
Sarika Bhagat
Master Arora
Ranjan Jena
Rajesh
Sachdeva
SA-121455 Harima
SA_121449 Khalid
4
6
25
40
24
11
27
8
12
5
12
5
26
6
4
6
7
M
M
F
F
M
M
M
F
M
M
M
M
F
M
Chirag Delhi Io
Sadiq Nagar 9
Ghaziabad I
Greater Kailash 9
Masjid Moth ?
Bara Hindu Rao^
Gole Mkt. /3
Greater Kailash 9
Rani Bagh 7
Gujaranwala To y
2
Hari Nagar
A.V. Nagar
Jangpura /O
2
22-Sep-96 No
I
22-Sep-96 INo
22-Sep-96 INo
22-Sep-96 No
i
22-Sep-96 No
22-Sep-96 No
22-Sep-96 No
22-Sep-96 No
22-Sep-96 No
22-Sep-96 No
22-Sep-96 No
22-Sep-96 No
22-Sep-96 No
21-Sep-96 No
21-Sep-96 No
21-Sep-96 No
21-Sep-96 No
21-Sep-96 No
21-Sep-96 No
21-Sep-96 No
21-Sep-96 No
21-Sep-96 No
21-Sep-96 No
19- Sep-96 No
20- Sep-96 No
20-Sep-96 No
20-Sep-96 No
20-Sep-96 No
20-Sep-96 No
20-Sep-96 No
24-Sep-96 No
24-Sep-96 No
24-Sep-96 No
24-Sep-96 No
24-Sep-96 No
24-Sep-96 No
24-Sep-96 No
24-Sep-96 No
30-Aug-96 No
11-Sep-96 No
18-Sep-96 No
18-Sep-96 No
23-Sep-96 No
18-Sep-96 No
18-Sep-96 No
18-Sep-96 No
18-Sep-96 No
13-Sep-96 No
15-Sep-96 No
13-Sep-96 No
11-Sep-96 No
13-Sep-96 No
21-Sep-96 No
21-Sep-96> No
21-Sep-96i No
21-Sep-96i No
21-Sep-96i No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
Yes
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
DHF
No
DHF
No
DHF
No
DHF
No
DHF
No
DHF
No
DHF
No
DHF
No
DHF
No
DHf
No
DHF
No
DHF
No
DHF
No
DHf
No
DHF
No
DHF
No
DHF
No
DHF
No
DHF
No
DHF
No
DHF
No
DHF
No
DHF
No
DHf
No
DHF
No
DHF
No
DHF
No
DHF
No
DHF
No
DHF
No
DHF
No
DHF
No
DHF
No
DHF
No
DHF
No
DHF
No
DHF
No
DHF
No
DHF
No
DHF
No
DHF
No
DHF
No
DHF
No
DHf
No
DHF
No
DHF
No
DHF
No
DHF
No
DHF
No
DHF
No
DHF
No
DHF
No
DHF
No
DHF
No
DHF
No
DHF
No
DHF
No
Died
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
2
I
r
PatJD HospJD Hosp_N
Name
115 AllMS
SA-121444 Tanika Gupta
3
116 AllMS
SA-121441 Laid
117 AllMS
SA-121427 Rajani
473654
Rajesh Luthra
12
7
139 SJH
C/95319
Ajay
25
140 SJH
141 SJH
148236
Harish
27
146991
Govinda
25
142 SJH
143 SJH
144 SJH
62053
62077
Jeet Bahadur
Rajeev
30
20
C/148752
C/148414
Ramurisina
20
145 SJH
Subhash
21
146 SJH
C/148376
Sunita
13
147 SJH
62017
Snam Akina
9
148 SJH
61977
Ajahid
7
F
F
F
M
M
M
F
M
M
M
M
M
F
F
F
M
M
M
M
M
M
M
M
M
M
M
M
F
F
M
149 SJH
62159
A.B. Singh
7
150 SJH
62171
A.K.Shan
118 AllMS
119 AllMS
"'^122 AllMS
124 AllMS
-'326 AllMS
127 AllMS
128 AllMS
129 AllMS
130 AllMS
131 AllMS
132 AllMS
133 AllMS
134 AllMS
135 SJH
473613
473711
473702
121475
121472
121470
121461
121459
121457
121456
121453
473548
61968
136 SJH
137 SJH
138 SJH
151 AllMS
152 AllMS
' 154 AllMS
155 AllMS
157 AllMS
C/148075
C/95378
Sumit
Jasdeep Singh
25
1
10
Roni
5
Jenin
7
Gaurav
Puneet Sharma
Deepak
1
9
8
Anuj
5
Konika
7
Preeti
6
Taranjeet
5
Deepak
Girish
36
60
Panchsheel
14
R.N. Singh
Om Parkash
Onset AdmitDa Tour Plat_co MP_ Type
Age Sex Locality
50
25
Safdarjang Encl. 9
21-Sep-96
Gole Mkt.
/3
21-Sep-96
Tagore Garden
21-Sep-96
Sriniwas puri
Kotla Mubarakp Io
A.V. Nagar 7
21-Sep-96
21- Sep-96
22- Sep-96
Ansari Nagar
22-Sep-96
Masjid Moth 9
Ansari Nagar 9
22-Sep-96
A.V. Nagar
A V.Nagar
22-Sep-96
22-Sep-96
Moti Bagh
H.M. Pur
22-Sep-96
22-Sep-96
>5
22-Sep-96
Trilokpuri IX
22-Sep-96
Jangpura ID
Jaipur If
22- Sep-96
lC
18-Sep-96
Noida
23- Sep-96
Baba Colony
Nanak Pura 9
16-Sep-96
18- Sep-96
Dakshinpuri 9
Soami Nagar 7
16-Sep-96
Lajpat Nagar ID
VasantVihar 7
Vasant Vihar 7
Indira Park 7
19- Sep-96
Badarpur /O
Faridabad IjT*
15- Sep-96
20- Sep-96
20-Sep-96
20-Sep-96
16- Sep-96
18-Sep-96
18- Sep-96
Hauzrani 7
22-Sep-96
Hauzrani 9
20-Sep-96
M
Kotla Mubarakp {O
22- Sep-96
8
M
Lodhi Raod
473862
Jenam
7
M
Masjid Moth 9
23- Sep-96
4773860
Dr. Rajesh Vas
27
23-Sep-96
20
M Ansari Nagar
F S.J.Enclave
F Chattarpur 9
30
M
473854
473854
473891
Rupal
Dr.Janya Devis
Dr.Sridhar
6
(O
Masjid Moth 9
19- Sep-96
23-Sep-96
23-Sep-96
23-Sep-96
158 AllMs
473759
Girish
8
M
Khanapur 9
23-Sep-96
159 AllMS
473724
Sanjay
20
M
Trilokpuri IX
23-Sep-96
160 AllMS
473718
Mani Nath Jha
23
M
Chandnichowk (
23-Sep-96
161 AllMS
121358
Anuj Pukhral
11
M
Pushp Vihar 7
23-Sep-96
162 AllMS
472639
G. Jyoti
1
13-Sep-96
163 AllMS
472674
Garima
11
164 AllMS
165 AllMS
120918
Simran
120915
120914
Ravi
Vijender
1
1
F New Delhi IO
F Alaknanda 9
F Malviya Nagar
M 2
12
M
Ansari Nagar 7
14-Sep-96
120913
120907
Paul Mathew
1
7
A.V. Nagar
Safdarjang Hos ?
14-Sep-96
Sonu
M
M
169 AllMS
170 AllMS
171 AllMS
120905
472861 .
120929
3
9
1
F
F
Uttam Nagar
A.V. Nagar 9
172 AllMS
173 AllMS
174 AllMS
175 AllMS
120922
120921
472898
Annu
Teena
Akash
Shreeni
166 AllMS
167 AllMS
168 AllMS
Dhurv Suri
B.Rachel
176 AllMS
472859
473049
Ajay
Dr.J.Singh
177 AllMS
473049
Mona
7
11
1
11
26
4
M Madangir
F A.V. Nagar
M New Friends Col I10
F Lajwanti Garden ly
M Dabri Extn. 8
M Masjid Moth 7
F Saurav Vihar 0
13- Sep-96
14- Sep-96
14-Sep-96
14-Sep-96
14-Sep-96
14- Sep-96
15- Sep-96
15-Sep-96
15-Sep-96
15- Sep-96
14-Sep-96
19-Sep-96
16- Sep-96
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
Died
No
No
Dill
No
No
No
DI II
No
No
No
No
No
No
DHF
No
No
No
No
No
DHF
DI IF
Dill
DHF
No
No
DHF
Yes
No
No
No
DHF
No
No
No
No
No
DHF
DHF
No
No
No
No
DHF
No
No
No
DHF
No
No
No
DHF
No
No
No
DHF
No
No
No
DHF
Yes
No
No
DHF
No
No
No
DHF
No
No
No
DHF
No
No
DHF
No
No
No
DHF
No
No
No
DHF
No
No
No
No
No
DHF
No
No
No
DHF
No
No
No
No
DHF
DHF
No
No
DHF
No
No
No
DHF
No
No
No
DHF
No
No
No
DHF
No
No
No
DHF
No
No
No
DHF
No
No
No
DHF
No
No
No
DHF
No
No
No
DHF
No
No
No
DHF
No
No
No
DHF
No
No
No
DHF
No
No
No
DHF
No
No
No
DHF
No
No
No
DHF
No
No
No
Yes
No
No
DSS
DHF
No
No
No
No
No
DHF
DHF
No
No
No
DHF
No
No
No
DHF
No
No
No
DHF
DHF
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
DHF
DHF
DHF
No
No
No
No
No
No
No
DHF
DHF
Yes
No
No
No
No
DHF
No
No
No
No
No
No
No
No
No
DHF
DHF
No
No
No
No
J
PatJD HospJD Hosp_N
Name
Age Sex Locality
178 AllMS
473037
Bhola
3
179 AllMS
Shristhi
1
180 AllMS
473017
472994
Sonia
6
181 AllMS
182 AllMS
472968
472961
Bijender
12
1
Akash
183 AllMS
472945
120991
Mohd. Asim
Vikram
7
184 AllMS
186 AllMS
121067
Rajni
7
187 AllMS
121056
Monica
10
188 AllMS
121051
Deepak
5
189 AllMS
120992
Sunil Kumar
11
190 AllMS
473163
Indu
11
191 AllMS
473092
Neeraj
4
192 AllMS
193 AllMS
473023
194 AllMS
473070
473063
Phillip
Simmi
Master Arun
195 AllMS
473056
Ravinder
9
10
7
25
0
0
13
0
196 RML
Amir Lohar
197 RML
Harpreet Kaur
198 RML
AmitaKumar
199 RML
Y.P Kumar
200 RML
Sunil
201 RML
S. Dey
202 RML
Bhupesh
7
M
F
F
F
M
M
M
F
F
M
M
F
M
F
F
M
M
M
F
F
M
Onset AdmitDa Tour Plat_co MP_ Type
Kolla Mubarakp /o
16-S-ep-96
Nagar Q
16-Sep-96
V.K.Dutt Colony^*
Ansari Nagar *7
Ambedkar Naga <1
16-S ep-96
Ambedkar Naga 9
16-Sep-96
16-Sep-96
16-Sep-96
Gautam Nagar Q
Tagore garden-^
16- Sep-96
Masjid Moth^
17-Sep-96
Dabri Extn. 3
17-Sep-96
Lodhi Road Zo
17-Sep-96
Rewari, Haryan
17-Sep-96
Ansari Nagar (f
17-S-ep-96
17- Sep-96
Nagar 9
17-Sep-96
Mayur Vihar
_
Sangam Vihar /<?
17-Sep-96
17-Sep-96
Ghaziabad
Pandav Nagar J
17-Sep-96
26-Sep-96
Tilak Nagar
26-S«p-96
Shakarpur
26-Sep-96
7
M
Lawrence Road
Sultanpuri S
0
M
Kalibari, New D /3
26-S-ep-96
8
M
Uttam Nagar 3
26-Sep-96
Ansari Nagar
Masjid Moth ?
23-Sep-96
26-Sep-96
26-Sep-96
203 AllMS
C-2/ICU-I
Dr.Sakat Agga
24
204 AllMS
C-2/ICU
Dr.Rajan Jena
26
M
M
205 AllMS
C-2/17
Jagdeep Singh
16
M
A.V. Nagar 9
23-Sep-96
206 AllMS
D-2/9
Manju
21
F
Ansari Nagar 9
23-S-ep-96
207 AllMS
D-2/11
Dinesh Mehra
14
M
Faridabad
23-Sep-96
212 AllMS
C-5/24
Taranjit
5
F
Jangpura
/()
23-Sep-96
213 AllMS
D-5/ICU
Jariam Jhon
7
M
Masjid Moth 9
214 AllMS
D-5/ICU
D-5/37
Poonam
11
Greater Kailash 9
23-S-ep-96
23-Sep-96
Master Deepak
Geatash
6
A.V. Nagar
2
A.V. Nagar Cj
Mayur Vihar
217 AllMS
' 220 AllMS
221 AllMS
225 AllMS
227 AllMS
D-5/40
D-5/41
AB-6/22
AB-6/29
Master Bhola
9
3
Chitra Sharma
55
F
M
M
M
F
Roop Kishore
24
M
10
228 AllMS
D-6/28
Amit
229 AllMS
Pvt-108
Dr. B.N. Sharm
30
230 AllMS
Pvt-503A
Jenny Andrew
• 12
231 AllMS
Pvt.506
Nisha
27
232 AllMS
473710
Neelam
7
233 AllMS
473689
Jagdish
19
234 GANGA
301775
Ankita Verma
11
235 SJH
236 SJH
62253
Manoj
11
62278
Lalu
1
62286
62297
Dinesh
5
Nitin
12
62342
Sandeep
62364
62368
62385
62409
Pratish
Parul
Farkan
9
7
9
7
237 SJH
238 SJH
239 SJH
240 SJH
241 SJH
242 SJH
243 SJH
244 SJH
245 SJH
246 SJH
247 SJH
62421
62429
62493
62200
Anju
Hukam Singh
Bhupender
Sagar
Rekha
9
8
5
5
25
Dabri Extn %
23-Sep-96
23-Sep-96
23-Sep-96
23-Sep-96
23-Sep-96
23-Sep-96
M Madangiri
M A.V. Nagar
F A.V. Nagar
23-Sep-96
F
Masjid Moth
23- Sep-96
F
M
Hauz Khas
Saidul Ajaib Villi »S
Old Rajinder Na 3
Savitri Nagar *?.
22-Sep-96
F
M
M
M
M
M
M
M
M
F
M
M
M
F
Sangam Vihar /O
S.J. Enclave 9
q
Sadiq Nagar *
Bhagwan Nagar l|
Nanak Pura ‘y
Sarojini Nagar f }
Hauz rani
Masjid MothQ
IIT-Campus
Kolla Mubarakp 9
Nehru Stadium 10
Madanpur
23-Sep-96
23-Sep-96
22-Sep-96
21-Sep-96
24- Sep-96
24-Sep-96
24-Sep-96
24-Sep-96
24-Sep-96
24-Sep-96
24-Sep-96
24-Sep-96
24-Sep-96
24-Sep-96
24-Sep-96
24-Sep-96
24-Sep-96
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
DHF
DHF
DHF
No
No
DHF
DHF
No
No
No
DHF
No
No
DHF
No
No
DHF
No
No
DHF
No
No
DHF
No
DHF
No
No
No
DSS
DHF
Yes
No
No
DHF
No
No
No
DHF
DHF
No
No
No
DHF
No
No
DHF
No
No
DHF
No
DHF
No
No
No
No
DHF
DHF
No
No
No
DHF
No
No
DHF
No
No
DHf
No
No
DHF
No
No
DHF
No
No
DHF
No
No
DHF
No
No
DHF
No
No
No
DHF
DHF
DHF
No
No
No
No
No
No
No
No
No
No
No
No
DHF
No
No
DHF
No
No
DHF
No
No
DHF
No
No
DHF
No
No
DHF
No
No
DHF
No
No
DHF
No
DSS
DHF
DHF
No
Yes
No
No
No
No
DHF
DHF
Yes
No
No
No
No
DHF
No
No
DHF
DHF
DHF
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
DSS
DHF
DSS
DSS
DSS
DHF
No
No
DHF
No
No
Died
No
No
No
Yes
4
Pat_ID Hosp_ID Hosp_N
248 SJH
249 SJH
250 SJH
251 SJH
252 SJH
253 SJH
254 SJH
255 SJH
256 SJH
257 DDU
258 KWS
259 SJH
260 SJH
261 SJH
262 SJH
263 SJH
264 SJH
265 SJH
266 SJH
267 SJH
268 SJH
269 SJH
270 SJH
271 SJH
272 STH
273 STH
274 SJH
275 SJH
276 SJH
277 SJH
278 SJH
62229
149124
148749
149129
149172
62499
149567
149261
81630
12076
96240
96263
148690
149621
149691
149755
149521
149665
1492864
149837
62610
149885
148985
223554
1222798
61542
61491
61489
61451
61458
279 STH
280 LNJP
281 LNJP
282 LNJP
283 LNJP
964815
964748
964798
964809
964864
964942
964919
964252
963872
Name
Age Sex Locality
Rajesh
Onset AdmitDa Tour Plat_co MP_ Type
12
M
Kamal Cinema
Parminder
18
M
Laxmi Bai Naga
Guphan
Vicky
15
M
Janakpuri
25
B.P.Tyagi
30
M
M
Yudhishtar
21
M
Sangam Vihar /D
Basai Dara Pur 1/
Katwaria Sarai 5
Pintoo
12
M
Basant Vihar
Akai
Gablu
18
20
M
Vineeta
11
Lajpat Nagar (0
Faridabad
Raghuvir Nagar
Tilak Nagar
M
Megha
8
F
F
Dhishankon
21
M
Kotla Mubarakp
Rajinder
27
M
Anita
21
F
Aliganj Io
R.K.Puram 9
Shiv Kishan
36
M
Gautam Nagar
Vijay
32
M
Satyam Vihar
Madhav
20
M
Madakani Encla
Vinod Kumar
28
M
Haryana
1$
Vinod Kumar
17
M
Ashram
/o
A.K.Singh
27
M
Lodhi Road jo
Shiv Prasad
Laxmi
Reena Malhotr
Mangeram
29
19
14
M
F
F
M
Badarpur /V
Old Govindpuri /D
Zamrudpur Cj
Parvej
6
9
M
Konika
Paramjeet
11
F
Deepak
3
M
Puneet
12
M
Geeta
8
F
Shivam
6
M
Sanny
8
M
Pinky
3
F
Vivek
2
M
Rahul
10
M
Sidhartha Basti,
Gandhi nagar,D /«5
Anu
6
F
Tagore Road
Deepak
4
Delhi Gate |
16
F
Industrial Area
Loni.UP /S’
Dakshinpuri 9.
Sadiq Nagar
Laxmi Bai Naga^ ?
Sangam Vihar /O
Sarojini Nagar 10
Sadar Bazar
Ashok Nagar L/
Annu
2
Kapil
10
M
F
F
Manish
6
M
Narayana Gaon 3
Rakhee
8
F
Vinod Nagar
Rohit
9
M
Dabri village
Nihar
5
292 SUNDER 5514
Nishant Gujral
Ashok Vihar *7
Madhipur, Ronla 7
293 SUNDER
5542
294 SUNDER 5554
Baby Asha
Baby Gurjeet
12
6
7
M
M
F
F
Ashok Vihar
Neeraj
8
M
Majlis Park
Ashok Vihar 7
Kanchan
10
F
Sewa Nagar[0
Manju
12
F
Seelam Pur
Pragya
Vasim
Vidhisha
6
12
9
21
9
11
5
30
F
M
F
M
M
F
F
M
Saket
Seelampur 11
284 LNJP
285 LNJP
286 LNJP
287 LNJP
288 LNJP
*290 SUNDER 5325
291 SUNDER
295 SUNDER
296 AllMS
297 AllMS
298 AllMS
299 AllMS
300 AllMS
301 AllMS
302 AllMS
303 AllMS
304 AllMS
305 AllMS
5478
5636
474355
474346
474339
474315
474311
474308
474286
474284
474262
474253
Gopal Sharma
Neeraj
Manju
B.Pooja
ijay Kumar
LKR park
Delhi Gate |
^511
Vivek Vihar
Gaziabad, U.P
N.Delhi Iq
Tuglakabad lO
Sarojini Nagar
Shakarpur
24-Sep-96
24-Sep-96
24-Sep-96
24-Sep-96
24-Sep-96
24-Sep-96
24- Sep-96
25- Sep-96
25- Sep-96
26- Sep-96
19-Sep-96
25-Sep-96
25-Sep-96
25-Sep-96
25-Sep-96
25-Sep-96
25-Sep-96
25-Sep-96
25-Sep-96
*25-Sep-96
25-Sep-96
25-Sep-96
25-Sep-96
25- Sep-96
11-Sep-96
07-Sep-96
21-Sep-96
21-Sep-96
21-Sep-96
21-Sep-96
21-Sep-96
26- Sep-96
26-Sep-96
26-Sep-96
26-Sep-96
26-Sep-96
26- Sep-96
27- Sep-96
27-Sep-96
26- Sep-96
23-Sep-96
11-Sep-96
18-Sep-96
20- Sep-96
21- Sep-96
21-Sep-96
25-Sep-96
27- Sep-96
27-Sep-96
27-Sep-96
27-Sep-96
27-Sep-96
27-Sep-96
27-Sep-96
27-Sep-96
27-Sep-96
27-Sep-96
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
Yes
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
DHF
DHF
DHF
DHF
DHF
DHF
DHF
DHF
DHF
DHF
DSS
DHF
DHF
DHF
DHF
DHF
DHF
DHF
DHF
DHF
DHF
DHf
DHF
DHF
DHF
DHF'
DHF
DHF
DHF
DHF
DHF
DSS
DHF
DHF
DHF
DHF
DHF
DHF
DHF
DHF
DHF
DHF
DHF
DHF
DHF
DHF
DHF
DSS
DHF
DHF
DHF
DHF
DHF
DHF
DHF
DHF
DHF
Died
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
Yes
No
No
No
No
No
No
No
No
Yes
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
5
,3^ ■
J)
Model Surveillance Districts
Action Plan
Objectives:
develop and strengthen surveillance activities to promote earlv
tection of outbreaks and appropriate field action lor the
prevention and control of outbreaks.
h
M®6
^(3
^’2.
3.
Strengthen laboratory supportL for confirmation of diagnosis
from clinical specimens and for
^monitoring of environmental ’
samples—
j
d7s=Zlc^management
m^a8'™nI of°f reportable
r?ortabie and
and
p™■
4.
Strengthen basic entomological support services as relevent to
surveillance and detecting early warning signals
5.
Establish data base of reportable diseases
and previous
outbreaks.
6.
Institute an exclusive network of electronic communications for
rapid transmission of information
7.
futbUreeaksCOmmUnity participation in Prevention and control of
Methodo logy:
air?
■i
a
Strengthen and utilise e."-sting
... ___ E manpower, laboratory
and
health infrastructural facilities through!
lih^
1.
Training
2.
Modernisation of office and laboratory equipment
3.
Strengthening of linkages for disease surveillance from
peripheral to central levels
4.
Networking with state/regional and national institutions
tnrough electronic means of communication
5.
IEC activities. ’
3
1
D
I
Training:
1.
Categories to be trained:-
a) Rapid response team at state level (state level officer
designated by state govt as nodal officer for disease
surveillance, one epidemiologist/public health specialist, one
microbiologist, one entomologist, one clinician and one
statistician)
b) District rapid response team (same at (a) at district level). In
the absence of entomologist at District level, either
epidemiologist or imicrobiologist may be trained for same.
c) PHC medical officers (app. 25)
d) MPWs (male and female) (app. 150)
e) Lab personnel (app. 40)
0 Clinicians at state level - 25
2.
Except lor training of the Rapid Response teams at N1CD, other
training will be at state/district level. PState rapid response team will
act as trainers for training other medical & paramedical personnel at
state/district level.
N1CD faculty will participate in the training
programmes at state/district levels.
Training Material:
(a)
Modules to be used:
=> principles of outbreak prevention and control
=> case definitions and differential diagnosis of reportable and
epidemic prone diseases
=> clinical management, guidelines for referral
=> laboratory tests at PHC & district levels, collection, storage 8s
transportation of samples to state/regional/national lab
availability of media and reagents
=> guidelines for entomological surveillance
=> data collection, analysis, channels for reporting, line listing,
nil reporting, computer software
=> practical drills for outbreak investigations & control
(b)
Training material will be drafted and printed by N1CD
2
Laboratory strengthening
1. Checklist for documentation of available facilities and identification
of gaps at P1IC and district levels
2. Visit to facilities at district level/selected CHCs & PHCs by NICD
faculty/state officers
3. Training in laboratory techniques by NICD faculty at district level
4. Supply of essential equipment and supplies by NICD
5. Issue of guidelines for collection and transportation of samples for
which testing facilities are not available at district level.
6. Networking with state level and NICD through fax & E-mail by
district level
Clinical Management
1. Issue guidelines for case definition, differential diagnosis and
clinical management
2. Train selected medical officers
3. Networking with state level/NICD through fax & E-mail by district
level
Data base
1. Establish computer facilities with appropriate software and fax
2. Use relevant formats for feedback and reports
3. Prepare annual reports including investigation and follow up of
early warning signs of outbreaks.
Community participation
1. Use monthly visits to each village by FHWs for immunization
sessions to convey appropriate seasonal messages on outbreak
prevention and to collect information of unusual events
2. Hold open house meeting on fixed day & time every month at
PHC/CHC/district level whiHi private practitioners/members of
the public could attend. Topic for discussion could be seasonally
appropriate
3. Rapid response and investigation of untoward/unusual events
reported by the public
4. Involvement of school teachers and students by organising
meetings and preparation of relevant health education material
5. Involvement of ICDS as above
6. Involvement of NCOs
3
Other Government Department
i. Inter-department committee at state/district level
Meetings to be held regularly at pre-determined 1 at senior level,
frequency
of 2/3
months under the chairmanship of Director of Health
q
Chief Medical Officer respectively
SerV1CeS and
’ sS=S=
upply of essential equipment, supplies & reagents
1. Computer fn<-ilitie
state and district levels
2. Fax at state & dis
levels
3. Telephone facilities at CH
-I levels by State Govts
4. Lab equipment as appropriate
5. Contingencies for procurement of supplies and
appropriate
a reagents as
6. Contingency funds for sample collection/transportation etc.
Monitoring & Evaluation
Overall monitoring will be the responsibility of N1CD and it will
4
r>is iLf-.i®-
ISSUES RELATED TO THE LAUNCHING OF A
DISEASE SURVEILLANCE PROGRAMME
• TECHNICAL
• ADMINISTRATIVE
• FINANCIAL
TECHNICAL ISSUES:
1. Prioritisation of diseases to be put under surveillance
2. Surveillance type for each disease
3. Case definitions
4. Format for collection of information/report
5. Flow of information
6. Frequency of reporting
7. Analysis & interpretation of data and action
8. Monitoring for completeness & regularity
9. Laboratory support
•
•
•
•
•
•
Identification of laboratories
Supply of materials for sample collection
Formats for sending samples
Sample transportation
Laboratory supplies
Laboratory reporting
10. Rapid Response Team
•
•
•
•
Constitu/ivJJob responsibilities
Mobility & other supports
Mechanism of activities
11. Feedback mechanism
12. Contingency plan for outbreak control
13. Periodic publication of surveillance data/reports
14. Periodic evaluation mechanism
15. Trained and motivated manpower development
ANALYSIS & INTERPRETATION OF DATA AND
ACTIONS AT DIFFERENT LEVELS
Analysis (of variables):
* Number of cases & deaths
* Sex ratio
* Time of occurrence
* Place of occurrence
* Incidence
* Attack rate (age specific)
* Seasonal variation
* Case fatality rate
* % of samples found +ve
* % of sensitivity to antibiotics
* % of serogroups/types
Interpretation:
* Endemicity (same/less/more)
* Clustering of cases/deaths
* Increased mortality
* Impending outbreak situation
Action:
* Regular reporting sending
* Giving feedback
* Alerting for outbreak
* Outbreak investigation
29 September, 1997
RRT Training Course:
1000-1115 Role of lab. Infrastructure required, tests to be
performed, networking etc:
Dr Rajesh Bhatia
1130-1300 Diagnosis of cholera, LA, HbsAg, & meningitis,
biosafety
Dr Shashi Khare
1400-1530 Water bacteriology
Dr KV Chandersekharan
1600-1730 Microscopic examination
Dr Sunil Gupta
, re
t(2
I
NATIONAL DISEASE SURVEILLANCE PROGRAMME
TRAINING OF STATE LEVEL OFFICERS
(22.9.97-3.10.97)
NICD Seminar Room
Facilitator: 1. Dr A C Dhariwal
2. Dr B K Sainanee
3. Dr Jagvir Singh
4. Dr D Bora
Participants: 1. Dr Mahesh Bora, SNO, Rajasthan
2. Dr Santhamma Joseph, SNO, Kerala
3. Dr Kamal Chand Singhal, Physician
4. Dr Niti Talsania, P & SM
5. Dr Meera D. Meundi, Micro - A
6. Dr S.K. Ghosh, Entomology
7. Shri Inder Singh, Statistician
8. Dr Sanjay Mallik, Medical Spl.
4’
Position: 1725 (3 views)