Prevention and Control of Outbreaks of Meningococcal Meningitis
Item
- Title
-
Prevention and Control of
Outbreaks
of
Meningococcal
Meningitis - extracted text
-
Government of Karnataka
Department of Health & Family Welfare
Karnataka Health Systems Development Project
Prevention and Control of
Outbreaks
of
Meningococcal
Meningitis
Office of the
Additional Director, Communicable Diseases
Karnataka Health Systems Development Project
Department of Health & Family Welfare
Bangalore.
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CONTENTS
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Topics
1. Introduction
1
2. Indian,situatjopj .
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3. Causative agent
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4. Source of infection & ttahsiriissidn ■ .: <
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 Anncx-VIl
14-19
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3.2. lhe capsular polysaccharides of the organism
c_o_ 1
differentiate thirteen
serogroups. Among these serogroups of N. meningitidis, only
serogroup "A" is reported
4. Source of infection and its transmission:
4.1. Primarily the “sam^rs” (humans, who carry the <
organism in nasopharynx
Without getting the disease) are the source pf infection. Sometimes the patients'
; of
meningococcal meningitis can also be the sourse of infection.
dirP t 4'2/ T?S .1"fecti0n is transmitted through droplets during sneezing, coughing and
organist
naSOpharyngeal secretions. There is no extra-human reservoir of the
5. Incubation period:
The incubation period of the disease* is between 2-10 days, commonly 3-4 days.
6. Pathogenesis:
/
»a = X nCeS’>,
°r8’niSmS ,ransmi8ra,e lhr0U6" ,hese “lls
-bmuoXl
nfe t’i
'
!Vie 300635 t0 entCr caPillaries and ^erioles and lead to a systemic
mai
j
tu1S
Pr°CeSS thG
caPsular and surface antigens play a
(m^
f6' m ’S
SyStemiC lnfeCti°n Can be manifested
three ways: meningitis
LaingoLXiX men,n8°C°“'mia
a»d neningids »ith
7. Risk factors:
•
In endemic situation the attack rate is highest in children of 6 months to 1
year age group.
About 50 per cent of cases occur in children below 5
years and 80-85 per
cent of total cases occur in less than 25 years age group.
Attending physicians, health personnel and household members of patients
aic al mote risk of getting the disease.
t {. .
Overcrowding, enclosed population (hostel, jld/remand home etc.) and low
socio-economic status cart also increase^ the risk of disease spread.
2
8. Clinical manifestations:
C4- 5
f
headache, vomiiinrXfophoHa^/t5 1^COnimonly Presented with sudden onset fever
Petechial ra^di^^Sensmc £1 COnSCI1OUSness -d stiffne^.
case^ patient is usually comatose, ’in natienfoundT1 SlgnS
convulsi°ns3ln
severe
^j-g££Q1£d_^iJey^rJrritabilitv.
j usually
is
convulsi3iid2tj[gingL fontaQ££[e- petechial rash
floc'/
A
The clinical
presentations of meningococcal~^^iuii
^distinguishable
fro
are
^^omot
her acute bacterial meningitis.
8
8.2. When thee di,
disease is manifested as Menin
occur' without
bacteremia and sepsis
meningitis. Three-fourth of such -SQtescemia.
.
petechial rash i
cases may develop characteristic
"totongococcem." X ,ea “^fur^- “d “kl'!- About 10-20 per cent of all
I---r- ■■
high fatality
rate, y ieaa to fulminating stage with vaso-motor collapse, shock and
Both the types of the disease
epidemic situations.
may co-exist in endemic and
9. Case fatality;
lreat,„e„tJ0?“°"tie”h
ftoiityXXcFRl ra051
f°r S““essf“i
more during epidemic mainljl due to to» » M e'
“n b‘' “ hi8h as' M P« <=ent
an improper management. With early diagnosis aWareness’delay m hospitalisation
sopporhve measures, CFR can be brought down to folo'peTce'nf
°‘her
H). Clinical laboratory findings:
Apart from Gram’ raining of CSF, clinical laboratory siacfe t
establishing the diagnosis,
are of little value in
n acute bacterial meningitis, which deludes
meningitis, the characteristic CSF findings
---- * meningococcal
are:
i
*
• Colour:
• Pressure:
• Mononuclear cells:
• Polymorph cells:
• Protein:
• Sugar:
Turbid/Purulent
Increased
<50/cu.m.m.
200-3000/cu.m.m.
> 45 mg/dl.
< 40 mg/dl.
y
i
i
i.
3
i
r
11. Differential diagnosis:
0±"
meningococ
similar
‘“f
encephalitis, aseptic meningitis and braintbscess
tho^Tb8’
Cefebral malaria-
«o.tion „d laborMory investi8aiions Can he“ Io t‘hb°;x du"8’
12. Laboratory confirmation of diagnosis:
co„flmiatory test... But,, ,s
ve^ 4
a
antibiotics. Other methods (seroloeiel in 1 d r dl flCU ‘ after the Parents have taken
>„d Latex agglutination test.
°£‘"’m“"°-=l<»'rophoresis (C1E)
CSF. The Sgno^"au ii hXu70 SoZ"8'
agdluttnation. ™S eim
•”« L««
be
ecI>niques for Grain staining of CSF:
SiSSta hl°^SF s,w“'d be co"“,ed h
i^ntediaX XoiSr"
•
•
’
•
•
•
to
P'°^
Centrifuge CSF at 2000 rpm for 10 minutes
UsTI drTof UP.ernat7lt
reserve for Latex agglutination test.
Use a drop of sediment to make a smear on a glass slide. Air drv and
ix gently by passing through flame.
sFXoreiti';e'h “mOn,"m
"»'«> solution and iet
Rinse gently with tap water and drain off excess water
Flood smear with Gram’s iodine solution and let stand for 1 minute
minute.
Rinse with tap water as above.
no ior i minute.
Decolourise with 95 % ethanol for 5-10 seconds
‘ lSX"h Safranin for 2°-30 seco"ds °r ttuboi-fuctain for
Rinse the slide with tap water and blot dry.
condp45 Exa™ne the smear under oil-immersion lens with bright field
nogativ^a^Z^r
°r
appear intra- or
1ococci.
4
- Gram.
------- -
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.
MggQtjvg .reaction: The suspension remains homogenous and slightly
milky in appearance.
£.Q.SltiYC reaction: Within 10 minutes, agglutination (visible clumping) of
the latex particles occurs.
Demonstration of bacteria in the 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
he 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
lubes 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,
depending upon the facilities available, serology and microscopy are the best options in
older of preference. Eagh sample should accompany detailed information as indicated
below.
•
•
•
•
•
•
•
•
•
•
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:
a
•
•
•
•
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.
1 he 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 noninlectious 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
releyance 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
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 number of cases/deaths 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 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
rash.
In patient under piie year of
a suspect case occurs when fever accompanied by
a bulging fontanelle.
Probable case: Suspect case with vomiting and positive neck rigidity with or without
positive Kemig’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 positive cultivation 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
1 he 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 are available.
143. Type of Surveillance: Two types of surveillance are 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
.-.niciiLngitig. 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.
hospital & Medical college: Sentinel
surveillance of meningococcal meningitis.
14-4. Identification of sentinel centre^- 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.
143. Collection pf 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 pf 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. Ercqi».Qi.lgY_.Qf. reporting: All the reporting centres should send monthly
report. Formats for passive and sentinel surveillance centres are in Annex-Il & AnnexIII. The regularity of complete reporting, including ’’Nil” report has to be ensured.
In the event of unpending/continuing outbreak,
information should flow daily at all levels.
14.8. Elo_w qf jnfoimatiqq: 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. Flowever, 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 Aonex-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-V . With gradual
development of HMIS services, NICNET will be used in near future. Flow chart of
information is in Annex-VI. However, in case of emergency, FAX, telephone,
telegi am should be used for sending daily reports at all levels.
Data utilisation & monitoring: The data generated / received at different
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.
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
(Ccntial 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 (NICD), 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
mobihsed by the distnct/state health authorities for taking up and helping in early
implementation of the following control measures.
IZiL-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
reportis m A^nex VII^
inVeStigati011, Forniat for writin8 the outbreak investigation
In outbreak situation, laboratory' confirmation
of each case is neither required nor possible.
of surveillance:
Active surveillance of the cases and deaths should be started in the area by
health staff. For this 46 suspect case definition can be used in community.
10
•
Daily reporting of cases and deaths should be started at all levels from
periphery to State Health Directorate.
173. Patient care:
Provision should be made to treat and follow-up all cases at hospital/CHC/PHC.
H the situation demands, “Camp hospitals” should be established in school buildings or
similar structures.
-1- Earliest Pinstitution of specific antibiotic can cut down mortality
diastically. Information already available: on microbial scnsitivity/resistance can give
right direction in this matter.
li.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, Clicmoproi)liylaxis:
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, Rifampicini can be given orally. The
duration is 2 days. For adults 600 mg and for children 10 mi£/Kg body weight to be given
12 hourly.
I ZJk Immunisation:
The primary means of controlling epidemic of meningococcal meningitis is
vaccination.
In India, bivalent vaccine (against serogroups “A” & “C”) is
piesently imported from out side by the Central Govt., primarily for immunising
the Ilaj pilgrims.
II
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 TV. menuigitidid 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‘ ft 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, bat rack, 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/statcs.
12
be
provided
to
the
ANNEX-I
NATIONAL DISEASE SURVEILLANCE PROGRAMME
Meningococcal meningitis
(Foimat for collecting information on individual case in sentinel centres)
Name of the Centre:
District:
Patient's name:
Age:
IPD Reg.No.:
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:
• Anti biogram:
• Serogroup:
# Level of information to count a "case".
@ Level of information to count a "death".
LAMA: Left against medical advice
13
ANNEX-II
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
ANNEX-1 H t
NATIONAL DISEASE SURVEILLANCE PROGRAMME
Meningococcal meningitis
(Format lor sending report on meningococcal meningitis by sentinel centres)
Name of the centre:
District:
Reporting month:
Year:
Date of reporting:
Age group
(in years)
No, cases
Male
Female
Total
LLl deathsMale
Female
0-< I
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
ANNEX-IV
NATIONAL DISEASE SURVEILLANCE PROGRAMME
Meningococcal meningitis
(Format for sending report by district health office)
Name of district:
Reporting month:
Dale of reporting:
Number of cases
Acute meningitis________
Meningococcal meningitis
* Cases include deaths also
Signature of DHO
Date:
16
Number of deaths
ANNEX-V
NATIONAL DISEASE SURVEILLANCE PROGRAMME
Meningococcal meningitis
(Format for sending report by state nodal office)
Name of state:
Reporting month:
Date of reporting:
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;
NICD
CBHI
State Nodal Officer
' 4s
//T
/
1
'
i
I
l
District Health Officer
Passive reporting centres
PHC, CHC, Taluk hosp. etc.
Sentinel centres
X K
\'\
Rapid Response Team
Sub-centres
Community
Direction of flow of report----Direction of flow of feedback - Direction of action at community level ?
18
ANNEX-VII
national disease surveillance programme
(OUTBREAK INVESTIGATION REPORT)
os:
State
District
PHC/Town
Village/Ward :
Population
Background information-
Person reporting the outbreak
Date of report
Date investigation started
Person(s) investigating the outbreak •
P-£iails of investiga(ipn:
loci hospi,.,s; (d) re,ucsting „„„„ Jrke'”to
19
use search in the affected
”
Descriptive cpidcniiolog;y;
•
•
•
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;
I
Vector Surveillance
Entomological & Vector Control Aspects
Division of Medical Entomology & Vector Control
•l
•.
NatlooaleIu StitUte °f Cornrnunicable Diseases,
^2- Sham Nath Marg, Delhi - 110054
1
a
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
incrimmatioin 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:
EntoKflological aspects
Most of vector-borne diseases prevalent in the
the country
country are
are transmitted
transmitted
frOn? 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
/
Mosquitoes Vectors
vert
Mosquitoes are worTS^tfet^f^^^
subspecies of mosquitoes belonging to
ab°Ut 3450 sPecies and
n " Mosquk ab°Ut 300 SpeCieS of mosquitoes^
' Culicidae- <n
insects of similar
■
-
-■
0
j
the hind
ii)
and sucMnenXf f°7'ardly Projecting proboscis with piercing
g 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
bifurcated
ractenstic wing venation i.e. wing vein 2ne, 411. and
1.1 MglBhojo^ of mosquito
•
5,b
.
leng*. HowXer.'lome spp’may^lVsS? “j3811™8 about 3’6 mm. in
f
Mosquitoes j---mesothoracie forewings. The hind oair of X
7
Pair °f Actional
1 he hind pair of wings are i----small knob-like structures, the haheresTP T repres'nt^ by a pair of
while mosquito is flying.
leres., ”
hlch are the balancing organ
which
•
^The h d
pair of filamentousTnd s^gmeiidTat'ennae’^T'1 C°mpound eygs and a
whorls of short hairs (Pilose) whereas in mal
h females the antennae have
long hairs giving them feathprv ar^
the antennae bear a whorl of
antennae, head 'bear"
o
(P1Umose)’
below Jhe
and dilated or pointed af their "pTde^n^ P1
be short or Io"g
•
.
adults are anophelines or culicines AnV
UP°n tHe S6X and whether
elongated structure, the proboscis whichPalpi is a sing|c
types of stylets or mouth parts The larQ T
piercinS and sucking
is a long and flexible gutter - shaneH i n
CO™P°nent °f the mouth parts
small lobe like structure cLled S lab\Umuwhlch terminates in a pair of
labium almost encircle all the other & To 1Cb
sensory hr nature. The
^ath.
the other ™uth parts and serves as a protective
3
along i'ls'enZh?,0?' StrU,ClU/c' thc
is slender, pointed and grooved
like structured
a“'. >" ^tween the labrum and labium are hve needle
a single hoS dd 1^“““ ”a"diWon thdun add tak"B “°Od nK£‘1' thc tipS °f nash>r labin'n ar= Pla“d
ntaxilkjXX adhdrThiS a“0WS th,! Pa,red ma"dibl's aad
pumped into the hn^ bypOpba^nx to Penetrate the host skin. Saliva is
Fempiles mosoui^h b°dy throuSh th« hypopharynx. Blood is ingested by
icmaics mosquito through the pumping action of the pharynx.
maxillae and mi ^^^hoes are incapable of taking blood meals as the
maxillae and mandibles are vestigeal and feed on plant saps or nectar.
dull otTshinv°ThCnVered
and laterally With scaIes which may be
the^ dorsll Z’f;?;1^?™^’ bla?k In colour- The arrangement of scales on
mosquitoes7lS;
?
ClpS
identincation of some species of
uiu^quiLoes (Aeaes spp.)
a™« „gr■ long
‘O"8 and
ana relatively
relatI’cly narrow,
"arrow. ithe number and
veins arTloet d ^
1"8-,'''""5 is
‘S almost
a'm°St the Same
aU ™squito spp.The
wing^veins
same in all
or yellow
“i H
”hlCh are usually
usually brown,
br°wn. black,
black, white,
white, creamy
..
n coIour- The shape of the scales and pattern of their
Sittinr UaenwZleS f‘" difrcrent B'nera and- sPeci's °f mosquitoes. While
abdomen in the f the rmos?u>toes are placed across each other over the
abdomen m the form of a closed scissor. There are three pairs of tiny,
elongated legs which,i 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.
in a oair of smfn r ab^minal ^gment of the female mosquito terminates
termfnmX 1
flngeHike structure called cerci, whereas in males it
gcntalin , p-f1 a pair of promment claPers> which is a part of male
o
-I I Ct •
A 1g .
1 j
(
FOM< Uta
MIAO
• culwm
WIMQ
THORAX
haltbrb
v«ln
••utallum
ABDOUCN
fig 1
mino
laa
Diagrammatic representation of a female adult mosquito
tor
•’ An°Ph<!les
mainly responsible
ior me transmission of malaria in various parts of the world Out of 55
Zpbeto annul" ■
' 9
°f malria vt
minimus A van
a A'r S<ephensi’ A- Philippmensis, A. sundaicus, A.
minimus, A. varuna, A. cuhctfacies, A.fluviatilis and A. dirus.
habiSiSls:'aniLh7 f<. COmmonl
y found
commonly
found in
in 'arge
large numbers
numbers in
in human
human
hat.tations, ammal shelters
or
m
mixed
dwellings.
Anopheline
mosquitoes
- J or in mixed dwellings. Anopheline mosquitoes
have also been found
resting in outdoor situations on banks of stream ,
under culverts, and in thick shrub, forest etc.
H) Breeding habits
The eggs are deposited singly and generally laid on
the surface of clean and
4 iunpolluted 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!
r— •
Hi) R^stin^abits
Most of the anopheline mosquitoes are domesticated
and human h°h>drn
nUmber in indoor situations; in cattlesheds
. human habitations. However some of the species like A. dirus is an
outdoor rester (Exophilic). Males are usually found near the breeding
iv) gjlingLand feeding habits
I
' ’ mosquitoes can not suck blood and
Male
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 <—
uunrTnb^od""
got definite preference for h
v) Flying habits:-
muse
aompcH
Most domestic
1 km. of human
J1UUlallllS and /l- mUll,riUS ha-
“ '3S
. Aiiophftct rciliftg
raua<*i<t|.
,
.......
.MtM-.t
• •.-- •
X.
m.iquito
MilMla
1.3
f ‘‘"“□“qukoeT’Ire raarWs'by'
^
by culicine
Mans onia «species, Japanese encephalitis7 bv
Oengue/Dengi
transrnittcd
qUlnq^efasciatus and
gr°UP
dwellinJ^cattlesheC™a™°S’“d“'S5Por=^
Places and live in human
other such shelters.
outdoor situations in shrubs, grasses, forests etc5’
aIS°
- grasses, forests etc.
unused Wells.
mosquitoes lay their eggs in
Aedes .osquitoes^X^^^^.
6
£
such as earthen po s, cement tanks, glass or plastic containers,
tyres,
coolers,
sneoi, h Ta col'eotK>ns of ",alcr >n 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.
Hi) Resting habits:- Culex and Aedes
are found in human dwellings or
cattlesheds.
Mansonia species m
'
mainly rest in cattlesheds and human
dwellings but may also rest outdoor.
antlm^^hagtJr^ansS^^s Culex jI^5Sq^itoes are ^oophagous and
mcSqU^s Jte
Aedes
species prefers human blood.
hnTdiSSSa tCu'6*and Ma^pnia species of mosquitoes can fly upto a
nieht
7
r
C-'z/Ze-v resting position
1
/
i
I
i
I
•i
Fig-4
Japanese encephalitis (Viral)
a)^Principal vectors
Cx. tritaenirohynchus, Cx. vishuni and
Cx.pseudo vishnui
b) Suspected vectors
Cx.shitmorei,
Cx.epidesm.us,
Cx.gelidus,
A.barbirostris,
A.hyrcanus, A.subpictus
9
\
<
Aedey mosquito resting position
Aad«3 degypf?
Ae. eroopac.-us:
A* irrtiirtU£~ *
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) Bgg
Anophelines generally lay their eggs singly in clean, oxygenated
water. ]Each egg is boafshaped in ry;
appearance and has distinct float on
either side.
—. The number of eggs laid by a single female varies from 40-150.
CuZex 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 60IbO eggs in one oviposition. The eggs pf 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
° egg laying colour changes to black. The incubation period of egg stage is
ab^ut725^^duration under favourable climatic conditions (Tern. 27 C and
ii) 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 i_
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
oi 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
CHABACTE1HSTICS OF ANOPHELINES AND CULICINES
A NOPIIU.ES
AEOIjS
CUI.HX
i
V- , d
t)
’:^waK3ffip
FAM’ Mlft44
X.
••*«* MlnllT
vF
it
e*
u
x»lt
MS| ►
•'
Fig. - 6
12
J
"'<-
k) Laryal Density per dip
(laddie, larval net, well net)
—^°- of larvae collected
No. of dips taken
For_Aedes aegupti
i)
Container index
ii)
House index
No. of houses found positive
No. of houses searched
Hi)
Breteau index
No.:.of containers found positive x 100
No. of houses searched
- No. pf containers found positive x 100
No. of containers examined
c ) Precauations to be taken while collectin
x 100
mosquito larvae b
di
er
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.
for larvae to e „ t t
7 ‘h'
de to come to the surface once more.
and then wait for 3-5 minutes
df Precautions
Larvae may be collected from large ; '
stretches of water along the edge of
Streams, wells and other situations using a larval
diameter When eollecting iarvae, the net if held at an net of 20-25 cms.
angle and skimmed
aloPrigyve™Ustowhe SaUowCe "Th
or n°atin8 Ration oi pushed
AlterlaSyX^
tO
^e net.
e™dceo11eTXedn»Uh rZ«tde.and WaShed °Ut to “
15
“andthe8 la™
«) Precajitions
usin the well
using
above the ^ter^Af1/5 dlpped slowly into the well keeping half th n .
deicer. Alter waiting 9-^
,
u xvtcPing nail the border
return to the water surface the
t
,
anOW th' disturbed larvae l„
Possible around the edBe of’, ' a IL
S'O'vly
as quietly as
-t - 2.3 minutes then repeat. "
^-r.
✓
0 Precautions to be
taken while collecting adult
situations
ffipsqmtoes in indoor
mixed dwellings etc., on^should Sth™™ h^man dwellings, cattle sheds,
presence of snakes. 5corpions, p^Te^to pXnt X
thC
prevent any mishappening
i . .■
. i. •'
Mosquitoes
I
I •.
iLMalflria vectors
i
resistant to^DOT^d HCH
Stephe’,si’ major vectors of malaria are'
and f-"'
An. - stephensi,
- .n most pan of the eountty. In
pie resistance against DDT, HCH:
I
be susceptZtZZZS
annularis have been
iventional insecticides used under NMEP.
ilLDenKue/DHFVectprs
reported to
susceptible to orSphoXJes andTynSeL
pyreZid^
DieIdrin
resistant to
DDT
but
Vectors
orsanXein^Tnsect^derX
developed resistance
against .
suscephble to organophosphates and Dieldrin) but are reported to be
synthetic pyrethroids.
iv)_Fnariasis Vectors
Cx. <Quinquefasciatus, vector of
i
most of the
the corganochlorine and Bancroftian filariasis
— is resistant to
organophosphate compounds but
susceptible to synthetic
-----: Pyrethroids.
1.8
fiSi^MaSi2noiSusceptibility tost
A. Adults
intcrv;dUtoeaseblIity
Of
mosc^uitoe3 are carried out at six monthly
vanous msecXTd
h
SUSCePtibiUty sta^s of vectors against
appropriate insert Hbemg
Under PUbliC health Pr°grarnme. so that
nsecticide may be used for effective vector control.
i,nH,J7tShly fed female moscluitoes collected from the study area are keot
pertd of
*= healthy mosquitoes are exposed
method.
and m°rtallty count 13 made after 24 hrs. as per the WHO
^tHL&IIlgli^s^material and method used to determine
the insec tic ide
gujsc^Btibililty status of mosquitoes
’
■
‘
^LlAjLRinents/mate rial require d:
o
Dj^G
BOinibc
im
ruw.
rut(
-wi.PthG
HJ4C
iw
(Fig:7)
IQ
CompositionjfwHQ Test Ki(. .
(*)
(ii)
(iii)
(iv)
(v>
20 plastic tubes - 125 nun length and 44 mtn diameter.
8 tubes with red dot - exposure tube
ubes with green dot - control tube
1 n SCS Wlth green dot-holding tubes
and provided^th a S^mm
Insecticide impregnated papers
2o eQet °f pIam PaPer for lining of holding tubes
>2 silver
'XP0SUre tUbCS a"d
(vi)
t-rlass aspirator tube
(vii)
Adhesive tape, log probit paper
(viii
carbamates /?ynX^pyrXroSidOr8anOChl°rine /organPhosPhate /
Methqdology
Si.v=r
~
and put a
- Now put 15-25 r
per htube
the help of sucking tubemosquitoes
through lining
’ole' in each holding tube with
in sliding unit.
' ' SXdXutotX^^
f°r 1 h°ur “d
In exposure tubes put insecticide i-----different concentrations and one c<impregnated papers of
ontroluse
paper impregnated
clip. 01 S0 Vent)‘ T° keep the paPer in Position
-------: copper
spring wire
.
tubes/control tube from
holding tubes^wkh^LX^oS
up for^hour°SUre tUbCS Standin£ uPright with screen end
holding tubefseXAOsUre||Peri°d’ transfer the mosquitoes to
be kep! at the top o™"tZ0"
S°ak'd in
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.
Abotts’s formula =
-A test mortality - % control mortality
—
_______________ x 100
100 - % control mortality
General Remarks
1.
Lach 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
rescaled
Result / interpretation
i.
r
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
hsk
• Z 5- x
•.
* I----- —--
x
CSNT
,
I -c z
2 OZ
-l-O *
I □DT : ’
/.** 1 fi
• Z [: —
•j
"JP
<3j T~i CMJ —
JI exposure
”
1 "*"' * *"" "—7
xal-l
7
S5Q f
7:
=
4
ET~n+7---;
c CI
f: G
I
50
<O
30
l
.z
ro
s
5
I
5>
1
L_1
■
I -
0-5
i
0-1
i
(Fig. 8)
j
22
0817£
X
LIBRARY
library ^'X
AMD
'$ Z. g
AND
documentation J r
.
UNIT
-. Or.--
/
LARVAE
°f m°sc*uitoes can be
detern'iinedePbybleXos£gULtef
insecticide concentration in 500 ml pIs
1 instar larvae to various
mortahtv Vr
i g]
beaker f°r a period of 24 hrs’ a"d
thereafter larval i
‘ “
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.
g^de.lin^S.the following criteria is used for determining the
susceptible or resistant,> tolerent status of adults and larvae.
Range of Mortality
2.
Between 98% - 100%
Between 80% - 98%
3.
Below 80%
Status
Susceptible
Tolerant
(Verification required)
Resistance
91
Proforma of mosquito larval survey
Locality -
Date of collection -
PER DIP DENSITY IN + VE BREEDING PLACES
Sullage
water
drains
Septic
Tank
Cesspits
♦
ANOPHELINES
L-MI
L-II
PUPA
CULICINES
L-I-II
L-III-IV
PUPA
AEDES
L-i-n
L-III-IV
PUPA
OHT
Cistern/
Barrel
Ornamental Tank
Wells
♦
Irrgn.
Canal
Seepage
Water
Rice Field
Lake
Rain
Water
Collcti.
Rejected
Tyre
Utensil
Others
Proforma for Indoor Adult, Mosquito Collection .Record (MHD)
Distt.
Date
P.H.C.
Time
Method: Aspirator.
Village.
k
♦
LastSpray on:
House/ Cattle shed
Weather: Clear/Cloudy/Rainy
S.No.
Mosquito Species
Houses
Abdominal Conditions
UF
1.
2.
3.
F
I SG
G
Total
F
| Density
P.M.H.
(houses)
M
I
Time Spent
Cattle Shed
~~ I Total
Abdominal conditions
UF
Anophelines
Culicines
Aedes
UF = Unfed
F= Fed
SG = Semigavid
G=
i
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
ector 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
ii)
Repellents - These are substances applied to the
skin, clothings or
mbsquito net to repel the mosquitoes and prevent them from biting. The
most commonly used repellents are IDMP
------ ( Dimethyl phthalate) and DEET
(Diethyl toluamide). They provide protection for 3-4 hours.
iii)
Impregnated bed nets
Pyrethroids are last acting, broad spectrum insecticides with low
mammalian toxicity, Impregnation of bednet with synthetic pyrethroid
enhances its potential for ------reduction
1 or interruption of disease transmission
against endophagic or exophagic
<
species of mosquitoes. Impregnated bed
nets produce deterrent, repellent and killing action and help in
i reducing
man mosquito contact.
IV)
Coils- Mosquito coils containing natural pyrethrum and herbal
Produrts 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
A lethrk^ioLnoI
imfregnated Wlth synthetic pyrethroids viz.
Mosqu toes am !hn
* P'ate fitted in a sma11 electric device.
pyreZoid
Th^ martreP
/r
d°Wn by the VaP°r aCtion
^e
hours
Pr°V
Protection from mosquito bite for 10-12
vi)
Indogiyresidual insecticidal spray
Selective spraying is recommended
against vector mosquito species
which ]PA ™ently rest and feed in indoor
situations.
------- Depending upon
the susceptibility status of the vector
mosquito species to various
oi ganochloroine , organophosphate and
insecticide is to be chosen to which the local synthethic pyrethroids. The
vector is amenable to control.
ne details about the insecticide, dosage, the formulation
- 1 and application
etc. are given in the Table- 1.
'
vi i)
SgasesBiaying by Mist, Ther.na.l_foa!ini, or ULV spray
Space spraying has been successfully used to control outbreaks of
vector-borne
diseasesU such
pmutors
V • aS malaria’ dengue, Japanese encephalitis
Western
control the rZ
P a !tlS
SpaCS Spray is usually undertaken to
pyrethrumextract
° m°Squitoes either
using the natural
skuatioZtoZter unt to 7
°r malathion ^ing outbreak
form of mist toer
1 f
. transmission by crisis. This is done in the
their dosaces for mS Ogglng °r ULV sPray • Insecticides formulation and
“ii dosages for space spray are given in Table- 2.
2.
Antilarval measures
eontrOl'nandlaa7illr
are used as an adjunct to other methods of
con atoer b
?
7 US';d aS main "lethod °f “ntrol except against
confined or^oe^r SpeC1|'S °r a6a‘nst those mosquito species which breed in
□ Ai sundZ Wa'r b°dieS SUCh 35 ASdeS a^“’
w-. tor sneer.
Antilarval measures can also be tried in an area where
and exophaX Z'd *' to' tO C°ramonly used insecticide or exhibit exophily
cost IZltofZ rder th?Se ottuat'ons where adulticide measures are not
ost effective or tend to endanger the environment.
peri urban
Th
P'
coun'r‘'s
™inly used in urban nr
stoaUonslke m
measures can be used in certain special,sed
tclsm e \„d
, ?r’"8i ,rr‘Sat.on wells, tanks etc. if they are operationally
prerem reduce
r01'’' The baSiC idea °f aU a"tila"al '"easures is
aniilareoirn UCe
f3" th<! breedinf! plaCea Cl!rtain “"inronly used
antilai val measures are briefly discussed below:
?
27
>
’ll
’ °ilinE iS
Oiling of a breedingZs
' where
nOt be cost effective'
film fis cutting the oxygen supply
their spiracles with <’i>
egg laying.
SUPply' !t aIso deter the adult mosquitoes from
m 7^g-gEgen (Copper aceto-arsenite) - r
hasi been
successfully used
breX7V°ntrO1i Pr°gramme
the controlIt of
’
-- anopheline and culicinc
gis applied as dust or granular formulation.
’
Widely US<:d
und'r
-osquitoes . Larvicide formuiati °„3 a7d IZdZZZgZi '
urban
2.3
WHO expert committee on T’
Vector Biology and Control in 1979
defined environmental management as follows:
modification and/o^XaniX^f1711^8
monitoring of activities for
interaction with man
envmonmental factors of their
man Zh
with na view >to ZeZ;":'
population and reducing
. Or minimising vector
J man-vector pathogen control.”
This rapproach which should be carried out 1
...... .......... .......
which limit
measure^hn
i)
ii)
iii)
iv)
V)
f’"'3 an atternPt to extend and
breeding, survival and contact with
ve many constraints and limitations viz.
viz
’
Selective application,
Require high degree of inter-sectoral coordination,
Capi al investment of some of the methods is high,
Maintenance is very essential and
Active and sustained community involvement.
t
prevemion If moTouito'
‘C'h
"0 dependable m<!thod
°l =ltainalio,i or
most simple
and
i
breeding by lden
identifying
breeding sites mosquito
of mosquitoes
hfying the active and potential
of mosquitoes. Environmental r'
much suited for the vectors of n^lronme'ltal management of vectors are
of urban
vectors mainly bmed vectors
in overhead
T malaria and Dengue/D«P aa their
in overhead tanks,
containers in domestic and peridomesdcskuationT
m3n
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.C.nmJniited by Emulating an
<
effective drainage system which will not permit
water stagnation and
-----1 mosquito breeding.
•i)
roads and railways anTmoProFtT113 ®en^rated durinS the construction of
ontrol measures in an integrated way.
-brigation and mosquito breeding
Engineers should incorporate various
engineering devices in
oir the i
W1'h PUbliC health exPerts to inc|ude
an inbuilt system to drain
the seepage water for its better utilization in agriculture.
2.4
Biological control -
larval breeedtagatSomePofltHeenS °r.par!!sites r"av be used for the control of
f the important biocontrol agents are given below:
i)
parviyorous fishes
be the” XrXm^^dXu' tarVi7°US fiSheS are Stil1
breeding m unused weHs p‘he C°ntrol °f
">
The Poecilia reticulata and CnL
d
fountains’ P^ddy fields etc.
larvivorous fishes used world n
a^niS are the two most important
They were introduced in India in ^iTl n°r a
contro1 of mosquito breeding,
been acclimatized in vaFitus tvr
nd 19,28 respectively and have since
considered to be most imnorX i
ecol°glcal conditions.
They are
because of their small size vorac’
arviyorous fishes for field operation
agility and adaptability to var'^3 r^L00 mosPulto larvae, hardiness,
commonly known as guppy is a both- ° r abltatS'
The PoeciHa reticulata
of pollution. It may be used efr a.m eeder ’ can tolerate very high degree
whereas G. affinis is a surfar eCf1V’y °r the control of Culex breeding
ozy^genated water and is suitable
th
prefers to breed in clean
Fishes can be easily cultured on 1
T control of anopheline breeding,
transportation to any distant place.'^
? 'nK rCf|U,rC mi,liniu,n
’or
29
5
ii)
Bigcides^The toxins of certain spore-forming bacteria viz. Bacillus
thlmngiensis variety israelensis H,14 strain and Bacillus sphaericus have
rccen y been shown to hold great promise as a microbial control agent for
mosquitoes. These bio-larvicides are host specific, safe to predators and
h icnd y to the environment. Of several indigenous, and imported
ormulations of bio-larvicides, wettable powder formulations of B. sphaericus
(Spheux) and BTI-H-14 IBactoculicide 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 moie
an one vector control method simultaneously or consequently in a
given area to control vector borne diseases. When available options are
selected on the basis of epidemiological
paradigms, vector behaviour,
uman 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
compe ence, managerial skills and sound understanding of vector and its
environment.
Marsh alteration
(ditching, impoundment)
Other s
Inundative releases of
natural cncrnics
Zooprophylaxis
I
Basic sanitary
/ measures
/
Introduction of exotic
natural enemies "x.
Xz o V
o Z
o /
Genetic
. K
manipulations
XV —Uarricr
plantings
O
CD
'Z-
'
INTEGRATED
House
screening,
bed nets
◄
CONTROL
Micicbin! insecticides
Filling, grading
& drainage
V
Personal
protection
.
Others
Others
Chcmostcrilanti
Developmental inhibitors7
i
*
I
Insecticides
Repellents
Attractants
Fig. 9
30
2.6
The role of public health education is
.ndementatton of vector control measures, in vital for the effective
respect of vector-borne
The-tirn’or
ar°Und man an,:1 his
helfth eduM^'7
malaria, Dlariasis ,nnl1
should 'be to famiharise^nd
following aspects of the d,sense
'h<! COn‘rO' of ’e«°r-borne diseases like
and Kala-azar
3
Pe°Ple by hiShli8h«ng
Causation and mode of disease transmission
areness about the early signs and symptoms of the disease
w,th (he public hcaith
by clinical symptoms and "l^X^
diagnostic tests
Usefulness of taking proper and adequate treatment of disease
^pecTe^86 ab°Ut tHe breeding’ feedin§ and resting behaviour of vector
the control of m<
'
osquito/sandlly
Inna t
cs t0 *‘‘“8 ' Jowrl vector density and to ’curtail
------- 1 their
on8evity to interrupt disease transmission
bome1^8 °f inSeCIicidaI sPray
LXbS, «calf±mtantS frOnI mUd Plast,!ri'>S of walls of houses.
cattlesheds
etc.
‘ ‘
.
etc. for
for ;a minimum
period of two months after the spray m
retain the residual effect of insecticide for the effective control of
mosquitoes and sandflies
PersonaloXefentet meaSU(r<!S
ordinary impregnated
bednets < repellents to prevent mosquito/sandfly bite
To educate masses to sleep
on the cots/benches instead of on floor Io
prevent sandfly or flea bite
re^n^TnH6 bio;environment measures to reduce the
breeding
breeding,
cattles^eds etc.66
around human habitations’
Use of mass media Jike iradio,
’ television,cinema slides, re
newspapers,
posters and film showsetc
Involvement of Social workers,, teachers,
school
children,
gpublic
health
workers ”
‘
Voluntary
Health
OiganisaLions/ Resident
—. Welfare Associations should be involved for31
oXTmeVner^10 ‘J1'0''6 8iVCn information bX holding group meetings
off/
P
’ communication, Health exhibitions etc. to get rid
off/ reduce mosquito breeding.
8
COMMUNITY PARTICIPATION
WHO Alma Ata Declaration (1973) envicaopd
CarreC(raC)n T^il b' 7nsidered as a crucial component of Primal Heahh
fond hope that it win3 °r co“mUnity Participation was developed with the
integration of art'
7 dls':ase control programme more effective. The
considered advant
■
COntr°‘ °f c°m"”a"icable diseases was
morbHire and mo f7°HUSa ‘n’Pr°’<i ‘he qUality of Pcc’cntive care, reduce
partis,pX„ of oeo1^
f0 communica“c diseases and encourage the
vector control nL P
InV°lvement of community for the success of any
revolve>s mamlv arcStm greater S1gnificance as the problem
perceive the mnaet f
hlS environmenL The community will
involvement in PHO
i? ' . meaSUres which wil1 sd™late their active
involvement in PHC socially, culturally and technically.
in m i
nsequent upon the resurgence of Kala-azar in Bihar in 1977 Pl'itnir
nd ;“uri“d19G9urr,n t and ^^/PUb
dhp'iC hea'th edUCalil"’
about vemor borne d^^ s"" “oo^
practically nil
ms
•*,
it is fek that for th
community participation was
C 1S leit that for tde control of vector-borne diseases
impteZTatZof'"t0'"31^
C°’°Perate a"d Part“Pate
would be able to exte d°th
Strategy' After motivation, the community
^t esheds eto snra H
t^1 CO-°Peration in gettin§ their dwelling unit^
cattiesheds etc sprayed, with insecticide and should restrain from mud
m:Xsnfor htehemretCemide ‘7“a. —m “nod ofZ!
„
mtion of residual effect of insecticide. Besides thn
rX”aino7
frotlVated tO Undertake bio-environmental measures like
filling of alf crJks a^t
ar0Und the bouses, pigsties, cattlesheds,
ventHated andTght d
—
species.
P
breeding, resting and feeding of vector
frequeLrinteracdnnVb
contro1 programme, there has to be
a
they may accept the
,"T
hea‘th workers and the P^P1' ”°
only trt.s approach 'l l bXhM?or?7heaeifrtht- " '’'‘’‘’t'6'5 Pr°gra"’me’
contrnl
lor the effective implementation of vector
the country. 27
& V1S COntro1 of vector-borne diseases in various parts of
vectorXlmne^Hst0 be Undertaken by various agencies for the control of
vector-borne diseases are summarised below:
■ \ .v
32
X>\>S'3I0 4^\,bRary
f r
*-v''D
J p >|
0817E i /, 00c>jw:nt Anof,y ■ /
\
>;.. ...... ^-../
3.
leishmaniasis
the transmission of visceral and
leishmaniasis or Kala-asar is r
L
the coi-n,try Whereas, visceral
cutaneous leishmaniases XhTa"8™''"*^ ™eimtomUs argent,pes,
transmitted by Phiebotomuspapatasi, P_ saleij JX" se^enti
"
P. argentipes is widely distributed •
species in India and found in
nnUth TCe Wbere Climate iS Warm and moist,
■ P. argentipes can be identified
on the basis of silvery white legs.
R papatasi is founcT mainly iin plains where climate is
hot and dry. |(
is yellowish brown in colour.
3•1 -Morphology of sandfly
is light, yellowish to greyish brown1^6 ;nSect o^about 2-3 mmlength. H
The males and females can easily pass thTouah 'T COnSpiCOUS dark
body of sandfly is completly covered wTth lon^h
u °SqUlto neL Thc
sucking type of mouth parts and nnl
hairS’ head be&rS piercin« an(l
whereas males feed on plant saps
tHe bb<’d
by the presence of a oair .,11..
'
n be eaSiIy recognised m nature
upward on the body and makes6'?" h °nJated wlnes which remain erreel
maies are identrfied on rhT basis of mT appearan“ *hil= «««"». Th,abdomen and fema.es by the presenoeX'Xheca"' 'he
C"d
Fig. 10
Life cycle
The life cycle of sandflies is
comprised of four stages viz. egg, larva.
pupa, and adult fig.l 1.
33
’)
- The eggs are laid in moist cracks and crevices containing
decaying organic matters. The female P. argentipes lay eggs ranging from 5whereas P. pgpatast, 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
aays under laboratory conditions at 28 + 2 C and 95% R H
ii)
Larva -The larva is creamy white in colour and possesses a number of
ans on its body. The body is divided into head, thorax and abdomen.
Alter emergence, larvae feed on decaying organic matters. Sandflies have
foui larval stages. The total larval period of P. argentipes and P. papatasi
was recorded to be 11-29 days and 12-26 days respectively.
ni)
PyjnL - Pupa is elognated and coma- shaped in appearance and is a
non-feedmg stage. The pupal period varies from 6-10 days for P. argentipes
and 6-13 days for P. papatasi under optimum laboratory conditions.
iv)
,-dult
- The adult emerges through a longitudinal slit on the middorsal ^part^of cephalothorax of pupa. Mating in sandflies usually occur on
host while feeding but may also takes pl
. lace 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
, 11
34
3 3 Habits and habitats*
lheyH“remain hidde^in'era'cks"Zetices8
cuttlesheds. P arqentipes and P
,
d
Postered houses and adfoming eatdefhedT'
br" “b ‘‘“A'’8 d‘’y
k corners of houses and
8en'ra“y f°Und
"Uld
•9
a ;a^of mam7,s *"
bovine, whereas P. papatasi prefers to
feed on human beings.
iii)_Resting habits situations in houses,
ind""r
hopping cements
recorded to be 207-505 meters fromS SnZpiaeS"^
h'"
be 207-505 meters from the
’o'b^S^d™e nW‘in,Um ‘onsevity-orp. argents has been reported
3.4
Sampling Techniques
x:nd suction tub: meth"d
sim>.at
. of Per Man Hour Density tPMHm ,PfSLTf 1 “ndfl es is expressed in term
Density (PMHD) (Proforma enclosed)
Other methods of sandhy collections are:
i)
Sticky trap method
ii)
CDC light traps
iii)
Funnel traps
iv)
Bait collection
3.5 —Susceptibility staf-nq
to insecticides
suscemible^to DDt’ ?7CtOr of Kala'azar has been reported to be highly
tsceptible to DDT. However, P. papatasi vector of cutaneous leishmaniasis
35
18 highly resistant
other insecticides. to DDT and Dieldrin but
3.6
susceptible to Malathion and
^ttro£of sandflies -
i)
——dfhylatlcmeasures
- use of bed nets and
man/sandfly contact.
repellents to proven (
ii)
Environmental
measures
.
used io
houses
iii)
Chemical Control
—
undertaking residual cp -P. argentips Ccin easily be <controlled
by
spray of DDT.
Two
rounds
of
indoor
residual
spraying is undertaken- iin endemic areas @ 1
feet height.
gm per sq. meter upto ()
36
4.
fleas, vector of plague
Plague which ceased m
m
dZTVm1^ 1966 has ^surged in the"1 for^T heaJth Problem in the
Trbr a"d P~m
B-<'
detect nt
haS necessiated to intensify dV
,
StL °f Guju,‘"
count-• , P gue activity and to monitor 0pa 7 ^ease/vector surveillance
iy o undertake timely intervention measures^ m Vari°US parts of 'b<-
namely
cheopl X
compressed insects andboT
transmitted by three
* bras^species of Ocas
Fleas are laterally
divided in head, thormc and ahJ
fr°m 1'4
mm. The body is
directed spines. It has^hr
abdomen and is
covered with backwardly
developed and modified for
°f
hind
pnirs of legs are very well
-eking type and both the seleXck Jloo^
parts are of piercing and
F
r-
cycle - There-are f„ur stages in [he lifc
larva’ PL1Pa and adult, (fig. 13’).
•<)
The c~^ are laid in cIusters ln and i
It is small i
around the nest of hosi
’•'■"PO and gii^-ing
°-4
0-S> 'inn. in length, oval in
glistering while
Yellow colour after few hours
PP.Carcncc wl’cn laid but changes (o c|u||
of lay.ng. A single x
may lay
37
300-400 eggs during its life time. The
incubation period of egg is about 2-4
days
ivnes of n
H
chewm8
of mouth Parts and feed on all
The a.d rganic debris- l^iere are 3 larval stages which last for 14-16 days,
nunat^
an/a When fUlly gr°Wn emPties it’8 alimentry canal and
w&tSX^S^86 meshed cocoon of thread around i(
’/Upa 1S7SUrally encl°sed in a cocoon and emerges into adult
p i r
u dayS under favourable ‘ climatic conditions ( Temp 27C and
Relative humidity 80-90%).
1
P'
iv) Adult - After emergence adults usually
hours. Mating usually occurs on host.
takes blood meal after 24
4.2 JBiology and ecology :::
taking blood or as free living and their immature stages are found inside the
rodent: burrows.
c^eo^>!s and X.^asti^generany fowKl on^o^lent^species, “b" h°StS a'S'>'
M
Restingjiabit: - After taking blood meal fleas i ..
rest in rodent burrows,
erac s and crevices having microclimatic condition
favourable for (he
maturation of their eggs.
4.3
Sampling; Techniques -
indices
colIected by combing the rodents.
mences used for monitoring rodent and flea are given below:
38
Various
Indlcos-used to determine
G) Trap positivity rate
~ -N°^oLTraps found_+ve for rodents, x 100
No. of traps laid
b) Total flea index
c)-Specific flea index
rodent/flea densit
.Total No, of fleas collected
Total No. of rodents examined
- Total No. of fleas collected of a species
No. of rodents examined
d) cheopis index
Total No. of X.cheopis collected
...
No- of rodents examined
present occtXo':?“1e“e1“Pt
“ PlagU' e"de”ic
areas Io
Proforma for monitoring rodent/flea population is enclosed.
- Th' «-=“ «‘r,eeed from th,.
efXrTHlSS^^
77 ; n
.
Preserved tn 70% alcohol containing a droo „r
glycerine.
-.
he tubes should be labelled properly giving the following dtlads
Name of the area Date of collection Name of host
i)
Mpjinting procedure
a)
Transfer the flea to water for one
b)
Keep flea material in 10% KOH solution at room temperature for
one
10 two days t1U the specimen become yeliowish tranXnt
c)
Keep material in water for few minutes
d)
Transfer to 5% aqueous solution of glacial acitic acid for 30 minu(es
c)
Transfer to water for an hour with several changes
a)
Permanent mounting
hour to get rid off 70% alcohol
(i)
Ci-T' TP (lPaSfS the neas ^ough 50%, 70% and 90% alcohol for
dehydration, thereafter,
, treat with absolute alcohol for one hour
39
(ii)
Clear the specimens in
clove oil for few hours,
(u)
Keep the fle.
a material in xylol for 1O minutes
(iv)
Mount flea
(b)
Preferably for a day
specimen in Canada balsam
Tern orar
-Siountin
After ;steP (e) fleas c
Can be directly mounted in
medium and
«n be dried over hot ptae
a drop of Hoyer’s
feei-s medium
Distilled water -50 ml
Gum. arable
qn
Chloral hydrate - Mn™
Glycerine7
.
^•5 Susce tibilit
insecticides is
(WHO Tech. Report sUnder taken as per stanH^01 r
measures.
/cP°rt Senes No 443) rn
P
standard WHO
O method
Jisecticides impregnated fin
3 ’ In thls rnethod fleas are
hour and —
’ °f eXpOSUre-
Current insectio-d
efeopte from dS“
nrl) V SCeptlbiIity status
-itra), Varanasi (Uttar Pmj of Xenopsijlld
“aiathioha^S:^
Tadesh) and Delhi
resistant to DDT & HCH but
susceptible (o
4.7 Con trol of flea*
The flea Population can be
insecticide as
by the applieatton , °f appropriate
powder.
burrows and run ways The ho,
mam Sites of treatment
■
are
rodent
walls and the floor for an area oT
°ther Structures, the 1 '
'
bottom
of all
treated with the dust formufotSn n
1 15'3° Cms
wall
he wafl and along the rafters where mt ru
appl*ed —
on1 should be
the top of
habitats such as Pfles of
J^re rat runways are present,
treated with the insecticide dust 5
W°Oden structures etc. Other rodent
should also be
40
BHC fteothV" Vie"'that'he vector flea ■
species are iresistant to DDT arid
and p
msecticides
1 ermethrin (0.5 %) dust hl<e Malathion (5.0 /0)i Deltamethrin
can be used for th
(0.005%)
-^e control of rat fleas.
^Sldication
The roldentthfreaPPllCati°n °f dust
the hand
-ntrol fleas oTentM SitCS should
! ’
be |*thoroughly co
qU'tC Use,u|gnly
covered
with
dust
t
sufficient fo each h
about 30
ur each burrow.
3 Eras Of th' dust formX,„
41
Annexure -
Proforma for surveillance of rodent/flea population
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
Name of Distt.
Village
PHC_________
Date of Collection
S.No
Time Habitat
Spent
________ Sandfly Species Collected
Sergentomyia sp.
P.papatasi
P. argentipes
M
F
T
DPMH
M
F
T
DPMH
♦
1.__
2.
3.
4.
5. __
6. __
7. __
8. __
9.
10.
11.
12.
13.
43
M
F
rp
DPMH
Insecticide
Spray Status
Remark:
f-
Mosquito Control measures which may be undertaken by Individuals and Community
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]
Destruction of
adult mosquitoes
Destruction of
larvae
Source
reduction and
Source
alteration
k
♦
♦
i) Use of adulticides or aerosols
available in the market
i) Indoor residual spraying of chemical insecticides
ii) Thermal or cold fogging (ULV)
i) Emptying water containers
periodically, scrubbing and cleaning
(specific to Ae. aegypti).
ii) Use of temephos sand granules for
water containers (specific to Ae.
aegyptt\ & 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) 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
v) Reclamation of land
f
*
>44-
4
‘r
rian of action for control of DF/DHF vectors in urban and Rural areas
Control Methods
Expected
Agencies
Source reduction
methods for larval
control
Community
t
Activities Expected
Ways and Means
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
f
iii) School children/housewives healt
ii) Mass media (Radio, TV, Film shows, N-
iv) Volunteers
papers etc.)
m -ition
»*. aT
♦
v) PHC workers
vi) Community- leaders
Government
1.Solid waste management to
prevent mosquito breeding
2. Provision for reliable piped
water
3. Legislative measures
4. Monitoring and assessment
I) To set up a core working committee for inter-and interasectoral coordination
- Media
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