EPIDEMIOLOGICAL SIGNIFICANCE OF IMMUNE STATUS OF COMMUNITIES IN KALA-AZAR ENDEMIC AREAS
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- Title
-
EPIDEMIOLOGICAL SIGNIFICANCE OF IMMUNE
STATUS OF COMMUNITIES IN KALA-AZAR ENDEMIC AREAS
- extracted text
-
TITLE
epidemiological significance of immune
STATUS OF COMMUNITIES IN KALA-AZAR
endemic areas.
f
h
A CROSS SECTIONAL AND COHORT STUDY.
I
Dissertation submitted in partial fulfillment
of the requirement of the Dr. MGR Medical
university for the
degree of M.Sc Epidemiology.
MARCH 2001.
I
CERTIFICATE
I
!/
This IS
certify ,hat lh. the8,3 Bn,„|et) ..Ep|DEM|OLOG
S1GN,
- ^UHE STATUS OT COMMUN,TIES ,N KAUA-AZAK ENDEM1C
COMMUNITIES IN
AREA" Is a
.
by Dr.Pajan R.Patil in
•1 <n partial fulfillment
of the rules and
regulations for MSc. Epidemiolo
GV examination of The
Tamllnadu Dr. MGR
Medical University Chennai to
be held in March 2001.
bonafide work bv Dr Paian o
i
i. .
Thesis guide:
i
■
1 I
Dr.Jayapra
Mdfiyil BSc.,MD.,MPH.,Dr.PH(Epid.).>
Professor
munity Medicine and Vice Principal,
Christian Medical College,
Vellore-632 002.
-
"’'fl
I
77
ACKNOWLEDGEMENTS
lam greatful to the following for
- siring me tMr consent and approval to
carry out my thesis work on Kala azar
In Jharkhand & West Bengal.
Dr. JAYPRAKASH MULIY1LL (CMC.Vellore)-
Personality for humility & clarity in
Dr. RAVI NARAYAN
for his support,
My guide, an incredible
teaching and patience
i guiding.
---- in
( CMC, Bangalore) - My mentor,
an inspiring personality,
encouragement and guidance.
MY FAMILY- My strength and vulnerability, for
unwillingly agreeing to send
me.
Veto by any of the three above
would have had the idea
stage, and this study in Jharkhand state would have
aborted at conceptual
never taken off.
My gratitude
abraham , New Dcll„h for flnanctal contrlbutjon
contribution and
me to stick to the tdea oi do.ng my dissertation woridng
tribais
- -OKed throu6h the „itty
“ CHATTERJI
— - Bihar. .0 he,P. over ,2 my
2 7—&
r,
Dr. A NANDY( Calcutta) - for
preparing required antigens,
to visit the study
I
and taking time off
area during vital leishntanln skin test survey.
indebted to tei.„lcal „5sis,a„„ g. ,cn |)y
collecting the
and helping
W.Bengal respectively.
I
*
L '
and
specimens
J
P. Patro in
■1
me with the field work in Bihar and
I am thankful to following for all the medical care and help given to me
during my illness and convalescence during my study in Jharkhand
Dr. MURMU| Bihar) - a humble physician heading a mission hospital, my first
contact during any illness during the study period.
Dr. MANOJ AGRWAL( Calculla) - (histroentrologist (a CMC alumni)
treating and managing my Intestinal bleeding, during my Typhoid
for
illness in
Calcutta.
Dr. A NANDY - for
treating and managing me through my chloroquine
resistant falciparam malaria in Calcutta.
Dr. ANAD ZACHARIAH ( CMC vellorc)- for being supportive
and
always
available to me on phone and giving timely medical advises.
Dr. SAMARESH (Calcutta)- for medical care
-
flratcful to the following Institutions and Organizations.
1. Centre for Tropical medicine and Parasitology, Calcutta - for lab support.
2. School of Tropical Medicine, Calcutta.- for lab support.
3. Pahadia Seva Samithl, Bihar.- for accommodation and Jeep.
4. St. Lukds Hospital, Biahar - for Guest house facility and medical care.
5. Child In Need Institute (CINI) Calcutta.- for accommodation
6. Soil Salinity Research Institute, 24
parganas,(WB)- for guest house
facility.
7. Christian Medical College (CMC)
& Community Health Cell, (CHC)
Bangalore
guidance by eminent and respectful
for the team support and
consultants.Last but not the least the people of Jharkhand and West Bengal
for participating in the study.
2
TABLE OF CONTENTS
S.No.
CONTENTS
1.
INTRODUCTION
3
2.
JUSTIFICATION OF THE STUDY
6
3.
OBJECTIVES
7
4.
LITERATURE REVIEW
8
5.
MATERIALS AND METHODOLOGY
33
6.
RESULTS
37
7.
DISCUSSION
57
8.
SUMMARY AND CONCLUSIONS
65
9.
LIMITATIONS
68
10.
RECOMMENDATIONS
69
II.
BIBLIOGRAPHY
70
12.
APPENDIX
75
PAGE
INTRODUCTION
Kala azar is a disease
of public health problem predominantly in the
third world countries. India [Bangladesh and Nepal account
for 90%
of the disease burden of the world. Il comes under the so called 'orphan
diseases' owing to its neglect both at national and international level.
Kala-azar is an endemic disease in parts of India. It is a serious problem
in the states of Bihar and West Bengal. Annual reported number of cases
is 24665 with frequency of 36.8/100,000 in 1996 in Bihar. In West
Bengal total reported cases for the same time period is 1987. UP
occasionally is in news, with sporadic outbreaks. The case fatality rate of
the disease in untreated cases is close to 90%, which with treatment
-
reduces 15% and is 3.4% even in specialized hospitals1 .
Planning for Kala azar is hindered by conflicting reports of official and
actual figures.Just to give an instance, 54650 cases were reported from
Bihar In 1990, but an expert team constituted by government of India in
1991chaircd by CP Thakur, put the actual numbers closed to 250000.
The latest annual figures were 15485 and 6750 cases in 1998(till May) of
I9972
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Kala azar
has re-emerged from near eradication all over the world. Its
annual estimate for incidence and prevalence worldwide is 0.5 million
and 2.5 million, respecliveiv
I
India too showed the same trend, an epidemic of kala-azar in Bihar.
PJSOs died out within
decade, as a collateral effect to the DDT
spraying which was part of ihe National Malaria Control Programme.
Sand flies disappeared from the house sprayed with DDT to eliminate
Anopheles mosquitoes. The disease became rare. When spraying was
I
discontinued however, sand flies surviving in cattle shed returned to the
!
houses and some became minlected with Leishniania,
possibly by '
feeding on the remaining Post kala-azar Dermal Leishmaniasis (PKDL)
cases 3
For prevention and conuoi of the disease epidemiological wor ks at field
)
level is a must to understand the burden of the disease. The diagnosis
and treatment arc important aspect of kala
azar control programme.
I
Reliable and valid diagnostic tools are required for the success of control
programme.
WHO has laid emphasis on developing simple tests for diagnostic as well
R
lI
as screening pjgi animes. The aldehyde and bonemarrow aspirate tests
presently used are seen wanting in sensitivity and specificity. Morever
they cancbe employed for the screening programmes.*5
•I
More studies are recommended to assess the utility of newer serological
tests like Direct agglutination test for diagnostic as well as screening
progammes5
Leishmanin skin test is valuable tool for epidemiological works
to
measure past and possibly future incidence in the world6
5
JUSTIFICATION OF THE STUDY
♦ Information on the
magnitude of kala-azar in endemic areas and
among tribal communities is limited.
♦ Uncertainty regarding the usefulness of serological tests used in the
screening as well as diagnosis of kala-azar.
♦ Need for developing indicators for assessing factors responsible for
the disease transmission, which would be in
turn help in assessing
impact of intervention programmes.
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OBJECTIVES
1. To estimate the prevalence of Kala
azar infection (present and
past) in Pahadias and Santhal tribal
communities of Jharkhand
state.
2. To study the dynamics of the antibodies in cured cases of kala-
azar for its implication on the validity serological test.
t
I.
s
7
4.1 HISTORY OF KALA-AZAR
Kala-azar has been occurring in India in epidemic and sporadic form
over the past centuries. The earliest epidemics of Kala-azar were
confused with those of malaria. However, the first recorded epidemic
which could be attributed to the manifestations of the disease in India
could be in 1824-25 in Jessore (Elliot). Burdwan fever of 1854-75 was
also attributed to Kala-azar (roger). The first epidemic in Assam is
supposed to have occurred in 1870 in Garo Hills. However, Carke first
described the disease in Assam in 1882 iin his Sanitary report of Assam
based on the report on MC Naught , the then Civil Surgeon of Turf.
Kaladukh in Purnea (Brown 1898) and the Kala- azar in Darjeeling
(Ross 1899) are attributed to Kala azar. The epidemic fever indinaz pur and
Rungpur Between 1871-76 and in Patna during 1856-59 could also be
attributed to Kala-azar.7
Leishman in 1903 reported peculiar bodies in the spleen of a soldier who
died of Dum Dum fever in Netlcy Hospital. Donavan in the same year
reported detection of similar bodies in the spleen of the patients in
Madras suffering from prolonged fever with splenomegaly. Theraftcr,
conclusive evidence was obtained and the causative agent i.e., the
parasite was named an after Leishman and Donovan 8
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1
4.2 kala-azar distribution -PLACE AND PERSON.
Apart from several states in India, the disease i
--------- is present in East and
North Africa, Sudan, Bangladesh,
parts of china and USSR, South Iran,
Arabia, Mediterranean
countries of Europe, Ethiopia, Kenya and South
America, inciuding Braz.l and Venezuela. In India, the disease is most
endemic in eastern half, but isoiated pockets exist in almost all regions
from where sporadic cases and even small outbreaks have
been reported
from time to time.
In Mediterranean region, infants and children are almost exclusively
are almost
affected. In other endemic areas including India, though these are
more
frequent in
children and
the young, older
age groups are also
susceptible. Males are affected
more than females. Kala-azar
more
----- isismore
prevalent in rural settings where conditions
exist for multiplication of the
main vector sand fly Phleobtomous
argentipes. Only females act as
vectors.9
4.3 RESERVOIRS OF INFECTION IN INDIA
No anima! reservoir has been found in india and
transmission of kala-
azar
occurs
from
man
to
man
through
the
recognized
vector
cutaneous or dermal ieshmaniasis
is is
is caused by
L.tropica and this is restricted to Rajasthan where it is soonotiejo
P.argentipes.The
In some regions such
as northeastern India, human
own reservoir and several factors
serve to facilitate
appear to be their
person-to-person
transmission. The vector P
blood. The parasite is found
argentipes, has a preference for human
circulating monocytes in mdian cases of
Kala-azar more frequently than usual. Dermal lesions that develop after
the initial d.sease in mdian patients' may he an additiona! source of
parasites for the vector.
4.4 RESERVOIRS OUTSIDE INDIA
A common transmission cycle involving man and animal is
seen between
humans and dogs which
act as canine reservoir. The domestic dog, as
wild canines such as the lox, develop , a chronic
systemic disease very
similar to that of humans
when infected with L. donovani. But an
additional unique feature of leishmnaial in canines is
the frequent
presence of organisms in the skin including the nose and ears, which
are
fovorim feeding sites
s„„J n,e„. An epitlemiologienl eye,... „r
parawite
involving „|Id foxes> donlcst|c dog8_ and human
via the vector
Lutzokmyia longipapis has been documented in
northeastern Brazil. The
domestic dog has a.so been incriminated as an important reservoir host
for visceral leishmaniasis of the Mediterranean
region and in certain
areas of China.
Rodents are the likely reservoir in the Sudan,
Phlebotomies orientalis, is high in
and activity of the vector,
clumps of acacia woodland
near
villages. In Kenya, ;
transmission of disease is
associated with termite
hills, which serve as resting places for the
vector P.martini, and around
&
io
which village men gather in the evening. However, the animal reservoir
in Kenya has not been identified.11
4.5 VECTORS
Sinton originally suggested Sandfly as a possible vector in 1922.
There are about 600 species of the phlebotomine sandflies distributed
through out the world and among these 70 are proven or suspected
vectors of leishmaniasis. In India, the only proven vector of kala-azar is
phlebotomus argentipes. The biology of this vector in West Bengal has
been worked out in details. It breeds in cowsheds. They can attack man.
The vector can invade the clean biotype from the nearby resting places,
attacking man out
doors, hence acquiring out door infection is also
possible. It was revealed that they could take 5 blood meals in nature,
especially in rainy season, indicating high vector potentiality. In this
connection it may be mentioned that period of peak transmission
usually corresponds to the time when vector population is relatively old
I
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(as in rainy season June to September).
P. argentipes may disperse 500 m from the place of release. The flies can
invade the living rooms and both exit and
cowshed and human habitation. 12
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II
entry activities concerning
'
8. Age and sex have no influence on the epidemic pattern. There
was a
definite decline in cases of Kala- azar in India from 1961. In
1960
there was 3916 number of cases and in
1961 only 196 cases were
recorded. In that time^ Kala-azar
was not at all a public health
problem. The factors responsible for the decline were associated to’ :
•
Effective treatment of cases,
•
DDT spraying under NMEP during 1953-57 and under NMEP
from 1958
•
Increased immunity inihe population
4.9 INCUBATION PERIOD
It has been difficult to estimate the incubation
period of kala-azar.
Usually it is between 2-6 months but could be
as short as 10 days or as
long as 9 years
The ratio of clinical to subclinical infection
may range from 1:5 4 12 is
4.10 IMMNUNITY IN KALA AZAR
Kala-azar unlike other diseases
(parasitic) is characterized by near
absence of a second attack after
J
I
Leishmania
parasites
are
immunocompetent individual
successful cure of the first.
able
to
persist
very
successfully
in
and they are also able to suppress the
immune response suggesting that relationship of the
is very old.12
15
parasite with man
Visceral leishmaniasis
has always been thought to be unique, in that
infection of man with L.donovani resulted in kala-azar syndrome with
little or no immune response, poor cellular tissue
response, many
parasites and no delayed hypersensitivity. However it was found that
delayed hyersensitivity and a positive leishmr^nin skin developed after 6
months of treatment henceforth such cases were immune to reinfection.^
Resistance to Leishmania depends upon the development of specific cell
mediated immunity. The capacity of the individual
to mount such
response varies, and consequently Leishmaniasis presents a spectrum of
disease in the same way that leprosy does. At
lie
visceral
leishmaniasis
diffuse
and
one end of the spectrum
cutaneous
Leishmaniasis,
characterized by abundance of parasites, absence of lymphocytes in
in
lesions, insensitivity to leishmanin, and poor prognosis. At the other end
lie the sc 11 - hca 1 i ng sore,
with
relatively scanty parasites, marked
lymphocytic infiltration, and leishmanin
sensitivity. Accompanying cell
medi^Ued immunity is delayed hypersensitivity
to numerous parasite
antigens, which causes the destructive pathology of leishmanial
ulcers,
especially i„ chronic conditions of espundia and Leishmaniasis recidivia
in which the normal balance between
been k(t. The mechanism
immunity and hypersensitivity has
undeil^ing these abnormal immune response
arc not understood.16
16
The major biological properties of viscero-tropic leishmaniasis is its
invasive character which permits escape from the cellular defenses of the
host at the portal entry. The rapidly multiplying parasites within the
cells of mononuclear phagocytic system disseminate widely in the
tissues of the host particularly in the haemopoietic and lymphopoietic
system. .
The initial response to Kala-azar seems to stimulate both specific and
non specific increase of immunogloblins. The specific response to
leishmama antigens'jiot pherhaps protective. The non-specific increase
of immuonglobulins in Kala-azar may be the result of deviation to
systemic lymphoreticular system of antigens. which are normally
mopped up by the kupffer cells of liver.
Spontaneous cure as well as 'premunition' or 'sterile' resistance due to
sub clinical infection in endemic zones is more frequently encountered in
Indian Kala-azar. It appears that in Kala-azar, there isfexaggerated
is ^exaggerated
stimulation
of the production of immunoglobulins some specific and
other non-specific. On the other hand, it fails to stimulate requisite CMI
necessary for spontaneous cure and sub clinical infection, suggests that
the human host can mount up sufficient immunological reactions both
humoral and cell medicated, to protect the individual.
CMI probably
plays the crucial role but the T cells are suppressed during active phase
of the disease. 17
17
The parasite stimulate
several antibodies producing B-cell including
group and genus-specific
(polyclonal)
as well
as
species
specific
(monoclonal) cells. Since the antibodies elicited are more of a reactionary
than protective in nature.
The seropositivity in kaia-azar is a iong lasting (few
years), during any
serological assessment a positive test, is
an indication of recent or past
infection and not active disease.
There are several hypotheses
1- Agglutination antibody h
2. a
clinical
antibodies,
on why the antibodies linger very long after cure : •<>
ave longer life span
infection
could
treatment
having
have
not
persisted,
been
eliciting
sufficient
to
circulating
result in
parasitological cure
3. cured patients had been re-exnosed tn
exposed to Leishmama in endemic area, is
These circuiating antibodies of immoral immumty offers vety little help
in
oroteefino
protecting
against
r
re-infections.
he
Cell
mediated
immunity
(CMI)which is suppressed during the
active disease, develops well
following treatment
or self resolution. The leishmanin skin test is, /
always negative during the active phase of the disease
and becomes
positive after six months of initiation of treatment.
18
»
With development CMI, pauents
i;
recover from infections and
achieve
lifelong immunity. No record of second attack of visceral leishmaniasis is
there. Positive leishmanin test, acquired naturahy from inapparent
infections also protects from infection.>2
In the absence of recovery in Leishmaniasis, there is bonemarrow
suppression, impairing the immune response to
host of infections like
tuberculosis, pneumococcal
pneumonia etc. Leishmaniasis has been
recognized as one of the infection
that may complicate the
course of
AIDS.15
4.11 CLINICAL MANIFESTATIONS OF LEISHMANIA DONAVANI
INFECTION
UNAPPERENT INFECTION.
At this stage the infection by
the parasite although is
unable to produce
disease, resulls in stimulation of immune system.
OLIGOSYMPTOMATIC/SUBCLINICAL INFECTION
1 n this cond.tton there might be transient ciinieai expression in the form
of fever and hepatosplenomegaiy. Many of these individuais might cure
themseives spontaneousiy without specif,c treatment. A smail proportion
of these cases might progress
to develop frank kala-azar and /or dermal
leishmaniasis within a period ranging from 4
:q
weeks to few months.
lymphatic leishmaniasis
This is condition of generalised lymph node involvement by the
I
parasite
leishmania donavani
without clinical signs of enlargement
of liver or
spleen.
kala-azar.
Kala-azar is the severest form of c,illical expressionjinfection^shmania
donavani
uonavam iin man and is a result of
parasites because of cell
uninhibited multiplication of the
mediated immunosuppression. If
not treated,
majority of the cases end up fatally.7
Clinically it presents with fever of
varying duration and types often for
years. The onset is usually insidious, especially in indigenous peoples
especially in
over 80 percent of cases, however, the fever
characterise pattern with twice daily elevations
eventually develops a
and may undulate as in
brucellosis. Splenic
enlargement is not necessarily rapidly progressive,
nor does the size of the spleen correlate with duration of the disc.
ase. In
".any instances, however, it reaches the right iiiac fossa,
The liver
ges more slowly and becomes palpable in 20% of the
cases ond is
likewise firm and not tender.19
Pigmentation of skin. - around
il t, li )Oncs nil(1. lcnqpIcs and
around m
malm
mouth (hence labeled black sickness
II
I
I
I
around the
kala-azar) Hair becom cs dry, thin
and brittle.
20
I
I
Haemorrhagic manifestations- epistaxis
seen often, haemorrhages of
skin, mucous,membranes and retina are rare.
In the most acute cases lever and toxemia may be the only signs
Tongue is always nearly clean.20
POST KALAZAR DERMAL LEISHMANIASIS (PKDL)
PKDL is perhaps second to no other disease in
regard to its enigmatic
eitiophathogenesis.
Although the same parasite causing kalazar is
responsible, vety iittle is Knorvn about the mechanism of deveiopment of
PKDL. This is a condition, which primarily affects skin and in late cases
may involve mucus membranes of
eye, respiratory tract. GI tract and
genitalia, In majority of cases there would be
a past history of Kala-azar
however a sizeable
proportion do not provide such
past histories,
although there are evidences of prior visceralisation.
Some Kaia-nsar cases mny ..... ........ p,)s,
(•
) tins apparent change ,n viscerolropic properties of L donovani to
derntatotropism
ls heiieved
believed
lo be
lnduced
by iommunoregu]atoiy
mechanism in cured Kala-azar patients.
PKDL shows
important differences
from
important in terms of epidemiology
Kala-azar,
which are
♦ About 20% „r Indian patients develop a rash
one to two years after
treatment or spontaneous
recovery. The lesions develop slowly and
'It.
7
may last for several, 20
years. 1 n Africa the rash develops in 2
percent of cases, usually during treatment.17
♦ Maximum number of cases have been described
Bangladesh, In other endemic
from India and
regions PKDL is rare or absent.8
♦ Unlike kala-azar, PKDL iis never fatal and
can remain active and a
potential source of sand Hy infection in untreated patient for at least
35 years. Unless free ......„„„„
rc
c|i„|cs
treatment and |,.
free
arc
Offeredfpoor parents, they seldom report for treatment of disease with
relatively mild symptoms.3
♦ Possibility of PKDL cases, as a
potential source of reservoirs of
infection in a community,
except for theoretical basis has
never been
verified.
4.12 DIAGNOSIS OF KALA-AZAR
In Kala-azar endemic
duration, which do
areas, all the fever cases of more than two
not respond to anti-malarials, should be
for Kala-azar
Laboratory confirmation
weeks
suspected
diagnosis is by demonstrating Leishmania
donavani in Stained smears from bone
marrow, spleen, liver, lymph
glands or blood and by
recovery of the parasites by culture of these
materials on NNN media
1- Examination of peripheral blood
smear, leukopenia with relative
neutropenia is seen
2.
There is marked production
azar. This increase in
globulin by the plasma cells in Kala-
globulin is detected by aldehyde test, ft .
heeomes positive on.y after 2.3 months of infection. Napier, aWehydc
ne ml of clear serum from the patient and a drop of fromaline
patient and
at room temperature. A positive reaction is
positive
gellification and
opocification of serum within 3-30minutes.
3- Serdogica. tests such as by indirect immunonuorescence (IFr ) &
Enzyme hnked immunosorbent Assay (Elisa)
4.13 DIAGNOSTIC TESTS
DIRECT EVIDENCES.
This method involves demonstrat,on w
paras.te
of the
amasdgotes) culture (to demonstrale promastigote|
smear (for
BONE Marrow examination
Bone marrow
aspirations is
experienced medical
painful
persons. However the
technique is its poor sensitivity, which
technique and also needs
greatest disadvantage of the
ranges from 55%-70% depending
upon the duration and severity of the disease. Because of its
People have not accepted this method very well.’
pain, the
SPLENIC ASPIRATION
Although splenic aspiration gives
a positivity rate of about 85%-90%,
this method is totally unsuitable for
many rural situations because of
the danger of intraperitoneal hemorrhage
abnormality in
leading to death due to
blood coagulation during Kala
-azar
disadvantage of the method is tliat it
The other
cannot be done in smaller sized
spleen (which should be more than 4-5
cms. Below the left costal
margin) thereby failing to diagnose early
cases when the spleen size
would be very small.7
ALDEHYDE TEST
One drop of 30% formaldehyde or commercial formalin i
-------- is added b 1 ml. •
Of serum of patient's blood. The tube is
well shaken and placed at room,
temperature. Jollification with opacity like the
of parboiled
egg
occurring within 60 minutes is a positive reaction,
This test becomes
positive within 1 -2 months of development of Kala-azar.
4.14 SEROLOGICAL TEST.
Serological tests derive there
main advantage from the fact that the
antibodies appear much before the parasites
are demonstrable in the
clinical materials at a si
gmficantly early stage, so much so
these methods onecan identify prospective kala
2-1
that by using
-azar cases 2i
Advantages 7
1. diagnosis of active cases of all forms of leishmaniasis
2. diagnosis of infection, before clinical presentation
3. screening a population for endemicity of the disease
4. screening a population for mass diagnosis
5. as a surveillance tool to monitor intervention activities.
In patients with kala -azar antibod}' production i
----- is vigorous and rapid.
Various techniques of scrodiagnosis of kala
azar are based on polyclonal
stimulation of B-cell (non -specific) or clonal stimulation
of 0-cell
(specific tests) 22
4.15 NON-SPECIFIC TESTS
Infection by L.donavani stimulates
“
production of immunolobulins by B-
I’""111’'>rnlbu.»i„ i» bumpered lauding tn reversed
albumin-glnbubn ratio . This increased production of immunoglobulins
is used quite frequently as diagnosis of Kala-azar at less- equipped,
peripheral laboratories. Some of
tesis are Napier's aldehyde test
of these
these tests
and Chopra’s antimony test. These tests are
easy to perform but have
high false-positive rate due to over production of immunoglobulins in
many other diseases. Since these tests fail to detect cases of early
to detect
leishmaniasis, the sensitivity of these tests is around 85% only.
25
4.16 SPECIFIC TESTS.
Specific serological techniques are based
on demonstration of antibodies
produced against the circulating parasitic antigens. The specificity of
various tests depends on the antigen or its epitome used in the test, as
the parasite will stimulate severai
several antibodies producing B-cell including
group and
genus- specific (polyclonal} as well as
species specific
(monoclonal) cells. Therefore, the sensitivity may depend on the test
and its methodology by the
specificity will depend on the antigen
rather than method used.
Some serological tests are:
DAT - Direct agglutination test.
This test has been found to have a
sensitivity of 96.5-100% and
specificity 91-95%. Its
strength is its high sensitivity and specificity in
early diagnosis of kaia-azar paiienis. The draw back is that it remains
positive for more than 5 years after complete cure.
ELISA
The sensitivity of ELISA is
nearly 100%, but specificity is not
very high as cross-reaction with
were from patents with TB and
toxoplasmosis has been recorded.
Dot-ELISA
IS another method that has been
developed in which
interpretation can easliy^ade by visua! inspection of reaction
end
points, obviating the need for ELISA reader. '9
26
4.17 STUDIES ON VALIDITY OF DAT TESTS.
♦ A sensitivity of 100% and specificity of 99.3% and 100% were
reported by HARITH et al (1986).23
In one study on direct agglutination test for visceral leishmaniasis, IFAT
and ELISA were applied to sera of patients with visceral leishmaniasis,
African, American trypanosomiasis other parasitic infection and healthy
controls. The sensitivities of 3 tests were comparable (96.3% to
100%): excluding patients with African and American trypanosmiasis,
the specificities of DAT and IFAT were 100% and ELISA 87.3% 5
Following studies recommend different cut off values :
Study done in India showed, serum dilution of 1:800 differentiates a
case of visceral leishmaniasis from healthy controls. Therefore any
serum specimen with titre of > = 1:800 was considered to contain antileishmanial agglutinating antibodies, Fifty-six of 58 sera (96.5%) from
confirmed
cases
of
visceral
leishmaniasis
had
anti
leishmanial
antibodies, while none of the clinically suspected cases, apparently
healthy control subjects, tuberculosis or malarial cases had significant
titres i., e > 1:800. The mean titre of agglutinating antibodies in visceral
leishmaniasis cases was significantly higher than that of the control
subjects. Although the mean titres for patients with malaria and
tuberculosis where higher than those of both the endemic and non-
27
endemic control subjects how ever the highest titres in these groups
were below the cut-off value 1:800. 24
4
Relatively high levels of agglutinating antibodies iin apparently healthy
subjects from an endemic area, compared to these in subjects living in
non-endemic areas might be due to previous exposure of the former to L.
Donavani, through the bite of an infected vector, resulting in some
degree of humoral response. The relatively high titres in sera from cases
of tuberculosis may be due to the presence of antigenic determinants of
L.donavani
promastigotes
cross
react
with
mycobacterium
tuberculosis24.
In patients with recent kala-azar,titres of 1:5200 or higher
were
found. Cured Kala-azar patients treated 4-14 months before testing,
showed the titres in the range of 1:3200 to
> 1:5200.Healthy and
diseased controls had titres below 1:1600 with the
exception of
African trypansomiasis patients who showed titres 1:200 tol: 12800,
overlapping with the titres of cured
Kala-azar patients. Where
trypanosomiasis is not a consideration, a titre of
1:1600 could
considered indicative of visceral leishmaniasis, the sensitivity and
specificity were then 100%. =3
A titre of 1:3200 or greater in an area considered to be free of African
Trypanosomiasis is highly predictive of visceral leishmaniasis (recent or
Past).. In areas where trypanosomiasis occurs, further serum dilution
The DAT appears to be a useful tool for screening, with a high sensitivity
and a high predictive value of negative test. However, the DAT cannot
differentiate between past kala-azar, sub-clinical infection, and active
disease. 25
Anti-leishmanial antibodies have been demonstrated in clinical cases of
visceral leishmaniasis by variety of immuno diagnostic tests but these
tests may give false positive results with case of typhoid, malaria and
tuberculosis. Thus attempts have been
made to develop a simple but
specific diagnostic serological tests for the early identification of cases of
Visceral leishmaniasis. The DAT has been
shown to be not only highly
sensitive but also a specific and simple test for
confirming the diagnosis
of visceral leishmaniasis. However, further investigation is required to
assess the specificity and sensitivity of DAT in different
geographical
areas. 24
Since DAT has a high negative predictive value the absence of antibodies
detectable by DAT could tend to rule out active kala
suspected cases. Furthermore
-azar in clinically
assessing the titres of agglutinating
antibody could nronitor effectiveness of therapy. However, investigation
on larger number of cases is required before a final conclusion can be
drawn.
I
4.19 LEISHMANIN AS SCREENING TEST.
Leishmanin is a suspension of 10 to the power of 6 promastigotes in 1
ml of .5 percent phenol saline. The test is an index of delayed
hypersensitivity. It has been also used as important epidemiological tool
to assess the immune status of population against leishmanial infection
and the spread of disease within and from an epidemic focus. It is not
species specific. It is used to map out the extent of past infection in
community and may be of help in diagnosis in individual patients.16
Interpretation of the results of a leishmanin test survey requires
consideration of factors such as the time during the epidemic when the
survey was conducted, past experience of the community of such
epidemics, the age of the community at that particular geographical
location and the frequency of population exchange.26
True second attack of Kala-azar after successful recovery from the first is
almost
unknown although there arc some isolated reports needing
verification.27 The sensitivity of leishmanin test is reported to be 93%28
The leishmanin test is specific for leishmaniasis but is not species
specific. Leishmanin positivity increases with age in endemic areas of
cutaneous leishmaniasis and in endemic kala-azar areas leishmanin
positivflY is acquired without any clinical evidence of infection
and
varies inversely with incidence of kala-azar indicating population
immunity. Leishmanin positivity has also been shown to develop without
clinical signs of infection in Northern Italy during an outbreak of kala-
1
azar.6
- 31
31
06754
Oot
Ff
■
Leishmanin positivity deontes an immune state that prevents further
\
infection provided no immunosuppressive factors intervene and this ■
immunity has been demonstrated. In old endemic foci where there are
frequent contacts with infected sand Hies only new generation of children
are likely to contact the infection since the older generation are already
immune. This phenomenon is aided^the fact that foci often remain
constant, strictly limited to the same district or to the same group of
houses or even the same house for years. It could be used as indirect
diagnostic reaction. If someone is suspected of having kala-azar and the
leishmanin test is positive in one or more members of household, this
observation along with negative reaction in the patient can suggest the
diagnosis.
These observations suggest that the leishmanin skin test is valuable tool
to measure the past present possibly future incidence of kala-azar in all
areas of the world.6
Interpretation should be done carefully inter observer variation is
significant.29
5 MATERIALS AND METHODOLOGY
5.1 STUDY AREA
Litipara block (Jharkhand)
Litipara block is the most predominant tribal block in Pakur district of
Jharkhand state with 25% Pahadias and 50% Santhal tribes.ao r is one
A
■? j
a
among the six blocks of Pakur district of newly created Jharkhand State.
Jharkhand literally means ‘Jhar’ (cluster of thick
(tract of road.31).Tribal population in this
the forest produce, which they cither
forest) and ‘khand’
area is mainly dependent on
sell in the market or exchange for
the food grains.
•1:■?
41
Out of four villages chosen for the study,
tribe and rest three villages
i by the Pahadia tribe
Pahadias have a dravidian background,
<1
■ 1 -1
*
i|
one is inhabited by Santhal
speak dravidian language who
migrated from south India.32 The total number of this tribe is less than a
lakh, there is concern that they might become
extinct. Government has
banned family planning programmes in this community.
•f
5.2 NORTH 24 PRAGANAS DIST.
■X,
•' ’■I
<J
I
Residents of north 24
(West. Bengal)
Parganas district of West Bengal district.
Predominently rural area. The paddy and fisheries
form the economic
lifeline of the region. Muslims are in
significant numbers in the
population
33
5.3 TESTS USED
DAT - After cleaning the thumb, the skin
lancet, a large drop of blood
was punctured with a sterile
was allowed to fill the circles on the DAT
filter paper. It was allowed to air dry ,25
leishmanin skin test - After antiseptic
measures, Injecting .1 ml of
antigen intradermally into the volar surface of the forearm . A palpable
nodule, 5 mm or more in diameter after 48-72 hours, is considered
IS considered
positive.16
methodology
5.4 For Community based -
cross sectional study
1. Census of entire populotion of the four
was
conducted tor sampllng purpose.
according to hierarchy W the family was
2. Population in the
enumerated.
census record formed
Systematic Random
sampling technique,
enlisted as the study sample.
3. The sampled individuals
sampling frame. Through
every fourth individual was
-ere visited at their place of residence, and
purpose of the study was explained
4. Voluntary informed
clinical informatio
5.5 Hospital based
consent was obtained before taking
n and subjecting them to the
necessary
screening tests.
-cohort study.
1.
Data of treated Kala-azar cases from r
Irom Government Hospital in 24
Paraganas district of West Bengai, was obtained for the
• n
(12000.
^or the period of 1999
2.
cases were selected on the basis of
completion of treatme
of 0,3,6,9 &12 (treatment cohorts) months from
the reference m onth August 2000 (±lo days) was short-listed.
3.
The cases were traced and explained the purpose of the study.
After obtaining the voluntary informed consent, they were subjected to
DAT.
4.
The same treatment cohorts were repeat tested again after three
months (Nov.2000) by applying DAT test.
5.
The titres of phase one and phase two tests were analysed fox
dynamics of the antibodies for the period.
r,
3*c rr io
r-
- C1 1"
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.
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JM
1 i
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IF
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ilfl Jn
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If©bt£>6<> a j y@
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U7
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^ly®
I
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l]K
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JF
If
I
H
<r
I
\
ll
ll
t
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I
RESULTS
6.1AGE AND SEX DISTRIBUTION OF STUDY POPULATION*
Table -1.
AGE GROUP
MALE
FEMALE
0-.9
26
(41.3%)
63
10-19
12
37
(58.7%)
13
(52%)
16
25
(44.4%)
36
13
(52%)
1
25
(1J.1%)
9
2
(20%)
10
20-29
(48%)
20
(56.6%)
30-39
12
40-49
Above 50 year
• about
(48%)
8
1889?^
8
. (80%)
TOTAL
peopie could not be .neluded In this table since the^age was
not available.
6.2 PREVALENCE OF LEISHMANIN SKIN TEST POSITIVITY
In Paharias and Santhals community
Prevalence - 44.4% (95%CI = 33%-55%)
6.3 PREVALENCE OF DAT SEROPOSIVITY (> 1:800)
In Paharias and Santhals community
Prevalence - 44% (95%CI=35%-53%)
38
6.4 ANNUAL RATE OF INFECTION IN AGE GROUPS
Table No-2.
AGE
GROUPS
CUMULATIVE
INCIDENCE
1-10 yrs
19.4%
ANNUAL
RATE OF
INFECTION
4%
1 1 -25 yrs
61.1%
5%
26-40 yrs
66.7%
3%
> 40 yrs
36.4%
.8%
CALCULATION OF ANNUAL RATE OF INFECTION
e-«‘ = 1- CI
I =
-In (1-CI)
t
where,
CI- Cumulative Incidence.
I = Incidence.
t = Time (median age)
19
Graph No. 1
LEISHMANIN TEST POSITIVITY RATES AMONG AGEGROUPS
LEISHMANIN SKIN TEST IN AGEGROUPS
70-------------------------------------------------------------- - --------
t
I
60'
50403020
10__
1-10
11-25
26-40
age groups
1
40
>40
6.5 EFFECT OF SEX ON LEISHMANIN SKIN TEST
Table -3.
MALE
(48)
45.8%
FEMALE
(51)
43.1%
no. in parenthesis is no. of people examined
% is percentage positivity
X 2 = .67 ( P>.O5 )
OR = 1.12
[ 95% CI .47 to 2.66 ]
6.6 EFFECT OF AGE ON LEISHMANIN SKIN TEST
Table - 4.
1-10 yrs
(36)
19.4%
11-25 yrs
(18)
61.1 %
26-40 yrs
(33)
66.7%
40 yrs
(1 1)
36.4%
no. in parenthesis is no. of people examined
% is percentage positivity
X 2 for linear trend =5.287 (P< .05 )
•ll
6.7 EFFECT OF DAT TEST ON LEISHMANIN SKIN TEST
Table -5.
DAT >800
(35)
48.6%
DAT < 800
(43)
44.2%
no. in parenthesis is no. of people examined
% is percentage positivity
X 2 =
.15
(P> .05 )
OR =1.19
[ 95% CI=.44 to 3.22 ]
6.8 EFFECT OF FAMILY SIZE ON LEISHMANIN SKIN TEST
Table -6.
FAMILY>6
(30)
73.3%
FAMILY<6
(59)
37.3%
no. in parenthesis is no. of people examined
% is percentage positivity
X 2 =
3.03
(P=.O8 )
OR
2.06
42
[ 95% CI = .84 to 5.06
]
6.9 EFFECT OF SPLEEN SIZE ON LEISHMANIN SKIN TEST
Table -7.
PALPABLE
(43)
32.5%
NON
PALPABLE
(30)
53.6%
no. in parenthesis is no. of people examined
% is percentage positivity
X2 =
4.35
(P> .05 )
OR
.42
( 95% CI= .17 to 1.03 ]
6.10 EFFECT OF FEVER ON LEISHMANIN SKIN TEST
Table -8.
FEBRILE
(20)
35%
AFEBRILE
(79)
46.8%
no. in p.w cn11 icsi3 is no. of people examined
% is percentage positivity
X 2
.91
(P> .05 )
OR
.61
-13
[ 95% CI = .19 to 1.87 ]
6.11 EFFECT OF SEX ON DAT POSITIVITY
Table -9.
MALE
(77)
46.75%
FEMALE
(69)
40.5%
no. in parenthesis is no. of people examined
% is percentage positivity
X2 =
.56
(P> .05 )
OR = .78
[ 95% CI= .38 to 1.58
I
V
I
I
6.12 EFFECT OF AGE ON DAT POSITIVITY
Table -10
110 yrs
1 1 -25 yrs
I
I
li
26-40 yrs
>40 yrs
(43)
39.5%
(29)
48.3%
(40)
50%
(17)
4 1.2%
no. in parenthesis is no. of people examined
% is percentage positivity
I
I
X 2 for linear trend = . 197 ( P>.05)
I
44
I
]
6.20 EFFECT OF CUT-OFF TITRE > 1: 6400 ON VALIDITY OF
DIRECT AGGLUTINATION TEST
Tabic-18.
D+
D-
DAT >800
38
2
DAT<800
44
116
82
1 18
Sensitivity-
46 X
Specificity -
98-Z
Likelihood ratio- 23
50
6.21 MEAN TITRE LEVELS OF ALL TREATMENT COHORTS IN
PHASE-1
Table-19.
TREATMENT
COHORTS
UNDER
LOG MEAN
TITRE
GEOMETRIC
MEAN TITRE.
4.05
11220
3 MONTHS
3.51
3235
6 MONTHS
3.60
3981
9 MONTHS
3.46
2884
12 MONTHS
3.60
3981
TREATMENT(O)MC)NTH
Note : TIijii . ven afler 12 months of treatment the titre remain very high above
the seropositive cut off of >1:800 within the treatable range.
06754
_
6.22 MEAN TITRE LEVELS OF ALL TREATMENT COHORTS IN
PHASE-2
Table-20.
TEATMENT
LOG MEAN
GEOMETRIC
COHORTS
TITRE
MEAN TITRE.
3 Months
3.97
9332
6 Months
3.26
1819
9 Months
3.17
. 1479
12 Months
2.72
524
15 Months
2.96
912
note that The Nine month group has become sero negative < 800 in the
12th month in 2nd phase.
52
6.23 COMAPARISON OF MEAN TITRES OF ALL THE TREATMENT
COHORTS.
Table-21.
TREATMENT
GEOMETRIC
GEOMETRIC
COHORTS
MEAN TITRE.
MEAN TITRE
IN PHASE-1
IN PHASE-2.
0 Month
1 1220
9332
3 Month
3235
1819
6 Month
3981
1479
9 Month
2884
524
1 2 month
3981
912
note the differences increasing widely with increasing time .
53
I
I
I
Graph-2
INDIVIDUAL LOG TITRES OF TREATMENT COHORTS IN
PHASE ONE AND PHASE TWO
I
5
I
Individual logtitres in phase-1
4
(/)
0)
3
HF;
2
I
I
1
Q
0
CD
O
I
3
0
I
9
6
12
15
Treatment duration
I
I
Graph-3.
Individual Logtires in Phase- 2
5l----------------------------------- —___________
4
CM
(D
(/)
GJ
CL
O
39.
1.
o °’
0
3
PHASE2
6
9
12
15
TREATMENT DURATION PHASE - 2
I
54
I
18
interesting finding, especially so when compared annual rates of
infection for disease like TB which is about 1%. in India.
While Leishmanin test is a good indicator of the past infection in the
community shown by
hypersensitivity to the leishmanin antigen by cell
mediated response, it docs not give any information about recent
infection which mainly elicit humoral response in the body. Since our
objective was to study the prevalence of leishmania infection in the
community irrespective of whether it was past or present , we had to
employ another serological test called Direct Agglutination test,
which
reacts to the circulating antibodies. Leishmanin skin test in recent
infection or active disease will be negative due to suppression of cell
mediated immunity there by not picking up active infections.
With Leishmanin picking up the past infection and DAT picking up the
recent infection and active disease
we could have a better assessment
disease burden in the community.
In our study area prevalence of sero positivity ( titre
> 1:800) to
leishmania infection was 44% ( 95%CI=‘35%-53%). By employing DAT
test we could capture extra 18 (23.1%) cases in the community in whom
the leishmanin skin test was negative.
Having both serological and leishmanin test result to our disposal, our
interest was to look for any correlation between between the two results
59
and especially to see whether leishmanin skin test positivity was higher
in seronegative as compared to the seropositive. No negative correlation
was seen.
Earlier studies have shown male preponderance in kala
-azar 6. n a
retrospective study conducted on the Bihar epidemics in
70s by CP
Thakur ^'showed the male
male latio was 5.5 .*1. In our community
such phenomenon was not observed. In
our hospital study there was
male preponderance, however this raises two key issues whether the
probablity of disease given infection is lower for females or is it due to
health seeking behavior difference between sex.
The young and
Middle age groups showed higher rates of leishmanin
skin test positivity 61% and 66.7 %
respectively compared to the
extremes in the age spectrum 1 9.4% in children and 36.4% in above 40
years groups. This is attributed to the high transmission of infection in
kala-azar endemic areas, where the population get infected early in
childhood, consequently by middle age, half of the population
would
have experienced ieishmanial infection and hence be immune to disease.
i
i
Middle aged group showing
higher infection is also reported by CP
Thakur14. One possible reason for the low leishmanin skin
test positivity
in old age groups could be due
to fading immunity. Nandy ct al
reported 19.2% in 1-10 years group 25.6% after 40 year. Studies from
Mediterranean region6 showed
aEc group 50-70 year with maximum
I
leishmanin positivity. Badaro et al reported predominantly higher higher
I
60
infection in children under 15
in Brazil, where adults get rarely
infected.1*
In sharp contrast to leishmanin skin test, there was little difference in
DAT sero positivity in different age groups.
The absence of association between Family size and kala-azar can be
explained on the fact that, over crowding has no bearing on the
transmission of leishmania infection, unlike in diseases like tuberculosis
or measles.
We looked for any association between DAT sero positivity with fever and
splenomegaly as surrogate variables for kala-azar, since the probability
of the kala-azar is higher in cases with these signs in endemic area, but
no association could be found. Reasons for absence of correlation
between
scropositvity
with
surrogate
variables
like
fever
and
splenomegaly could not be explained since DAT is a test for recent
infections.
High titre of antibodies can be elicited in subclinical and aymptomatic
cases. Although the mean level in such cases will always be lower than
clinical cases.35
Incidentally DAT posed more questions in our study than it could solve,
l.what is the status of the individuals who are apparently healthy, being
negative to the leishmanin
skin test but seropositive to DAT.
61
2.Why there was no difference in seropositivity rates, between different
age groups as in leishmanin skin test.
We attempted to find the answers for the above questions by conducting
a hospital based study with the objective of studying dynamics of the
sero titre in kala-azar cases after the cure. We began studying the
dynamics of the antibody level in cured kala-azar cases, by measuring
the antibody levels in two phases. In the first phase blood samples were
collected 82 kala azar cases based on their completion of treatment like
0( just completed),3,6,9,1 2 months prior to the reference month (June)
when our community study was conducted,
15 cases were recruited in
each treatment cohort. Same cases were repeat tested after Smonths.
The results of the hospital based study showed declining pattern in the
antibody levels in 82 cases successfully treated for kala-azar, but did not
show any definite trend in relation to time. The titre
seem to decline
with time but the consistency was absent. The mean titre level during
the treatment was 11220, which went down to 3235 at 3rd month then
increased to 3981 at 6 months, dipping to 2884 in 9 months again. The
upsurge to 3981 at 12 months could not be explained, which in effect
meant the antibody titres returning
back to 6 month level,
The
fluctuations especially the upsurge towards the later months could not
be accounted for. Sintc
5
< )nly
one cohort (9 month ) showed its mean
titre dipping from 288 1 to529 wc could not tell with conviction, how long
do the
kala azar cases take to convert into sero-negative status
62
which needs an elaborate cohort study which is out of scope for our
present study.
We could show the means of differences between the logtitre values of
phase one and phase two was significant F statistics=7.41 (pc.05) The
differences increased with the time after completion of the treatment.
This implied that the fall in antibodies is slower in the beginning and
gradually accelerate with the time.
The variation and inconsistency in the antibody dynamics lowers validity
as diagnostic test, which explains misclassification of many normal
people in the community as < liseased through seropositvity with higher
titres, seriously undermining the validity of DAT as diagnostic test.
Since the validity of any given test is dependent on prevalence of the
disease, we were prompted to look into the validity of DAT with different
cut-off titre. For this reason we recruited (n=82) treated kala-azar cases
from referral hospital of West Bengal into case series and study subjects
from community without fever (n=118)were included into control series.
We looked at the effect on the validity on DAT with different cut off titres.
The cut off titre of 1:1600 gave better validity (sensitivity=.84 and
specificity--^.82)
than
(in i cntly
sensitivity=.63 and spccificity = ,83)
used
cut
off
litre
of
1:3200
(
8. SUMMARY kND CONCLUSION
Kala-azar is a major public health problem In our country. We have to
tackle it by
giving due priority. Our study showed 44.4% leishmanin
skin test positivity
and 44%
DAT seropositivity , indicating
high
prevalence rates of leishmania infection in the tribal community
. The middle age groups showed higher rates of positivity.
Leishmanin skin test showed significant association with age. The male
I
to female ratio for disease was similar, wc did not find the male
preponderance.
r>
Leishamnin
skin
test
had
clear
cut
results
for
population as to past infected or not.
DAT was found to be good epidemiological tool for community survey
but its validity as diagnostic test was not very high. There was no
association
between DAT seropositvity and other variables like age,sex
or surrogate variables for kala azar like splenomegaly and fever. DAT
7
results showed ambiguity in classifying the population into recent and
past infection.
Our hospital based study showed declining trend iin the antibody levels
with no definite trend in relation with time. The variation in declining
antibody level was high. The means of differences of antibody levels in
the phase-1 and phase- 2 was statistically significant. The effect on the
DAT Validity was measured by adopting different cut-off titres of
antibody levels. The titre of 1:1600 was found to have the best diagnostic
65
t
validity for DAT in Santhal parganas area with sensitivity of 84% and
specificity of 86%. The likelihood ratio for 1:1600 cut-off titre was 4.6.
This was much better than the 1:3200 cut-off titre presently used in the
area which had specificity of 83% and a low sensitivity of 63%.
Our study gives the baseline information of the magnitude of the disease
and infection in the tribal communities in Santhal parganas area. Clear
j
Idea of the magnitude is necessary in any area for taking on intervention
programmes. The impact of the intervention programme should be
measurable in any evaluation.
Il
For disease control and prevention, test/s used for
and
screening programs should conform to criteria like Validity,
repeatability,
ii
community surveys
acceptability,
simplicity,
rapidity,
safety,
administration and low cost36. Both Aldehyde and Bone
which are the most widely used test for diagnosing kala
ease
of
marrow tests
azar, are not
feasible for screening purposes.
Sternal bone
marrow puncture and aspirate the definitive test for Kala-
azar diagnosis is very painful procedure, intimidating the patients.
Moreover it involves technical expertise and therefore is not feasible in
field conditions.
•I
Aldeyhyde test is a very simple but has low sensitivity and specificity. It
continues to be mainstay for lab diagnosis of Kala-azar infection in rural
66
and semiurban
areas where
the disease burden of kala-azar is
maximum.Aldehyde test is not positive until a few months after disease
rus lunlnr missing the disease in undetected cases of Kala-asar
DAT test is a very simp|e lcst lo car^outj
specimen is eerj, snnple, involving collection few drops blood
sample
from finger prick on the filter
paper, which could then be sent to
concerned laboratory', even by post.
Thus, ideally suited for Seroepidemiological work
The
DAT
and
Leishmanin
epidemiological tool
skin
tests
are
most
widely
used
all over the world for conducting field studies
assess the magnitude of the disease in the community
to
9. LIMITATION
Bone marrow test could not be carried out for definitive diagnosis of
kala-azar .
The Hospital cases could not be followed for longer time due to time
constraints.
Many of the cases of kala-azar in referral hospital were diagnosed on the
basis of DAT
68
10. RECOMMENDATION
Use of rnnhiple test in series or parallel to increase sensitivity and
specificity, for diagnosis, in the absence of Bone marrow test.
An elaborate Cohort study to understand the long term dynamics of
antibodies.
12. BIBLIOGRAPHY
1.
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1999;12(2):
2.
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3.
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ncBlcclcd aspect of kala-azar control proRrammes. Ann Trop Med
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4.
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5.
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R. K.t.gu S, Laarman JJ. Equation of a newly developed direct
..RRha,nation test (DAT) for serodiagnos.s and sero-epidemiological
stud,cs of V.seeral leishmaniasis comparison with IFAT and
ELISA. Irons Roy Soc Trop Med Ilyg 1987;81:603-6
6.
Patnpiglione S, Manson-Bhar PEC, Placa La. M, Borgatli MA
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S.
Studies
in
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leishmaniasis
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Chattcrji KD, Parasitology
protozoology and Helminthology in
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• Chatterjee Medical
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•'0
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Krishna das KV, A Short text book of Medicine. New Delhi: Jaypee
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Prasad LSN. Kala-azar. Indian J Pcdiatr 1999;66:539-46.
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Saunders, 1988,: 1869-75.
12.
Ilati AK. Kala-azar-an enigmatic disease,Ind J Pub Healh 1989
April-June;33(2): 45-54.
13.
Plorde James J. Leishmaniasis. In: Issebacher Kurth J, Adan
Raymond D,Braunwal Eugone, Robert G, Dorf Peter S, Wilson
Jane D [editors].Harrison's principles of internal medicnine,9th ed
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14.
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July S< pt;21(3).
15.
Souhami KL, Moxham J [editors]. Text Book of Medicine. New York
:Churchill
livingstone, 1990
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blood
protozoa) [leishmaniasis]
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Dermott Walshfeditors]. Text Book of Medicine. 14,h ed. Toronto
:WB Saunders, 1975: 490-495.
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Aikat BK.Pathania AGS.Sehgal Shobha.Bhattacharya PK.Dutta
Usha,Pasricha Neelam, et.al. Immunological responses in Indian
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18.
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post treatment antibody levels in visceral
Trans
leishmaniasis.
Roy
Soc
Trop
Med
Hyg
Sept-
1990
Oct;84(5):673-5.
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Bryccson Anthony DM. Visceral leishmaniasis. In : Wayngarden
James B, Smith Lloyd 11,Cesil[editors|. Text Book of Medicine Vol2.Mexico: WB Saunders, 1982 :1869-75.
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Vakil Jal Rustam. Text Book of Medicine.2 nd rev.ed.Bombay : The
Assn. Of Physicians of India, 1973 : 182-9.[kalaazar]
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Thakur CP. Leishmaniasi. In : Sha Shanti J[editor].APl Text Book
of Medicine. 4 th ed. Bombay : Association of Physicians of
India,1988:131-3
22.
Aggrawal Praveen.Handa Rohini.Singh Sarman and Wali Prakash
Jyolhi. Kala-azar- new developments in diagnosis and treatment.
Ind J Pediatr 1999;66:63-71.
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Harith E,Kolk AH J,Eager PA.Leeuwenburg J.Muigai R,Eiugu S,
Simple
and
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ct.al.
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agglutination
studies
of
test
for
visceral
leishmaniasis. Trans Roy Soc Trop Med Hyg 1986; 80:583-7.
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Singh Neena,Singh GS, Sundar Shyam, Vinayak VK.Evaluation of
direct agglutination test as an immunodiagnostic tool for kala-azar
in India. Trans.Roy Soc Trop Med Hyg 1993;87:276-8.
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Maria,Ghalib
WH,
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PA.
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test
for
diagnosis and sero-epidemiological of kala-azar in Sudan. Trans
Roy Soc Trop Med Hyg 1991; 85:474-6.
i
7">
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74
11. APPENDIX I
PROFORMA FOR COMMUNITY BASED STUDY
ID NO.
NAME
GUARDIAN NAME
AGE
SEX
FAMILY SIZE
TRIBE
VILLAGE
H/o KALAAZAR
C/O OF FEVER
SPLEEN SIZE
DAT TITRE
LEISHMANIN SKIN TEST
75
11.2 APPENDIX II
PROFORMA FOR THE HOSPITAL
BASED STUDY
ID NO
NAME
AGE
SEX
VILLAGE
TREATMENT MONTH
DAT
76
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