What
is (Leishmaniasis) Kala-azar?
Kala-azar
is a slow progressing indigenous disease caused
by a protozoan parasite of genus Leishmania
In
India Leishmania donovani is the only parasite causing
this disease
The
parasite primarily infects reticuloendothelial system
and may be found in abundance in bone marrow, spleen
and liver.
Post
Kala-azar Dermal Leishmaniasis (PKDL) is a condition
when Leishmania donovani invades skin cells, resides
and develops there and manifests as dermal leisions.
Some of the kala-azar cases manifests PKDL after
a few years of treatment. Recently it is believed
that PKDL may appear without passing through visceral
stage. However, adequate data is yet to be generated
on course of PKDL manifestation
Source
The
history of kala azar in India is one of the great
stories of tropical medicine. The invaluable account
of this disease from the time great epidemics swept
across vast tracks of the Indian subcontinent leaving
misery and poverty in their wake up to the present
time is foretold in the publication launched during
WorldLeish4, Kala Azar: An Odyssey into the Past,
ISBN 81-8189-281-X.
Visceral Leishmaniasis (VL): The Indian subcontinent
(India, Nepal & Bangladesh) is one of the main
areas affected by VL worldwide. It accounts for
about 67% of total cases reported with almost 200
million people at risk of contracting the disease.
The governments of India, Bangladesh and Nepal have
launched a joint programme to eliminate VL as a
public health problem by the year 2012.
Source
Epidemiology
of visceral leishmaniasis in India.
Kala-azar has re-emerged from near eradication.
The annual estimate for the incidence and prevalence
of kala-azar cases worldwide is 0.5 million and
2.5 million, respectively. Of these, 90% of the
confirmed cases occur in India, Nepal, Bangladesh
and Sudan. In India, it is a serious problem in
Bihar, West Bengal and eastern Uttar Pradesh where
there is under-reporting of kala-azar and post kala-azar
dermal leishmaniasis in women and children 0-9 years
of age. Untreated cases of kala-azar are associated
with up to 90% mortality, which with treatment reduces
to 15% and is 3.4% even in specialized hospitals.
It is also associated with up to 20% subclinical
infection. Spraying of DDT helped control kala-azar;
however, there are reports of the vector Phlebotomus
argentipes developing resistance. Also lymphadenopathy,
a major presenting feature in India raises the possibility
of a new vector or a variant of the disease. The
widespread co-existence of malaria and kala-azar
in Bihar may lead to a difficulty in diagnosis and
inappropriate treatment. In addition, reports of
the organism developing resistance to sodium antimony
gluconate--the main drug for treatment--would make
its eradication difficult. Clinical trials in India
have reported encouraging results with amphotericin
B (recommended as a third-line drug by the National
Malaria Eradication Programme). Phase III Trials
with a first-generation vaccine (killed Leishmania
organism mixed with a low concentration of BCG as
an adjuvant) have also yielded promising results.
Preliminary studies using autoclaved Leishmania
major mixed with BCG have been successful in preventing
infection with Leishmania donovani. Until a safe
and effective vaccine is developed, a combination
of sandfly control, detection and treatment of patients
and prevention of drug resistance is the best approach
for controlling kala-azar.
Source
Key
facts
-
There are 3 main forms of leishmaniases – visceral
(also known as kala-azar and the most serious
form of the disease), cutaneous (the most common),
and mucocutaneous.
-
Leishmaniasis is caused by the protozoan Leishmania
parasites which are transmitted by the bite
of infected female phlebotomine sandflies.
-
The disease affects some of the poorest people
on earth, and is associated with malnutrition,
population displacement, poor housing, a weak
immune system and lack of financial resources.
Leishmaniasis is linked to environmental changes
such as deforestation, building of dams, irrigation
schemes, and urbanization.
-
An estimated 700 000–1 million new cases and
20 000 to 30 000 deaths occur annually.
-
Only a small fraction of those infected by Leishmania
parasites will eventually develop the disease.
Leishmaniasis
is caused by a protozoa parasite from over 20 Leishmania
species and is transmitted to humans by the bite
of infected female phlebotomine sandflies. Over
90 sandfly species are known to transmit Leishmania
parasites. There are 3 main forms of the disease:
- Visceral
leishmaniasis (VL), also known as kala-azar
is fatal if left untreated in over 95% of cases.
It is characterized by irregular bouts of fever,
weight loss, enlargement of the spleen and liver,
and anaemia. It is highly endemic in the Indian
subcontinent and in East Africa. An estimated
50 000 to 90 000 new cases of VL occur worldwide
each year. In 2015, more than 90% of new cases
reported to WHO occurred in 7 countries: Brazil,
Ethiopia, India, Kenya, Somalia, South Sudan
and Sudan. The kala-azar elimination programmes
in South-East Asia are making sustained progress
towards elimination, and cases are declining
in the three major endemic countries: Bangladesh,
India and Nepal.
-
Cutaneous leishmaniasis (CL) is the most common
form of leishmaniasis and causes skin lesions,
mainly ulcers, on exposed parts of the body,
leaving life-long scars and serious disability.
About 95% of CL cases occur in the Americas,
the Mediterranean basin, the Middle East and
Central Asia. Over two thirds of new CL cases
occur in 6 countries: Afghanistan, Algeria,
Brazil, Colombia, Iran (Islamic Republic of)
and the Syrian Arab Republic. An estimated 0.6
million to 1 million new cases occur worldwide
annually.
-
Mucocutaneous leishmaniasis leads to partial
or total destruction of mucous membranes of
the nose, mouth and throat. Over 90% of mucocutaneous
leishmaniasis cases occur in Bolivia (the Plurinational
State of), Brazil, Ethiopia and Peru.
Source
Video
links
What
is Leishmaniasis? An introduction and overview
Leishmaniasis
- Leishmania donovani - Tropical parasites - Protozoa
- Kala Azar - Black Fever
Life
cycle of Leishmania in the human host
Visceral
leishmaniasis
Visceral
leishmaniasis (VL), also known as kala-azar, is
the most severe form of leishmaniasis and, without
proper diagnosis and treatment, is associated with
high fatality.Leishmaniasis is a disease caused
by protozoan parasites of the genus Leishmania.
The
parasite migrates to the internal organs such as
the liver, spleen (hence "visceral"),
and bone marrow, and, if left untreated, will almost
always result in the death of the host. Signs and
symptoms include fever, weight loss, fatigue, anemia,
and substantial swelling of the liver and spleen.
Of particular concern, according to the World Health
Organization (WHO), is the emerging problem of HIV/VL
co-infection.
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