Leishmaniasis - Kala Azar

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

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.

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.

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.


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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