Geographical Distribution of Kala-Azar in South Asia

Abstract

Kala-azar or visceral leishmaniasis (VL) is a parasitic disease caused by the trypanosomatid parasite Leishmania donovani on the Indian subcontinent, where it is transmitted by the sandfly Phlebotomus argentipes. Leishmaniasis is found in about 88 countries, where 350 million people are believed to be at risk. About 500,000 cases of VL occur annually, mostly affecting countries in the tropics and subtropics. More than 90% of the world’s cases of VL occur in India, Bangladesh, Nepal, Sudan, and Brazil, affecting largely the socially marginalized and the poorest communities. In South Asia, kala-azar occurs in India, Bangladesh, and Nepal, with a small focus reported from Bhutan. Nearly 200 million people are considered to be at risk of contracting kala–azar in this region. In May 2005, the health ministers of these three countries signed a memorandum of understanding in Geneva during the World Health Assembly, making a commitment to eliminate kala-azar from their respective countries by 2015. The target of the elimination program is to reduce the incidence of kala-azar to less than one case of kala-azar or post-kala-azar dermal leishmaniasis per 10,000 population at the district (in Nepal) or subdistrict/upazila level (in Bangladesh and India). As of 2008, kala-azar was endemic in 52 districts in India, 12 districts in Nepal, and 45 districts in Bangladesh.