Kala-azar or visceral leishmaniasis (VL), also known as black fever and Dumdum fever is most severe form of leishmaniasis. It is slow progressing indigenous disease caused by single-celled parasite of Leishmania family.
It belongs to Neglected Tropical Disease (NTD) family of diseases which affect poorest populations. Its infection is transmitted by sand fly (Leishmania donovani), a blood-sucking pest, which is one-third size of mosquito and found in moist (humid) mud and sand and in close proximity to livestock
It is second-largest parasitic killer in world after Malaria. It is endemic to Indian subcontinent in 119 districts in four countries (Bangladesh, Bhutan, India and Nepal). India accounts for half the global burden of Kala-azar disease.