Visceral leishmaniasis control: a public health perspective

Visceral leishmaniasis (VL), also known as kala-azar, is a vector-borne dis ease caused by a protozoan of the Leishmania donovani complex. A phlebotomi ne sandfly transmits the parasite from person to person or via an animal re servoir. VL is a severe, debilitating disease, characterized by prolonged f ever, splenomegaly, hypergammaglobulinaemia and pancytopenia. Patients beco me gradually ill over a period of a few months, and nearly always die if un treated. Case-fatality ratios are high even in treated patients. Worldwide an estimated 500000 VL cases occur each year. This study reviews clinical, epidemiological and public health aspects of the disease and shows how crit ical adequate case detection is for the success of VL control. Examination of the issue of VL diagnosis with respect to the global challenges in VL co ntrol leads to the observation that a sound diagnostic-therapeutic algorith m for the health services in endemic areas is badly needed. Serological tes ts could be an alternative to parasitological diagnosis and the direct aggl utination test (DAT) was found to fulfil many criteria for a 'field test', including cost effectiveness. Although research needs on vaccine and better drugs continue to be high on the agenda, a VL test-treatment: strategy bas ed on currently available highly sensitive serological tests, such as the D AT, should be introduced in the health services in endemic areas.