The epidemiology of visceral leishmaniasis in Bangladesh: prospects for improved control.

The parasitic disease kala-azar (visceral leishmaniasis, VL) was first described in 1824 in Jessore district, Bengal (now Bangladesh). Epidemic peaks were recorded in Bengal in the 1820s, 1860s, 1920s, and 1940s. After achieving good control of the disease during the intensive vector control efforts for malaria in the 1950s-1960s, Bangladesh experienced a VL resurgence that has lasted to the present. Surveillance data show an increasing trend in incidence since 1995. Research in recent years has demonstrated the utility of non-invasive diagnostic modalities such as the direct agglutination test and rapid tests based on the immune response to the rK39 antigen. In common with its neighbours India and Nepal, VL in Bangladesh is anthroponotic. Living in proximity to a kala-azar case is the strongest risk factor for disease, while consistent use of bed nets in the summer months and the presence of cattle are protective. Shortages of first-line antileishmanial drugs and insecticide for indoor spraying programmes have hindered VL treatment and vector control efforts. Effective control of VL will require activities to improve availability and access to diagnostic testing and antileishmanial drugs, enhanced surveillance for kala-azar, post-kala-azar dermal leishmaniasis and VL treatment failures, and increased coverage and efficacy of vector control programmes.