Annual incidence of visceral leishmaniasis in an endemic area of Bihar, India.

The study presents the findings of a population-based survey of the annual incidence of visceral leishmaniasis (VL) in the rural areas of one VL-endemic district in Bihar, India. Stratified multi-stage sampling was applied in the selection of blocks, villages, hamlets, and households. We screened 15 178 households (91 000 individuals) in 80 villages in 7 of 27 administrative blocks of the district, East Champaran. We identified 227 VL cases that occurred in the past 12 months: 149 treated individuals who survived, 14 who died from VL, and 64 active cases. The high-incidence stratum had an estimated incidence of 35.6 cases per 10 000 persons per year (90% CI: 27.7-45.7). The annual incidence rate in the medium stratum areas was 16.8 cases per 10 000 (90% CI: 9.3-30.6). The combined annual incidence rate for the high and medium areas combined was 21.9 cases per 10 000 per year, (90% CI: 14.0-34.2). The Government of India's VL elimination goal is to reduce the VL incidence to one case per 10 000 at the sub-district level; thus, a 35-fold reduction will be required in those areas with the highest VL incidence.