Onchocerciasis in Taraba State, Nigeria: intensity, rate of infection and associated symptoms in 14 communities of Bali district.

An epidemiological study of 14 communities situated along the major road passing through Bali district in Taraba State, Nigeria, was carried out in continuation of a statewide filariasis survey which began in 1989. Of the 4,024 people that were examined for Onchocerca volvulus microfilaria and for clinical symptoms of the disease, onchocerciasis, an unusually low 13.3% prevalence rate was recorded with a range between 1.1% and 45.5%. Only one community had prevalence rate beyond 30.0%, six had infection rates between 10 and 29% while the remaining seven had less then 10% prevalence of the disease. However, infection was recorded in every community. The prevalence of physical symptoms was equally low. Pruritus was 7.3% and leopard skin was 0.4%. The prevalence of onchocerciasis increased with age in both male and female thus supporting the age and sex specific pattern of infection that had been reported in other parts of the state. A case is made for the continued prospection for onchocerciasis in the other districts of the state in order to identify and treat all communities that must benefit from the ongoing ivermectin treatment.