Onchocerciasis: a prevalence study in Bebeka, Ethiopia.

A prevalence study was made in Bebeka, the largest coffee plantation enterprise in Ethiopia. The enterprise had a house-to-house censused population of 7,122 persons from whom 1,611 were examined for onchocerciasis using either taking of skin-snips or the Mazzotti test or both. The overall prevalence was 30.9%. It was analyzed according to sex, age, and origin of the sampled population with regard to previous residence in areas endemic for onchocerciasis or not. The prevalence differed significantly between different age groups, i.e. it increases with age. Among male persons the prevalence was higher than among the female population. A higher incidence was observed among persons originally coming from endemic areas.