Onchocerciasis endemic in the State of Bolivar, Venezuela

Microfilariae of Onchocerca volvulus were demonstrated by single shoulder-skin biopsy in 42.8% of inhabitants of seven Amerindian villages in an area of approximately 10,000 km2, near the Brasilian Roraima Territory. The highest prevalence was found among the Yanomama Indians of Chajuraña (84.6%, with a mean of 61.3 microfilariae per mg of skin). The six other communities were affected, but with lower prevalence and microfilaria skin densities. The absence of lymphoedema and the few subcutaneous nodules and eye lesions found among the infected individuals suggest a relatively recent introduction of the disease to the region. Mansonella ozzardi infections were also detected in the area.