Epidemiology of Mansonella perstans filariasis in the forest region of south Congo.

A study of Mansonella perstans filariasis conducted in the Chaillu mountains, Southern Congo, showed that 108 of 134 Pygmies (80.6%) and 79 of 302 Bantus (26.2%) presented with microfilaraemia. The mean microfilarial densities were also significantly higher in the Pygmies (1213 ml-1 of blood) than in the Bantus (136 ml-1). Ninety eight per cent of the Culicoides taken which had bitten man in the daytime were C. grahamii, and 0.8% of these were infected with filarial larvae. Two other species of Culicoides (C. kumbaensis and C. rutshuruensis) might also play a role in the transmission of M. perstans.