Preliminary studies on the histochemical differentiation of strains of Onchocerca volvulus microfilariae in Togo

Skin snips were taken from 75 people living in four villages of northern Togo. The 7824 microfilariae that emerged were examined by staining for the presence of acid phosphatase. Four distinct patterns of enzyme staining were observed, and descriptions of the stained microfilariae are given. The study confirms the view that a number of biological strains or variants of Onchocerca volvulus coexist in West Africa, and suggestions are made for further research that could result in the practical application of these observations in onchocerciasis control programmes.