The morphology of O. volvulus microfilaria in the northwestern onchocerciasis endemic foci, Ethiopia.

Microfilariae obtained by corneoscleral biopsy machines from persons in the Humera area along the Sudan boarder in Northwestern Ethiopia were stained using hematoxylin. Morphological measurements were made using a microscope fitted with micrometer and camera, as well as map curvimeter. The mean size of microfilariae was 189 microns by 5.8 microns. The percentage of nucleifree cephalic space as percent of total body length was 3.4 and is close to reports in the literature. The measurement of the distance of the anterior end nerve ring as a percent of the total body length (22.1%) is also close to measurements obtained elsewhere. Although the microfilaria encountered in this study are of the short variety, morphological measurements and the absence of sheath suggests that the microfilaria observed belong to O. volvulus.