Co-infection of Onchocerca volvulus and intestinal helminths in indigenous and migrant farmers in southwest Ethiopia.

A cross-sectional survey on onchocerciasis and intestinal helminthic infections was conducted in two villages around the town of Teppi, south-west of Ethiopia on a total of 308 subjects of which 180 indigenous and 128 migrant settlers aged 10 years and above who lived in the area for at least 5 years. Of the total study subjects, 65% were males. The majority (64%) of the study subjects were in the age range of 21-40 years. The results of stool and skin snip examinations for ova/parasite and microfilaria revealed that, 62% (190) and 81% (248) of the study subjects were positive for intestinal parasites and microfilariderma respectively. Fifty percent (154) of the total subjects in the two villages had both onchocerciasis and intestinal helminthic infections. However, 80% (94/118) of the stool negative subjects also had onchocerciasis indicating that onchocercal skin infection has no significant influence on the acquisition of intestinal helminthic infections or vice versa [(relative risk 1.04, 95% CI 0.91, 1.18) P > 0.05]. Sixty-five percent (161/248) of the total skin snip positive individuals had microfilarial load of > 10 mf/mg of skin snip. The proportion of multiple infections with 2 or more intestinal helminthes was recorded in 51% (96/190) of individuals positive for intestinal parasitosis. There was a significant (x2 = 8.41, P < 0.005) difference in the onchocerciasis infection rate among indigenous (88%) and migrant (75%). No direct association was observed between onchocerciasis and intestinal parasitosis in the two study groups (indigenous and migrant settlers). The public health significance of coexistence of the two diseases, and the need for intensive control measures are discussed.