Morbidity from Schistosoma mansoni infections: an epidemiologic study based on quantitative analysis of egg excretion in two highland Ethiopian villages.

Although human infection with Schistosoma mansoni is known to be widespread in Highland Ethiopia, no information is available on its public health impact. A sample of the inhabitants of two typical villages in the endemic region north of Lake Tana were studied by clinical and quantitative parasitologic methods. One village had a moderately high prevalence (43.3%), while the second, chosen for comparison, had a very low prevalence (10.7%). No evidence of severe hepatosplenic disease was found in 343 persons examined. Symptons and mild hepatomegaly compatible with S. mansoni infection were common, and in the high prevalence village complaints of abdominal pain and blood in the stool were significantly related to S. mansoni egg counts. However, all signs and symptoms compatible with S. mansoni infection, including hepatomegaly, were of greater or similar frequency in the village with the low prevalence of infection. The findings of minimal morbidity are compatible with the level of intensity of infection found in the area and are consistent with the findings from morbidity studies based on quantitative egg counts in other areas of the world.