An epidemiological study of foci of S. mansoni bilharziosis in Minkana and Nalassi (Lekie Division, Cameroun) (author's transl)]

The epidemiological survey involved the examination of the total population of the two villages as well as the investigation of the freshwater snails in the neigbouring waters bodies. Biomphalaria camerunensis and Biomphalaria pfeifferi were found to be the intermediate hosts of Schistosoma mansoni. The cassage of eggs in the stools was more frequently observed in two groups, those aged 10-19 years and in the elderly women. The study of the prevalence of the disease by means of the indirect immunofluorescence technique on frozen sections of S. mansoni revealed that already in childhood the percentage of subjects with circulating antibodies is high. This percentage remains elevated in subsequent age groups. The geometrical mean reciprocal titers show an age and sex pattern similar to that found for prevalence. Both the percentage of positive indirect immunofluorescence tests and their respective titers were higher in patients with eggs in their stools. The immunological reaction using homologous S. mansoni antigen is more sensitive than that with heterologous S. haematobium antigen.