Schistosomiasis in the Finchaa River Valley, Wellega Region, western Ethiopia

Parasitological and malacological surveys were carried out in the Finchaa Valley; Wallega Region; Western Ethiopia. Stool examination of 960 persons in the 10 communities surveyed showed an average human prevalence of 12.4 per cent for Schistosoma mansoni. Infected individuals were present in 6 communities; but prevalence was greater than 10 per cent in only three of them; reaching 40 per cent among school children in one community. In endemic localities; the intensity of infection in terms of eggs per gram of faeces were 200 and 199 among school children and farm labours respectively. The age specific prevalence and intensity of infection were highest among the 5-14 year age group. The intermediate host of S. mansoni; Biomphalaria pfeifferi were collected from three sites; but transmission was identified at only one site located in the lower portion of the valley. Bulinus truncatus; the potential intermediate host of S. haematobium in Ethiopia; was also present in the area. The occurrence of infected human subjects and snail intermediate host confirm that Schistosoma mansoni is well established in the valley; particularly in the lower portion where a large irrigation development is under way. In this report; the threat posed by the S. mansoni and S. haematobium is discussed and the preventive/control measures to be taken are suggested

Transmission of schistosoma mansoni in three ecological settings in Ethiopia : epidemiological aspects

The epidemiological indices of Schistosoma mansoni for three communities in Ethiopia; Jigga (Northwest); Metahara sugar estate (Southeast) and Lake Zway (Central); each representing the three major transmission ecologies in the country; the stream; irrigation scheme and lake; respectively were studied and compared. A total of 2897 people (913; 1614 and 370 from the stream; irrigation scheme and lake; respectively) was examined for S. mansoni ova by the Kato's smear method. The highest human prevalence (58 per cent) and intensity of infection (geometric mean of 450 EPG) were recorded for the lake ecology; whereas the irrigation scheme and stream showed moderate (218 EPG) and light (172 EPG) intensities of infection; despite fairly high disease prevalences of 20 per cent and 41 per cent respectively. Age-specific analysis of prevalence; intensity of infection and relative index of potential contamination (RIPC) indicated that children in their second decade of life to be most responsible. Nevertheless; the decline of all indices with increasing age was less obvious in the lake area than others. The disparity between prevalence and intensity of infection and their implication in disease control tactics are discussed