ABSTRACT
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