Abstract
A survey made on the prevalence and intensity of schistosomiasis in 14 localities in 4 areas in Somalia has revealed the presence of urinary bilharziasis among the inhabitants of all these localities, this being much higher in the two areas where water development has been accomplished. The mean prevalence of infection was found to be 27.2% and 58.1% in the two areas where water development has only been planned, while it was 58.7% and 75.6% in the two areas where the extension of irrigation was achieved years ago. Snails were collected from the habitats visited and these were identified. The role of Bulinus abyssinicus in the transmission of infection was proven.