ABSTRACT
Schistosomiasis is one of the most thoroughly studied vector-borne diseases in Ethiopia. This chapter focuses on the ecology of both types of schistosomiasis and critically reviews past control programs with a view of improving their effectiveness and sustainability. Schistosomiasis is a three-factor disease involving pathogenic schistosomes, certain species of aquatic snails, and man. The three interrelated subsystems representing different stages of the transmission cycle and points susceptible to various control measures are the man-host snail relationship, the snail-parasite relationship, and the man-parasite relationship. Most schistosomiasis control efforts in Ethiopia have been directed toward reducing the snail intermediate host through the application of endod and synthetic molluscicides, with limited case treatment, health education, and environmental sanitation and water supply. The discontinuous distribution of both types of human schistosomiasis in Ethiopia despite the widespread distribution of intermediate host snails and infected people indicates the relatively greater role of altitude, climate, and other environmental factors than poverty and use of natural water bodies.
