Search

The parasitic disease schistosomiasis is a major health problem in many tropical countries and over 300 million people are infected. Freshwater snails act as intermediate hosts for the parasite and because of that, the infection is transmitted among humans on water contact, mainly in rural areas with minimal domestic water supply and poor sanitary facilities. It has been realized that eradication of the disease is impossible with the available resources and therefore the immediate aim is control of morbidity. Despite the success of some control programs, the prevalence of schistosomiasis remains constant, largely because population growth and development of man-made water resources is continuing (WHO, 1993). Treatment of water bodies with molluscicidal compounds, in order to reduce the number of transmitting snails, is considered an important element in integrated strategies for morbidity control. However, large scale use of synthetic molluscicides are impeded by the high costs and thus there is a demand for inexpensive alternatives (Mott, 1987). The interest in studying plant material containing molluscicidal compounds is based on the idea of producing a local supply of molluscicides in the endemic areas at low cost and by simple technologies.