Schistosomiasis research and the European Community.

Schistosomiasis research within the framework of the Commission of the European Communities 'Science and Technology for Development' (CEC/STD) Programme is targeted at three specific problems: diagnosis of infection and disease; the dynamics of transmission, immunity, and morbidity; and the need for improved tools and strategies for control. Several important advances have been made over the past decade. Improved methods of diagnosis by detection of circulating antigens are in an advanced stage of development and have already undergone field trials in several epidemiological settings. Treatment and reinfection studies combined with immunological observations have allowed the elucidation of possible mechanisms leading to acquired resistance, and have shown that repeated chemotherapy with praziquantel can substantially reduce morbidity. Other projects have studied the epidemiological and ecological determinants of transmission, infection and disease in various endemic situations and also in newly established, epidemic foci where remarkable observations on chemotherapeutic responses were made. Important advances have been made towards the development of a vaccine. The glutathione-S-transferases of the major species of schistosomes have been cloned, sequenced and expressed, and their biological function studied. In a variety of vaccine formulations and animal systems GST has been able to confer protection against infection and to reduce worm fecundity. GST and a series of other crude and defined antigens have been evaluated with varying results in Schistosoma japonicum and S. bovis in cattle. Much work has yet been done, however. Recommendations as to possible future directions for research are provided.