Advances in epidemiology survey methodology and techniques in schistosomiasis.

Quantitative techniques are now recognized to contribute to the validity and comparability of data from epidemiological studies in schistosomiasis. These methods have been developed and tested in field investigations in areas where Schistosoma mansoni is endemic and, to a lesser extent, S. haematobium endemic areas. Carefully planned epidemiological investigations using standardized and quantitative methods have contributed to our understanding of the relationships between intensity of infection and morbidity, as well as to the development of improved control strategies relevant to these areas. This article reviews the newer parasitological techniques, methods of morbidity assessment, and data analysis procedures employed in current epidemiological studies in schistosomiasis, as well as the analytical questions involved in research on the epidemiology of schistosomiasis.