Center for Field and Applied Research, Ministry of Health, San Juan Laboratories, Bureau of Laboratories, Center for Disease Control, Public Health Service, U. S. Department of Health, Education, and Welfare, Qalyub, Egypt
We report the preliminary findings of a comprehensive schistosomiasis survey in the Qalyub region of the Nile Delta. A systematic sample of households in eight villages was studied, and 8,712 individuals submitted stool and urine specimens for parasitologic examinations. The prevalence of Schistosoma mansoni infection (40.5%) was much higher than that reported previously in this area, and the prevalence of S. haematobium (27%) was much lower. The geometric mean egg output for both parasites was surprisingly low. The apparent increase in S. mansoni infection may be largely due to the use of a very sensitive parasitologic technique, but the decrease in S. haematobium prevalence is unexplained. Preliminary results of snail surveys, however, indicate a profound decrease in the population levels of Bulinus species, a phenomenon which may be related to ecological changes since construction of the Aswan High Dam.
Director, Center for Field and Applied Research.
Formerly Director, San Juan Laboratories. Present address: Department of Tropical Medicine, Tulane Medical Center, 1430 Tulane Avenue, New Orleans, Louisiana 70112. Send reprint requests to this address.