RECENT TRENDS IN THE PREVALENCE AND DISTRIBUTION OF SCHISTOSOMIASIS IN THE NILE DELTA REGION

ln 1983, a survey of 71 villages in the Nile delta demonstrated that t he overall prevalence of Schistosoma mansoni and S. haematobium infect ions was 39% and 5%, respectively. Recent increased availability of pr aziquantel, combined with Egyptian Ministry of Health-sponsored media efforts to educate the public about schistosomiasis, prompted us to de termine the current status of S. mansoni and S. haematobium infections in the delta and evaluate any changes that may have occurred since th e previous survey. The same villages that participated in the 1983 sur vey were resampled in 1990. Stool and urine samples were requested fro m all occupants over the age of two years in a 5% sample of houses wit hin each village. Stool (Kato) thick smears and urine sediments were r ead qualitatively at the rural health station. Field-prepared Kato sme ars and a 20% sample of urine specimens were forwarded to the Ministry of Health Laboratory, where quantitative readings were also performed . Analysis of samples obtained from 17,310 persons revealed that S. ma nsoni prevalence had decreased to 23% and that S. haematobium prevalen ce had decreased to 3% (P < 0.001). The highest levels of schistosome infection were found in governates located in the eastern section of t he delta. The observed changes in the prevalence of S. mansoni and S. haematobium suggest that control measures are having a favorable impac t on schistosomiasis transmission in this region.