V. Evaluation of Cross-Immunity against Type 1 Dengue Fever in Human Subjects Convalescent from Subclinical Natural Japanese Encephalitis Virus Infection and Vaccinated with 17D Strain Yellow Fever Vaccine
A large scale mollusciciding and chemotherapy program in the Fayoum area of Egypt was reported to have decreased prevalence of schistosomiasis haematobia from 46% to 7% in approximately 12 years. In order to assess the uniformity of results reported, we have studied the prevalence and intensity of urinary tract disease in a random sample of children aged 6 months–12 years in 3 areas selected on the basis of distance from the main canal supplying Fayoum and where mollusciciding was applied. Only 1 location near the main canal showed low prevalence (2.2%), while in the other 2 areas prevalence was 75.3% and 61.3%. Intensity of infection and disease were significantly more in the latter 2 locations. Following chemotherapy, a marked reduction in prevalence and intensity of infection and reversal of pathology was seen. Since the reported favorable results of the Fayoum project were used to implement a wider control program in southern Egypt, an independent assessment must be included in future plans.