Long-term suppression of adult bladder morbidity and severe hydronephrosisfollowing selective population chemotherapy for Schistosoma haematobium

Repeated selective population chemotherapy of school age children reduces i nfection and morbidity associated with Schistosoma haematobium infection. T o examine the long-term effect of this treatment on susceptibility to re-in fection and late disease, a cohort of Kenyans (n = 194) were re-examined fo r infection and urinary tract morbidity 7-13 years after they underwent ann ual ultrasonography and treatment for an average of 5 years beginning in 19 84 as children. Controls were previously untreated age-matched individuals residing in the same or adjacent villages. The overall prevalence and inten sity of infection were equivalent between the 2 groups. In contrast, the pr evalence of bladder wall pathology was 11-fold lower in previously treated (1.5%) versus untreated subjects (17%). Severe hydronephrosis was completel y reversed. These data demonstrate that treatment significantly reduced uri nary tract morbidity despite re-infection, and suggest that the important r isk factors for urinary tract morbidity in adulthood are cumulative intensi ty and duration of infection during early adolescence.