Efficacy of metrifonate in a highly endemic area of urinary schistosomiasis in Kenya.

In a community in Kwale district, Kenya, selective mass chemotherapy with metrifonate caused a marked reduction in the intensity of Schistosoma haematobium infection from 46.5 to 9.4 eggs/hr and a sharp fall in prevalence of gross hematuria from 18.3% to 5.1%, although overall prevalence was reduced only slightly from 67.4% to 54%. The effect of metrifonate on cure rate and reduction of infection intensity was limited by both age and pretreatment infection intensity. Rate of improvement from gross hematuria was similar in all ages and in all classes of intensity of infection. Two doses of metrifonate reduced the prevalence of gross hematuria as much as 3 doses did, while the effect of a single dose on morbidity remains to be clarified.