Schistosomiasis prevalence after administration of praziquantel to school children in Melela village, Morogoro region, Tanzania.

A study of the prevalence of schistosomiasis was carried out in 253 school children in Melela, Tanzania, one year after a single dose of praziquantel, 40 mg/kg body weight. The cure rate was 90.4%. However the new incidence estimate was 21.2% in children who were initially negative. The use of reagent strips in urine tests for the detection of urinary schistosomiasis was also evaluated. The presence of blood in the urine was highly sensitive (> 96%) and specific (87%). The sensitivity of proteinuria was less, but it was highly specific (94%). This study shows that chemotherapy will have to be combined with other measures to achieve lasting benefits and raises the question as to how often the population should be treated. It also confirms the value of urine test strips as an indirect diagnostic test for urinary schistosomiasis in an endemic area. Further follow-up is necessary to make useful predictions concerning incidence and reinfection rates in the community. This will also help in deciding how often chemotherapy should be given to the population.