Urban schistosomiasis and soil transmitted helminthiases in young school children in Dar es Salaam and Tanga, Tanzania, after a decade of anthelminthic intervention

Rapid urbanization in resource poor countries often results in expansion of unplanned settlements with overcrowding and inadequate sanitation. These conditions potentially support transmission of schistosomiasis and soil transmitted helminths (STH), but knowledge on the occurrence, transmission and control of these infections in urban settings is limited. The present study assessed the status of urinary schistosomiasis and STH across two different-sized cities in Tanzania - Dar es Salaam and Tanga - after a decade of anthelminthic intervention. Primary school children were examined for parasite eggs in urine and stool. Questionnaires were administered to the children, and observations were made on the urban environments. The burden of urinary schistosomiasis and STH was found to be low in both cities (overall 1.2% in Dar es Salaam and 0.3% in Tanga for urinary schistosomiasis; overall <1% in Dar es Salaam and 1-2% in Tanga for each STH infection), and the identified cases showed no clear pattern of spatial distribution. The findings indicated that a marked decrease in prevalence of these infections had occurred in the two cities during recent years. The observed promising developments appeared to have been accomplished by implementation of drug based intervention programs, in combination with environmental change (fewer snail habitats) and generally improved levels of hygiene. Continued efforts, including anthelminthic treatment and health education, are important to maintain these positive achievements.