Prevalence and Infection Intensity of Soil-Transmitted Helminths and Schistosomiasis Among Preschool Children in Mainland Tanzania.

Soil-transmitted helminths (STHs) and schistosomiasis (SCH) are significant public health concerns in Tanzania, known to impair cognitive and physical development in young children. To effectively guide control programs, a comprehensive understanding of their current prevalence and intensity is essential. This cross-sectional study was aimed at determining the prevalence and intensity of STH and SCH infections and associated anemia among preschool children aged 12-59 months across seven agroecological zones in Tanzania. A total of 1612 children were examined using the Kato-Katz technique for Schistosoma mansoni and STH eggs, urine filtration for Schistosoma haematobium eggs, and the HemoCue photometer for anemia. Statistical associations were assessed using chi-square tests (p < 0.05). The prevalence of any STH infection was 4.82% (95% CI: 3.84-6.02), with hookworm being the most prevalent (3.56%; 95% CI: 2.63-4.55), followed by Ascaris lumbricoides (1.19%; 95% CI: 0.65-1.79) and Trichuris trichiura (0.07%; 95% CI: 0.01-0.37). The overall SCH prevalence was 0.90%, and 34.06% of children were anemic (95% CI: 31.78-36.41). All STH infections were of mild intensity, and among SCH cases, infection intensity was predominantly light, with only one child exhibiting a heavy S. mansoni infection. Children residing in rural areas exhibited a 2.57-fold higher likelihood of helminth infection compared to urban children (p < 0.001). While 85.2% of parents reported knowledge of helminthiasis, only 57.57% reported a history of deworming. The observed low prevalence of STH and SCH suggests a potential positive impact of the national deworming program. However, ongoing surveillance and regular evaluations are crucial to monitor program effectiveness, address persistent anemia, and optimize intervention strategies.