Prevalence, intensity, and associated factors of soil-transmitted helminth and schistosome infections after multiple rounds of preventive chemotherapy among schoolchildren in five selected district councils in Tanzania

Background

Schistosomiasis and soil-transmitted helminthiasis (STH) are widespread in Tanzania mainland, affecting all 184 districts. The Ministry of Health, through the National Neglected Tropical Diseases Control Program (NTDCP) has addressed these parasitic infections by administering annual preventive chemotherapy (PC) with praziquantel for schistosomiasis and albendazole for STH. This study aimed to assess the prevalence, infection intensity, and associated factors of schistosomiasis and STH among school-aged children (SAC) in five selected district councils of Tanzania after a minimum of five rounds of PC.

Methodology/Findings

A cross-sectional survey was carried out in five district/town councils; Iringa District Council (DC), Nanyamba Town Council (TC), Ruangwa DC, Tanganyika DC, and Kalambo DC. We randomly selected 15 wards within each DC/TC and then chose one primary school from each ward, totaling 15 schools per district. From each school 30 children (15 boys and 15 girls) aged 10–14 years were sampled, totaling 2250 participants. Urine samples were analyzed using filtration methods to detect schistosomiasis, while stool samples were examined using the Kato-Katz method. Demographic, and water, sanitation and hygiene (WASH) data were also collected through standardized questionnaires. The prevalence of any STH infection varied across the councils, with the lowest prevalence in Iringa DC (0.7%) and highest prevalence in Tanganyika DC (7.1%). For schistosomiasis, the overall prevalence of any schistosome infection was 9.3%. Nanyamba TC reported the highest prevalence at 21.8%, while Iringa DC recorded the lowest at 2.0%.

Conclusion

The study indicates that STH prevalence remains relatively low (< 10%) in the majority of surveyed districts, however four out of five surveyed districts require distribution of PC once per two years for five years. For schistosomiasis, all district had at least one ward that require annual distribution of PC for the entire population (aged ≥2 years) for 5 years.