Prevalence of Schistosomiasis and Soil-Transmitted Helminthiasis and Their Risk Factors: A Cross-Sectional Study in Itilima District, North-Western Tanzania

Schistosomiasis and soil-transmitted helminthiasis remain a public health concern in Tanzania. This study investigated the prevalence and intensities of Schistosoma haematobium, S. mansoni, and soil-transmitted helminths and associated factors in Itilima district, north-western Tanzania. A cross-sectional survey was conducted between August and September 2020 among 3779 primary schoolchildren in 62 primary schools and 1122 adults in 19 villages. Urine samples were obtained from each participant and examined visually for the presence of macrohaematuria, microhaematuria, and S. haematobium eggs using a urine dipstick and urine filtration test. A single stool sample was obtained from each participant and screened for S. mansoni and soil-transmitted helminths using the Kato Katz and formalin-ether concentration techniques. A questionnaire was administered to schoolchildren to elucidate the risk factors for schistosomiasis. The overall prevalence of S. haematobium in adults was 8.1% (95% confidence interval (CI), 6.6-9.8%). In total, 3779 schoolchildren had complete results from urine testing, and the overall prevalence of S. haematobium was 10.1% (95% CI, 9.1-11.1%). The prevalence of S. mansoni and soil-transmitted helminths was relatively low among both children and adults compared to S. haematobium. Factors associated with S. haematobium infection among schoolchildren were the mother's occupation, children aged 11-15 years, and water contact behaviour. The odds of having schistosomiasis infection among children aged 11-15 are 40% higher than those aged 5-10 (95% confidence interval (CI), 10-80%, p = 0.04). Children of parents who are livestock keepers have 12.3 times higher odds of having infection compared to those who have small-scale businesses (95% CI, 1.0-5.4, p = 0.03). Children who are in contact with infested water more than three times a week have 2.1 times higher odds of having an infection compared to those who do not (95% CI, 2.1; 1.6-2.8, p < 0.001). The findings provide updated geographical information on prevalence, yielding insights into the planning and implementation of mass drug administration in rural Tanzania.