Epidemiological Survey of Human Zoonotic Fascioliasis and Schistosomiasis in the Lake Victoria and Southern Highland Ecological Zones of Tanzania

Background: Zoonotic fascioliasis and schistosomiasis, caused by trematode parasites transmitted by freshwater snails, are neglected tropical diseases with medical and veterinary importance. There are currently knowledge gaps regarding the transmission dynamics of these infections in humans and animals in endemic communities, especially on the African continent. Therefore, the current study aimed to determine the burden of human zoonotic schistosomiasis and fascioliasis among different age groups, focusing on the Lake Victoria and Southern highlands of Tanzania. Methods: A cross-sectional study was conducted among preschool, school-aged children, and adults. A total of 1557 stool and urine samples were collected, 400 from preschool children, 804 from school-aged children, and 353 from adults. Stool samples were processed using the Kato-Katz and the formol-ether concentration methods to examine Schistosoma mansoni (S. mansoni) and Fasciola, respectively. Urine samples were processed using the urine filtration method to examine for Schistosoma haematobium (S. haematobium) infection. While the data analysis was done using Stata V 17, t-test or One-way ANOVA was used to assess the statistical differences in mean egg counts of S. mansoni and S. haematobium exposure groups. Results: The overall prevalence of S. haematobium was 4.9% (95% CI: 0.4–6.1%), S. mansoni was 1.2% (95% CI: 0.7–1.9%) with no age difference but with a significant difference among sex groups 1.8% [ꭓ2(1) =4.47, P =0.034]. Males have a higher prevalence of S. haematobium and S. mansoni than females. The prevalence of Fasciola infection was 0.9% (95% CI: 0.4–1.5%), with the highest prevalence found in adults (≥18 years). Conclusions: Zoonotic schistosomiasis and fascioliasis are prevalent in the study area, affecting all age groups. However, this is the first study of its kind to report the presence of Fasciola infection in Lake Victoria and the Southern highlands of Tanzania. This calls for the Ministry of Health, through the Tanzania NTDs control program, to recognize and include them in the neglected tropical diseases control program as a disease of high priority.