Prevalence and Determinants of Gastrointestinal Parasites in Rodents: A Cross-sectional Study in Tanga City, Tanzania

Background: Rodents are important reservoirs and amplifiers of zoonotic pathogens, often harboring gastrointestinal (GI) parasites asymptomatically, posing significant public health risks, particularly in tropical urban settings. This study aimed to determine the prevalence, diversity, and risk factors associated with zoonotic GI parasites in rodents in Tanga City, Tanzania. Methods: A cross-sectional study was conducted from March to June 2025, during which 356 rodents were systematically live-trapped from five purposively selected villages across peri-domestic and indoor habitats. Gastrointestinal tracts were examined for parasites using formalin-ethyl acetate concentration and simple flotation techniques. Multivariable logistic regression was used to identify determinants of infection. Results: Overall, 84.8% (302/356) of rodents were infected with GI parasites. Helminths were predominant (81.7%, 291/356), with Hymenolepis spp. (45.2%) and Strongyloides spp. (40.4%) most common. Protozoa were detected in 23.6% (84/356), mainly Eimeria spp. (22.2%). Logistic regression revealed that rodents from indoor habitats had 0.34 times the odds of infection compared to peri-domestic rodents (OR = 0.34; 95% CI: 0.17–0.67; p < 0.001), and female rodents had 1.47 times higher odds than males (OR = 1.47; 95% CI: 0.88–2.45; p = 0.14), though the latter was not statistically significant. Conclusion: Indoor environments are hotspots for zoonotic GI parasite transmission in Tanga City. Integrated One Health interventions, including improved environmental sanitation, sustainable rodent management, and community education, are important to reduce the risk of zoonotic spillover.