Girmay Gebrezgi2025-06-172025-01-25https://repository.mu.edu.et/handle/123456789/53910.82589/muir-47110.82589/muir-471Trematode infections are a significant cause of disease and economic losses worldwide. However, limited research has been conducted in the South and Southeastern zones of Tigray, Ethiopia, regarding the local epidemiology, transmission dynamics, and management strategies. To address this gap, a cross-sectional study was conducted from December 2023 to December 2024 to investigate the prevalence of trematode infections in cattle and sheep and the spatial distribution of freshwater snails in these areas. Simple random sampling was used to select study animals, and descriptive statistics were computed using STATA version 16. In total, 1536 fecal samples (768 from cattle and 768 from sheep) were examined, alongside snail collection. Additionally, 13 laboratory-bred mice were exposed en masse to Schistosoma cercariae for confirmation of transmission. The study revealed that the majority (60.29%, 463/768) of cattle and 53.5% (411/768) of sheep had either single or multiple trematode infections. Among cattle, 19.01% were testing positive for fasciolosis, while 20.7% exhibited mixed infections of Fasciola and Paramphistomum species. In sheep, 21.74% were positive for fasciolosis and 18.23% for mixed infections. The South zone had the highest prevalence in both cattle and sheep. Furthermore, most of the positive rates were exhibited in adult cattle with poor body condition scores while in adult sheep with medium body condition scores. Logistic regression showed a significant association between zone and bovine fasciolosis (OR = 1.76; P = 0.000), but no significant association for ovine fasciolosis. A total of 1269 snails were collected, identified as Biomphalaria pfeifferi, Bulinus truncatus, and Lymnaea natalensis. Intermediate hosts for schistosomiasis collected during the survey were found to be shedding Schistosoma cercariae. Furthermore, en masse cercariae-exposed laboratory-bred mice confirm the active transmission of schistosomiasis in the study area. The study highlights the trematode infections and the heterogeneous distribution of snails in the study area are a significant health concern for cattle and sheep, underlining the need for targeted control measures to mitigate the public health and economic impacts in the regionenCattleCoprologicalSheep. SnailTigrayTrematodeThesis