Prevalence and Diversity of Helminth Parasites in Tilapia (Oreochromis niloticus) from Sewage Ponds in Kano, Nigeria

Background and Objective: Helminth infections in aquaculture species pose significant threats to fish health, productivity, and food safety. However, data on the prevalence and species composition of helminths infecting Tilapia (Oreochromis niloticus) in sewage-fed ponds of Kano State, Nigeria, remain limited. This study aimed to determine the prevalence, species diversity, and site-specific distribution of helminth parasites in O. niloticus from two sewage ponds. Materials and Methods: A total of 385 O. niloticus were randomly sampled between January, 2024 and March, 2025 from Bayan Gari Pond (Pond A, n = 257) and Kukkuba Pond (Pond B, n = 128). Fish were examined using standard parasitological techniques to recover helminths from the gastrointestinal tract and gills. Parasites were morphologically identified using established taxonomic keys. Statistical analysis was conducted using Chi-square tests to determine differences in prevalence between ponds, with significance set at p<0.05. Results: The overall prevalence of helminth infection was 31.43%, with a significantly higher prevalence in Pond A (35.4%) compared to Pond B (23.44%) (χ² = 5.62, p<0.05). Three helminth species were identified: Clinostomum spp., Euclinostomum sp., and Polyonchobothrium polyepiteri. Trematodes accounted for the majority of infections (84.8%), affecting both gill and intestinal tissues, while the cestode P. polyepiteri was restricted to the intestines. Conclusion: This study demonstrates that sewage-fed ponds serve as important reservoirs for helminth parasites in O. niloticus, posing risks to public health and aquaculture productivity. Findings highlight the need for improved pond management and monitoring strategies to mitigate parasite transmission from contaminated habitats.