Gastrointestinal parasitic infections and anthelmintic effectiveness in captive animals: A study at Chattogram zoo, Bangladesh

Objective: Gastrointestinal (GI) parasitic infections are a common health issue among captive wildlife and can compromise animal welfare and management in zoological settings. This study aimed to assess the overall prevalence of GI parasites and evaluate the effectiveness of anthelmintic treatments in different animal groups at Chattogram Zoo, Bangladesh. Materials and Methods: A total of 45 fecal samples were collected from various species and subjected to both qualitative (direct smear and flotation) and quantitative (McMaster technique) coproscopy at 6-week intervals. Parasite egg counts [egg per gram (EPG)] were recorded before and after treatment. Three anthelmintics—triclabendazole (25%), levamisole (37.5%), and fenbendazole (37.5%)—were used based on the species and severity of infection. Results: GI parasite infections were detected across various captive animal species, with the highest egg counts observed in Barking Deer (Paramphistomum spp., 1,800 EPG) and monkeys (Oesophagostomum spp., 1,650–1,800 EPG). Other species, including foxes, lions, hippopotamus muses, emus, turkeys, and ostriches, exhibited low EPGs (100–200). Following anthelmintic treatment, parasite loads in llamas decreased significantly (p < 0.05). At the same time, nematodes persisted in Barking Deer (100 EPG) and trematodes in wild beasts (180 EPG) and Sambar Deer (150 EPG), indicating species-specific variation in drug response. Conclusion: The findings highlight a significant burden of GI parasitism among zoo animals, particularly among avian species. Regular parasitological surveillance and strategic anthelmintic administration are crucial for controlling infections and enhancing animal health in zoological institutions.