Gastrointestinal Helminth Infections in Captive Wild Animals of Bangladesh: Implications for Zoo Health Management and Zoonotic Risk.

Gastrointestinal helminth (GIH) infections remain a significant but undercharacterized threat to captive wildlife health and may contribute to zoonotic transmission at the human-animal interface, particularly in Bangladesh, where zoological facilities are located near densely populated urban centers. This study investigated the prevalence, diversity, and host distribution of GIHs among captive wild animals in two major facilities-the Bangladesh National Zoo and Tilagarh Eco Park, Sylhet-between May and December 2023. In a cross-sectional design, 80 fecal samples from mammals, birds, and reptiles were analyzed using a modified formalin-ether sedimentation technique, and parasites were identified based on morphological criteria. Overall, 51.25% (41/80) of animals were infected with at least one helminth species. Five helminth taxa were detected, including members of Ascarididae and Capillarinae with known zoonotic relevance. Infection prevalence varied by host group, with the highest burden observed in reptiles (100%), followed by herbivorous mammals, whereas carnivorous and omnivorous mammals had lower prevalence (16.67%). Mixed infections occurred in 27.78% of infected animals. The low occurrence of trematodes and cestodes likely reflects the limited availability of intermediate hosts under captive conditions. Despite the absence of overt clinical signs, the high prevalence suggests substantial subclinical infection that may compromise animal welfare and increase zoonotic risk. These findings highlight critical gaps in parasitological surveillance and management in captive wildlife systems and underscore the need for integrated One Health approaches, including routine monitoring, improved husbandry, and targeted parasite control strategies to mitigate infection risks at the human-animal interface.