Prevalence and molecular characterization of enteric zoonotic pathogens in zoo-housed mammals in Korea

Zoos represent important One Health interfaces where captive wildlife, animal caretakers, visitors, and shared environments are closely connected. This study investigated intestinal parasites and selected zoonotic pathogens in zoo-housed mammals in Korea and characterized the detected enteric pathogens. A total of 367 individual fecal samples were collected from mammals in nine zoos between September and November 2025. Microscopic examination and molecular assays targeting Giardia intestinalis, Cryptosporidium spp., Enterocytozoon bieneusi, Toxoplasma gondii, Coxiella burnetii, Blastocystis sp., and severe fever with thrombocytopenia syndrome virus (SFTSV) were performed. The overall positivity rate was 6.0%. Microscopy detected coccidian oocysts, ascarid-type eggs, hookworm-like eggs, and trichostrongyle-type eggs. Molecular analysis identified E. bieneusi as the most frequently detected pathogen, followed by G. intestinalis and C. parvum, whereas T. gondii, C. burnetii, Blastocystis sp., and SFTSV were not detected. Phylogenetic analysis showed that G. intestinalis sequences clustered with assemblage B and C. parvum sequences clustered within the C. parvum clade. ITS sequence and phylogenetic analyses further identified E. bieneusi genotype Type IV within Group 1 and a distinct genotype provisionally designated SealKB1 within Group 11. To the best of our knowledge, this study provides the first molecular evidence of G. intestinalis in African crested porcupines and E. bieneusi in Eurasian lynxes and harbor seals in Korea. These findings provide baseline data for zoo-based pathogen surveillance and support continued One Health monitoring in zoological institutions.