Molecular evidence of host range expansion of Enterocytozoon bieneusi in captive wildlife at Beijing Zoo, China

Enterocytozoon bieneusi has become a significant public health concern due to its ability to infect both humans and animals on a global scale. However, there is a paucity of epidemiological data regarding this pathogen in captive wildlife. In this study, 445 fecal samples were collected from captive animals at Beijing Zoo and analyzed using PCR targeting the internal transcribed spacer (ITS) of the nuclear ribosomal DNA of E. bieneusi. The overall prevalence was determined to be 7.0 % (31/445), with infection rates of 7.1 % (23/322) in mammals and 6.5 % (8/123) in Aves. Genotypic characterization 12 distinct genotypes, including 11 known genotypes belonging to Groups 1 (EbpA, PigEBITS7, D, HND-1, SC02, CM16, MJ13), 2 (BEB6), 7 (CM 4), and 13 (CHB1, CHK1), along with one novel genotype (BJZ-1) in Group 1. The detection of zoonotic genotypes from Groups 1 and 2 underscores the potential for cross-species transmission between captive wildlife and humans. Notably, this study presents the first molecular identification of E. bieneusi in caracals, polar bears, giant anteaters, and grey herons, thereby significantly expanding the known host range of this pathogen. These findings emphasise the necessity of implementing One Health surveillance strategies to monitor and mitigate zoonotic risks at the human-animal interface.