Abstract
Background: Enterocytozoon bieneusi (E. bieneusi) can infect a broad range of animals, and also the major pathogen for human microsporidiosis. The risk of zoonosis is uncertain because of limited research on red pandas. In addition, the semi-free range breeding enables the red panda direct contact with tourists. It is essential to investigate the prevalence and genotypes and to evaluate the safety of this breeding mode. Methods: Based on nested PCR, 198 fecal specimens were sampled from 6 zoos in Sichuan province from July 2020 to December 2020, to identify positive samples by amplifying the internal transcribed spacer (ITS) region of ribosomal RNA with specific primers. The correlation analysis of infection rate was carried out between different breeding modes (captive and semi-free-range). To cluster the identified genotypes with related genotypes to deduce zoonotically potential by phylogenetic analysis. In addition, Multilocus genotypes (MLGs) in ITS-positive samples were performed using the Multilocus Sequence Typing (MLST) tool.Results: The Polymerase Chain Reaction (PCR) results showed that 12.1% (24/198) samples were positive for E.bieneusi. The infection rates varied from 0% to 18.0% in different zoos and were significantly different in different breeding methods (χ2=5.442, P=0.0197). Genotypes D, SC02, and SCR1(novel) were clustered in zoonotic group 1, while genotype PL2 is clustered in group 2-like with uncertain risk by phylogenetic analysis. Furthermore, 3 distinct multilocus genotyping were formed in ITS-positive isolates.Conclusions: These results revealed the circulating of E. bieneusi in zoo red pandas, indicating that red pandas may be a source of human microsporidiosis and that semi-free range breeding mode as a risk factor increased the E. bieneusi infection rate and potential cross-species transmission.