Molecular characterization and new genotypes of Enterocytozoon bieneusi in pet chipmunks (Eutamias asiaticus) in Sichuan province, China

Background: Enterocytozoon bieneusi, the most commonly identified microsporidian species in humans, is also identified in livestock, birds, rodents, reptiles, companion animals, even wastewater. However, there is no information available on occurrence of E. bieneusi in pet chipmunks. The aim of the present study was to determine the genotypes, molecular characterization of E bieneusi in pet chipmunks, and assess the zoonotic potential. Results: A total of 279 fecal specimens were collected from chipmunks from seven pet shops and one breeding facility in Sichuan province, China. The prevalence for E bieneusi was 17.6% (49/279) based on nested PCR targeting the internal transcribed spacer (ITS) region. The prevalence of E bieneusi in chipmunks < 90 days of age was significantly higher than that in older chipmunks; however, differences among different sources and between genders were not significant. Eight genotypes of E bieneusi were identified, including four known genotypes (D, Nig7, CHG9, and CHY1) and four novel genotypes (SCC-1 to 4). Phylogenetic analysis classified these genotypes into four distinct groups as follows: genotypes D and CHG9 clustered into group 1 of zoonotic potential; genotypes Nig7 and CHY1 clustered into group 6 and a new group, respectively; the four novel genotypes (SCC-1 to 4) formed a separate group named group 10. Conclusions: To the best of our knowledge, this is the first study reporting the prevalence and genotypes of E. bieneusi in pet chipmunks in China. Genotypes D and Nig7, found in chipmunks in this study, have also been previously identified in humans, which suggests that chipmunks might play a role in the transmission of this pathogen to humans.