Prevalence and genotypes of Enterocytozoon bieneusi in wildlife in Korea: A public health concern

Background: Enterocytozoon bieneusi is a unicellular microsporidian fungal pathogen that infects a broad range of animal hosts, including wild and domestic animals and humans. The infection burden of this parasite in wild animals in Korea is largely unknown. In this study, the occurrence and genotypes of E. bieneusi were investigated in wild animal populations in Korea. Methods: A total of 157 fecal samples (97 from Korean water deer, 48 from raccoon dogs and 12 from other taxa) were collected from wild animals at five wildlife centers in Korea. Genomic DNA was extracted from the samples and screened by nested-PCR targeting the internal transcribed spacer (ITS) region of rRNA, followed by sequence analysis to determine the genotype(s) of E. bieneusi. Results: The overall prevalence of E. bieneusi was 45.2% (71/157), with rates of 53.6% (52/97) in Korean water deer, 35.4% (17/48) in raccoon dogs and 16.7% (2/12) in other taxa. We detected seven ITS genotypes, including one known (genotype D) and six new genotypes (Korea-WL1-Korea-WL6). Phylogenetically, all detected genotypes clustered with counterparts belonging to group 1, which includes isolates from different animal hosts and humans, suggesting their zoonotic potential. Conclusions: Our survey results indicate that E. bieneusi circulates widely in wild animals in Korea. These findings address the role of wildlife as a potential source of microsporidiosis in domestic animals and humans.