Enterocytozoon is a genus of microsporidian parasites, with Enterocytozoon bieneusi being a well-known species. It infects various mammalian hosts, including humans, and exhibits zoonotic potential. Out of the 97 fecal and intestinal samples collected from wild raccoon dogs in Korea, 12 (12.4%) tested positive for E. bieneusi via PCR, revealing 2 genotypes: genotype D and EbpA. Both genotypes were found to belong to the zoonotic Group 1. Notably, this study is the first to report the EbpA genotype in Korea. Although studies on E. bieneusi in raccoon dogs are relatively limited, the findings suggest potential public health concerns.

Enterocytozoon bieneusi is an opportunistic microsporidian parasite with zoonotic potential that causes gastrointestinal illness in humans and animals. This study aimed to investigate the presence and genetic diversity of E. bieneusi from cats in Korea and to assess the potential public health risks associated with zoonotic genotypes. Among the 137 feline fecal samples, 4 (2.9%) were PCR-positive for E. bieneusi. In addition, 2 E. bieneusi genotypes were identified: Type IV, a known zoonotic genotype belonging to Group 1, and KCAT1, a novel genotype with zoonotic potential belonging to Group 1. This study is the first to report on these genotypes from cats in Korea, most of which were companion cats visiting veterinary clinics. Despite the low detection rate, the presence of zoonotic genotypes in companion cats is a potential public health concern because of the close physical interaction between cats and their human caregivers. These findings indicate the importance of routine monitoring and the molecular characterization of E. bieneusi in companion animals to comprehensively understand their zoonotic transmission patterns and to guide future risk assessments and preventive strategies.