Molecular detection and genotyping of Enterocytozoon bieneusi in family pet dogs obtained from different routes in Japan.

The present study determined the prevalence of Enterocytozoon (E.) bieneusi infection and genotyped the isolates in family pet dogs obtained from three different routes in Japan. Fresh fecal samples were collected from 597 family pet dogs. A nested polymerase chain reaction (PCR) assay targeting the internal transcribed spacer (ITS) region of ribosomal DNA was employed for detection of E. bieneusi, and the obtained positive PCR amplicons were sequenced for genotyping. The overall prevalence of E. bieneusi in family pet dogs was 4.4%. Significant differences in prevalence were found among the categories of age (<1 year: 8.3% vs. ≥1 year: 3.4%), obtained route (from private owner: 3.2% vs. from pet shop: 3.9% vs. from breeding kennel: 14.3%), and living regions (ranged 0-10.3%). However, no significant differences were observed in the prevalence of living condition (indoor: 4.6% vs. outdoor: 2.0%), and fecal condition (formed: 4.5% vs. soft: 4.7% vs. diarrhea: 0%). Of the 26 sequenced samples, all were identified as genotype PtEb IX, which belongs to the dog-specific genotype. In conclusion, although E. bieneusi infections are relatively common in family pet dogs in Japan, the risk of zoonotic transmission from dogs to humans is likely to be low.