ABSTRACT. From 2012 to 2021, prevalence of pathogenic Yersinia in wild rodents captured in Fukushima Prefecture, Japan was investigated twice a year to clarify the ecology of this pathogen in wild rodent populations. Pathogenic Yersinia enterocolitica O8 was isolated from 13 (1.7%) of 755 wild rodents. The Y. enterocolitica O8 isolates harbored three virulent genes (ail, fyuA, and
virF). This pathogen was isolated repeatedly from wild rodents in April 2015, 2016, and 2017,
in June and November 2020, and in April 2021, which was 6 of 19 times of observations. All
Y. enterocolitica O8 isolates showed the same PFGE patterns. These results indicated that the
same clone of pathogenic Y. enterocolitica O8 has been maintained in wild rodent populations
in Fukushima Prefecture. Therefore, wild rodent populations contribute substantially to the continuous transmission of Y. enterocolitica O8 and its persistence in the ecosystem. This is the first report on the isolation of pathogenic Y. enterocolitica O8 in wild rodents in Fukushima Prefecture, Japan.

KEY WORDS: ecology, epidemiology, prevalence, wild rodent, Yersinia enterocolitica O8