No Evidence of SARS-CoV-2 Infection in Urban Wildlife of Hokkaido, Japan

Various domestic and wildlife species have been found susceptible to and infected with SARS-CoV-2, the causative agent of COVID-19, around the globe, raising concerns about virus adaptation and transmission to new animal hosts. The virus circulation in the white-tailed deer population in North America has further called to action for virus surveillance in the wildlife. Here, we report on the first SARS-CoV-2 survey of wild animals in Japan, where frequent wildlife invasions of urban areas have occurred due to the limited predation, field abandonment, the increase of human acclimatization. Genetic testing using nasal swabs and serological screening have been conducted for sika deer, brown bears, raccoons, and raccoon dogs captured in Hokkaido prefecture from the end of the Delta variant wave to the spread of the Omicron variant, between March 2022 and February 2023. No viral RNA was detected in raccoons (0/184), sika deer (0/107), and brown bears (0/14) indicating that the virus was unlikely to spread within the population of these animal species. Among 171 raccoons, 20 raccoon dogs, 100 sika deer, and 13 brown bears, one raccoon, one brown bear, and two deer tested positive in the antibodies screening with multispecies SARS-CoV-2 N-protein ELISA. Still, ELISA-positive samples tested negative in three other serological tests, emphasizing the importance of confirming serological screening results. Our results suggested that SARS-CoV-2 was unlikely to spillback from humans to wildlife in Hokkaido during the study period, with the emergence of new variants, continuous surveillance is of utmost importance.