Likely circulation of a coronavirus in roe deer ( Capreolus capreolus ) populations suggested by SARS-CoV-2 serological investigation in France

The risk of viral transmissions from domestic and wild animals to humans is of high concern for human health. Humans can also transmit viral infections back to domestic and wild animals, which can then act as reservoir for the maintenance of viruses, with the risk of epidemic diseases re-emergence. The Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), causing the COVID-19, likely originated from wildlife and has already been evidenced to be transmitted from humans to captive, domestic and wild animals. In particular, white-tailed deer ( Odocoileus virginianus ) show high-prevalence of SARS-CoV-2 following human contamination, and recent data suggest that white-tailed deer could act as an emerging virus reservoir. Here, we investigated whether SARS-CoV-2 could also have emerged in several longitudinally-monitored populations of European roe deer ( Capreolus capreolus ) in direct contact with humans in France. We performed indirect tests (serological ELISAs and seroneutralization) on serum collected pre- and post-emergence of the virus in human populations. We also performed direct tests (nasal swabs followed by RT-PCR) to detect the presence of SARS-CoV-2 RNA in those populations in 2022. We also investigated the exposure and prevalence of the virus in three other cervid species in France. ELISA tests were positive for 2.20 % of the sera tested, both pre- and post-emergence of the virus, but all positive samples were negative with seroneutralization. Direct PCR testing showed no positive results in 2022. Thus, although seroprevalence increased after the COVID-19 emergence (2022) in one out of three roe deer population, our results suggest that SARS-CoV-2 has not emerged in those populations, and that ELISA cross-reaction with another circulating virus, possibly an unidentified bovine coronavirus, is possible.