Possible exposure to unidentified coronaviruses in roe deer ( Capreolus capreolus ) populations suggested by SARS-CoV-2 serological investigation in France

Abstract The risk of viral transmissions from domestic/wild animals to humans is a major public health concern. Humans can also transmit viruses back to domestic and wild animals, acting as a reservoir for virus maintenance and a source of epidemic diseases re-emergence. The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), causing COVID-19, likely originated from wildlife and has been evidenced to transmit from humans to captive, domestic and wild animals. White-tailed deer (Odocoileus virginianus) show high SARS-CoV-2 prevalence following human contamination, suggesting they could act as an emerging virus reservoir. We completed recent research on European cervid species by investigating whether SARS-CoV-2 had emerged in longitudinally monitored European roe deer (Capreolus capreolus) populations in direct contact with humans in France. We performed indirect tests (serological enzyme-linked immunosorbent assays and seroneutralization) on sera collected before and after the virus emergence in humans, and direct reverse transcriptase polymerase chain reaction tests on nasal swabs collected in 2022. We also investigated the virus exposure and prevalence in three other cervid species. Enzyme-linked immunosorbent assay tests were positive for 2.20% of sera, pre- and post-pandemic, but seroneutralization and polymerase chain reaction tests were negative. Although one population showed increased seroprevalence post-2020, results suggest that SARS-CoV-2 has not emerged in those populations and that enzyme-linked immunosorbent assay cross-reaction with one or several unidentified circulating coronaviruses is possible.