ABSTRACT
Wildlife reservoirs of SARS-CoV-2 may enable viral adaptation and spillback from animals to humans. In North America, there is evidence of unsustained spillover of SARS-CoV-2 from humans to white-tailed deer (Odocoileus virginianus), but no evidence of transmission from deer to humans. Through a biosurveillance program in Ontario, Canada we identified a new and highly divergent lineage of SARS-CoV-2 in white-tailed deer. This lineage is the most divergent SARS-CoV-2 lineage identified to date, with 76 consensus mutations (including 37 previously associated with non-human animal hosts) and signatures of considerable evolution and transmission within wildlife. Phylogenetic analysis also revealed an epidemiologically linked human case. Together, our findings represent the first clear evidence of sustained evolution of SARS-CoV-2 in white-tailed deer and of deer-to-human transmission.
ABSTRACT
White-tailed deer are susceptible to SARS-CoV-2 and represent a relevant species for surveillance. We investigated SARS-CoV-2 infection in white-tailed deer in Quebec, Canada. In November 2021, 251 nasal swabs and 104 retropharyngeal lymph nodes from 258 deer were analyzed for SARS-CoV-2 RNA, whole genome sequencing and virus isolation and 251 thoracic cavity fluid samples were tested for neutralizing antibodies. We detected SARS-CoV-2 RNA in three nasal swabs from the Estrie region and virus was isolated from two samples; evidence of past exposure was detected among deer from the same region. Viral sequences were assigned to lineage AY.44, a sublineage of B.1.617.2. All deer sequences clustered with human GISAID sequences collected in October 2021 from Vermont USA, which borders the Estrie region. Mutations in the S-gene and a deletion in ORF8 encoding a truncated protein were detected. These findings underscore the importance of ongoing surveillance of key wildlife species for SARS-CoV-2.
