SARS-CoV-2 exposure in deer increases with use of human-modified habitat

Abstract

Deer can transmit severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) to humans and harbour human-extinct variants. Despite this public health threat, ecological mechanisms driving exposure patterns in deer populations remain poorly understood. Our objective was to identify behavioural risk factors by linking serostatus of individual deer to their movement and space use using multilevel logistic regression. We examined serosurveillance data of white-tailed (Odocoileus virginianus) and mule deer (O. hemionus) wearing global positioning system devices across an urban-rural gradient in the United States (1151 individuals, 20 sites, 8 states). Seropositivity was positively associated with average human footprint index and negatively associated with average SARS-CoV-2 human wastewater concentration. Seropositivity was not associated with time spent in GAP-modelled deer habitat. Together, these findings provide evidence that human-to-deer transmission could be a primary source of deer SARS-CoV-2 exposure and deer populations may struggle to maintain transmission without repeated spillover from humans. Integrating human and environmental indices with movement behaviours and space use can thus clarify pathways that facilitate cross-species transmission in wildlife.