Cross-sector collaboration reduces SARS-CoV-2 risk in deer (preprint)

One Health helps achieve optimal health outcomes for people, animals, plants, and their shared environments. We describe a multidisciplinary effort to better understand and mitigate SARS-CoV-2 spread in white-tailed deer across One Health sectors. We first framed the risk problem with three governance sectors that manage captive and wild deer and human public health. The framing included the objectives for each sector, interactions that facilitate human-to-deer and deer-to-deer transmission, and alternatives intended to reduce risk. We then developed a dynamic compartmental model that linked wild and captive deer herds and humans and simulated SARS-CoV-2 dynamics. For baseline conditions, we estimated that median SARS-CoV-2 prevalence in wild and captive herds varied between 0.03-0.07, incidence between 0.68-1.46, and probability of persistence between 0.64-0.97 across 120-day simulations. We then tested single-sector alternatives alone and in combination with other sector actions. We found that single sector alternatives varied in their ability to reduce transmission and that the best performing alternative required collaborative actions among wildlife management, agricultural management, and public health agencies.

Epidemiological modeling of SARS-CoV-2 in white-tailed deer (Odocoileus virginianus) reveals conditions for introduction and widespread transmission (preprint)

Emerging infectious diseases with zoonotic potential often have complex socioecological dynamics and limited ecological data, requiring integration of epidemiological modeling with surveillance. Although our understanding of SARS-CoV-2 has advanced considerably since its detection in late 2019, the factors influencing its introduction and transmission in wildlife hosts, particularly white-tailed deer (Odocoileus virginianus), remain poorly understood. We use a Susceptible-Infected-Recovered-Susceptible epidemiological model to investigate the spillover risk and transmission dynamics of SARS-CoV-2 in wild and captive white-tailed deer populations across various simulated scenarios. We found that captive scenarios pose a higher risk of SARS-CoV-2 introduction from humans into deer herds and subsequent transmission among deer, compared to wild herds. However, even in wild herds, the transmission risk is often substantial enough to sustain infections. Furthermore, we demonstrate that the strength of introduction from humans influences outbreak characteristics only to a certain extent. Transmission among deer was frequently sufficient for widespread outbreaks in deer populations, regardless of the initial level of introduction. We also explore the potential for fence line interactions between captive and wild deer to elevate outbreak metrics in wild herds that have the lowest risk of introduction and sustained transmission. Our results indicate that SARS-CoV-2 could be introduced and maintained in deer herds across a range of circumstances based on testing a range of introduction and transmission risks in various captive and wild scenarios. Our approach and findings will aid One Health strategies that mitigate persistent SARS-CoV-2 outbreaks in white-tailed deer populations and potential spillback to humans.