How Is COVID-19 Evolving in Deer Due to Human Contact?

The coronavirus that causes COVID-19 in humans has been detected in wild white-tailed deer in several US states and Canadian provinces, raising concerns about the potential impact of this cross-species transmission on the pandemic. Scientists are trying to understand how the virus gets into deer, how it spreads among them, and what risks it poses for other animals and humans.

According to a study by the US Department of Agriculture’s Animal and Plant Health Inspection Service, people spread the virus to deer more than 100 times in late 2021 and early 2022, based on genetic analysis of viral samples. The study also found evidence of human-to-deer and deer-to-human transmission in at least four states, suggesting that the virus can move back and forth between the two species.

The study also revealed that the virus has been evolving in deer, acquiring mutations that alter its spike protein, which is the key that allows it to enter cells. Some of these mutations have been seen before in human variants, such as Alpha, Delta and Omicron, but others are novel and have not been reported in any other host. The researchers warn that these changes could affect the virus’s transmissibility, virulence and immune evasion.

The implications of these findings are not yet clear, but they raise the possibility that deer could become a reservoir for the virus, meaning that they could harbor it for a long time and potentially transmit it to other animals or humans. This could pose a challenge for controlling the pandemic and preventing new variants from emerging.

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However, experts say that there is no need to panic, as there is no evidence that deer are driving the pandemic or causing severe disease in humans. They also point out that the virus is still primarily spreading among humans, who are its preferred hosts and where it is most likely to mutate. Therefore, the best way to prevent further spillover events and reduce the risk of new variants is to vaccinate as many people as possible and follow public health measures.

In addition, scientists are monitoring the situation closely and conducting more surveillance of wildlife to track the spread and evolution of the virus in different species. They are also studying how the virus affects deer health and behavior, and whether it can infect other animals that interact with deer, such as predators, scavengers or livestock. By understanding how the virus adapts to different hosts, they hope to gain insights into its biology and ecology, and inform strategies to prevent future outbreaks.