A third of US deer have had COVID—and they infected humans at least 3 times

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Findings come from a study funded by the National Science Foundation and led by researchers at the University of California, Davis. The researchers collected blood samples from 385 deer across four US states, and found that 33% of the animals had antibodies against SARS-CoV-2, the virus that causes COVID-19.

The study also found evidence of virus transmission between deer and humans. At least three cases were identified where deer appear to have transmitted the virus back to people, including one instance where a deer hunter showed symptoms of COVID-19 after handling a deer carcass.

While the study suggests that the virus can be transmitted from people to deer, it is not yet clear how common this type of transmission is. The researchers note that more research is needed to better understand the risks of virus transmission between humans and wildlife.

The study’s lead author, Nohra Mateus-Pinilla, said that the findings highlight the importance of better understanding the role of wildlife in the ongoing pandemic.

“Wildlife can act as reservoirs for human disease,” she said in a statement. “It’s important to understand that we are part of a larger ecosystem and that we need to be aware of the potential risks of spreading pathogens among wildlife and humans.”

The study’s findings are published in the journal Scientific Reports.

The USDA study involved testing over 6,000 wild and captive white-tailed deer from across several US states between January and March 2021. The researchers found that 40% of the wild deer and 33% of the captive deer had antibodies against SARS-CoV-2, indicating prior infection.

The study indicates that the virus could be easily transmitted among wild deer populations and also raises concerns about the potential for deer to serve as a reservoir for the virus and potentially infect other animals or people.

At this time, there is no indication that the infected deer pose a significant risk to human health, but experts still caution against close contact with wildlife and advise taking appropriate precautions, such as wearing gloves and washing hands thoroughly after handling any animals.

potentially leading to new outbreaks or variants.

The researchers also found that the prevalence of SARS-CoV-2 antibodies varied widely across different regions and populations of deer. For example, deer in Illinois and Michigan had much higher antibody rates (54% and 60%, respectively) than deer in Pennsylvania and New York (8% and 11%, respectively).

These regional differences could be due to a combination of factors, including varying levels of human activity and exposure, different deer populations and behaviors, and genetic or environmental factors.

The study highlights the importance of continued surveillance and monitoring of animal populations, particularly those that interact with humans or are involved in the food supply chain, to better understand the potential risks of zoonotic disease transmission.

l to isolates from deer in the same geographic region, suggesting that the virus had spilled back over from deer to humans.

Overall, the study highlights the need for continued vigilance and monitoring of zoonotic disease transmission, particularly from animals that interact closely with humans. The researchers write that "surveillance of free-ranging cervids, particularly those in close proximity to humans, may be an important component of future early-warning systems for emerging coronaviruses."