White-tailed deer in Illinois and other states can be infected with COVID-19, and Illinois researchers have concerns about how humans passed on the virus and what it means for the future of pandemic.

“The concern is that white-tailed deer are pretty much everywhere in the country,” said Rebecca Lee Smith, epidemiologist and veterinary researcher at the University. “And once the infection is established in that population, we will never be rid of it.”

There are also concerns that the virus, using deer as a reservoir, can be transmitted to humans, though Smith said scientists haven’t found any evidence suggesting this.

“If deer become a reservoir, there is another place for the virus to evolve,” Smith said. 

This can mean new variants or mutations that allow the virus to adapt to different environments, she said.

In November, hundreds of white-tailed deer in Iowa tested positive for COVID-19, suggesting that humans are spreading the virus to animal populations and among one another.

This came after the U.S. Department of Agriculture released a study in August stating that COVID-19 antibodies were found in deer populations in Illinois, Michigan, New York and Pennsylvania. These antibodies suggested that deer were exposed but potentially not infected.

It’s not just deer that have become infected, but other animals like hippos and minks, Smith said.

“This particular virus, we’d say it’s very promiscuous,” Smith said. “It gets into a lot of different species.”

She said researchers in Illinois are now interested in conducting Illinois-specific studies to determine how widespread infection is in white-tailed deer.

“We have a combination of a really well-monitored deer population and really good testing in Illinois, so we know where the human cases are,” Smith said.

The research will involve working with the Illinois Natural History Survey, where some scientists study disease in wild animals.

Eric Schauber, director of the Illinois Natural History Survey, said human disease isn’t isolated from animal disease.

“We know that interactions between wild animals and domestic animals is often a place where we can get, kind of a bridging event to humans,” he said.

For Schauber, the primary concern is how humans transmitted the virus to deer in the first place.

He said it’s the first time researchers are able to observe this transmission in real time.

“Our ability to really track that give-and-take of pathogens is dramatically better now than it ever has been in human history,” he said.

While it’s an exciting time in terms of research, Schauber said it’s another reminder that human health isn’t isolated from animal health.

One such researcher working on deer and COVID-19 is Nohra Mateus-Pinilla, wildlife veterinary epidemiologist at the Illinois Natural History Survey.

Mateus-Pinilla’s studies diseases in deer, and said she is concerned about how to prevent spreading COVID-19 to animals. She emphasized how there isn’t any evidence that deer are infecting humans.

“We are the ones that are creating spaces for the virus to change and to reach our animals and other people,” Mateus-Pinilla said.

She said it’s our responsibility to protect both wildlife and humans.

“I think our relationship with animals continues to be extremely important in the sense that we need to be respectful of their spaces,” she said. “Understand that in the case of wildlife, wildlife needs some natural resources, and we need to preserve those natural resources.”

For all the interest in COVID-19 and deer, Smith said it’s even more important for humans to continue safe health practices. This means getting tested, social distancing and getting COVID-19 booster shots.

“The situation in deer, that’s interesting and it’s worth studying,” she said. 

“But really, for most people right now, what they need to be concerned about is protecting themselves from infection from other humans.”

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