Deer are catching the COVID-19 virus. What does that mean for humans?

A whitetail deer lays in the snow near a pine tree.
A white-tailed deer near New Haven, Ohio. Earlier this month, researchers announced that a stunning number of deer in Iowa had been found to be infected with the coronavirus.
Michael Williams | Getty Images

Last year, researchers at Penn State and the Iowa DNR tested hundreds of samples collected from white-tailed deer in Iowa for the coronavirus. They were shocked by what they found: One-third of the deer sampled had been infected.

And, amazingly, from late November 2020 to early January 2021, a whopping 80 percent of the sampled deer tested positive — a rate of infection 50 times that of humans in Iowa in the same period.

This study has yet to be published in a peer-reviewed journal, but scientists are already concerned about its ramifications for the COVID-19 pandemic.

Jeff Bender is a veterinarian and professor of public health at the University of Minnesota. He told host Cathy Wurzer that humans somehow transmitted the coronavirus to white-tailed deer, but how exactly that transmission happened is unknown.

So far, there is no evidence of the coronavirus spilling from deer back to humans, Bender said. But in the long term, mutations in the coronavirus could develop as it transmits among deer, and spillover from deer to humans could occur, which concerns Bender.

As for the health of the deer, there is no evidence yet that they have been sickened by the coronavirus, Bender said.

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Bender is currently testing wildlife samples from Minnesota for the coronavirus as part of his research. He said he hasn’t found any positives yet, but he expects to find evidence of spillover from humans by the end of the study.

For Bender, this development underscores the need for a robust surveillance system that can detect virus variants and catch spillover events to and from animals.

Use the audio player above to listen to the full conversation.

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