Study: Ohio deer found infected with COVID-19: Why 'this changes the game' on pandemic - Detroit Free Press
Wild deer in six northeast Ohio locations were discovered infected with at least three virus variants of COVID-19, a team of Ohio State University researchers has reported.
The finding, from nasal swabs of 360 white-tailed deer, is among the first evidence showing active COVID infections in wild deer populations through exposure from the virus shed from people, likely in their feces and urine.
If the coronavirus is found to sustain itself in wild deer populations, perhaps passing the virus to other animal species or even back to humans, it could prove a large complication to getting past the global pandemic that has contributed to nearly 5.5 million deaths since late 2019. But whether that is happening is not yet clear and requires more research, scientists said.
The Ohio State deer study was published Dec. 23 in the peer-reviewed scientific journal Nature. Its findings come after the U.S. Department of Agriculture last year detected SARS-CoV-2 antibodies in deer from four states, including Michigan.
That indicated that the deer were exposed to the COVID-19 virus, but not that they were necessarily sickened by it, or transmitting it, said Andrew Bowman, an associate professor of veterinary preventive medicine at Ohio State and author of the study.
"Our study is showing that deer are infected, and they are replicating the virus, they are shedding viable virus," he said.
That "changes the game of SARS-CoV-2 and COVID," Bowman said.
"To this point, we've really been focused on just the human hosts — as we are looking at what is the next variant to arise, we are looking at people, sampling them," he said.
"If we do have SARS-CoV-2 established into another host species — and especially in this case, a free-ranging wildlife species — it certainly changes the potential control and mitigation of SARS-CoV-2 for the foreseeable future. Because we will have to consider viral variants that may arise within an animal population, and actually spill back into humans at some point in time."
The Ohio State study took nasal swabs from 360 "urban and suburban" white-tailed deer, culled in population control efforts from nine northeast Ohio locations. Using polymerase chain reaction, or PCR, tests to detect genetic material from the coronavirus, scientists detected at least three different COVID strains in 129 of the sampled deer, almost 36%.
Each site was sampled between one and three times, a total of 18 collection dates. The prevalence of infection varied from between 13.5% to 70% across the sites, with the highest prevalence in four sites surrounded by more densely populated neighborhoods of people.
"We have evidence of six different viral introductions into those deer — it's not that a single deer population got it once and then it spread," Bowman said. He noted that the sampling was conducted from January through March 2021, "the peak of our winter 2021 SARS-CoV-2 viral shed in humans" through their waste.
"The viral load in the environment was probably quite high coming from humans — whether we're talking about potential storm water contamination, food contamination."
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There are an estimated 30 million wild deer in the United States, including abundant populations of white-tailed deer in each of Michigan's 83 counties. Contagious diseases such as bovine tuberculosis and chronic wasting disease have sustained themselves in the state's wild deer populations, likely spread as deer exchange saliva while feeding on the same food, or through being nose-to-nose over food.
Michigan Department of Natural Resources spokesman Ed Golder said the agency is aware of the ongoing research looking at the connection between deer and the coronavirus.
"Based on our understanding of research done by others, and in consultation with public health officials in Michigan, we have not seen a need as yet to change our recommendations to hunters or our deer management strategies," he said.
The DNR continues to urge hunters and others to follow CDC guidelines for safely handling and cooking wild game, including wearing a mask and rubber gloves while cleaning game and cooking all meat thoroughly to an internal temperature of at least 165 degrees Fahrenheit.
Viruses hopping from animals to humans is nothing new, as both bird flu and swine flu demonstrate. Though scientists do not have a consensus over how and from where COVID-19 originated, a sizable contingent of researchers believe it originated in bats, made its way to some not-yet-identified intermediate animal, and then infected humans.
The findings of the Ohio State study raise many questions that will require additional research, Bowman said. How specifically do deer get infected from human-shedded COVID viruses? What about other wildlife species?
"Deer were kind of an easy target for us, a convenient sampling that we could easily get our hands on," he said. "We need to think about some of those other species that maybe aren't as convenient to sample, and understand if they are experiencing a similar sort of thing."
The deer sampling was also over a short time frame, Bowman noted.
"We really don't have enough time there to look at viral persistence," he said.
As part of a phased, multiyear monitoring and surveillance project, the U.S. Department of Agriculture's Animal and Plant Health Inspection Service last year began studying the prevalence of the coronavirus in wild white-tailed deer across 30 states and tribal areas.
"It's important to remember that the risk of animals spreading SARS-CoV-2 to people is considered low," agency spokeswoman Tanya Espinosa said. "The greatest risk of new variants comes from those formed in and spread by people.
"There is also no evidence that white-tailed deer or other native, free-ranging wildlife have spread the virus to people. (But) because wildlife can carry other diseases, even without looking sick, it is always important to enjoy wildlife from a distance."
Contact Keith Matheny: 313-222-5021 or [email protected]