Study: White-tailed deer in Ohio ‘frequently infected’ with novel coronavirus

Columbus, Ohio — White-tailed deer are ‘highly susceptible’ to infection from the novel coronavirus, according to a study published in December in the journal Nature.

More than one-third of 360 deer swabbed across nine locations in northeast Ohio between January and March 2021 were found to be infected with three variants of the novel coronavirus, one of which was predominant among humans at the time.

The finding raises the possibility that white-tailed deer could provide a new reservoir for the virus, which causes COVID-19, to evolve and mutate into new variants and potentially transmit them to other wildlife species or humans, according to Andrew Bowman, associate professor of veterinary preventive medicine at Ohio State University and senior author of the study.

“If we are able to establish a wildlife host, that changes the game of SARS-CoV-2 essentially forever because we will have to consider what viruses are circulating in a wildlife host, in addition to humans,” Bowman told the Dispatch, referring to the official name of the novel coronavirus issued by the World Health Organization.

Although there is no documentation of deer transmitting the virus to humans or vice versa, it’s important to study how that could happen, said Dr. Joe Gastaldo, medical director of infectious diseases at OhioHealth.

“Let’s say, hypothetically, there is another variant out there that’s even more transmissible that originates in deer,” he said. “In that regard, there would be a lower threshold for a hunter to come into contact with secretions from a dead carcass to get it.”

Hunters should take precautions while dressing deer

It’s possible for humans to contract coronavirus from dead bodies, and the same could be true for dead deer, according to Gastaldo.

“However, over time, within a day or so, once the body is dead, the virus dies, too, and you’re not able to get it in that regard,” he explained.

Bowman said that hunters and wildlife biologists still should take precautions such as wearing a mask when in close proximity with deer, dead or alive.

The deer that were sampled were euthanized as part of a deer population management program about six weeks after the peak of Ohio’s last winter surge of COVID-19. The alpha and delta variants were not identified in the samples, as they became widespread in humans only after February.

Unclear how deer contracted virus, or whether it’s spreading among them

Two questions remain unanswered by the study. How are deer contracting the virus? And how is the virus potentially transmitting between deer?

It’s possible the deer in northeast Ohio contracted it from contaminated water, since the novel coronavirus is shed in human waste. But alternative sources – such as trash, backyard feeders, bait stations and wildlife hospitals – have to be considered, Bowman said.

“We need to understand how that’s happening so we can potentially prevent it from happening in the future and understand how we might mitigate that risk,” Bowman said. “If we’re able to prevent that virus from getting established in wildlife that would be great. If it’s already in, we need to understand how that happened so we can prevent other similar events in the future.”

Bowman said not enough is known about possible deer-to-deer transmission.

“We just don’t have enough surveillance that’s occurred at this point to really understand (whether) they are able to maintain the virus that’s introduced to them on their own.” he said.

Bowman said the study is the first of its kind in showing the novel coronavirus established in wildlife. The U.S. Department of Agriculture last year conducted a study that showed 40% of deer tested across four states, not including Ohio, were positive for antibodies, meaning they had been exposed to the virus at some point. But the study did not look for the virus itself.

Infections of the novel coronavirus linked to human exposure also have been reported in domestic animals, such as cats, dogs, and wildlife under human care, though severe illness among animals is extremely rare, according to the Centers for Disease Control and Prevention.

No critical signs of the COVID-19 disease were observed in sampled deer prior to their deaths, Bowman said.

“This really is the first study to come up with a significant proportion of a wildlife species where we’re actually finding the virus in them,” he said. “We’ve had these kind of one-offs here and there, whether it’s domestic animals or zoo animals.”