White-Tailed Deer Found to Be a Reservoir for Novel Coronavirus: At Least Three Variants Detected in the U.S.

At least three novel Coronavirus variants have been detected in free-range white-tailed deer at several sites in northeast Ohio, us, according to a study published in Nature.

Previous studies led by the US Department of Agriculture showed evidence of antibodies in wild deer. This new study is the first to report that the growth of laboratory virus isolates supports COVID-19 activity in white-tailed deer, suggesting that researchers have recovered viable samples of novel coronavirus, rather than just its genetic traces.

Based on genome sequencing of samples collected between January and March 2021, the researchers determined that the mutant strain infecting wild deer matched the strain circulating among Ohio coronavirus patients at the time. The collection of samples occurred before the spread of the Delta variant, and the variant was not detected in these deer. The team is testing more samples to see if they are new or old variants, and the persistence of these variants suggests that the virus can linger and survive in the species.

Andrew Bowman, an associate professor of veterinary preventive medicine at Ohio State University and senior author of the paper, said the fact that the deer may have been infected “leads us to the possibility that we may have actually established a new maintenance host outside of humans,” which “could complicate future mitigation and containment plans for COVID-19.”

White-tailed deer photo source: website screenshot

The team collected nasal swabs from 360 white-tailed deer at nine sites in northeast Ohio. Using PCR, the scientists detected genetic material from at least three different virus strains in 129 deer (35.8%) sampled.

The analysis showed that the B.1.2 virus, which was dominant in Ohio during the first months of 2021, spilled multiple times into deer populations at different locations. The evidence shows that six different viruses were introduced into these herds, so it’s not like a deer gets infected once and spreads.

Based on the findings, the researchers estimated infection rates at the nine sites ranged from 13.5 percent to 70 percent, with the highest rates observed at four sites in densely populated neighborhoods.

As a novel Coronavirus reservoir, white-tailed deer could lead to two outcomes, Bowman said: the virus could mutate in deer, facilitating the spread of new strains to other species, including humans; Or the virus could infect deer without mutating, while continuing to evolve in humans, and at some point those variants could jump back into humans when humans have no immunity to strains that infect deer.

But how the virus spread in these deer in the first place, and across species, are unanswered questions related to the new findings. The team speculates that the white-tailed deer became infected by environmental means, perhaps from drinking contaminated water. Studies have shown that the virus spreads in human feces and can be detected in wastewater.

Novel coronavirus has been detected in white-tailed deer in the United States, researchers at Pennsylvania State University said in a pre-publication paper on October 31. Previous studies published by the US Department of Agriculture also showed novel coronavirus infections in white-tailed deer in 2019.

The infection rate was 82.5%
In samples of white-tailed deer collected between 23 November 2020 and 10 January 2021, US researchers found novel coronavirus infections in 80 of 97 white-tailed deer in Iowa, that is, an infection rate of 82.5%.

Tony GOLDBERG, ANIMAL Epidemiologist, UNIVERSITY of Wisconsin-Madison: It means that not only did white-tailed deer have multiple Novel coronavirus infections from humans, but there was rapid transmission from white-tailed deer to white-tailed deer.

So far, us researchers have not detected novel Coronavirus transmission from white-tailed deer to humans, but researchers are beginning to worry that, with such high infection rates, white-tailed deer are likely to act as a reservoir of Novel coronavirus transmission, and that it cannot be ruled out that white-tailed deer could mutate to infect humans in the future.

The USDA found that white-tailed deer were infected as early as 2019
In fact, in August of this year, the USDA released the results of a study they completed in July, in which they collected 385 serum samples from white-tailed deer in the northeastern states of Michigan, Pennsylvania, Illinois, and New York, and found that novel Coronavirus-related antibodies were detected in 40% of them. Several U.S. biological laboratories, including Fort Detrick, are also located in the northeast.

More notably, novel Coronavirus-related antibodies have also been detected in a 2019 sample. This most likely means that novel coronavirus transmission has occurred in humans in the United States since 2019, which in turn has infected white-tailed deer. The first human case of novel coronavirus infection in the United States was reported on 21 January 2020.

White-tailed deer are widely distributed in the United States, and only a few states select a few hundred samples of serum from the USDA for testing. Is this detection range really an accurate reflection of white-tailed deer infections prior to the Novel Coronavirus pandemic? If the 2019 sample pool is expanded, will more white-tailed deer be found to have been infected before the Novel Coronavirus pandemic?

Or evolve into new strains to infect humans and evade existing vaccines
Some previous studies have hinted at the possibility of transmission of the virus from humans to deer, as many other animals besides white-tailed deer can also be infected with novel coronavirus, the New York Times noted. These include ferrets and primates that were deliberately infected in laboratory experiments, zoo animals that caught the virus from keepers, and captive minks that came into contact with farm workers.

If the virus becomes endemic in wild animals like deer, it could evolve over time to be more capable, and a new strain could then infect humans that might be able to evade existing vaccines.

“If deer can re-transmit the virus to humans, it will be a turning point.” Tony Goldberg, a veterinarian at the University of Wisconsin-Madison. He studies the evolution of infectious diseases between animals and humans. “It’s very rare and unfortunate for a wild animal to become a reservoir of a virus when it gets infected from a human,” he says.