The complicated case of COVID-19 and white-tailed deer | Covid-19


State College – Scientists at several institutions, including the USDA, Cornell and Penn State, are currently struggling to understand how deer continue to be exposed to SARS-CoV-2, among other related issues.

The problem has been of great concern to both environmentalists and epidemiologists, who fear the virus could mutate and return to humans or infect other animals. The case even caught the eye of the US government: following initial studies, the American Rescue Plan Act allocated $ 6 million specifically to research the coronavirus in white-tailed deer.

How do deer get the virus?

The short answer: we don’t know.

Have you been so close to a live white-tailed deer that you can breathe on it lately? We neither. With the exception of deer frequently handled on farms, the obvious explanation for the spread of SARS-CoV-2 from humans to deer by aerosols seems unlikely. However, unlikely is not the same as impossible, so that possibility remains on the table.

A Penn State study of deer in Iowa from April to December 2020 found an increase in the number of deer exposed during peak hunting season, but that doesn’t necessarily mean hunters are breathing COVID in them. deer.

The study only analyzed 283 deer, which were part of the state’s chronic wasting disease surveillance program. With the limited sample size and the realization that many CWD tests are performed on parts of deer donated by hunters (meaning that more specimens in general will appear during the hunting season), there is no t’s not easy to attribute this to hunters with bad breath.

A seemingly more plausible explanation is that deer drink contaminated water or eat contaminated waste. One of the ways to monitor the spread of COVID is by taking sewer samples; Frankly speaking, the virus continues to survive in people’s poop for a while.

Deer could very well sip virus-laden sewage or eat corn on the cob in the trash that an infected person has munched on. It is currently unknown whether the virus can spread from person to person through feces – it is difficult to find test subjects willing to do this sort of thing.

A third theory suggests that people spread SARS-CoV-2 to another animal who then gave it to the deer. Pets and farm or zoo animals that contract the coronavirus are relatively common – someone’s cat who contracts COVID and sneezes on a deer is not the most outrageous idea.

What we do know from Penn State and USDA research is that viral transmission of SARS-CoV-2 from man to deer has occurred multiple times: every time a new variant of COVID spreads through people in the United States, somehow the deer ends up with the same.

Does the deer get sick?

No. Deer that have been exposed to SARS-CoV-2, whether they have antibodies or viruses active in their system, have shown no signs of disease so far.

Should we be worried about hunting / venison?

Not really. You have to be careful with diseases when harvesting, of course, but there are no evidence that eating or preparing to meet deer can transmit COVID humans right now. However, animal-to-human transmission is not unheard of: in late 2020, a mink on a farm caught the virus from humans, then transmitted it to humans, resulting in the slaughter of tens of millions. weasels.

Just keep your tools clean, wash your hands, and cook your game to a safe temperature.

If deer don’t get sick or make people sick, why is that a problem?

Imagine the COVID-19 pandemic was over and I could finally stop writing about it. We have managed to eradicate it, become immune to all known varieties, vaccinate it or mutate into such a weak form that it is only a slight inconvenience. The only Delta variations we need to worry about are the faucet design choices and all is well with the world.

Next, a white-tailed deer on a farm in Minnesota pushes a wild deer through the fence with its nose. About a week later, the deer nudges a farmer with its nose, exhaling a form of SARS-CoV-2 so mutated that the farmer’s immune system doesn’t know how to fight it.

Suddenly we are back to square one as the deer farmer spreads the disease to everyone he knows and so on.

Unlike the cases of COVID on mink farms, the 2009 swine flu, and the 2014 bird flu, diseases transmissible to humans from animals are much more difficult to control when they spread to wild populations. Animals on farms can be slaughtered for disease control – a disaster for business, but not a terrible ecological tragedy.

The could be a terrible ecological tragedy, however.

Humans aren’t the only organisms we need to consider. Mink are not completely confined to farms. Unlike deer, mink suffer from serious illness when exposed to the virus. If deer transmit the virus to susceptible animals like mink, it could devastate wildlife populations.

The above scenarios are just a few of the worst possibilities. If we’re lucky, the virus will stay in the deer population as is, doing next to nothing. Currently, USDA data suggests that the chances of wild animals spreading COVID to humans are low.

And after?

In addition to academic institutions, the Pennsylvania Game Commission is testing deer specimens donated by hunters and road-killed deer to assess the extent of SARS-CoV-2 in Pennsylvania deer. Less extensive testing will be done on the elk.

There’s not much the public can do about this one. Keep using common sense while interacting with the wild animals and hope for the best.

USDA continues to track confirmed SARS-CoV-2 infections in animals in the United States. A regularly updated page with public records on animal infections is available here.

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