Melissa Harris-Perry: I'm Melissa Harris-Perry and this is The Takeaway. Over the past two years, we've heard of cats and dogs, our pets at home being infected by the coronavirus. There's even been news stories of some zoo animals, but an analysis by Penn State and Iowa researchers found that the COVID-19 virus may be fairly widespread among white-tailed deer.

Up to 80% of the deer sampled in Iowa from April 2020 through January 2021 were infected with COVID-19. The US Department of Agriculture has confirmed COVID infections in deer in at least 15 states. These findings worry experts about the possibility for the virus to mutate in wild animals and cause other variants. Here to talk more about this research is Suresh Kuchipudi, who led the research team and is a professor and chair in emerging infectious diseases at Penn State University. Thanks for joining us, Suresh.

Suresh Kuchipudi: Hi, Melissa. Thanks for having me.

Melissa: What led you to test the deer for COVID?

Suresh: Melissa, we at the Penn State University and our collaborators are interested in investigating the susceptibility of animals to COVID virus. As we were exploring this, there are several indications that pointed to the fact that deer are susceptible. It is based on computational studies and experimental studies. The USDA also provided a proof of antibody evidence of exposure of wild white-tailed deer in four different states of the US. Therefore, we partnered with the Department of National Resource at Iowa. Leveraging their ongoing chronic wasting disease surveillance program, we investigated the exposure of deer in Iowa for SARS-coronavirus-2.

Melissa: Now, when deer are COVID-positive, are they symptomatic?

Suresh: Yes, that's a great question. We need to understand that when we say "COVID," we are actually talking about the disease. The coronavirus disease is the outcome of infection of SARS-CoV-2 in humans. What we have found so far is the infection of animals with the SARS-coronavirus-2. There are two experimental studies that were conducted with the deer. So far, our understanding is that when deer get infected with the SARS-coronavirus-2, they remain largely asymptomatic. They do not show any significant clinical signs.

Melissa: I just want to stick with the possibility that we care about deer lives themselves even before we ask about the relevance for human health. If deer are able to be positive without being symptomatic, does that suggest that having this infection is basically irrelevant for deer populations or is it that we just haven't yet seen what the relevance might mean for deer populations?

Suresh: It certainly is relevant to the deer populations. What it means is that our understanding is limited. We need to remind ourselves that when experimental studies are done, these are done with a small number of animals and healthy animals. These studies were also conducted with the earlier versions of the SARS-coronavirus-2.

Whether the recent variants do any different clinical symptoms in deer or deer in the wild settings that may be having a different aspect such as old age or underlying other conditions or stress or starving, in such circumstances if the deer may or may not show any symptoms, so that part is currently unknown. It's safe to say, we do not fully understand whether or not this is relevant to deer health. It could be and, therefore, it needs further investigation.

Melissa: Let's talk about what it means for potential human health, knowing that deer are able to be and apparently have these high infection rates.

Suresh: Currently, the major source of infection of SARS-coronavirus-2 to humans is another infected human being. In the medium to long-term if there is an animal reservoir or reservoirs that will allow the virus to continue to circulate, then it could potentially result in the virus evolution independent of human population and novel variants might emerge. While there is no maybe limited risk of exposure from deer to humans, at least right now because humans don't normally come in close contact with deer and there is already widespread circulation of virus in humans, but the main concern is that if we let this virus circulate unmonitored and that could result in emergence of novel variants down the road.

Melissa: Now, is this an indication that we should not be eating deer or is there any reason to think that's a route of transmission?

Suresh: The SARS-coronavirus-2 is very fragile. When anything is cooked, the virus gets destroyed. There is no risk if a deer meat or any contaminated meat is properly cooked. I think the foodborne transmission of the virus is not a major risk. The main thing is the risk is with the people who might be handling deer after hunting or processing. That's where perhaps there is risk, but not through eating the meat of the deer.

Melissa: Obviously, what you are is a researcher and so you may not be able to respond to this one. Perfectly fine if you can't. If someone is a hunter and is field-dressing a deer and obviously dealing with them in that circumstance uncooked, is there a protocol that hunters ought to be using?

Suresh: Melissa, before this discovery of SARS-coronavirus-2 in deer, in general, any wild animal species when people interact, it is always a risk of disease transmission. Hunters should already be aware of other diseases that might come from deer. Therefore, they should be wearing some personal protective equipment like gloves when they process the meat, so some of the diseases like chronic wasting disease or tuberculosis in some parts of the country.

In addition to that, now, we also know that some of the deer in many locations are also infected with SARS-coronavirus-2. It is a further reminder to continue to follow the recommendations that they have. If necessary when somebody's processing the meat very closely, it's also a good idea to wear a respiratory protection like a mask.

Melissa: Now, what about other wild animals? What about squirrels or raccoons, those that are quite common? Any reason or any evidence about the possibility that those wild animals may also be carrying COVID?

Suresh: Melissa, that's an excellent question and something that we keep wondering as well. Our understanding of the transmission networks of the virus in the wild. The question is, deer are getting infected and who else are they giving it to? That part is currently largely unknown. There is a possibility that many of these very domestic animals that you mentioned, rodents like mice or skunks or raccoons, they have been shown to be susceptible experimentally. Therefore, in the wild settings when these animals do interact, there is always a possibility of virus transmission between and among these animal species, but that part is currently unknown and that is something that also is a significant aspect that needs to be explored.

Melissa: Suresh Kuchipudi, professor and chair in emerging infectious diseases at Penn State University, thanks for being here.

Suresh: Thanks for having me, Melissa.

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