Penn State study finds deer infected with COVID-19 at high levels, reaching 80% last hunting season

This story comes from our partners at WPSU.

Two tigers at the Pittsburgh Zoo recently tested positive for Covid-19, after showing symptoms. These are just the latest examples of animals in captivity that have been infected with the novel coronavirus. There are also a lot of concerns about wildlife now.

Suresh Kuchipudi, professor of virology at Penn State, is a lead investigator in a study of SARS-CoV-2 in white-tailed deer in Iowa in 2020-2021. They found that the number of deer samples that tested positive increased over time, reaching 80% by the end of the year.

Anne Danahy of WPSU spoke to Kuchipudi about the results.

LISTEN to their conversation

Anne Danahy: What was your reaction when you saw that at first you were getting samples and there weren’t any positive results earlier in the spring, and then all of a sudden it doesn’t just increase, but it increases a lot?

Suresh Kuchipudi: It’s quite astonishing, to be honest, to see the level of positivity among the deer that we have seen. While there are indications that white-tailed deer are susceptible, there could be natural infections. But being able to detect viral nucleic acid in deer tissue at this level is quite astonishing. And we didn’t expect to see this level of positivity among these samples.

Danahy: Are there any assumptions about what is going on?

Suresh Kuchipudi is professor of virology at Penn State and one of the principal investigators of a study on SARS-CoV-2 in white-tailed deer in Iowa. Photo: Penn Stat

Kuchipudi: So the first point is why there were so many infected deer at that time. I think there could be a number of factors that may have contributed to this incredibly high level of positivity.

These included the time of year, which is peak hunting season, also coincided with when Iowa has the highest human cases of COVID-19 among people. So naturally there is a high level of infection burden among human beings.

Then the other aspect is that the hunt disrupts the movement of the deer, so they probably move to places where they might have been more likely to be exposed.

The other aspect is also that when the weather turns cold in Iowa in November and December, there isn’t much food left for the deer.

They are probably looking for anything or everything that they could eat and try to reach places where they could find something to eat.

So I think all of these factors may have contributed to this high level of positivity in deer.

The interesting observation we made is that there was not just one, but there were several independent overflow events in deer. Thus, in different locations simultaneously across the state, which would indicate that there were human-to-deer virus transmission spillover events occurring in different locations at the same time. They were all independent.

Then the second point is that there was the transmission from man to deer, but also followed by transmission from deer to deer in these places. The reason we were able to say this is because we analyzed the virus genomes of the deer samples. Then we compared them to viral sequences from human cases at around the same time and in the same places.

We were able to match the genetic information of what was infecting people at that time, that was indeed what was infecting deer as well. That was the real power of this scientific inquiry.

Danahy: Do you know how it is transmitted from humans to deer?

Kuchipudi: Yeah, that’s a great question. We do not know exactly what are the possible routes by which the virus is transmitted from deer. This is probably less likely to be a direct interaction between a person and the deer.

But we can hypothesize in several ways that this can happen. The reason is that, based on experimental studies, we know that deer are very sensitive. They could be very easily infected if there is a source of the virus.

I am thinking of several activities that could make the virus accessible to deer. Many different attractions of humans, for example, feeding the deer or throwing a half-eaten apple, or leftover food or… in contact with them.

Danahy: So your study was in Iowa, and there are other studies in Ohio. Is it safe to assume, however, that this happens wherever deer are found?

Kuchipudi: I think we now have three independent pieces of evidence. One is our study where we demonstrated viral nucleic acid in deer and followed by the Ohio study, which also did the same in a different location, in a different time period.

There was also the USDA study which found antibodies in four states which included Pennsylvania, Michigan, Illinois and New York. Now, if you take it collectively, that makes six different states. So based on that observation and the fact that deer are, now we know, very sensitive, white-tailed deer, I think it’s very likely that this has to happen wherever there are populations of sensitive deer.

Danahy: It’s scary, but it’s so interesting and fascinating that you could have found this. Nothing else?

Kuchipudi: Although we have a reasonable mechanism internationally or globally, to monitor the evolution of the virus, so we started with the original Wuhan version of the virus. Then several variants emerged in different parts of the world.

The reason we learned about it is that there is a mechanism that monitors the genetic analysis of viruses from people in different parts of the world. We are monitoring the evolution of the virus.

So now the important aspect is that whether it is humans or white-tailed deer or other animals, when a virus continues to circulate in a given species, it is likely to change and it will continue. to mutate. While we’re not sure exactly how it might end, it could get more or less serious. But it is still important to watch so that we are prepared. Otherwise, we might be taken by surprise.

We really have to fight: “How do you deal with this? I think the important aspect now is to be proactive. We therefore continue to monitor the evolution of the virus in the animal population so that we are informed and also can be better prepared with the necessary tools and strategies that we need in the event of an emergence of a variant that has increased. pathogenicity to humans or could potentially undermine the current vaccines we have in the United States

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