The coronavirus spreads in deer and other animals. Scientists are concerned about what that means for people

(CNN) – Scientists have discovered that the SARS-CoV-2 coronavirus spreads among white-tailed deer and other wildlife in the United States.

People are the likely source, but that doesn’t mean the virus can’t evolve between these animals and then back into humans, and researchers are concerned about what this spread means for the risk of future pandemics.

There is little doubt that SARS-Cov-2, the virus that caused the ongoing pandemic, came from an animal, almost certainly a bat. And the prevailing scientific opinion is that there is an intermediate host, an animal of some kind, that was infected by a bat or bats and then infected people.

It is also clear that people can infect animals. Pets like cats, zoo animals like gorillas and snow leopards, and farm minks can become infected. Several cases have been reported, and evidence of changes in the viruses that infect mink has led to massive slaughter of these animals on farms.

The latest species of wildlife animal to catch the eye of biologists is white-tailed deer. It’s no wonder farm deer catch the virus from people. Any visitor to a deer farm knows that the animals behave like goats, poking their wet noses into the pockets, hands, and faces of visitors or human caretakers as they clamor for food and treats, leaving them exposed to infection.

But how do wild deer spread?

Spread of coronavirus among deer

“If someone bites into an apple and throws it or even sneezed into a tissue and dropped it (creates contagion),” speculated Dr. Suresh Kuchipudi of the Pennsylvania State University Animal Diagnostic Laboratory, who helped conduct a study published earlier this month, which found that a third of the deer tested in Iowa between September 2020 and January 2021 showed evidence of COVID-19 infection.

Sewage has been found to carry the virus, so contaminated water could be a source, he added, or that people spit or pollute the environment in other ways. Therefore, deer can spread the virus to each other.

“Keep in mind that these are highly susceptible animals, although it is not known how much virus they need to become infected,” Kuchipudi told CNN. “An urgent question arises: We know that deer are effectively transmitting viruses to each other, and so who are they transmitting it to?”

It is also possible for another species to contract the virus from people and infect deer.

“We don’t know what’s going on in our own country and we need to find out,” said Hon Ip of the US Geological Survey in Wisconsin.

Viral hotspots among rodents

Ip and his colleagues tested animals they found around a mink farm that was the site of an outbreak in Utah and found that skunks, mice and other animals were susceptible to a variety of coronaviruses.

They were originally concerned that mink, which contracted the virus that causes COVID-19 in people, could infect local wildlife. They found no indication of that. “It was a very pleasant surprise,” Ip told CNN.

But mice, raccoons, skunks and other animals carried a load of other coronaviruses. “The amount of coronavirus and the diversity was a surprise,” Ip said.

“Our findings indicate an unexpectedly high prevalence of coronavirus among domestic and wild animals tested on mink farms and raise the possibility that these operations could be potential hotspots for future trans-specific viral spread and emergence of new pandemic coronaviruses, “they wrote in a report published in the Viruses magazine in October.

Researchers like Ip and Kuchipudi say many more studies like this are needed.

Kuchipudi and his colleagues conducted their study after the United States Department of Agriculture publish an investigation in July it found that 40% of deer tested in four states had antibodies to SARS-CoV-2, evidence that they had been infected.

There are several reasons why scientists do not want a virus like the one that causes COVID-19 to infect animals. For one thing, it creates what’s known as a reservoir, so that even in the unlikely event that everyone gets vaccinated and the virus stops circulating between people, it would still circulate between animals and could re-infect people with the virus. weather.

However, the risk that it may change and evolve is more likely. This can happen in two ways.

One is constant adaptation. As it infects different species, the virus will change to better suit those species and that could make it more or less dangerous for humans.

Another route to change: Viruses can take shortcuts by exchanging large chunks of genetic material in a process called recombination. The flu is especially good at this, but coronaviruses can do it too. If an animal is infected with more than one coronavirus at a time, the two types can mix and match genes and potentially present new variants.

“Recombination is one of the main mechanisms for the evolution of the coronavirus,” said Ip. So if animals are already carriers of their own strains of coronavirus, and people are infecting them with strains that cause pandemics among humans, there is a possibility that these viruses infect animals at the same time, exchange genetic material, and den rise to new viruses. Pandemic viral species.

Origins of the pandemic

“This raises very urgent questions about the trajectory of this pandemic,” Kuchipudi said.

If there are animals like the white-tailed deer that become infected with SARS-CoV-2 so easily and spread the virus between them so easily, that is a red flag.

That means much better surveillance is needed to see what other animals might be being infected by people or other animals, and what threat they might pose to other animals and to people.

“We need to be prepared for any variant that may arise,” he said.

Additionally, Ip said, surveillance is needed to find out which coronaviruses live in animals that could be the source of the next pandemic, not just among bats in remote caves in Southeast Asia, but perhaps among mice, deer or raccoons in the backyards of the Midwest United States.

And people must remember that humans are the main source of the spread of the virus. Even if covid-19 originally came from animals, humans are the species that have amplified and spread it.

And there is an answer to that extension.

“Vaccination rates are not uniform across the world,” Kuchipudi said. “As long as there are susceptible humans, we provide opportunities for the virus to circulate and change. More concerted efforts need to be made to vaccinate as many people as possible so that we can at least minimize human-to-human transmission.”