A new study has revealed that white-tailed deer in Ohio are infected with the virus that causes Covid-19. Worryingly, the results also show that viral variants evolve about three times faster in deer than in humans.
Between November 2021 and March 2022, scientists collected 1,522 nose samples from free-range deer in 83 of the state’s 88 counties. More than 10% of the samples were positive for SARS-CoV-2 and at least one positive case was detected. In 59% of the districts where the test was conducted.
Genomic analysis and results
Genomic analysis revealed that at least 30 of the infections in deer were transmitted by humans, which surprised the research team.
“We usually talk about crossing over as a rare event, but this was not a huge example and we were able to document 30 side effects. It moves quite easily between humans and animals,” said Andrew Bowman, associate professor of veterinary preventive medicine at Ohio State University and co-author of the study. It looks like it does,” he said.
“And there’s more and more evidence that humans can get it from deer, and that’s not surprising. It’s probably not a one-way pipeline.”
Collectively, the findings suggest that white-tailed deer species are a reservoir for SARS-CoV-2 and allow for continued mutation, and that circulation of the virus in deer could lead to spread of the virus to other wildlife and livestock. The study was published today (August 28, 2023) in the journalism. Nature Communication.
Preliminary observations and extensions
Bowman and colleagues previously reported detection of SARS-CoV-2 infections in white-tailed deer at nine locations in Ohio in December 2021 and are continuing to monitor the deer for infection with the new variants.
“We’ve scaled across the state of Ohio to see if this is a localized issue – and we’re finding it in many places, so it’s not just a localized event,” Bowman said. “At the time, some thought it could only be in urban deer as they were in closer contact with humans. But we do find a lot of positive deer in rural areas of the state.”
In addition to finding active infections, the researchers also found that about 23.5 percent of the deer in Ohio became infected at one time or another, through blood samples containing antibodies that showed previous exposure to the virus.
Variant analysis
The 80 whole genome sequences from the collected samples represented different variant groups of the virus: the highly contagious delta variant and Alpha, which was the dominant human species in the United States in early fall 2021 and accounted for about 90% of the sequences, and Alpha, of concern spreading among humans in the spring of 2021. the first named type.
The analysis showed that the genetic makeup of delta variants in deer matched dominant lineages in humans at the time, indicating cases of spread, and deer-to-elk transmission occurred in clusters, some spanning multiple counties.
“What we found probably has a temporal component; we’re near the end of the delta peak in humans and then we see a lot of delta in deer,” Bowman said. “But we are long past the final detection of the alpha channel in humans. So the idea that deer descended from extinct lineages among humans worried us.”
The study suggested that vaccination against Covid-19 could help protect people from serious illness if the disease is transmitted to humans. Analysis of the effects of deer variants on Siberian hamsters, an animal model for SARS-CoV-2 research, showed that vaccinated hamsters did not contract the infection as much as unvaccinated animals.
The rapid evolution of deer
It is worrying that the varieties circulating in deer continue to change. A study of mutations found in samples showed that both alpha and delta variants evolved more rapidly in deer compared to humans.
“Not only do deer become infected and perpetuate SARS-CoV-2, but the rate of change in deer is accelerating – far from potentially infecting humans,” Bowman said. said.
How the virus infects white-tailed deer from humans remains a mystery. Although approximately 30 million deer live in the United States so far, there has been no outbreak of any deer-related species among humans.
Potential consequences
But the probability of roaming among animals is quite high. About 70 percent of Ohio’s free-range deer are uninfected or not exposed to the virus, Bowman noted, “so there are a lot of naïve animals where the virus can spread quite freely.”
“Having a host animal in the game creates things that we need to be careful about,” he said. “If this trend continues for years and we have a deer-adapting virus, will it become a route to other animal hosts, wild or domestic? We just don’t know.” Source
Source: Port Altele
