select scholars A new highly mutated version of coronavirus in white-tailed deer in southwestern Ontario, a species that may have evolved in animals since the late 2020s.
They also found very similar viral sequences in a local person who had been in close contact with deer, which is the first evidence that the virus can be transmitted from deer to humans.
“The virus evolves in deer and differs in deer, a far cry from what we clearly see evolving in humans,” said Samira Mubarak, a virologist at Sunnybrook Research Institute and the University of Toronto and author of the new paper.
The report has yet to be published in a peer-reviewed journal, and there is no evidence that the deer breed is spreading among people or posing an increased risk to them. Preliminary laboratory experiments indicate that the strain is unlikely to evade human antibodies.
But the diary was published online a few days later. Inform another team The alpha variant may have continued to spread and evolve in Pennsylvania deer even after its disappearance in humans.
Together, the two studies suggest that the virus can circulate among deer for long periods of time, increasing the risk of this disease. Animals can become a long-term reservoir of the virus and a source of future variants.
“There is absolutely no need to panic,” said Aringai Banerjee, a virologist at the University of Saskatchewan who was not involved in any of the studies.
But, he added, “the more hosts you have, the greater the chance the virus will evolve.”
Previous studies have shown that The virus is spreading On the white-tailed deer. Research indicates that humans have repeatedly introduced the virus to deer, who pass it on to each other. How humans transmitted the virus to deer remains a mystery, and so far there is no evidence that animals transmit it to humans.
The Canadian study was a collaboration of more than twenty researchers from institutions in Ontario. Scientists collected nasal and lymph node tissue samples from 300 white-tailed deer killed by hunters in Ontario between November 1 and December 31, 2021. Six percent of the animals, all from southwestern Ontario, were tested positive for the virus, indicating that they were actively infected when they died.
The researchers sequenced the complete viral genomes of five infected deer and discovered a unique constellation of mutations that had not been previously documented. A total of 76 mutations – some of which have already been found in infected deer, mink and other animals – differentiate the breed from the original version of the virus.
The deer samples were most closely related to viral samples taken from human patients in Michigan, not far from southwestern Ontario, in November and December 2020. They were also similar to samples from humans and you in Michigan earlier this fall. .
These findings, along with the rate at which the virus accumulates mutations, suggest that the new strain may have deviated from known versions of the virus and been evolving undetected since late 2020.
But his exact background is unclear. One possibility is that humans could have transmitted the virus directly to deer, and the virus then accumulated the mutations by spreading between the cervix. Alternatively, the breed may have evolved, at least in part, into other intermediate species—perhaps bred or wild mink—which somehow pass it on to deer.
“We don’t have all the pieces of the puzzle,” Penn State veterinary microbiologist Dr. Suresh Kochipudi, who was not involved in the research, said via email. “We cannot exclude the involvement of an intermediary host.”
A virus sample taken from a human patient in southwestern Ontario in the fall of 2021 matched samples from deer. This person is known to have been in close contact with deer, The researchers said.
(They could not reveal more details about the nature of this contact for confidentiality reasons, although Dr Mubaraka noted that people should not worry about casual and indirect encounters, such as simply ‘have a wandering deer in the yard.)
Scientists have warned that the sample size is small and there is no conclusive evidence that the person contracted the deer virus. “We still don’t have enough information to confirm that this transmission has passed back to humans,” said Roderick Ganey, wildlife disease ecologist at the University of Pennsylvania School of Veterinary Medicine.
But at the time the human sample was taken, Ontario was collecting samples of the virus from everyone in the region who had tested positive for PCR. The researchers did not find other people who had similar versions of the virus, making it less likely that it would develop independently in humans.
“If it had been so prevalent in humans, even in humans in a restricted way, I think we would have caught it,” Dr. Mubaraka said.
There is also no evidence that someone infected with the strain transmitted the virus to another person.
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Early data suggests that current vaccines should still be able to protect against the strain. Scientists found that antibodies from vaccinated people were able to neutralize pseudoviruses – harmless, non-replicating viruses – designed to resemble a strain of deer.
In the second study, scientists from the University of Pennsylvania Schools of Medicine and Veterinary Medicine analyzed nasal swabs from 93 deer that died in Pennsylvania in the fall and winter of 2021. 19% were infected with the virus . When the researchers sequenced seven of the samples, they found that five of the deer were infected with the delta type, while two were infected with the alpha type.
At the time the samples were collected, delta was prevalent among humans residing in the United States, but the alpha wave that hit Americans in the spring of 2021 was long gone.
“Alpha appears to persist in white-tailed deer even during the period when it is not circulating in humans,” said Iman Anis, a microbiologist at the University of Pennsylvania School of Veterinary Medicine and study author. .
In fact, delta samples in deer were genetically similar to those in humans, indicating that they crossed species lineages relatively recently. But the alpha sequences diverged more significantly from the human strains. (They were also significantly different from each other, indicating that the variant was introduced into the deer group at least twice.)
“The main implication is that deer maintain transmission and inflammation among their populations,” said study author Dr. Jani from Pennsylvania. “It’s not just an indirect human event where deer get infected and then die.”
It is unknown whether these lineages will continue to spread and evolve in deer, as well as the risks they may pose to humans and other animals.
“Based on current information, I would say the risk of the virus spreading among wildlife, including deer, is low,” said Jeff Bowman, a researcher with the Department of Northern Development, Mines, Natural Resources. and Forests of Ontario. Canadian newspaper writer.
But scientists said constant monitoring was essential. Dr. Mubarak suggested authorities increase sewage filtering in Ontario and other nearby areas to specifically look for the deer breed and ensure it doesn’t spread further.
Experts have also urged people to continue to follow guidelines set out by public health agencies, including not feeding deer or other wildlife and wearing gloves when hunting game.
“We also need to reduce the biggest reservoir of this virus, which is us, to make sure we don’t constantly pass it on to deer and create these new strains,” Mubaraka said.
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