Why it matters: Deer can be a source of new species.
There is no evidence that deer play a role in the transmission of the virus to humans, but the transmission of the virus from people to animals raises several public health concerns.
First, the animal reservoir may allow viral variants that have disappeared from human populations to persist. In fact, the new study confirms previous reports that some coronavirus types, including alpha and gamma, continue to circulate in deer even after they have become rare in humans.
New animal hosts provide new opportunities for the virus to mutate and evolve, leading to new variants that can infect people. If these variants differ from those previously circulating in humans, they may evade some of the immune system’s defenses.
Background: Scientists have found signs of widespread infection in deer.
Researchers from the Animal and Plant Health Research Service, along with other government and academic scientists, began looking for the coronavirus in free-ranging white-tailed deer in 2021 after studies suggested the animals might be susceptible to the virus.
During that first year of monitoring, the scientists eventually collected more than 11,000 samples from deer in 26 states and Washington, D.C. Almost a third of the animals had antibodies to the coronavirus, suggesting they had been previously exposed, and 12 percent were active. affected, APHIS said Tuesday.
For the new Nature Communications paper, scientists from APHIS, the Centers for Disease Control and Prevention, and the University of Missouri sequenced nearly 400 samples collected between November 2021 and April 2022. They found several versions of the virus in deer, including the alpha. , gamma, delta and omicron types.
The scientists then compared virus samples isolated from the deer to those from human patients and mapped the evolutionary relationships between them. They concluded that the virus had moved from humans to deer at least 109 times, and that deer-to-deer transmission occurred more frequently.
The virus also showed signs of adaptation to deer, and researchers identified several cases in North Carolina and Massachusetts in which humans were infected with these “deer-adapted” versions of the virus.
What’s next: Monitoring will continue.
APHIS has expanded its surveillance to additional states and species.
Many questions remain, including exactly how people transmit the virus to deer, and the role the animals play in maintaining the virus in the wild.
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