Why this matters: Deer may be the source of the new variant.
There is no evidence that deer play a major role in spreading the virus to humans, but the transmission of viruses from people to animals raises several public health concerns.
First, animal stocks may allow viral variants that have disappeared from human populations to persist. Indeed, the new study confirms earlier reports that some coronavirus variants, including alpha and gamma, continued to circulate in deer after they became rare in people.
New animal hosts also give the virus new opportunities to mutate and evolve, potentially giving rise to new variants that can infect people. If these variants are significantly different from variants that have previously circulated in humans, they may escape some of the immune system’s protection.
Background: Scientists have found signs of widespread infection in deer.
Researchers from the Animal and Plant Health Inspection Service, in collaboration with other government and academic scientists, began looking for the coronavirus in free-roaming white-tailed deer in 2021 after studies showed the animals were susceptible to the virus.
In that first year of monitoring work, scientists ultimately collected more than 11,000 samples from deer in 26 states and Washington, DC. About a third of the animals had antibodies to the coronavirus, indicating they had been exposed to it in the past, and 12 percent were active. infected, APHIS said on 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 the deer, including the alpha. , Gamma, Delta and Omicron variants.
Then, the scientists compared viral samples isolated from the deer to samples from human patients and mapped the evolutionary relationships between them. They concluded that the virus was transferred from humans to deer at least 109 times and that transmission from deer to deer occurred more often.
The virus also showed signs of being adapted 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 next: Monitoring will continue.
APHIS has expanded its monitoring to additional states and species.
Many questions remain, including how people are transmitting the virus to deer, and what role the animals may have played in maintaining the virus in the wild.
