Why it matters: Deer are a potential source of new variants.
Although there is no evidence that deer play a major role in the spread of the virus to humans, human-to-animal transmission of the virus raises several public health concerns.
First, animal reservoirs may persist variants of viruses that have disappeared from human populations. Indeed, the new study confirms previous reports that some coronavirus variants, including alpha and gamma, continued to circulate in deer after becoming rare in humans.
New animal hosts also give the virus new opportunities for mutation and evolution, potentially creating new variants that can infect humans. If these variants are sufficiently different from those that have circulated in humans so far, they may be able to bypass some of the immune system’s defenses.
Background: Scientists have found signs of widespread infection in deer.
Researchers at the Animal and Plant Health Inspection Service will work with other governments and academic scientists to begin searching for coronaviruses in free-ranging white-tailed deer in 2021, after research suggested animals were more susceptible to the virus. rice field.
In the first year of surveillance, scientists ended up collecting more than 11,000 samples from deer in 26 states and Washington, DC. Nearly one-third of the animals had antibodies to the coronavirus, suggesting that they had been previously infected, and 12% were actively infected. APHIS announced on Tuesday that it had an infected person.
For a new paper in Nature Communications, 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 multiple versions of the virus, including alphavirus, in deer. , gamma, delta and omicron variants.
The scientists then compared virus samples isolated from deer and human patients to map the evolutionary relationships between them. The researchers concluded that the virus had been transmitted from humans to deer at least 109 times, with frequent subsequent deer-to-deer transmissions.
The virus shows signs of adapting to deer, and researchers have identified several human infections with these “deer-adapted” versions of the virus in North Carolina and Massachusetts.
What’s next: Monitoring continues.
APHIS has expanded its coverage to more states and species.
Many questions remain, including exactly how people transmit the virus to deer and what role animals play in maintaining the virus in the wild.
