Study shows deer can transmit COVID for up to five days

New research published in PLoS Pathogens shows that white-tailed deer (Odocoileus virginianus) can transmit COVID up to five days after infection. Moreover, like humans, the virus reproduces in the upper respiratory tract of deer, especially in the nose. 

Study co-author Dr. Diego Diel is an associate professor and director of the Cornell University Virology Laboratory in the College of Veterinary Medicine’s Animal Health Diagnostic Center.

“It’s a relatively short window of time in which the infected animals are shedding and are able to transmit the virus,” said Dr. Diel.

For the investigation, the researchers infected six captive white-tailed female fawns, who were less than eight months old, along with six adults, who were three to four years of age. Six fawns were used as contact animals, and three were used as controls. For the adult portion of the study, two animals were used as controls.

Over approximately 20 days, the researchers introduced the contact fawns to the virus. They monitored the animals and took biological samples to determine which animals were infected and to learn more about how they carried the virus. Although there is no evidence that humans have caught COVID from deer (evidence points rather to transmissions from humans to deer), the researchers feel this study is important because they believe white-tailed deer could become a reservoir species for the virus. The study authors are particularly concerned about transmission through the hunting of deer in the United States.

“Given the broad practice of deer hunting in the U.S., knowing the sites of virus replication is important to minimize the risks of exposure and transmission from these wild animals that could potentially transmit the virus back to humans,” said Dr. Diel.

The researchers hope that by learning more about where the virus replicates, they can educate hunters on the best practices to avoid infection. For example, the study shows that the virus replicates in deer tonsils, lymphoid tissues, and the central nervous system. Hunters might want to take extra precautions when handling these areas.

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By Erin Moody , Earth.com Staff Writer