SARS-CoV-2 [the virus that caused COVID] evolves three times faster in white-tailed deer than in people, making NIAID-funded scientists at The Ohio State University and colleagues ask whether deer are an important reservoir for emerging virus variants—similar to how influenza virus evolves and spreads from pigs.

The Ohio State project, published August 28 in Nature Communications, examined infection rate, persistence, spread and evolution of SARS-CoV-2 in deer throughout Ohio. Scientists collected more than 1,500 deer nasal samples in 83 of the state’s 88 counties and, from antibody results, estimated that 23.5% of the animals had been infected with SARS-CoV-2. Their work also identified more than 30 instances where the virus had spread from people into deer between November 2021 and March 2022. For the next eight months, they then documented the virus further spreading among deer, noting that the alpha and delta virus variants evolved in deer three times faster than in people.

Their study found no concerning evolutionary changes—the virus efficiently transmitted among deer without significant changes. But their study also noted that “SARS-CoV-2 viruses have transmitted in white-tailed deer populations for a relatively short duration, and the risk of future changes may have serious consequences for humans and livestock.”

The work has drawn attention from NIAID viral ecology colleagues at Rocky Mountain Laboratories (RML) in Hamilton, Montana, who approached the Ohio State team to collaborate on new investigations. [the virus t The RML scientists plan to expand the Ohio State work by assessing how different SARS-CoV-2 variants respond in deer cells and whether new variants are emerging.

“SARS-CoV-2 is currently not considered an important risk for North American livestock,” the Ohio State study states. “But the continued spread of the virus in white-tailed deer, humans, and other hosts could open new pathways for SARS-CoV-2 evolution that we are only beginning to uncover.”

This NIAID News blog post was published by the National Institute of Allergy and Infectious Diseases on August 28, 2023.