A report yesterday in Nature Communications details the spread and evolution of SARS-CoV-2 in white-tailed deer across the United States, including at least 109 spillover events from people and 39 instances of deer-to-deer transmission. Researchers also noted three cases of potential spillover from white-tailed deer back to humans.

The findings are based on 8,830 respiratory samples from free-ranging white-tailed deer across Washington, DC, and 26 US states from November 2021 to April 2022. A total of 944 samples were positive for SARS-CoV-2, and researchers sequenced the genomes from 391 samples.

Sequencing showed Alpha, Gamma, Delta, and Omicron lineages, and multiple lineages were circulating among deer at the same time.

"Out of the 282 white-tailed deer viruses analyzed, 238 were found to be grouped into 109 clusters that also contained human SARS-CoV-2 viruses," the authors said. "For each cluster, a SARS-CoV-2 genomic sequence from a human was identified as the precursor virus with at least 99.85% nucleotide identity, indicating at least one independent spillover event from humans to white-tailed deer."

3 human-to-deer-to-human events

Of the 109 spillover events, 106 were within the same state, including 64 that were human-to-deer, 39 that were human-to-deer-to-deer, and 3 human-to-deer-to-human.

White-tailed deer are some of the most common mammals in the United States, with approximately 30 million animals in both rural and urban settings and a high number of human interactions, the authors said. Previous studies showed approximately 40% of tested white-tailed deer were exposed to SARS-CoV-2, as early as January 2020, in four sample US states.

Continued large-scale surveillance of white-tailed deer is necessary.

"Continued large-scale surveillance of white-tailed deer is necessary to understand the evolution and distribution of genetic variants in white-tailed deer, evaluate whether the white-tailed deer are a potential reservoir for SARS-CoV-2 viruses, and the role of white-tailed deer in ecology and natural history of SARS-CoV-2," the authors concluded.

Data on chronic wasting disease (CWD) sampling in Wyoming's large game animals for 2022 suggests a slow rise, with the disease spreading from east to west, according to an update last month from the Wyoming Game & Fish Department (WGF).

Tests are done on submissions from hunters, road-killed animals, and animals found dead or in poor condition. Most samples are from hunter check-in stations. Of 6,701 samples from big game animals that were tested, 826 were positive for CWD, similar to 2020 and 2021.

The prevalence of CWD is slowly increasing in many deer and elk herd units.

Jessica Jennings-Gaines, a WGF wildlife specialist, said comparing the numbers each year can be misleading, because the surveillance program focuses on different deer and elk herd unit each year.

"We can say that the prevalence of CWD is slowly increasing in many deer and elk herd units in the state," she said. "The western half of Wyoming has several deer hunt areas where CWD has not been detected; however, the disease continues to spread west and was detected in two new deer and five new elk hunt areas last year."

Listening sessions on CWD herd certification

In other CWD developments, the US Department of Agriculture (USDA) Animal and Plant Health Inspection Service (APHIS) today announced five virtual listening sessions on CWD herd certification standards. In a statement, officials said they're looking for input on the program's direction, ways to increase enrollment, biosecurity, and CWD prevention.

The sessions, held on Zoom, begin on July 27 and run through September 14. Topics vary by date, and APHIS is also accepting written comments.

• In an update on the next steps with COVID-19 vaccines, the Department of Health and Human Services said that August 3 is the final day that health providers can order vaccine from the federal government through the traditional system. After that, the new monovalent (one-strain) vaccine that targets the XBB.1.15 Omicron subvariant will be available through the commercial market. The Centers for Disease Control and Prevention (CDC), however, will offer access to COVID-19 vaccine for uninsured adults through the temporary bridge access program and for uninsured children through the existing Vaccines for Children program.
• The US Department of Defense late last week announced the destruction of the final munition in the country's obsolete chemical weapons stockpile, a disarmament milestone that it says was decades in the making. The final sarin nerve agent rocket was destroyed on July 7 at the Blue Grass Army Depot in Kentucky, ahead of a September 30 commitment by the United States to complete its destruction operations. In a statement congratulating the federal departments that took park in the efforts, the CDC said more than 30,000 tons of American chemical warfare agents were destroyed. "This milestone has successfully eliminated a major public health threat for communities, the U.S., and the world," it said.

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  Mandy Cohen, MD, MPH, was sworn in yesterday as the CDC's new director. Cohen is the CDC's 20th director and was appointed to the post by President Joe Biden on June 16. Cohen is an internal medicine doctor and North Carolina's former health secretary. She worked with federal health officials during the Obama administration and was a healthcare executive before accepting the CDC director post.