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.

Peru's health ministry on July 8 declared a health emergency due to a rise in Guillain-Barre syndrome (GBS) cases, and yesterday the Pan American Health Organization (PAHO) fleshed out some of the details, including that 191 cases meeting the country's case definition have been recorded, 4 of them fatal.

Eight departments have reported cases, with Lima and La Libertad among the hardest-hit locations. Nearly 58% of the patients are males, with an average age of 41 years. PAHO said Peru typically averages about 20 GBS cases a month, but 96 cases were reported in June.

Of the GBS patients, 23.0% initially presented with gastrointestinal symptoms, and 24.1% first had respiratory symptoms. And, of samples collected from patients, 11 were positive for Campylobacter jejuni.

PAHO said Peru experienced an unprecedented GBS outbreak in 2019 that affected people in multiple parts of the country. The investigation found that it was associated with the Campylobacter jejuni ST2993 genotype.

As part of the current health emergency, Peruvian officials have implemented a plan, including buying human immunoglobulin for treating GBS patients and stepping up surveillance and response actions. PAHO said it is supporting the country's health ministry in managing the event.

• 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.