Scientists are unsure whether wild deer may be reservoirs of the SARS-CoV-2 virus.
Scientists have traced infection to at least three types of the virus that causes COVID-19 In free white-tailed deer in six Northeast Ohio locations, the research team has reported.
Previous research led by the US Department of Agriculture had shown evidence of antibodies in wild deer. This study, published today (December 23, 2021) nature, details the first report of active COVID-19 infection in white-tailed deer supported by the development of viral isolates in the laboratory, indicating that the researchers had recovered viable specimens of it. SARS-CoV-2 Virus and not only its genetic traces.
Based on genomic sequencing of samples collected between January and March 2021, the researchers determined that the variants infecting wild deer matched the strains of the SARS-CoV-2 virus that were present in Ohio COVID-19 patients at the time. were popular. Specimen collection took place before the delta variant became widespread, and that variant was not detected in these deer. The team is testing more samples to check for new variants as well as older variants, whose continued presence suggests the virus can set up shop and survive in this species.
The fact that wild deer can become infected “leads to the idea that we may have actually established a new maintenance host outside of humans,” said associate professor of veterinary preventive medicine at Ohio State University and the paper’s senior. Writer Andrew Bowman said.
“Based on evidence from other studies, we knew that they were being exposed in the wild and that in the laboratory we could infect them and spread the virus from deer to deer. Here, we are saying that in the wild, They are infected,” Bowman said. “And if they can sustain it, we have a new potential source of SARS-CoV-2 coming into humans. This would mean that in addition to keeping track of what is in people, we also need to know what is in deer.
“This could complicate future mitigation and control plans for COVID-19.”
A lot remains unknown: how deer got infected, whether they can infect humans and other species, how the virus behaves in animal bodies, and whether it is a transient or long-term infection.
The research team took nose swabs from 360 white-tailed deer in nine northeastern Ohio locations. Using PCR testing methods, the scientists detected genetic material from at least three different strains of the virus in 129 (35.8%) of the deer sampled.
The analysis showed that the dominant B.1.2 virus in Ohio spread several times to deer populations in different locations in the early months of 2021.
“The working principle based on our sequences is that humans are giving it to deer, and apparently we’ve given it to them multiple times,” Bowman said. “We have evidence of six different viral introductions in those deer populations. It’s not like the same population got it once and spread.”
Each site was sampled between one and three times, adding up to a total of 18 sample collection dates. Based on the findings, the researchers estimated the infection prevalence in the nine sites ranged from 13.5% to 70%, with the highest prevalence seen in four sites that were surrounded by more densely populated neighbourhoods.
Bowman said one of two outcomes could result from the white-tailed deer acting as a viral reservoir of SARS-CoV-2. The virus may mutate in deer, potentially facilitating transmission of new strains to other species, including humans, or the virus may survive in deer without mutating while it simultaneously continues to evolve into humans, And at some point when humans don’t have immunity. The strains that infect deer, those types can be spread back to humans.
How transmission initially occurred in these deer, and how it may have occurred across species, are among pending questions related to these findings. The research team hypothesized that white-tailed deer were infected by an environmental route – possibly by drinking contaminated water. Research has shown that the virus is shed in human feces and can be detected in wastewater.
The white-tailed deer tested for this study were part of a population control initiative, so they are not a transmission threat.
Although there are an estimated 600,000 white-tailed deer in Ohio and 30 million in the United States, Bowman said this sample is concentrated in places close to dense human populations and is not representative of all free-ranging deer.
Reference: 23 December 2021, nature,
This work was supported by the Ohio State Infectious Disease Institute and the National Institute of Allergy and Infectious Diseases. In addition to USDA, NIAID, Ohio Wildlife Center and Cleveland Metroparks contributors, Ohio State co-authors include Vanessa Hale, Patricia Dennis, Dylan McBride, Jacqueline Nolting, Christopher Madden, Deora Hugh, Margot Ehrlich, Janesa Winston, Dabraska Diaz-Campos Huh. Page Yaxley, Alexis MacLean, Risa Pesapane, Mark Flint, Jailyne Flint, Anastasia Vlasova, Scott Kenny, Qiuhong Wang, Linda Saff and Seth Faith.