SARS-CoV-2 was detected in common wildlife species

SARS-CoV-2, the virus responsible for COVID-19, is widespread among wildlife species, according to Virginia Tech research published Monday (July 29, 2024) in Nature communications. The virus was detected in six common backyard species, and antibodies indicating previous exposure to the virus were found in five species, with exposure rates ranging from 40 to 60 percent depending on the species.

Genetic monitoring in wild animals confirmed both the presence of SARS-CoV-2 and the existence of unique viral mutations with variants that closely matched humans at the time, further supporting human-to-animal transmission, the study found.

The highest exposure to SARS CoV-2 was found in animals near hiking trails and in high-traffic public areas, suggesting the virus passed from humans to wildlife, according to scientists at the Fralin Biomedical Research Institute at VTC, the Department of Biological of Science in Virginia. Tech’s College of Science and the Fralin Life Sciences Institute.

The findings highlight the identification of new mutations in SARS-CoV-2 in wildlife and the need for widespread surveillance, the researchers say. These mutations could be more harmful and contagious, creating challenges for vaccine development.

Scientists stressed, however, that they found no evidence of animal-to-human transmission of the virus, and people should not fear typical interactions with wildlife.

The researchers tested animals from 23 common Virginia species for both active infections and antibodies indicating past infections. They found signs of the virus in deer mice, Virginia opossums, raccoons, porcupines, eastern cottontail rabbits and eastern red bats. The virus isolated from an opossum showed previously unreported viral mutations that could potentially affect how the virus affects humans and their immune response.

“The virus can jump from humans to wildlife when we are in contact with them, like a hitchhiker switching rides to a new, more suitable host,” said Carla Finkielstein, a professor of biological sciences at the Fralin Biomedical Research Institute in VTC and one of the corresponding authors of the newspaper. “The goal of the virus is to spread to survive. The virus aims to infect more people, but vaccinations protect many people. So the virus turns to animals, adapts and mutates to thrive in new hosts.”

SARS CoV-2 infections have previously been identified in wildlife, mainly in white-tailed deer and wild mink. The Virginia Tech study greatly expands the number of species examined and the understanding of virus transmission to and between wildlife. The data suggest that exposure to the virus was widespread in wildlife and that areas of high human activity may serve as hotspots for transmission between species.

This study was really motivated by the identification of a large, important gap in our knowledge about the transmission of SARS-CoV-2 in a wider wildlife community. Many studies to date have focused on white-tailed deer, while what happens to much of our common backyard wildlife remains unknown.”

Joseph Hoyt, assistant professor of biological sciences in Virginia Tech’s College of Science and corresponding author on the paper

The research team collected 798 nasal and oral swabs in Virginia from animals that were either live-trapped in the field and released or treated by wildlife rehabilitation centers. The team also obtained 126 blood samples from six species. The sites were chosen to compare the presence of the virus in animals in locations with different levels of human activity, from urban areas to remote wilderness.

The study also found two mice in the same spot on the same day with the exact same variant, indicating that either they both got it from the same person or one infected the other.

Researchers are unsure of the means of transmission from humans to animals. One possibility is sewage, but Virginia Tech scientists believe garbage cans and discarded food are more likely sources.

“I think the big message is that the virus is pretty ubiquitous,” said Amanda Goldberg, a former postdoctoral fellow in Hoyt’s lab who is the study’s first author. “We found positives in a large suite of common backyard animals.”

While this study focused on the state of Virginia, many of the species that tested positive are common wildlife found throughout North America. They are likely to be exposed in other areas, and surveillance in a wider area is urgently needed, Hoyt said.

“The virus does not care whether its host walks on two legs or four. Its primary goal is survival. Mutations that do not provide a survival or reproductive advantage to the virus will not persist and will eventually die out,” said Finkielstein, the who is also director of the Virginia Tech Molecular Diagnostics Lab. The Roanoke lab was established in April 2020 to expand COVID-19 testing.

“We understood the critical importance of sequencing the genome of the virus that infects these species,” Finkielstein said. “It was a monumental task that could only be accomplished by a talented team of molecular biologists, bioinformaticians and modelers in a state-of-the-art facility. I am proud of my team and my partners, their professionalism and all this contributed to ensuring our success.”

Surveillance for these mutations should be continued and not dismissed, the scientists said. More research is needed on how the virus is transmitted from humans to wildlife, how it can spread within a species and perhaps from one species to another.

“This study highlights the potentially large host range that SARS-CoV-2 can have in nature and really how widespread it can be,” Hoyt said. “There is much work to be done to understand which wildlife species, if any, will be important for the long-term maintenance of SARS-CoV-2 in humans.”

“But what we’ve already learned,” Finkielstein said, “is that SARS CoV-2 is not just a human problem, and that it takes a multidisciplinary team to effectively address its impact across species and ecosystems.”