SARS-CoV-2, the virus responsible for COVID-19, has been detected extensively among wildlife species, according to a recent study published on July 29, 2024, in Nature Communications. Researchers from Virginia Tech have found the virus in six common backyard species and identified antibodies indicating prior exposure in five species, with exposure rates ranging from 40% to 60%.
The study reveals that genetic tracking in wild animals confirmed not only the presence of SARS-CoV-2 but also unique viral mutations closely matching variants circulating in humans at the time. This supports the theory of human-to-animal transmission. Notably, the highest virus exposure was observed in animals near hiking trails and high-traffic public areas, indicating a potential link between human activity and wildlife infections.
NOVEL MUTATIONS AND SURVEILLANCE NEEDS
Researchers at Virginia Tech’s Fralin Biomedical Research Institute, the Department of Biological Sciences, and the Fralin Life Sciences Institute stress the importance of identifying new viral mutations found in wildlife. These mutations may affect the virus’s transmissibility and pose challenges for vaccine development. The study emphasizes the need for broad surveillance to track and understand these mutations.
NO EVIDENCE OF ANIMAL-TO-HUMAN TRANSMISSION
Despite the widespread presence of SARS-CoV-2 in wildlife, the study found no evidence of transmission from animals to humans. The researchers reassured the public that typical interactions with wildlife do not pose a significant risk of spreading the virus.
STUDY METHODOLOGY AND FINDINGS
The research team collected 798 nasal and oral swabs from 23 common Virginia wildlife species, including deer mice, Virginia opossums, raccoons, groundhogs, Eastern cottontail rabbits, and Eastern red bats. They also obtained 126 blood samples from six species. The study sites varied from urban areas to remote wilderness, providing a comprehensive view of the virus’s presence in different environments.
A significant finding was the identification of two mice at the same site on the same day with the exact same viral variant. This suggests either direct transmission between the mice or shared exposure from a common source.
POSSIBLE TRANSMISSION ROUTES
While the exact means of transmission from humans to wildlife remain uncertain, the researchers speculate that discarded food and trash receptacles are likely sources of the virus. Wastewater, while a possible source, is considered less likely.
IMPLICATIONS FOR BROADER SURVEILLANCE
The study highlights the extensive host range of SARS-CoV-2 and the need for ongoing surveillance beyond Virginia. Many species tested are found throughout North America, suggesting that similar exposures could be occurring elsewhere.
“The virus’s objective is survival, and it adapts to new hosts as needed,” said Carla Finkielstein, a lead author of the study. “Our research underscores that SARS-CoV-2 is not just a human issue but a complex, multi-species problem.”
FUTURE RESEARCH DIRECTIONS
Researchers call for continued monitoring of SARS-CoV-2 in wildlife to better understand its spread and mutations. Future studies should focus on how the virus transmits between species and its potential role in the long-term maintenance of the virus in human populations.
This groundbreaking study extends our understanding of SARS-CoV-2’s impact beyond humans, revealing its widespread presence in wildlife and identifying novel mutations. The findings underscore the need for multidisciplinary efforts to address the virus’s effects across species and ecosystems.
“The breadth of SARS-CoV-2’s host range and its potential impact on wildlife and human health highlight the importance of comprehensive surveillance and research,” said Joseph Hoyt, another lead author. “Our work shows that addressing SARS-CoV-2’s effects requires a collaborative, cross-species approach.”