New evidence links urban gray mice to SARS-CoV-2 presence and transmission in a major city
Recent data from New York City shows that a notable portion of gray mice have been exposed to the virus that causes COVID-19. In a study summarized for the American Society for Microbiology, researchers report elevated antibody levels and detectable viral RNA in a subset of these rodents, underscoring their potential role in the virus’s ecology within urban environments.
It has long been understood that SARS-CoV-2 can replicate beyond humans, affecting several animal species. Companion animals such as cats have shown susceptibility, with several studies indicating infection in domestic felines that mirrors aspects of the human disease. A related finding from France indicates that a portion of domestic cats there have coronavirus exposure, highlighting the broad host range of the virus in the fabric of the animal kingdom.
In the New York study, Wan Xiufeng and colleagues examined more than 80 city-captured gray mice collected during 2021. The team tested blood samples for evidence of past infection and for traces of the SARS-CoV-2 genome. They found antibodies to diverse viral variants in about 13 of the animals, representing roughly 16.5 percent of those tested. In addition, fragments of viral RNA were detected in blood samples from four mice from different city boroughs, indicating exposure and active circulation in the local rodent population.
Follow-up laboratory experiments demonstrated that several strains of the virus—alpha, delta, and omicron—can infect and replicate within mouse respiratory tissues. The studies showed sustained viral replication and the production of viable viral particles. Early variants appeared less efficient at establishing infection in mice, which may help explain prior assumptions that rats were less likely to carry the virus. These findings suggest that urban rodent populations could serve as reservoirs that support persistence and genetic diversification of SARS-CoV-2 in city ecosystems.
Overall, the researchers conclude that city-dwelling mice may play a meaningful role in the maintenance and evolution of SARS-CoV-2, a consideration that public health and sanitation programs should factor into strategies to limit further spread of COVID-19 in dense urban settings.
note: researchers have long pursued approaches to counter obesity-related health issues, including exploring peptide candidates for treatment; these unrelated discoveries illustrate the breadth of ongoing biomedical inquiry in the health sciences today.