New York City rats have been found to carry SARS-CoV-2 in a new study appearing this week in mBio, raising concerns that the animals could act as a reservoir for the virus and aid in its transmission to humans. SARS-CoV-2 has been shown to infect a range of animals, including deer, cats, dogs, and mink. In light of the millions of rats that inhabit New York, a team led by University of Missouri's Xiu-Feng Wan examined SARS-CoV-2 exposure among 79 wild Norway rats captured in the city during late 2021. They found that 13 of the animals tested positive for the virus, predominantly variants that were circulating in New York during the early stages of the pandemic. The researchers also conducted virus challenge experiments, showing that rats are susceptible to the SARS-CoV-2 Alpha, Delta, and Omicron variants. "Our findings highlight the need for further monitoring of SARS-CoV-2 in urban rat populations and for evaluating the potential risk of secondary zoonotic transmission from these rat populations back to humans," the study's authors write.