The results of the study, published yesterday in the journal mBio, showed that 13 out of 79 mice (16.5 percent) tested positive for the virus.
This means that potentially 1.3 million of the city’s eight million mice could be positive.
In addition to the mice being infected with Alpha, Delta, and Omicron variants, the researchers discovered that SARS-CoV-2 mutated to adapt to its new hosts after infecting the mice.
Researchers are now trying to estimate the likelihood of the strains reappearing and reinfecting people.
“The findings highlight the need for further monitoring of SARS-CoV-2 in mouse populations for potential secondary zoonotic transmission to humans,” lead researcher Henry Wan said in the press release.
Mice are not alone in their susceptibility to the virus that causes COVID-19.
About 17 million mink were killed in Denmark in 2020 after they were found to be infected with a new strain of the virus.