Virus Variants Can Infect Mice, Scientists Report

In the study, the researchers introduced the virus into the nasal passages of laboratory mice. The form of the virus first identified in Wuhan, China, cannot infect laboratory mice, nor can B.1.1.7, a variant that has been spreading across much of Europe, the researchers found.

But B.1.351 and P1, the variants discovered in South Africa and Brazil, can replicate in rodents, said Dr. Xavier Montagutelli, a veterinarian and mouse geneticist at the Pasteur Institute in Paris, who led the study. The research, posted online earlier this month, has not yet been reviewed for publication in a scientific journal.

The results indicate only that infection in mice is possible, Dr. Montagutelli said. Mice caught in the wild have not been found to be infected with the coronavirus, and so far, the virus does not seem to be able to jump from humans to mice, from mice to humans, or from mice to mice.

“What our results emphasize is that it is necessary to regularly assess the range of species that the virus can infect, especially with the emergence of new variants,” Dr. Montagutelli said.

The coronavirus is thought to have emerged from bats, with perhaps another animal acting as an intermediate host, and scientists worry that the virus may return to what they describe as an animal “reservoir.”