Coronavirus variants can infect mice

Some of the new coronavirus variants can cause COVID-19 in mice, researchers have found.

The implications, such as whether mice could then transmit the virus to humans, will require further study, they said. The original virus strain identified in Wuhan, China, could not produce illness in mice because the spikes on its surface could not bind well to the ACE2 receptor protein on the animals’ cells.

Some of the new concerning variants – particularly the ones first identified in South Africa and Brazil – have mutations that overcome this challenge, giving them the ability to infect and sicken the mice, researchers reported on Thursday on bioRxiv ahead of peer review.

“This is indeed great news for animal studies to better understand the infection and disease as mice are widely available … to study many pathologies, and easier to work with than larger animals such as hamster or ferret,” said coauthor Etienne Simon-Loriere of Institut Pasteur in Paris.

Whether mice can transmit the virus to each other or to humans remains to be determined. “We do not have expertise to evaluate the health risk posed by this newly acquired capacity of SARS-CoV-2, but this is definitely something that will need to be done,” Simon-Loriere said.

“No one wants the virus to move to a new reservoir from where it could come back to humans, as was feared with mink farms, and hopefully it will not happen.”