Cats can get, and transmit, Covid-19
That’s the crux of it. A University of Wisconsin researcher found that humans can infect cats with SARS-CoV-2, and those cats can then spread it to other cats. In the research, none of the cats showed symptoms, and all eventually cleared the virus from their systems.
[R]esearchers advise that people with symptoms of COVID-19 avoid contact with cats. They also advise cat owners to keep their pets indoors, in order to limit the contact their cats have with other people and animals.