NEW YORK (NYTIMES) - Cats can infect each other with the new coronavirus, but they may not have any symptoms, researchers reported on Wednesday (May 13) in The New England Journal of Medicine.

The report follows earlier laboratory research and cases of domestic cats, as well as tigers and lions at the Bronx Zoo, that tested positive for the coronavirus. In several cases, those cats showed mild symptoms, but the six cats in the new experiment did not get sick at all and cleared the virus from their bodies on their own.

Dr Yoshihiro Kawaoka of the University of Wisconsin School of Veterinary Medicine and Dr Peter Halfmann of the University of Wisconsin-Madison, along with other researchers from both the United States and Japan, conducted the study in which three domestic cats were inoculated with the virus and three additional uninfected cats were put in cages, one with each of the inoculated cats.

First the cats that had been given the virus tested positive. Then their cage mates also caught the virus. None were sick and all were virus free after, at most, six days.

Cats have also contracted the virus from humans, but there are no reports of a person becoming infected with the virus from a cat, although the authors suggest that the possibility deserves more research.

The cats, once infected, shed virus particles in the same way that humans do. And it is the same coronavirus that infects people. That makes it theoretically possible for cats to give the virus to humans, said Dr Karen Terio, chief of the Zoological Pathology Programme at the University of Illinois College of Veterinary Medicine.

Still, Dr Terio, who was not involved in the study, wrote in an e-mail that "given the limited social circle of most domestic cats, cats are most likely to become infected after contact with a human member of their household".

The researchers urged people not to forgo the comforts of feline companionship; humans are the clear danger in terms of disease transmission, not pets.

If someone with a cat has the virus, Dr Halfmann, of the University of Wisconsin-Madison, said to use common sense.

"No cat kisses," he said.

The Centres for Disease Control and Prevention as well as other organisations suggest keeping pets away from humans who have tested positive.

If you are healthy, Dr Halfmann said, life can go on as usual.

"My cat sleeps on a pillow right next to me."

Asked if the results of the experiment had changed that habit, he said: "He was there last night."