Update (April 8): The study described in this article has now been published in Science.
Cats and ferrets can both be infected with SARS-CoV-2, the virus that causes COVID-19, and can pass the infection on to other members of the same species, researchers reported in a study preprint on March 31. The study indicates that ferrets may be a suitable laboratory model for studying the disease (indeed, researchers are already using ferrets in their SARS-CoV-2 studies), but experts say it doesn’t reveal whether pets could transmit the infection to people.
In the study, which has not undergone peer review, researchers put viral particles into the noses of a small number of cats. They euthanized a few of the animals four days later and tested their organs for SARS-CoV-2 genetic material. They found viral RNA in the cats’ noses, soft palates, and tonsils, but not in their lungs. Other exposed animals were housed in cages near unexposed animals. The researchers later detected viral RNA in one of the three cats that had been housed near an infected cat.
The team, led by Zhigao Bu of the Harbin Veterinary Research Institute, also ran tests on ferrets, dogs, pigs, chickens, and ducks, and found viral RNA in the ferrets after their exposure. Two of the five exposed dogs had viral RNA in a rectal swab, but not an oronasal swab, two days after infection, while none of the pigs or fowl tested positive for viral RNA at any of the time periods tested.
Jonathan Ball, a virologist at the University of Nottingham in the UK, tells The Guardian that cats had similarly been found to be susceptible to infection with the virus that caused the SARS outbreak of 2003, which is related to SARS-CoV-2. “However, it should be remembered that cats are not playing much, if any, role in the spread of this virus,” he says. “Human to human transmission is clearly the main driver, so there is no need to panic about cats as an important source of virus. Obviously, if you think you have Covid-19 and share a house with a cat, then it would be sensible to limit close interactions with your furry friend until you are better.”
Virologist Linda Saif of the Ohio State University notes in an interview with Nature that none of the infected cats showed symptoms of illness, and that only one out of the three felines housed near infected cats caught the virus. “This suggests the virus may not be highly transmissible in cats,” she says.