Coronavirus Highly Contagious Among Cats After Humans Infect Them, Researchers Find

The novel coronavirus that has proven to be highly contagious among humans can also spread quickly among cats, new research published Wednesday showed.

In a study published in the New England Journal of Medicine, researchers in the U.S. and Japan led by a professor at the University of Wisconsin School of Veterinary Medicine said healthy cats that interacted with COVID-19-positive cats contracted the virus as soon as one day after exposure. All cats that were exposed tested positive within three days of exposure, researchers said.

"There is a public health need to recognize and further investigate the potential chain of human–cat–human transmission," the study said, citing earlier reports of cats contracting the virus from humans.

Cat at San Diego Humane Society
A cat that is not eating or drinking is assessed at the clinic at the San Diego Humane Society on April 21, 2020 after two cats in New York became the first pets in the U.S. to test positive for the new coronavirus. According to a study published Wednesday, healthy cats can easily contract COVID-19 from other cats that have tested positive for the virus. ARIANA DREHSLER/AFP via Getty Images

Health officials around the world have so far said that, while more research was needed to determine the threat infected animals pose of transmitting the virus to humans, their potential ability to do so was not a primary concern.

"The risk of animals spreading COVID-19 to people is considered to be low," the Centers for Disease Control and Prevention (CDC) said in its guidance for pet owners. The World Health Organization and the World Organization for Animal Health both agreed with the CDC's assessment, saying there has been no evidence so far that humans can contract the virus from their pets and that the primary mode of transmission has been among humans.

Still, the virus' ability to jump from humans to animals has raised questions regarding whether transmission could go in the opposite direction. The first reported case of an animal in the U.S. contracting the virus from a human carrier occurred in early April at the Bronx Zoo, when a tiger with a cough tested positive for COVID-19. Two domestic cats in the U.S. also had respiratory symptoms after contracting the virus, according to the American Veterinary Medical Association.

Unlike those cases, none of the six cats that were part of the study published Wednesday had symptoms, researchers said. All of the cats recovered from the virus less than a week after they were infected, the study's data showed.

"Cats may be a silent intermediate host of [COVID-19], because infected cats may not show any appreciable symptoms that might be recognized by their owners," the study warned. But in a news release announcing the team's findings, researcher Keith Poulsen of the University of Wisconsin-Madison said chances of pet cats contracting the virus from their owners were still greater than those of the virus jumping from cats to their human companions.

"Cats are still much more likely to get COVID-19 from you, rather than you get it from a cat," Poulsen said.