Because monkeypox can spread through close contact with an infectious person, people who have tested positive should be careful when cuddling or petting animals, according to Centers for Disease Control and Prevention guidance issued Friday. Pets may also pick up the virus through blankets or other household items used by patients, the CDC said, and if a pet appears to be sick, owners should contact a veterinarian. 

“Pets that had close contact with a symptomatic person with monkeypox should be kept at home and away from other animals and people for 21 days after the most recent contact,” the Atlanta-based CDC said in a statement on its website dated Aug. 12. “Infected people should not take care of exposed pets.”

The CDC updated its guidance after a dog was reported to have contracted monkeypox from its owners in what is thought to be the first case of human-to-dog transmission. The four-year-old greyhound developed lesions almost two weeks after his owners, a non-monogamous gay couple, began showing symptoms of monkeypox, according to a report published Aug. 10 in The Lancet medical journal. The dog’s owners, who were both positive for monkeypox, reported allowing the dog to sleep in their bed.  

“Our findings should prompt debate on the need to isolate pets from monkeypox virus-positive individuals,” the authors of the Lancet study concluded. “We call for further investigation on secondary transmissions via pets.”

Monkeypox is a zoonotic virus that, like the coronaviruses that cause SARS, MERS and Covid-19, can jump from humans to animals. In past monkeypox outbreaks, the virus primarily spread to humans through direct contact with infected animals, including through consuming their meat. 

In 2003, monkeypox spread to 47 people in the US who had contact with infected pet prairie dogs. The rodents were infected after being housed near imported small mammals from Ghana, according to the CDC. 

Monkeypox can also jump back to animals from humans, something experts have warned could complicate efforts to stop the current outbreak. Other animals susceptible to monkeypox infection include squirrels, groundhogs, chinchillas and dogs, the CDC said. Rabbits may be vulnerable to infection, and it’s not yet known whether cats are. 

The outbreak has spread primarily among men who have sex with men, mostly through close, intimate contact, but animals can also contract the virus if they’re exposed to someone who is infectious. But recent reports of animals getting monkeypox have already led to rampant misinformation on social media — prompting World Health Organization experts to respond.

Rosamund Lewis, the WHO’s technical lead on monkeypox, called one since-deleted tweet from a New York-based doctor “deliberately misleading” because it appeared to suggest the pet greyhound dog in Paris could have contracted the virus sexually from its owners. 

“Orthopoxvirus infections often cause mucosal lesions regardless of the mode of transmission,” Lewis wrote. “As a urologist you should know this.”