The first suspected case of human-to-dog transmission of monkeypox has been reported in Paris, leading the U.S. Centers for Disease Control and Prevention to update its website to include dogs among animals susceptible to catching the virus.

The disease can spread between people and animals, said the CDC, which is studying which animals can contract monkeypox, which the United States declared a public health emergency this month. The CDC lists 10 animals, including dogs, that can be infected with monkeypox.

Monkeypox particles (red) found within an infected cell (blue), cultured in the laboratory that was captured and color-enhanced at the NIAID Integrated Research Facility (IRF) in Fort Detrick, Md. National Institute of Allergy and Infectious Diseases via AP

The evidence of spread from humans to dogs, published in the Lancet, could lead to further guidance on how pets should be cared for if they’re in a living space with an infected person, Rosamund Lewis, the World Health Organization’s lead on monkeypox, told The Washington Post on Monday.

Monkeypox usually spreads from human to human through direct contact with infectious rashes, scabs or bodily fluids. It can also be transmitted from respiratory secretions during prolonged face-to-face contact, or during intimate physical contact, such as kissing, cuddling or sex.

The potential case of human-to-dog transmission was discovered in a 4-year-old Italian greyhound 12 days after its owners had an onset of monkeypox symptoms, according to the Lancet report.

The dog had lesions on its skin and mucous membranes, pustules on its abdomen and a thin anal ulceration. Medical staffers matched one of the dog owners’ infections to the one detected in the animal.

Researchers said the dog belonged to two men who were in a nonexclusive, cohabiting relationship with each other. One of the partners is a 44-year-old man, and his partner is a 27-year-old man, according to the report.

The couple reported that they let their dog sleep in the bed with them and that they had prevented their pet from being in contact with other humans and pets based on the onset of their own symptoms.

Monkeypox has been roaring through communities of men who have sex with men, increasing anxiety and concern in cities with high populations of gay and bisexual men, and prompting the WHO to advise those groups to limit sexual partners to reduce risk of exposure.

About 99% of monkeypox cases worldwide are found in men, and 98% of those cases involve men who have sex with men, Lewis said Monday, shortly after the Lancet report surfaced.

Lewis also addressed transmission of the monkeypox virus between humans and animals, sharing that there have been cases of people getting the virus from newly acquired pets.

“This is the first incident that we’re learning about where there is human-to-animal transmission,” she said of the Lancet report’s findings. “So, on a number of levels, this is new information. It’s not surprising information, and it’s something that we’ve been on the watch out for.”

In the report, researchers called for further investigation on secondary transmissions via pets.

“Our findings should prompt debate on the need to isolate pets from monkeypox virus-positive individuals,” they said.

Lewis said messaging has encouraged people to isolate their pets from family members who may be infected with monkeypox – a precautionary approach as scientists continue to study the virus’s spread, she said.

“So again, we don’t know if that dog can go and transmit the infection to anyone else, for example,” she said. “This is an example where most pets will not be at risk. It may only be those who are actually in the household of someone who’s infected.”