A dog tested positive for monkeypox, and may have contracted the virus from his owners, raising questions about human-to-animal transmission

• An Italian greyhound tested positive for monkeypox in Paris after its owners contracted the virus.
• The owners developed pus-filled blisters and fevers 12 days before the dog also got a rash.

Researchers described the first suspected canine monkeypox case in a dog that shared a bed with its infectious owners, and the case, raising new questions for researchers about human-to-animal transmission.

The dog owners, two men in a non-exclusive partnership, began experiencing symptoms of monkeypox at the end of May when they presented at a hospital in Paris, according to a report published in the Lancet on August 10.

Both men developed fevers, fatigue, and headaches after noticing pus-filled blisters on their bodies. They were careful to avoid contact with other people from the onset of their symptoms, and they quarantined their 4-year-old Italian greyhound as well.

The dog developed pus-filled blisters on its stomach and a small anal lesion about 12 days after the humans in the house began showing symptoms. Testing revealed that both the men and the dog were infected with identical monkeypox virus.

Monkeypox is known to infect a wide variety of mammals, and scientists are still learning which species can transmit the virus. Before this case, there were no reports of sick people spreading monkeypox to animals, according to the Centers for Disease Control and Prevention.

"This is the first case that's occurred that we're aware of, at least in the Western world during this latest outbreak, so it clearly isn't something that happens very easily," Colin Parrish, a professor of veterinary virology at Cornell University, told Insider.

Spillover infections in dogs are probably rare

Parrish said that it is unlikely that human-to-dog transmission, or vice versa, poses a major risk in monkeypox outbreaks.

"At the moment, there's no evidence that dogs are going to become a standing infected host for monkeypox," he said.

It's more likely that the case is a rare spillover infection, where a virus jumped to a new host outside of its primary host species. Dogs and cats have been known to contract flu viruses that typically infect humans, but infections in pets are uncommon, Insider previously reported.

If viruses could easily spread between humans and dogs, there would be a lot more shared diseases between people and their pets, Parrish said.

Still, the case shows a need for further research on monkeypox transmissions to and from pets, the authors of the Lancet report concluded. While there's not enough information to say that dogs are a secondary host for the virus, it's cause for consideration of how pet owners should self-isolate if they get monkeypox.

Use common sense

Dog owners who get monkeypox don't need to panic or send their pets away, but they should take sensible precautions to avoid close contact, Parrish said.

"Sharing a bed or having close contact with the animal certainly wouldn't be advised, but I would say that you can keep the dog in your house," he said. "As long as the dog isn't coming in contact with the lesions, then it's probably going to be fine."

The CDC says people with monkeypox should avoid contact with animals, including pets and wildlife, to prevent spreading the virus. The agency does not recommend surrendering, euthanizing, or abandoning pets just because of a potential exposure or monkeypox case. Instead, simply avoid cuddling, kissing, and sharing sleeping areas or food with pets while you're infectious.