A four-year-old Italian greyhound in Paris appears to be the first domestic dog infected with the monkeypox virus. Researchers reported that the animal broke out in suspicious blisters 12 days after its owners developed pus-filled lesions. Tests confirmed that the same strain of monkeypox infected one of the two men and their dog.
Given the closeness we share with our pets, “this was not unexpected,” says Colin Parrish, a professor of veterinary virology at Cornell University who studies newly emerging canine viruses. It’s been a theoretical risk because we pet and kiss our dogs, cuddle them on our laps, and share food with them. They lick us and often sleep with us, as the greyhound did with his owners, Parrish notes.
Although the dog recovered, this canine case has prompted concerns among pet owners who wonder if they could get the virus from their dogs or cats or worry that their pets may be in danger.
These fears are largely unfounded, according to Parrish. “Don’t overreact. Don’t panic. The risk is very low.” With tens of thousands of human infections, if dogs were very susceptible, “we would have had a lot of cases by now,” he says. With just a single documented case, he considers it safe to take dogs to the park or doggie day care.
Can dogs pass the virus?
Overall, relatively little is known about monkeypox in companion animals such as dogs and cats, says Jeff Doty, the One Health team lead for the monkeypox response at the U.S. Centers for Disease Control and Prevention (CDC).
The study documenting the greyhound’s case didn’t elaborate on the animal’s symptoms or the severity of his illness, but the CDC has compiled a list of possible symptoms that dogs may experience: lethargy, refusal to eat, coughing, runny nose or eyes, and a blistery rash.
It’s unclear whether dogs that contract this virus can pass it to other dogs or to wild animals, or whether they might retransmit it back to humans. Doty says that depends on how much virus they shed and how they do so.
If dogs or other species can effectively amplify and then shed enough of the virus to trigger disease remains unknown, he says. And though researchers found that some animals, such as prairie dogs, seem to be able to spread monkeypox in nasal secretion and feces, “we just don’t know that for dogs.”
Parrish notes that hypothetically, if you rubbed against a dog with lesions, you could pick up the virus, but “the biggest risk is still human-to-human contact.”
How to protect your pet—and yourself
While case numbers continue to rise, “most of the general population are not at risk of contracting monkeypox,”Mike Ryan, executive director of the Health Emergencies Program at the World Health Organization, said in a news conference last week. He added that “animals and pets are not a risk to people right now.”
In fact, people present more of a risk to animals. Public health agencies emphasize that those who contract monkeypox should avoid contact with pets, livestock, and other captive animals, as well as wildlife.
If pets have not been exposed, the CDC recommends that symptomatic owners hand them off to family members or other caretakers until they have recovered––and disinfect the house before the pets return home. If that’s not possible, the agency recommends isolating the animals and keeping them quarantined for 21 days.
Some people may have no other option than to care for their pets. “Normal, sensible precautions are almost certainly sufficient,” Parrish says. He notes the importance of wearing clothes that cover the rash, washing hands, using hand sanitizer, wearing gloves and a mask around animals, and keeping them away from contaminated bedsheets and towels. Careful waste management is critical to prevent spread to neighborhood animals that might rummage through garbage.
The CDC warns against attempting to bathe pets in disinfectants, alcohol, hand sanitizer, or other chemicals that could poison them.
In the unlikely event that you’ve been diagnosed with monkeypox, and your pet breaks out in lesions or develops two or more symptoms within 21 days of exposure to you, the agency advises that you call your veterinarian.
Vigilance is needed. There are effective human vaccines, and “we should try to control and eradicate the virus from humans if we can,” says Parrish. There are no licensed vaccines available for dogs or cats.
“We need to be cautious,” Ryan says, because the more viruses spread, “the more they can evolve.”
Animal to human transmission
Like some 60 percent of human diseases, monkeypox is zoonotic: it originated in animals and then infected people. The disease was named in 1958 after being discovered in captive monkeys that were used for research in Denmark, but it’s primarily a rodent virus.
Monkeypox’s main animal reservoir(s) remains a mystery. But public health experts do know that small rodents—rope and sun squirrels, Gambian pouched rats, and African dormice—harbor the virus in the tropical rainforests of Central and West Africa, where it’s endemic.
The first human case was diagnosed in 1970, 12 years after monkeypox was first identified. For decades, infections were likely “spillover” events, with the virus jumping to individuals as they handled infected animals while hunting, butchering, or eating them.
By 2010, reports of human-to-human transmission began to emerge, and in 2017, a localized outbreak in Nigeria began. The virus has now spread between people across the globe.
While the risk to dogs and cats seems to be slim, there is limited information on which animals are susceptible to monkeypox.
Squirrels, monkeys, great apes, and some types of rats and mice can be infected, as well as hedgehogs, shrews, chinchillas, and other small mammals. There are questions about cows, since a relative of monkeypox—cowpox—infects the bovids. Whether cats, gerbils, rabbits, hamsters, raccoons, skunks, and other species are at risk is still not known.
There’s particular concern that monkeypox could infiltrate U.S. rodent populations, which often live in large social congregations. The West’s dense prairie dog colonies are on that list. In 2003, a shipment of 800 small mammals imported from Ghana to Texas for the exotic pet trade brought monkeypox to the U.S. The prairie dogs caged beside them caught the virus and then infected 47 people who bought and handled them, were bitten by them, or were simply in the same room.
Some good news comes from lab studies showing that the ubiquitous urban rats of the genus Rattus that infest the world’s cities seem to develop immunity to monkeypox just days after birth, Doty says.
Growing human cases have put public health officials on high alert. Spillback from humans into animals could create new endemic reservoirs and brand-new chains of transmission, says Andrea McCollum, an epidemiologist with the CDC’s 2022 Monkeypox Outbreak Response effort.
“What we don’t want to see happen,” says WHO’s Ryan, “is disease moving from one species to the next.” That could make monkeypox nearly impossible to eradicate.
Adapting to a new host allows a virus to evolve, with the possibility that it will develop and mutate differently,” says Rosamund Lewis, WHO’s technical lead for monkeypox. That means it could become more or less contagious, weaker—or more virulent.
“We know that there are genetic changes going on, Doty says, but we don’t know what [they] may mean for susceptibility or the ability of the virus to infect different animal species.”
However, when zoonotic viruses contaminate a new species, it’s usually a dead end,” says Sylvie Briand, WHO’s director of global infectious hazard preparedness. “It stops there because the virus is not very fit for this species.”