A dog has caught monkeypox. What does this mean for our pets and other species?
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 had infected one of the two men and their dog.
The virus, which is transmitted through physical contact, was declared an international health emergency in July. Cases currently number 44,503 in 96 countries and territories.
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 new emerging canine viruses. It was a theoretical risk because we pet and kiss our dogs, hide them in our laps, and share food with them. They often lick us and sleep with us, as the greyhound did with its owners, notes Parrish.
Although the dog has recovered, this canine case has raised concerns among pet owners who wonder if they could catch the virus from their dogs or cats or fear that their pets are 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 highly susceptible, “we would have had a lot of cases by now,” he says. With only one documented case, he considers it safe to take dogs to the park or dog daycare.
Can dogs transmit the virus?
Overall, relatively little is known about monkeypox in companion animals such as dogs and cats, says Jeff Doty, One Health team lead for monkeypox response at the Centers for Disease Control and Prevention. (CDC) of the United States.
The study documenting the greyhound’s case did not specify the animal’s symptoms or the severity of its illness, but the CDC has compiled a list of possible symptoms dogs may experience: lethargy, refusal to eat, cough, runny nose or eyes, and a blistering rash.
It is not known whether dogs that contract this virus can pass it on to other dogs or wild animals, or if they could pass it on to humans. Doty says it depends on how much virus they release and how they do it.
Whether dogs or other species can effectively amplify and then clear enough virus to trigger disease remains unknown, he says. And while researchers have found that some animals, like prairie dogs, appear to be able to spread monkeypox through nasal secretions and feces, “we just don’t know about dogs.”
Parrish notes that hypothetically, if you rub 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
As the number of cases continues to rise, “most of the general population is not at risk of contracting monkeypox,” said Mike Ryan, executive director of the World Health Organization’s Health Emergencies Programme, at a press conference last week. He added that “animals and pets are not a risk to people at this time.”
In fact, people pose more risks to animals. Public health agencies stress that those who contract monkeypox should avoid contact with pets, livestock and other captive animals, as well as wildlife.
If pets haven’t been exposed, the CDC recommends symptomatic owners turn them over to family members or other caregivers until they recover — and disinfect the home before animals do not return home. If that’s not possible, the agency recommends isolating the animals and keeping them in quarantine for 21 days.
Some people may have no choice but to care for their pets. “Normal and reasonable precautions are almost certainly sufficient,” says Parrish. 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 sheets and towels. Careful waste management is essential to prevent the spread to neighborhood animals that may rummage through the trash.
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 are diagnosed with monkeypox and your pet shows lesions or develops two or more symptoms within 21 days of your exposure, the agency advises you to call your veterinarian.
Vigilance is required. There are effective human vaccines, and “we should try to control and eradicate the virus from humans if we can,” Parrish says. There are no approved vaccines available for dogs or cats.
“We have to be careful,” says Ryan, because the more viruses spread, “the more they can evolve.”
Transmission from animals to humans
Like about 60% of human diseases, monkeypox is zoonotic: it originated in animals and then infected people. The disease was named in 1958 after it was discovered in captive monkeys used for research in Denmark, but it is primarily a rodent virus.
The main animal reservoir(s) of Monkeypox remain a mystery. But public health experts know that small rodents – rope and sun squirrels, Gambian rats and African dormice – harbor the virus in the rainforests of central and western Africa, where it is 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 spreading to individuals when they handled infected animals while hunting, skinning or eating them.
In 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 world.
While the risk to dogs and cats appears to be small, there is little information on animals 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 bovids. It remains unclear if cats, gerbils, rabbits, hamsters, raccoons, skunks and other species are at risk.
There are particular concerns that monkeypox could infiltrate American rodent populations, which often live in large social congregations. Dense colonies of western prairie dogs are on this list. In 2003, a shipment of 800 small mammals imported from Ghana to Texas for the exotic pet trade brought monkeypox to the United States. Prairie dogs caged next to them caught the virus, then infected 47 people who bought and handled them, were bitten by them, or were simply in the same room.
Good news comes from laboratory studies showing that the ubiquitous urban rats of the genus Rattus that plague cities around the world appear to develop immunity to monkeypox just days after birth, Doty says.
The rise in human cases has put public health officials on high alert. The return of humans to animals could create new endemic reservoirs and chains of transmission, says Andrea McCollum, an epidemiologist with the CDC’s Monkeypox 2022 Outbreak Response Effort.
“What we don’t want to see happen,” says Ryan of the WHO, “is for the disease to jump from one species to another.” This could make monkeypox nearly impossible to eradicate.
Adapting to a new host allows a virus to evolve, with the possibility that it grows and mutates differently,” says Rosamund Lewis, WHO technical lead for monkeypox. This means that it could become more or less contagious, weaker or more virulent.
“We know there are genetic changes going on, says Doty, but we don’t know what [they] can mean for the susceptibility or ability of the virus to infect different animal species.
However, when zoonotic viruses infect a new species, it is usually a dead end,” explains Sylvie Briand, director of global infectious risk preparedness at WHO. “It stops there because the virus is not very adapted to this species.”