With more than 31,000 confirmed cases of monkeypox worldwide, health authorities are warning that it's not just people who are at risk from the disease: Pets can get monkeypox, too.
Just this month, researchers reported what appears to be the first case of human-to-dog monkeypox transmission in the current outbreak. Prior to this case, experts knew that monkeypox could spread to rodent species, but weren't sure if other mammals could be affected.
So we're still learning the extent to which humans can transmit the virus to animals. And this report suggests there's good reason to keep pets in mind as the outbreak continues.
Monkeypox can infect animals — especially rodents
Yes, monkeypox can infect animals. But the term "monkeypox" is actually a misnomer because monkeys are not the natural reservoir for the virus, Dr. Jane Sykes, a professor in the UC Davis School of Veterinary Medicine who studies infectious diseases in animals, told TODAY.
"Monkeys (can be) infected, but they're not necessarily the animal that is associated with ongoing infections," Dr. Isaac Weisfuse, an epidemiologist and adjunct professor in the master of public health program at Cornell University, told TODAY. Instead, the most likely natural reservoir is African rodents, both experts said.
In fact, animals like these were at the root of the 2003 monkeypox outbreak that spread to an estimated 47 cases in six states. In that outbreak, investigators found that "a shipment of African rodents was kept near prairie dogs," Weisfuse explained. "And the prairie dogs were then bought by people in the United States as pets." (The outbreak led to CDC restrictions on importing African rodents that are still in place today.)
Looking at five rodent species, research published in 1976 found the virus was most likely to infect mice and rabbits, Sykes said. But that research was performed "quite a long time ago," she said, and the animals were infected with the virus through an injection directly into the bloodstream, which is not how the virus normally spreads.
Still, the fact that so many rodent species (domesticated or in the wild) could become infected with monkeypox is a real worry.
"That's a concern because it could become endemic, for example, in squirrels, which are all over the place," Weisfuse said. "The squirrels may not be affected in terms of their health, but it could sort of re-emerge from squirrels if people had contact with them."
And recent research suggests that, while dogs are less likely to get monkeypox than rodents, they can still become infected. In a new case report, published last week in The Lancet, researchers describe the case of two men living together in France. In June, the two developed monkeypox lesions and, 12 days later, so did their 4-year-old Italian greyhound. Eventually, all three tested positive for the virus.
The men reported allowing the dog to sleep in bed with them. But, after they developed symptoms, they kept their dog from interacting with other animals or people.
While monkeypox transmission between humans and wild animals had been seen previously, "Infection among domesticated animals, such as dogs and cats, has never been reported," the authors wrote.
If you have monkeypox, you should isolate from your pets
For the vast majority of pet owners, monkeypox isn't really something to be worried about, Weisfuse said.
But if you're diagnosed with monkeypox or it's highly likely you have a case of the disease, public health agencies say you should isolate yourself from other people and, if possible, your pets.
Guidelines from the Centers for Disease Control and Prevention, U.K. Health Security Agency and the European Center for Disease Prevention and Control all recommend that monkeypox patients stay away from animals — particularly mammals — in their homes.
If the person with monkeypox did not already have close contact with their pet, the CDC advises that a friend or family member should take the pet until the patient recovers. "Close contact includes petting, cuddling, hugging, kissing, licking, sharing sleeping areas and sharing food," the CDC says.
But, if the person with monkeypox has already potentially exposed their pet via close contact or they must take care of their pet, they should take precautions to prevent spreading the virus, the CDC explains. For instance, the CDC advises them to wash their hands before and after caring for the pet and to wear gloves and a well-fitting mask when they're interacting with the pet.
The UKHSA notes that transmission from people to pets is most likely in the case of rodents, like mice and rats, and specifically recommends people who have monkeypox temporarily remove pets like these from their homes for at least 21 days.
Evidence that the disease can spread to cats, dogs and other animals is less convincing than it is for rodents, as the UKHSA points out. But the CDC and European CDC both say that it’s best to avoid contact with all pets.
"We still don't know the full range of species that are capable of being infected," Sykes explained, which makes the extra degree of caution around all pets understandable. "But based on the studies that have been performed previously with this virus, these rodent species are more likely to be susceptible rather than dogs and cats," she said.
How to keep you and your pets safe
If you have monkeypox, it's important to follow the CDC's recommendations about caring for your pet while you're sick. And if your pet becomes lethargic or displays a lack of appetite, fever or rash-like lesions, get in touch with your veterinarian to see if your pet has monkeypox.
On a larger scale, this outbreak is a reminder that there are many illnesses that can be transferred between animals and their owners, Sykes said. Bacteria like Campylobacter jejuni, the tiny parasite giardia and even COVID-19 can spread between pets and people, for example. And we can't forget the threat of tick-borne illnesses, which people frequently encounter via their pets.
Considering how often people and pets may get sick with the same diseases, don't hesitate to disclose any recent illnesses you've had to your vet, especially if your pet comes down with something mysterious, Sykes said. And it may even be worth connecting the vet with your primary care provider for more context.
Knowing that animal and human health are so interconnected in this way should be a reminder to take care of all of us, Sykes said. And that it will take the teamwork of public health experts, veterinarians, ecologists and more "to help stop these types of diseases spreading more in the future," she said.