At least 118 people in 18 states were sickened by a bacterium called Campylobacter between January 2016 and February 2018, according to a new report from the Centers for Disease Control and Prevention (CDC). The surprising source of the outbreak? Pet-store puppies, apparently.
Initially, the humans who became ill were either employees or recent customers of Petland stores in Florida, Kansas, Missouri, Ohio, Pennsylvania, Tennessee, or Wisconsin—or they had recently visited a home with a puppy sold through the chain. But the CDC has since found five other pet store companies tied to the outbreak, and the new report says 29 of the 118 people who fell ill were employees.
We know what you’re thinking. It’s bad enough to hear about bacterial outbreaks traced back to the food we eat or the water we swim in. Now we have to worry about cuddling with cute baby animals, too?
To learn more about the outbreak—and the basics of dog-to-human illness transmission in general—Health spoke with Craig Altier, DVM, PhD, professor of population medicine and diagnostic science at Cornell University College of Veterinary Medicine. Here’s what he wants everyone to know.
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Campylobacter infections are unpleasant for people
Most people who become ill with campylobacteriosis get diarrhea, cramping, abdominal pain, and fever within two to five days of being exposed to the bacteria, according to the CDC. (Some lucky people don’t have any symptoms at all.) Nausea and vomiting can also occur, and the illness usually lasts about a week.
Most cases of camplyobateriosis aren’t life-threatening—but they can be very serious for people with compromised immune systems, children under 5, adults 65 and older, and pregnant women. Rarely the disease can lead to Guillain-Barre syndrome, a neurological disorder that can cause paralysis.
The recent outbreak hit individuals of all ages, from infants to the elderly, and 63% were female. No deaths were reported, but 24% of the people reported ill were hospitalized.
It can be transmitted through dog poop
The most common way people get sick from campylobacter is by eating contaminated food, says Dr. Altier. “It often comes from eating undercooked chicken, because chickens can carry this bacteria in their gut but not get sick from it,” he says.
Dogs can carry campylobacter as well, he adds, especially puppies. And while it’s a much less frequent way of transmission, it is possible for people to “catch” the infection by handling dog feces (or something contaminated with dog poop) and then touching your mouth or face.
“Fecal matter is all over an animal and its environment, so you can certainly get [the infection] even if you’re not directly handling animal waste,” says Dr. Altier. “And the more bacteria being produced by the gut, the more risk there is handling and being around the animal.”
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Symptoms in dogs can be mild
Most dogs infected with campylobacter do show some symptoms, says Dr. Altier. “They might get a little diarrhea, but the illness is usually mild,” he says. “It can be hard to spot, because puppies can get diarrhea from all kinds of things, like stress or a change in diet.”
When looking for a dog to buy or adopt, the CDC recommends choosing one that is bright, alert, and playful, with shiny, soft fur that is free of poop. Once you’ve got your pet home, says Dr. Altier, call the vet anytime he or she has unexplained diarrhea. “It may be something that can’t be transmitted to humans, like an intestinal parasite, but it could also be this,” he says.
Pet-store animals may be at higher risk
All puppies, no matter where they’re from, can carry campylobacter. But living in a pet-store environment likely increases a young dog’s chance of contracting the infection, says Dr. Altier. “It’s a perfect storm for infectious disease,” he says: “You have young animals in stressful conditions—like being moved from kennel to pet store—and often they’re being mingled together in close quarters.”
Scientists found that bacteria samples isolated from the stool of puppies sold through a Petland store in Florida were closely related to bacteria from the stool of a sick person in Ohio. Bacteria samples were also resistant to antibiotics often used to treat campylobacter infections, possibly because healthy puppies were given antibiotics, according to the new report.
In a 2017 statement, Petland said it was fully cooperating with the investigation, and that “the CDC has not identified any failures of Petland’s operating system that would lead to any campylobacter infection.” Petland “takes the health and welfare of our pets, our customers and staff very seriously,” the statement added.
Humans can get other illnesses from pets, too
Campylobacter isn’t the only bacteria that can be passed from dogs to humans, although “there’s only a small list of organisms that are,” says Dr. Altier. Salmonella is another pathogen that can live in an animal’s gut and can be transmitted through contact with fecal material. Fortunately, these cases are also fairly uncommon.
Dogs can also catch the flu, although they get different strains of the virus than humans do. Infectious disease experts worry that canine flu could one day mutate and become contagious for humans—the way bird flu and swine flu have in the past. But this hasn’t happened yet.
As for the other way around, experts say it’s extremely rare for humans to pass illnesses to dogs. So even though it’s a good idea to avoid close contact with other people when you come down with a cold or flu, experts say it’s still safe to snuggle with your canine companion.
If you play with puppies, wash your hands ASAP
Anyone who handles dogs in pet stores—whether they’re working there, shopping for a potential pet, or just getting a much-needed dose of puppy love—should wash their hands with soap and water or use an alcohol-based hand sanitizer immediately afterward, says Dr. Altier. “That’s a really good practice anytime you’re around animals, whether it’s a pet store in the mall or a petting zoo,” he says.
To protect your own pet, Dr. Altier recommends feeding dogs a healthy diet, getting them plenty of exercise, and avoiding stressful environments whenever possible. “They’re going to be less susceptible to infection if they are otherwise healthy and happy,” he says.
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