Puppies sold at Petland, a national chain of about eighty pet stores, have been linked to an outbreak of a disease that has hospitalized 13 people since mid-September, and sickened 55, according to the Centers for Disease Control.

The illness is caused by a bacteria called Campylobacter, which lives in the digestive tracts of most dogs and puppies. Campylobacter can spread through contact with dog feces.

Campylobacter is one of the most common causes of food poisoning in the United States—nearly 1.3 million Americans are infected with Campylobacter every year. But this outbreak is unusual because the vast majority of cases occur as isolated events, not as part of recognized outbreaks. The incubation period is 2–5 days and symptoms include bloody diarrhea, cramps, and vomiting. The illness itself lasts 2–10 days. 

As of October 3, the CDC reported a total of 55 cases of people with laboratory-confirmed infections or symptoms consistent with Campylobacter infection across 12 states, including (Florida, Kansas, Maryland, Missouri, New Hampshire, New York, Ohio, Pennsylvania, Tennessee, Utah, Wisconsin, and Wyoming).

People infected include 12 Petland employees in five states.

Other confirmed cases include people who bought puppies at Petland, came in contact with puppies at Petland, or live in a home with a puppy purchased there.

Another big worry is the fact that this Campylobacter strain seems to be resistant to many common antibiotics including azithromycin, ciprofloxacin, clindamycin, erythromycin, nalidixic acid, and telithromycin.

In a statement, Petland said, “Petland takes the health and welfare of our pets, our customers and staff very seriously. In a 2016 study, less than 1.2% of puppies purchased from Petland incurred any sort of medical issue requiring medical hospitalization. In addition, our extensive health warranty protects both our pets and our customers from bacterial, viral and congenital issues.”

The statement also noted that “The CDC has not identified any failures of Petland's operating system that would lead to any campylobacter infection.”

According to the CDC, Petland is cooperating with public health and animal health officials to address the outbreak.

The investigation remains ongoing.

Meanwhile, if someone’s going to buy a puppy, whether it’s from Petland or any other place, the CDC advises potential pet buyers to to pick a puppy or dog that is bright, alert, and playful. Puppies and dogs should have shiny, soft fur that is free of feces. They also advise that people to take their new puppy or dog to a veterinarian for a health checkup within a few days to a week after adoption.