The Centers for Disease Control and Prevention (CDC) warned Tuesday that pet store puppies have been linked to an infection outbreak among human beings in 13 states.

Thirty people have been infected with a strain of Campylobacter jejuni, according to a Tuesday release. Four hospitalizations have been reported, but no fatalities.

Symptoms from the infection include diarrhea, fever and stomach cramps two to five days after being exposed.

ADVERTISEMENT

The illnesses have been reported throughout the year, with those affected ranging from 8 months to 70 years old.

Cases usually last about a week, and most people recover without antibiotic treatment. The Campylobacter bacteria has been resistant to "commonly recommended, first-line antibiotics," according to the CDC.

The CDC interviewed 24 people infected with the strain, 21 of whom reported contact with a puppy. Fifteen of those 21 people reported contact with a puppy from a pet store, and 12 of those 15 people were linked to Petland, a pet store chain.

Petland said in a statement earlier this week that “more than one third of the cases have been found in people in 13 states where there are no Petland stores.”

“Petland takes the health and welfare of our employees, our customers and our pets very seriously,” the Monday statement said.

The CDC advises that pet owners always wash their hands with soap and water after handling a puppy or its food, as well as cleaning up after them. Pet owners should take a new puppy or dog to a veterinarian for a check up a few days after bringing it home.

Pet store employees should ask store management about training for washing hands, clean-up procedures and other “illness prevention measures,” according to the CDC. Employees should also wash their hands after handling dogs, eat and store food safely, and clean up messes safely.