(CNN) Puppies: cute balls of fur.

But according to the Centers for Disease Control and Prevention, they're also linked to a multi-state outbreak of an infection that's resistant to multiple drugs.

An outbreak strain of Campylobacter jejuni has been reported in 13 states and so far 30 people have been infected, the CDC said.

Four have been hospitalized but no deaths have been reported, the center said.

"Epidemiologic and laboratory evidence indicate that puppies purchased from pet stores are the likely source of this outbreak. Many of the cases had contact with puppies or were employees at pet stores, including Petland," it said.

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