The Centers for Disease Control and Prevention is investigating an outbreak of infections affecting people across seven states that it says may be linked to puppies sold through the national pet store chain Petland. As of Monday, there were 39 cases of human Campylobacter infections linked to puppies sold through Petland, the CDC said in a statement. The cases were found in Florida, Kansas, Missouri, Ohio, Pennsylvania, Tennessee and Wisconsin. Of those cases, 12 people are Petland employees in four states, and 27 people recently purchased a puppy at Petland, visited a Petland or visited or live in a home with a puppy through Petland, the CDC said on its website. “The CDC has not identified any failures of Petland’s operating system that would lead to any Campylobacter infection,” Petland said in a statement today. “Petland reinforces proper hand sanitization before and after playing with any of our puppies with the many sanitation stations in each store and has strict kennel sanitation procedures and protocols put in place by consulting veterinarians.” The company emphasized that any dog may carry Campylobacter, regardless of where it came from. Petland also said in a statement that the questionnaires the CDC used to link the infection cases to Petland “were not consistent and didn’t ask the same questions related to type of food the dogs ate or other contact with dogs.” The chain added that it is closely cooperating with the CDC. Campylobacter can be spread through contact with dog feces, according to the CDC, and usually does not spread from person to person. Symptoms of the disease include diarrhea, cramping, abdominal pain and fever, and the disease typically lasts about one week. Almost all people infected with Campyobacter recover without any specific treatment, according to the CDC.