Puppies sold at a national pet store chain have resulted in a multi-state outbreak of a bacterial infection landing some in the hospital.

The young dogs were handled and sold through the Petland chain, the U.S. Centers for Disease Control and Prevention announced today.

Thirty-nine human cases of Campylobacter infections occurred in Florida, Kansas, Missouri, Ohio, Pennsylvania, Tennessee, and Wisconsin.

Twelve of the cases were Petland employees, and 27 were people who had bought a puppy from Petland recently, or otherwise been in contact with one of the puppies.

No deaths have been reported – though there have been nine hospitalizations, the CDC added.

The bacteria is transmitted through contact with fecal matter.

The agency has sequenced the whole genome of bacteria samples found in feces from the canines in Florida – and it was closely related to one of the ill people from Ohio.

Campylobacter is one of the most common causes of diarrhea in the United States, affecting some 14 per 100,000 people each year. However, most are isolated cases that never reach the level of nationally-declared outbreaks.

Most people recover fully from the germ – although an estimated 76 Americans die annually from it. Those most affected are people with compromised immune symptoms like those with HIV or those undergoing chemotherapy treatments, the pregnant, the elderly, and young children.

Most cases are spread through food – especially undercooked meat. The treatment for the week-long infection is through fluids – although the most severe cases may require antibiotics, according to health experts.

The CDC recommends that pet owners be aware of symptoms in humans (diarrhea, fever, cramps, nausea, vomiting) and also the symptoms in dogs (sluggish movement, not eating, diarrhea, abnormal breathing).

Petland said that it already had stringent health and cleanliness standards in place - and emphasized that any puppy or dog could carry the bacteria.

"The CDC has not identified any failures of Petland's operating system that would lead to any Campylobacter infection," the company said in a statement. "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 veterninarians.

"Petland is proud of our commitment to quality controls and record keeping and we are happy to help the CDC in this new endeavor," the company added.

Washing hands, disinfecting surfaces, and other sanitation precautions are expected to curb the spread of the disease.

Domesticated animals at shelters and other densely-populated facilities like pet stores can breed disease that infects humans. For instance, last year’s flu season resulted in dozens of cats at a New York City animal shelter being quarantined after a strain of H7N2 influenza virus was found in the population.