Pets always welcome treats, but their owners may be putting themselves at risk of developing salmonella infection by handling beef or seafood snacks contaminated with the bacteria – so warned the authors of a report issued by the CDC.

The CDC study outlined nine cases of pet owners becoming sick with a specific type of infection, called Salmonella Thompson, in 2004 and 2005, after handling pet treats from two different manufacturers, one in the state of Washington and the other in British Columbia, Canada.

"This is the third outbreak in North America, the first in the United States, but we know these animal-derived pet treats are frequently contaminated with salmonella," said report co-author Fred Angulo, an epidemiologist at the CDC’s Division of Foodborne, Bacterial and Mycotic Diseases, part of the National Center for Zoonotic, Vector-Borne, and Enteric Diseases.

"There probably have been more cases," Angulo said. "There’s certainly salmonella being brought into people’s homes on pet treats. People are probably getting sick but not attributing it to contact with pet treats," he added.

All the patients included in the CDC report developed diarrhea, and one also experienced vomiting. That patient, an 81-year-old woman, required hospitalization, according to the report.

In each case, the illness was traced back to pet treats contaminated with Salmonella.

To prevent getting an infection from contaminated pet treats, the CDC recommends that people wash their hands thoroughly with soap and water after handling animal-derived pet treats. They also advise that children under the age of five, older adults and people with immune system problems stay away from animal-derived pet treats because of the possibility of severe infection or serious complications from salmonellosis.

The agency is also calling on pet store owners, health-care providers, veterinarians, and pet treat manufacturers to provide information to pet owners about the potential health risks of animal-derived pet treats and salmonellosis prevention.

In addition, they are urging pet treat manufacturers to use heat-treatment or irradiation that would destroy Salmonella and other bacteria during processing.