Rodents source of rare strain of salmonella
WASHINGTON – In case you needed more reasons not to kiss a mouse, health investigators have found a good one: salmonella.
So-called “pocket pets” – popular rodent species like hamsters, mice and rats – can infect their human owners with salmonella, including drug-resistant forms of the disease, the Centers for Disease Control and Prevention announced Thursday.
The warning came on the heels of an outbreak in which 14 pet owners in 10 states contracted a rare strain of salmonella, a gastrointestinal bacteria that causes diarrhea, vomiting and – in rare cases – death. Because salmonella is seldom reported, doctors investigating the outbreak suspect that many more people could have been infected by the rodents, which have been traced to pet distributors in 11 states and Canada.
“It’s basically all over the eastern half of the United States,” said Dr. Kirk Smith, supervisor of the Foodborne, Vectorborne and Zoonotic Disease Unit at the Minnesota Department of Health, which discovered the outbreak. “There’s a lot of movement between the breeders and the distributors and the pet stores.”
The investigation by the Minnesota Department of Health and the CDC began in August of last year, when a 5-year-old Minnesota boy fell ill four days after his family bought him a pet mouse. The mouse was visibly ill, but the boy “frequently handled and kissed” the animal anyway, according to a CDC report.
The incident was reported to the pet store distributor, whose veterinarian contacted researchers at the University of Minnesota and the Minnesota Department of Health. CDC officials declined to give the name of the distributor or individuals involved. Similar cases eventually were found in Georgia, Illinois, Kentucky, Michigan, Minnesota, Missouri, New Jersey, North Carolina, Pennsylvania and South Carolina.
Dr. Stephen Swanson, an officer for the CDC’s Epidemic Intelligence Service assigned to Minnesota, said pet rodents most likely have transmitted salmonella to human beings before, but this was the first time investigators were able to conclusively trace the disease. Because the strain of salmonella was an extremely rare one – accounting for only 23 of the nearly 18,000 salmonella samples the CDC keeps on file – investigators were able to discern a pattern in the infections.
“There may be more common strains of salmonella that are also being acquired from rodents, and we just don’t recognize it,” Swanson said.
Salmonella is found in animal feces, and humans can be exposed to it when handling live animals or food products such as eggs and raw chicken that have been exposed in processing to microscopic particles of such waste. The disease accounts for about 14,800 hospitalizations and 415 deaths annually, the CDC said.
Other animals often kept as pets already are known to transmit salmonella. Reptiles and amphibians are perennial culprits, and researchers identified an outbreak of cat-based salmonella in Minnesota in 1999. But this is the first time investigators have pinned the blame on rodents.
Swanson said that the news shouldn’t scare people away from buying the popular pets, but that owners should be mindful of hygiene while playing with the pocket pets. Owners should always wash their hands after playing with a pet and before eating, and they should avoid facial contact with the animal.
“This outbreak I think just highlights that there really is no such thing as a perfectly safe pet for children,” he said – although, he added, “I’m not sure about goldfish or something.”