Tiny Pets Can Hold Salmonella Dangers

Hamsters, other creatures linked to serious illness, experts say

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HealthDay Reporter

WEDNESDAY, Jan. 3, 2007 (HealthDay News) -- Beware the cute pet hamster.

It could be harboring salmonella, and it could pass the dangerous bacteria on to you, health experts are warning.

"Pet rodents can spread bacteria. They should be considered cute but contaminated," said Dr. Stephen Swanson, lead author of an article published in the Jan. 4 issue of the New England Journal of Medicine. "They are in schools and kindergartens and day care centers around the country, which is not to say they can't be, but if young children are going to handle them, parents and teachers need to be cognizant that these animals can shed these bacteria."

Most of the 1.4 million salmonella infections which occur annually in the United States come from food, but some come from contact with animals. Animal-related cases have also been documented from reptiles and amphibians, chicks, ducklings, kittens and hedgehogs.

But there had been no real connection between "pocket pets" such as hamsters and human cases of salmonella until an outbreak in August 2004.

"This is the first multistage outbreak of salmonella ever described from pet rodents," Swanson said. While working as an epidemic intelligence service officer for the U.S. Centers for Disease Control and Prevention, stationed at the Minnesota Department of Health, Swanson was the original lead author of a 2005 report which first connected rodents with human cases of salmonella. He is currently a pediatric infectious disease physician with the Hennepin County Medical Center in Minneapolis.

The trail started on Aug. 30, 2004, when a veterinarian for a Minnesota pet distributor notified the Minnesota Department of Health that two hamsters from a shipment of 780 had tested positive for salmonella and that the animals were dying in large numbers. Unbeknownst to her, the pet distributor had already shipped 243 of the original 780 animals to 15 retail pet stores in four states.

The strain of salmonella involved was a rare one, and investigators were ultimately able to identify 28 matching isolates in humans. Of 22 patients (or their parents) who could be interviewed, 13 (59 percent) had had contact with rodents purchased from retail pet stores. Two individuals (9 percent) had become infected through contact with a primary patient. Seven patients (32 percent) did not appear to have had any exposure to rodents.

One four-year-old boy in South Carolina had been hospitalized for five days in June 2004. Nine days before he fell ill, his family had purchased a hamster from a pet store. The hamster died two days later.

In August 2004, a five-year-old boy in Minnesota also fell ill four days after his family purchased a mouse. The mouse died one week after it was purchased.

A 23-year-old pregnant woman in Missouri fell ill after she purchased live rats and mice to feed her pet python. No salmonella was isolated from the culture of the snake feces, and the rodents and their cages weren't available for testing. The woman's baby, born prematurely after the mother fell ill, also had salmonella and was in intensive care for 56 days before going home.

Not only was this the first outbreak documented, the strain involved was resistant to several drugs.

"There was widespread abuse of antimicrobials within the [pet] industry," Swanson said. "Antimicrobial use in the industry is potentially contributing to the dissemination of multi-drug resistant types of salmonella."

The bottom line: People can and should keep their pets as long as they look healthy. But, experts say, a few simple tips can safeguard health:

  • Wash your hands frequently -- not just after handling the pet but also after touching cages and bedding.
  • Don't kiss or hold the rodents near your mouth.
  • Don't let the pets roam in areas where food is eaten or prepared.
  • Stay away from a pet who appears ill or has diarrhea, and don't buy a hamster, mouse or rat which appears sickly in any way.
  • Parents should supervise young children who handle the pets and have contact their environments.

Finally, certain individuals, such as people with compromised immune systems or pregnant women, may want to avoid direct contact with animals as they are a particularly vulnerable population.

More information

Find out more about reptile-linked salmonella from the U.S. Centers for Disease Control and Prevention.

SOURCES: Stephen J. Swanson M.D., pediatric infectious disease physician, Hennepin County Medical Center, Minneapolis; Jan. 4, 2007, New England Journal of Medicine

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