Rodents Spread Resistant Salmonella

A U.S. outbreak of resistant salmonella infections — which cause severe abdominal ills — has been tracked to pet rodents.

Researchers said Wednesday the outbreak that began in December 2003 and continued across 10 states through August 2004 resulted in 28 human infections, which were positively linked to eight hamsters from a Minnesota pet distributor.

About 1.4 million Americans are sickened by salmonella each year, usually through food exposure, said Stephen Swanson, an epidemiologist at the National Center for Infectious Diseases, a division of the Centers for Disease Control and Prevention in Atlanta.

Pet rodents probably are an under recognized source of human salmonella infection, Swanson said in a paper to be published in Thursday’s edition of the New England Journal of Medicine.

Government investigators traced the outbreak from the Minnesota distributor to pet stores in four states. Using sophisticated tests, they were able to show that the strain of salmonella that infected the rodents was identical to the infection in humans.

Of 22 patients or parents interviewed, 13 patients in 10 states reported exposure to pet hamsters, mice or rats, and 2 patients had secondary infections. The median age of the 15 patients with primary or secondary rodent exposure was 16 years.

In six patients the gastrointestinal consequences of the infection required hospitalization. Thirteen associated pet stores supplied by seven distributors were identified in 10 states. Several hamsters that were infected died.

Swanson noted that salmonellosis outbreaks have been associated with handling reptiles and amphibians, chicks, ducklings, kittens and hedgehogs.