Pet African dwarf frogs from a single California breeder caused an eight-month salmonella outbreak in 31 states, Web MD reports.

According to the page:

The frogs are hard to handle - they tend to rest at the bottom of aquariums - so most of the infections likely came from contact with the water in which the frogs swam. Nearly a third of contaminated households cleaned the frog aquariums in the kitchen sink, posing a risk for cross contamination with food preparation areas, according to the CDC.

Infections in Utah and Colorado came from frogs given away as carnival prizes. An infection in New Mexico came from a frog purchased in a pet store; one in Ohio came from a department store.

It took the CDC a long time to figure out that frogs were the source of the outbreak, as cheese-flavored crackers consumed by several early patients led disease detectives on a wild goose chase. Eventually, the frogs were traced to a single California breeder. DNA tests showed that salmonella in water tanks and gravel from frog habitats was the same strain that caused the outbreak.

The CDC notes that there's no law against selling small frogs. To prevent infections, the CDC advises pet owners to wash their hands thoroughly after touching animals or cleaning aquariums.

-- Sandra M. Klepach, SKlepach@News-Herald.com