Pet lizards called bearded dragons, the US Centers for Disease Control and Prevention (CDC) announced Thursday, are responsible for a nationwide outbreak of salmonella that so far has sickened 132 people in 31 states over the last two years.

No one has died from the outbreak, but the rare strain, called Salmonella cotham, has hospitalized 42 percent of those infected, and 58 percent of those infected are five years old and under - many of whom handled the bearded beast.

"We are confident bearded dragons are the source of the outbreak" Casey Barton Behravesh of the CDC told The Associated Press.

Bearded dragons, native to Australia, are desert animals that can grow about 20 inches long and can sell for $70 to $100 at pet stores. They may not look contaminated, but they secretly shed Salmonella germs via their skin-changing process.

The bearded dragons in question came from several pet stores, and no single chain or supplier has been identified as the source of the salmonella-infected lizards, Behravesh added.

The CDC's investigation began in January, LiveScience reported, when the Wisconsin Department of Health notified the agency of a cluster of rare Salmonella infections with most patients reporting contact with the pet lizards. Thus far, the CDC has interviewed 31 people, 27 of which have said they were in contact with reptiles and 21 specifically with bearded dragons. Other pets that can carry the rare bacteria are frogs, toads, turtles, snakes, hedgehogs, chicks, and ducklings.

Researchers collected salmonella samples from three patients and found one sample was resistant to ceftriaxone, an antibiotic used to treat serious salmonella infections. The researchers are continuing to test samples from more patients for antibiotic resistance.

CDC officials say owners should make sure they wash their hands with soap and water after handling their pets, and they should be kept away from small kids.