Hamsters, lizards and hedgehogs not allowed for kids younger than five

"Many parents clearly don't understand the risks from various infections" these animals often carry, said Dr. Larry Pickering, the report's lead author and an infectious disease specialist at the federal Centers for Disease Control and Prevention.

For example, about 11 percent of salmonella illnesses in children are thought to stem from contact with lizards, turtles and other reptiles, Pickering said. Hamsters also can carry this germ, which can cause severe diarrhea, fever and stomach cramps.

Salmonella also has been found in baby chicks, and young children can get it by kissing or touching the animals and then putting their hands in their mouths, he said.

Study co-author Dr. Joseph Bocchini said he recently treated an infant who got salmonella from the family's pet iguana, which was allowed to roam freely in the home. The child was hospitalized for four weeks but has recovered, said Bocchini, head of the academy's infectious diseases committee and pediatrics chairman at Louisiana State University in Shreveport.

Hedgehogs can be dangerous because their quills can penetrate skin and have been known to spread a bacteria germ that can cause fever, stomach pain and a rash, the report said.

With supervision and precautions like hand-washing, contact between children and animals "is a good thing," Bocchini said. But families should wait until children are older before bringing home an exotic pet, he said.

Data cited in the study indicate that about 4 million U.S. households have pet reptiles. According to the American Veterinary Medical Association, all kinds of exotic pets are on the rise, although generally fewer than 2 percent of households own them.

"Our recommendation is that no animal should be a pet for kids 5 and under," said Z.G. Standing Bear.