Who hands down the salmonella?

Remember those pint-sized turtles that proved such popular pets during the 1960s? The U.S. Public Health Service banned them in 1975 after researchers learned that the turtles can transmit Salmonella to their human friends. Now a report in the Jan. 24 MORBIDITY AND MORTALITY WEEKLY REPORT suggests that pet iguanas also pose a Salmonella threat.

Epidemiologist Daniel Dickinson of the Centers for Disease Control in Atlanta and his colleagues investigated two reports of Salmonella illness traced to pet reptiles.

In one case, the investigators learned that a newborn baby developed diarrhea soon after leaving the hospital in August 1990. The baby's stool specimen revealed Salmonella marina, a strain of Salmonella that rarely infects humans but is commonly found among iguanas. Sure enough, the baby's family had an iguana as a pet, and cultures from the reptile's glass terrarium also yielded S. marina.

In the second case, a-3month-old baby developed diarrhea in November 1990. Once again, specimens taken from the infant and the family's pet iguana revealed S. marina.

The investigators say they don't know the exact route of Salmonella transmission, but in each case at least one parent cared for both the baby and the reptile. The babies never played with or touched the iguanas, Dickinson notes. However, family members could pass the bug to the infant after touching the iguana or its cage, he adds.

Should families with small infants and a favorite iguana get rid of their pet? "We don't know the answer to that," Dickinson says. However, the researchers do advise family members to wash their hands carefully after handling pet reptiles.

Infections with S. marina represent a small fraction of the human cases of Salmonella-associated illness. A different strain of Salmonella, one that infects chickens and their eggs, remains a more serious public health threat, Dickinson adds.