Pet Dragons Linked to Salmonella Cases That Sickened Dozens of Children

“I have college students that will come to class with their bearded dragon on their shoulder, which is probably not the most hygienic thing,” said Brian Todd, a conservationist at the University of California, Davis, who specializes in reptiles and amphibians and was not involved with the study. “After you’ve handled one, you need to wash your hands, especially before preparing food or picking up your child.”

Bearded dragons aren’t the only source of reptilian-borne outbreaks. Last year, more than two dozen people in 11 states were sickened by salmonella linked to small turtles. That outbreak led to the hospitalization of nine people and prompted a warning from the C.D.C. against allowing children under 5 to have turtles as pets.

(The sale of turtles less than four inches has been banned since 1975.)

The study published this week in the journal Emerging Infectious Diseases used genetic whole-genome sequencing to determine the origin of salmonella infections that sickened two infants in Ontario, Canada. Researchers determined that the illnesses were caused by salmonella vitkin, a rare strain that had not been detected in Canada or the United States before 2021.

Dr. Katherine Paphitis, an epidemiologist at Public Health Ontario who was the lead author on the study, said the discovery prompted health officials in both countries to join forces to determine its origins.

Dr. Paphitis said that there are 2,500 serotypes of salmonella but that only about 100 sicken people, and just a handful are responsible for a majority of human infections. Older people, infants and those with weakened immune systems are especially vulnerable to serious illness, she said.

Sequencing of the bacteria allowed researchers at Public Health Ontario to link the two infants who had been sickened. Each family, they discovered, had bearded dragons. With genetic fingerprints in hand, Canadian officials reached out to their C.D.C. counterparts, who then identified a dozen cases of salmonella vitkin in the United States. Health officials in both countries warned pet shops and pet owners about the risks. “Don’t kiss or snuggle your bearded dragon,” the C.D.C. said, “and don’t eat or drink around it.”

The response to the outbreak showcased collaboration between the health agencies, Dr. Paphitis said, and also helped spread vital information about bearded dragons that seemed to elude many owners.

“If you are letting them free roam,” she said, “maybe don’t let them on to your kitchen countertop.”