Bitten by an iguana? You could be contracting a rare bacterial infection, a new study says

Iguanas, those pesky green creatures that come out in force during the summer months in South Florida, are more than just a nuisance. It also poses health risks.

While touching an iguana or its feces can cause salmonella, a new report from the Centers for Disease Control and Prevention links an iguana bite to a rare bacterial infection called mycobacterium marinum.

The discovery came after a 3-year-old girl from California and her family took a trip to Costa Rica. While eating cake on the beach, an iguana tore it from her left hand and bit it. The girl was immediately taken to a local clinic and found to have a superficial bite for which doctors administered a five-day course of oral amoxicillin. But five months later, a cyst appeared.

After it was removed and biopsied, scientists took a closer look at the growth in the lab and discovered that the child had a rare infection caused by the bite. This type of infection usually infects people only after a wound has been exposed to the bacteria in the water.

Most antibiotics alone don’t usually work on Mycobacterium marinum, so doctors put the girl on rifampin, an antimicrobial, and clarithromycin, an antibiotic often used for skin infections. One report shows that the infection responded well to treatment.

Out-of-control iguanas infesting South Florida

Dr. Jordan Mah, author of the report that will appear in the June 2023 issue of Emerging Infectious Diseases, the CDC’s monthly peer-reviewed public health journal, said it’s not unusual for an increase to take several months to surface. Mycobacterium marinum is usually associated with snake bites, he said.

“The course that this pathogen takes with this infection takes place over a period of time,” said Mah, an expert in medical microbiology who worked at the laboratory that tested the cyst as part of the Department of Pathology at Stanford University .

“I think the main thing is not to feed these animals so they don’t get used to associating humans with food,” he said. “I’m pretty sure the people on the beach fed him and that made him bite the baby to get food.”

Iguanas, especially the green iguanas abundant in South Florida, are herbivores and feed on foliage, flowers, and fruit. Some will eat animal material such as insects, lizards and other small animals, nesting birds and eggs.

Tom Portuallo, owner of Iguana Control, said South Florida residents are seeing more iguanas than usual for this type of year because of the unusually warm winter.

Portuallo, in the iguana removal business for 14 years, said he hasn’t heard of anyone being bitten by an iguana. “They’re not designed to kill prey, and they’re more likely to run away from you,” he said.

He has, however, seen dogs get sick from licking iguana feces and children get sick from touching iguana feces.

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Wherever they bask in the sun, iguanas leave behind excrement almost as large as dog excrement. Since lawns and pool decks are favorite spots, it’s easy to accidentally come into contact with their bacteria-filled droppings.

Portuallo says the iguanas cannot be moved. His company will kill the iguanas and turn them into fish.

Mah said Floridians shouldn’t worry about getting salmonella or mycobacerium marinum from an iguana swimming in their pool. “It’s chlorinated, so it’s supposed to kill the organisms. Even in a freshwater lake or river, you’d need a cut for the organisms to get in.”

Sun Sentinel health reporter Cindy Goodman can be reached at

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