A young California woman’s arm bump was mysterious – and growing. It wasn’t until she saw two doctors and underwent a biopsy that her family realized the cause: The baby had run into a hungry iguana with a sweet tooth, causing what may have been the first documented infection with the rare bacteria. Transmission to a human from an iguana bite.
The girl, who was not named in a scientific presentation of the case at the European Congress of Clinical Microbiology and Infectious Diseases in April, is recovering after her unexpected ordeal, which began on vacation in March 2022.
The girl and her family went on a trip to Costa Rica. A time to enjoy the country A very beautiful beach, the girl’s parents gave her a snack. But it turns out she wasn’t the only one hungry: a wild iguana came up as the girl ate cake by the water.
Iguanas are common in Costa Rica. They are harmless herbivores, mostly known to sunbathe under trees and eat fruit and leaves, but experts say this animal must have developed a sweet tooth.
The iguana ran up to the girl and bit her on the back of her left middle finger, causing her to lose her grip on the cake. The reptile then ran off with the snack, but left something else behind.
Dr. Jordan Mah, an author of the presentation and an expert in medical microbiology, worked on this topic Lab testing for cases as a part of the Department of Pathology at Stanford University. Mah said the girl’s parents probably weren’t thinking about the bite when they took her to the doctor because she had scratches on her arm.
“I think when they initially went to seek treatment for the bump, the type of bite slipped their mind because they didn’t see it as a potential exposure, because it just healed. And it’s only later in treatment, because it got worse, that it kind of jolted their memory and they brought it to the doctor’s attention,” he said.
Mah said parents were quick to react after the iguana encounter. The wound looked superficial, but they took the girl to a local clinic, where staff disinfected the wound with alcohol and gave her five days’ worth of antibiotics.
The wound seems to clear up in about two weeks. It was only five months later, when her parents noticed a dime-sized bump on the girl’s arm in the same spot, that they thought she should be taken to another doctor. The girl told them it didn’t hurt, and had no other symptoms.
Her pediatrician thought the bump might be a benign cyst and told her parents to keep an eye on it. But when the bump continued to grow and cause mild pain, her parents took the girl to an orthopedist, who recommended a biopsy.
The doctor removed the 2-centimeter mass. Scientists took a closer look at the growth in the lab and discovered that the child had a rare infection Mycobacterium marinum, A non-tuberculous mycobacterium that commonly causes a tuberculosis-like illness in fish.
It is ubiquitous in fresh and salt water but rarely infects humans. Usually, when people become infected, it is after exposure to the bacteria in water from a wound. most people People who get this infection develop a rash that may spread in a circular pattern. It may develop or become a nodule with pus an ulcer.
Most antibiotics alone Don’t usually work on this type of infection, so doctors put the girl on rifampin, an antimicrobial, and clarithromycin, an antibiotic often used for skin infections. The infection has responded well to treatment.
“Typically, with these infections, because they take so long to grow and they’re a little bit more aggressive, you have to treat them for a long time, sometimes months,” says Mah. “So he’s doing better. I wouldn’t say 100%, but he’s doing a lot better than he was at the beginning.”
Mah believes this is the first time a human has contracted such an infection from an iguana bite. He wanted to present the case to warn potential physicians.
Growing M in the lab. marinum requires lower temperatures than most bacteria. This particular bacteria prefers to grow at around 82 to 86 degrees Fahrenheit. Most bacteria grow around 95 to 98.6 degrees, So the diagnostics were a little different. Because lizards and iguanas have lower body temperatures than humans, Mah said, they may be perfect hosts for such bacteria.
“We know a lot about animal bites and bacteria, infections, following, dogs or cats, but not really that much for lizards other than iguanas,” he said. “I don’t think people should be scared, but doctors should be aware of the possibility.”
Living in South and Central America and Mexico, the iguana has become an invasive species South Florida, Hawaii, Texas and Puerto Rico, so people may encounter more with them. But experts who work with iguanas say they’re usually pretty harmless, so there’s no reason to fear them.
Anna Meyer, Operations Manager iguanaland, Florida’s largest reptile zoo said this one’s behavior is not normal.
“Usually, they’ll go about their day and don’t want to bother anyone or be bothered by anyone. But like any wildlife, if they start associating people with food, they’re going to risk getting closer,” Meyer said. In this case, other tourists in Costa Rica can feed the wild iguana until it gets used to people and about them. Creates some expectations.
“It’s an animal that just got used to people eating it,” Meyer said. It probably realized that it could get a “high value meal” from the baby without too much danger to itself.
The lesson here, he said, is that one should not feed wildlife, because it makes the animal think that stealing food from a child is like taking candy from a child.
“A cake has more calories than a mango or a leaf,” she said.