Ciguatera Toxin: Dangerous Fish Poisoning Underreported In Florida

The number of people in Florida who are sickened by a dangerous toxin carried by barracuda, grouper, and amberjack has been underreported, according to a new report.

The analysis, from researchers at the University of Florida’s Emerging Pathogens Institute and the Florida Department of Health, found Florida’s yearly rate of poisoning with a toxin called ciguatera is estimated at about 5.6 cases per 100,000 people.

Lead author Elizabeth Radke, PhD, said:

“The rate of illness was found to be higher than previously estimated. Areas around Miami and in the Florida Keys are particularly affected.”

That is far more than the previous estimate of .2 cases per 100,000, derived from reports submitted to the Department of Health by physicians. This level of underreporting is consistent with that reported for other food-borne pathogens.

Ciguatera causes severe nausea, vomiting and, occasionally, neurological symptoms.

Radke said that while the study concludes ciguatera poisoning is more common in Florida than previously believed, researchers found no evidence that poisonings are on the rise.

Ciguatera poisoning is the most prevalent form of fish-related food poisoning in the world.

The toxin itself is found in a species of algae that grows on coral reefs in warm tropical and subtropical ocean waters. Risk is highest in fish from the Caribbean Sea and the Pacific and Indian Oceans. As many as 3 percent of travelers to these areas get ciguatera.

It is initially transmitted to small fish that feed on reef vegetation. They then pass it along to larger fish, like barracuda and grouper that prey on them.

People who eat contaminated fish and ingest the toxin can experience symptoms of severe nausea and vomiting within one to three hours. But in some instances it can lead to pain and tingling in the hands or feet and joint and muscle pain.

Symptoms can persist for months or even years. Some patients report a reversal of hot/cold sensations, with cold surfaces feeling hot and vice versa.

Radke said the findings in her study reaffirm pre-existing warnings to avoid eating barracuda. But the data indicate that in Florida, grouper, amberjack, hogfish, snapper, mackerel, and mahi mahi harvested in tropical and subtropical areas were also associated with illness.

“I think there is a broader awareness the farther south you go that barracuda are carriers but perhaps not as much awareness that a fish like grouper or amberjack can carry ciguatera,” Radke said. “I don’t think that people necessarily need to stop eating these other fish,” she added, “but they need to be aware there is a risk, and if they start feeling sick after eating, they should see a physician.”

Elizabeth G. Radke, Andrew Reich, and John Glenn Morris, Jr.
Epidemiology of Ciguatera in Florida
Am J Trop Med Hyg Published online June 29, 2015; doi:10.4269/ajtmh.14-0400

Photo: Julia Koefender/flickr