Researchers have discovered that the number of people poisoned in Florida every year by a dangerous food-borne toxin carried by reef fish may be significantly underreported in public health records.

Share on Pinterest Barracuda are recognized as having a high risk of carrying ciguatera toxins.

Prevalence of the poisoning in the state was previously estimated to be 0.2 cases per 100,000 people. According to the new study, published in the American Journal of Tropical Medicine and Hygiene, the true number is estimated to be closer to 5.6 cases per 100,000 people.

The toxin in question is called ciguatera and is known to be carried by fish such as barracuda, grouper, amberjack, snapper, tuna and sea bass. Warnings already exist concerning the consumption of barracuda, but these do not extend to other popular sports fish.

“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,” says lead author Elizabeth Radke.

Ciguatera is a toxin found in algae that typically grows on coral reefs and is initially transmitted to small fish that feed on reef vegetation. In humans, ciguatera poisoning can lead to diarrhea and vomiting within 1-3 hours of consumption, along with aches and pains, painful urination and other neurological symptoms.

It is the most common form of fish-related food poisoning in the world and one of the most resilient. There are no tests to detect the presence of ciguatera, and the heat-stable toxin cannot be destroyed by cooking or freezing contaminated fish.

Due to the effects of climate change, experts have expressed concern that increasing seawater temperatures could lead to ciguatera migrating from the tropical and subtropical areas worldwide where it is most common.

“There have been cases reported as far north as Georgia and South Carolina, but those likely involved fish that picked up the poison in South Florida or the Caribbean and migrated north,” reports Radke. “But there needs to be continued surveillance at the toxin’s geographic borders.”

For the study, researchers from the University of Florida surveyed recreational fisherman across the state of Florida and analyzed reports of ciguatera made to the Florida Department of Health (FDOH). By identifying high-risk demographic groups, high-risk fish types and fishing locations, the researchers aimed to be able to adjust their findings for underreporting.