Because of harmful algal blooms, a rare illness caused by a toxin in fish is becoming more common in the United States. Ciguatera poisoning is the most common seafood-related illness in the world. It used to occur only in fishing communities located in the tropics, but the algae that produces the toxin has been found in fish caught off the waters in Florida, Texas, South Carolina, and Miami and caused outbreaks. And the globalization of our food supply has caused outbreaks in Alaska and Ohio.
Food poisoning usually occurs in several ways: You eat food infected with bacteria or viruses that cause an infection, or you ingest chemicals or toxins present in contaminated food. Parasites, prions (mad cow disease) and protozoa can also cause food poisoning.
Ciguatera is a foodborne illness caused by a toxin produced by microalgae called Gambierdiscus toxicus. The toxins gradually build up in fish as smaller herbivorous fish eat the algae, which are then in turn are eaten by larger carnivorous fish. Marine toxins are naturally occurring. Like many toxins, heat does not destroy the chemical, so even thoroughly cooking fish that contains ciguatera will not make the food safe.
Symptoms usually appear within a few minutes after eating the fish, although it may take up to 6 hours. The symptoms of ciguatera poisoning are similar to bacterial food poisoning:
- Nausea
- Diarrhea
- Body Aches
- Vomiting
But then uncommon symptoms manifest, including numbness, tingling in the hands, feet, or mouth, joint pain, and the reversal of hot and cold feelings. Poison control centers in the United States received 178 calls about ciguatera in 2010. There is no cure for this toxin, although there are effective treatments and it is rarely fatal. Symptoms usually go away in a few days or weeks, but some people feel the effects for years.
To avoid this toxin, follow these tips:
- Choose small fish, since larger fish have a greater concentration of the toxin. There are no tests for the toxin and the fish doesn’t have an off taste or appearance.
- If you fish in warmer waters, avoid fish that commonly acquire the toxin, such as barracuda, dog snapper, amberjack, king mackerel, and yellowfin grouper, among others.
- Always buy seafood from a reputable fishmonger.
