Fish Like Grouper, Barracuda May Pose Food-Poisoning Risk

They can sometimes contain toxin that can't be detected before eating, CDC warns.

THURSDAY, Jan. 31 (HealthDay News) -- People who eat large, tropical predatory reef fish such as barracuda and grouper may be at risk for a form of food poisoning called ciguatera fish poisoning, U.S. health officials reported Thursday.

Illness occurs when people eat fish that contain toxins produced by a marine algae called Gambierdiscus toxicus, according to the U.S. Centers for Disease Control and Prevention.

Some symptoms of ciguatera poisoning -- such as nausea, vomiting and diarrhea -- resemble other types of food poisoning. But ciguatera poisoning also causes neurological symptoms such as difficulty walking, weakness, tooth pain, and reverse temperature sensation (for example, cold things feel hot and hot things feel cold) that can persist for months, the CDC report said.

There's no cure for ciguatera but the symptoms can be treated and usually go away in days or weeks. However, symptoms can last for years in some people.

The CDC report said there was a significant increase in ciguatera poisoning cases in New York City among people who ate locally purchased barracuda or grouper in 2010 and 2011. Until then, ciguatera poisoning was fairly uncommon in the city.

During the period August 2010 through July 2011, city health officials received reports of six outbreaks and one single case of ciguatera fish poisoning, involving a total of 28 people. One of the patients was a physically active man who swam more than two miles a day before his illness. After the start of symptoms, he had trouble walking that lasted for several months, the CDC report said.

Ciguatoxins don't hurt the fish. And fish with the toxins don't look sick and don't appear, smell or taste different than fish without the toxins, the researchers noted.

Currently, there is no practical way to test fish for the toxins before they're sold. So prevention efforts depend on knowing which fishing areas have fish that might contain the toxins, along with accurate diagnosis of patients and consistent reporting of cases to public health agencies, according to the report, which is published in the Feb. 1 issue of the CDC's Morbidity and Mortality Weekly Report.

More information

The U.S. Centers for Disease Control and Prevention has more about ciguatera.