Ciguatera Fish Poisoning
Ciguatera fish poisoning occurs when humans eat contaminated tropical reef fish. There are no specific diagnostic tests for ciguatera fish poisoning in humans, and diagnosis is generally made based on symptoms and recent dietary history.
Ciguatera fish poisoning usually involves a combination of gastrointestinal, neurological, and cardiovascular disorders. Symptoms can vary with the geographic origin of toxic fish. Gastrointestinal symptoms such as diarrhea, vomiting, and abdominal pain occur first, usually within 24 hours of eating implicated fish. Neurologic symptoms may occur at the same time or may follow 1-2 days later, and include pain and weakness in the lower extremities and circumoral and peripheral paresthesias. Other frequent symptoms include temperature reversal (e.g., hot food tastes cold, cold food tastes hot) and “aching teeth.” Most patients recover completely within a few weeks, but severe cases may progress to coma and respiratory arrest within the first 24 hours of illness, while other patients may have intermittent reoccurrence of symptoms over a period of months to years.
Microscopic sea plants called dinoflagellates produce ciguatoxins. These toxins become progressively concentrated as they move up the food chain from small herbivorous fish to the larger fish that eat them, and reach particularly high concentrations in large predatory tropical reef fish. Implicated fish typically are large subtropical and tropical finfish, such as king mackerel; barracuda; black and yellowfin grouper; blackfin, cubera, and dog snapper; greater amberjack; hogfish; and horse-eye jack. These fish are typically caught by sport fishermen on reefs in Hawaii, Guam, and other South Pacific islands, the Virgin Islands, and Puerto Rico. The occurrence of toxic fish is sporadic, and not all fish of a given species or from a given locality will be toxic.
Ciguatera has no cure, but symptoms usually go away in days or weeks. In some instances, symptoms can last for years. People who have ciguatera may be treated supportively for their symptoms. People who are recuperating from ciguatera fish poisoning should avoid reef fish, fish sauces, shellfish, alcoholic beverages, and nuts and nut oils for 1-3 months following illness, because these foods may provoke recurrent symptoms.
People should avoid consuming large predatory reef fish (greater than 6 lbs) and known high-risk fish. Because certain anatomic parts of the fish tend to concentrate more toxin (i.e., head, gut, roe, and liver), the viscera and heads of reef fishes should not be consumed or used in fish soup. Ciguatoxins cannot be detected by sight, taste or smell and cannot be destroyed by cooking or freezing. Please seek medical care if you suspect you have ciguatera fish poisoning.