Ciguatera fish poisoning is a rare disorder that occurs because of the ingestion of certain contaminated tropical and subtropical fish. When ingested, the toxin (ciguatoxin), which is present at high levels in these contaminated fish, may affect the digestive, muscular, and/or neurological systems. More than 400 different species of fish have been implicated as a cause of ciguatera fish poisoning, including many that are otherwise considered edible (i.e., sea bass, snapper, and perch). These fish typically inhabit low-lying shore areas or coral reefs in tropical or subtropical areas. In the United States, ciguatera fish poisoning has occurred more frequently in the last decade perhaps as a result of a general increase in fish consumption.
The symptoms of acute ciguatera fish poisoning may begin as soon as 30 minutes after eating contaminated fish. The initial symptoms may include itching, tingling, and numbness of the lips, tongue, hands, and/or feet. Other symptoms during the first six to 17 hours are abdominal cramps, nausea, vomiting, diarrhea, and/or a red skin rash (pruritus). Chills, hot and cold temperature reversal, generalized weakness, restlessness, dizziness, wheezing, blurred vision, abnormal sensitivity to light (photophobia), muscle aches (myalgias), and/or joint pain (arthralgias) may also develop.
The acute symptoms of ciguatera fish poisoning generally disappear within a few days. However, neurological symptoms may continue for several months. Some affected individuals experience abnormally low blood pressure upon standing from a seated position (orthostatic hypotension). In severe cases, there may be rapid progression to breathing difficulties (dyspnea) and muscular paralysis. Life-threatening complications (i.e., abnormally slow heartbeat, respiratory arrest, convulsions, or coma) may occur in these severe cases within 24 hours.
Ciguatera fish poisoning is caused by a toxin (ciguatoxin) found in tropical or subtropical fish during certain times of the year. The source of the toxin responsible for ciguatera fish poisoning is found in high levels in a marine organism (dinoflagellate Gamabierdiscus toxicus) that typically inhabits low-lying tropical shore areas and coral reefs. As local fish feed on this organism, toxin accumulates in their bodies and ultimately causes ciguatera fish poisoning when humans consume the fish.
No known method of cooking can destroy the ciguatoxin in contaminated fish. It is possible that more than one form of the toxin may be present in a fish.
Ciguatera fish poisoning is a rare disease that affects males and females in equal numbers. This disease occurs with the greatest frequency in tropical and subtropical countries, particularly those in the Pacific and Caribbean areas. All age groups are at risk for this disease. However, a longer duration and more severe symptoms of ciguatera fish poisoning may be associated with increasing age. Children seem to experience milder symptoms for a shorter period of time. More severe symptoms may also be associated with the ingestion of a larger quantity of contaminated fish.
The presence of ciguatoxin has been reported in semen from affected males which can cause the symptoms of ciguatera fish poisoning in females after sexual intercourse. Since this toxin has also been identified in breast milk, it is also possible for affected mothers to pass this disease to their nursing children.
The treatment for ciguatera fish poisoning is usually the immediate pumping out of all stomach contents (gastric lavage). If this treatment is not available, then vomiting should be induced by the administration of syrup of ipecac. Persistent nausea and vomiting must be treated with the intravenous administration of fluids to avoid dehydration. If shock, convulsions or respiratory failure occurs, immediate appropriate medical measures must be instituted. Dextran (a polysaccharide drug), Normal Human Serum Albumin, or blood transfusion may be necessary to treat shock. Meperidine may also be prescribed for pain. Other treatment is symptomatic and supportive.
Travelers to endemic areas should be cautioned about the risk of contracting ciguatera fish poisoning. Since travelers are at the same relative risk as people who normally live in endemic areas, they should be warned not to eat barracuda and should exercise caution when considering other fish such as grouper and red snapper.
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