Ciguatera Fish Poisoning is the most common seafood illness reported in travellers. It is caused by eating fish contaminated with ciguatoxins which are produced by dinoflagellates – small marine organisms living on or near coral reefs – belonging to the species Gambierdiscus toxicus. Herbivorous fish feed on these organisms and the ciguatoxins bio-accumulate along the marine food chain to larger predatory fish, usually over 2.7 kg / 6 lbs.
Ciguatera Fish Poisoning commonly occurs in tropical and subtropical areas, particularly in the Pacific Ocean, the Indian Ocean, and the Caribbean Sea. Any reef fish can cause ciguatera poisoning, but species such as barracuda, grouper, red snapper, moray eel, amberjack, parrotfish, hogfish, sturgeonfish, kingfish, coral trout, and sea bass are the most commonly affected. Ciguatoxins are concentrated in the fish liver, intestines, heads, and roe. The toxins do not affect the taste, texture, or odour of the fish and cannot be destroyed by cooking, smoking, freezing, salting or any other method of food preparation. Outbreaks can occur seasonally or sporadically, particularly after storms. Not all fish of a given species or from a given area will be toxic.
Usually symptoms appear 1 to 3 hours after consuming contaminated fish. The illness is characterized by abdominal pain, nausea, vomiting, and diarrhea. This is followed by neurological complications appearing 3 to 72 hours later, including a tingling sensation, temperature reversal (cold items feel hot and hot items feel cold), itching, metallic taste in the mouth, feeling like teeth are loosening, blurred vision, and even temporary blindness. These symptoms usually last days to several weeks. Long term consequences include chronic fatigue, depression, muscle pain, headache, a slow or irregular heartbeat, and low blood pressure. Treatment includes supportive care of symptoms and can include intravenous mannitol to reduce neurological symptoms if given promptly.
Commercial ciguatera test kits are not always accurate and are expensive. There is no preventive medication or vaccine against Ciguatera Fish Poisoning.
Information last updated: February 23, 2021.