Ciguatera Fish Poisoning

What is Ciguatera Fish Poisoning?

Ciguatera fish poisoning is the most common marine food poisoning with over 50,000 cases reported worldwide.  

The organisms that produce the ciguatera toxins tend to grow on dead coral reefs, so the risk of acquiring ciguatera fish poisoning is likely to increase as coral reefs continue to die due to global warming, water pollution, direct damage, and other factors.

How do you get Ciguatera Fish Poisoning?

Ciguatera fish poisoning is acquired by eating large fish that have been contaminated with various toxins. The toxins (ciguatoxin,  maitotoxin and others) come from small marine organisms, known as dinoflagellates, who live in coral reefs. The toxins are concentrated when these organisms are eaten by small fish that are then eaten by larger carnivorous fish.

Susceptibility and Resistance

Anyone who eats large reef-dwelling fish in tropical areas can get ciguatera fish poisoning. 

Incubation Period

The incubation period for Ciguatera Fish Poisoning is 0-2 days.

What are the Symptoms?

The initial symptoms of ciguatera fish poisoning can occur within one hour of eating contaminated fish and usually within 24 hours of consumption. These symptoms include diarrhoea, vomiting, and abdominal pain, as well as low blood pressure. Neurological symptoms can occur at the same time as the initial symptoms or follow 1 to 2 days later. Symptoms can persist for weeks to months afterwards. These symptoms include pain and weakness in the legs, tingling or numbness around the lips, hot-to-cold reversal (ice cream tastes hot and coffee tastes cold), vertigo, blurred vision, and pain in the teeth. In severe cases, the neurological symptoms can progress to coma and respiratory failure in the first 24 hours of illness. 

Most people with ciguatera fish poisoning recover within a few weeks, however, symptoms can reappear intermittently in the following months or years. The mortality rate for ciguatera poisoning is only around 0.1 percent.

Preventative Measures

The fish that are most likely to cause ciguatera poisoning and should be avoided are large (greater than 6 pounds), carnivorous reef fish, such as amberjack, barracuda, grouper, moray eel, sea bass, or sturgeon. Other fish that pose a risk include parrot fish, surgeon fish, and red snapper. The toxins that cause ciguatera fish poisoning are not destroyed when the fish is cooked, smoked, frozen, or through any other method of food preparation. The toxins are also concentrated in certain parts of the fish, namely the liver, intestinal tract, roe, and head. These parts of the fish should be avoided if you must eat high-risk fish.

Treatment

There is no antidote for the toxins that cause ciguatera fish poisoning. Treatment involves supportive measures to lessen the impact of symptoms. The drug, mannitol, given intravenously, can dramatically reduce the length and severity of the symptoms, particularly if given early. This treatment can be life-saving in severe cases that may have progressed to coma without the intravenous mannitol. 

Where Does It Commonly Occur?

It occurs in tropical and subtropical marine waters, particularly in the Caribbean Sea and in the Pacific and Indian Oceans.

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