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Recommendation Ciguatera research by WEFTA wg 'Analytical Methods'

Ciguatera Fish Poisoning

Background:

Ciguatera fish poisoning is a food intoxication caused by consumption of fish containing ciguatoxins.
Ciguatera is the most common type of marine food poisoning worldwide with an estimated 10.000 to 50.000 people suffering from the disease annually.
In the past, ciguatera food poisoning in humans was mainly localized to the tropical and subtropical Pacific and Indian Ocean and the tropical Caribbean. However, with the increases in seafood trade from tropical fishing areas and with the growing international tourism, the ciguatera poisoning has become an international problem.

The toxin:

The toxins, so called ciguatoxins, are produced by a benthic dinoflagellate Gambierdiscus toxicus, living in tropical and subtropical reef systems between 32 ° N and 32 ° S. The dead algae are eaten from small herbivorous fish grazing on the coral reefs and the ciguatoxins accumulate in organs and muscle meat of bigger carnivorous fish that feed on these fish.
Ciguatoxins are complex lipid-soluble polyether compounds. Caribbean and Indian Ocean ciguatoxins differ from Pacific ciguatoxins. In general, more than 20 different congeners of ciguatoxins have been identified.

The species:

Many species and families of reef fishes are involved in ciguatera globally.
Herbivorous Acanthuridae and corallivorous Scaridae (parrot fish) are considered  to be key vectors in the transfer of ciguatoxins to carnivorous fish. 
Carnivorous fish causing ciguatera include Muranidae (Moray eels), Lutjanidae (snapper), Serranidae (groupers), Epinephelidae ( groupers), Lethrinidae (emperors), Scombridae (mackerel), Carrangidae (jacks) and Sphyraenidae (barracudas). More than 400 fish species have been reported to have caused ciguatera poisoning.

The poisoning:

Typical symptoms of ciguatoxin poisoning are gastrointestinal and/or neurological disturbances. Severe cases can involve hypotension with bradycardia, respiratory difficulties and paralysis. In few cases, the disease can be lethal.
Symptoms usually last for several weeks, although in some cases they may persist for months or even years.
Ciguatoxin cannot be identified by odour, taste or appearance of the fish. Neither cooking nor freezing or typical processing methods like drying, smoking and marinating destroy the toxins.

Cases reported in Europe mainly followed a travel (holiday) to tropical countries and were caused by the consumption of local fish meals.

Analysis:

Various analytical methods are described for the detection of ciguatoxins but most methods have a lack of specificity for individual toxins. There is a need for a fast and reliable screening method.   

Statement of the WEFTA Working Group:

Many of the tropical and subtropical fish species being imported into the European Union have been fished in waters between 32 ° N and 32 ° S. Therefore it is most likely that ciguatera toxins can be present in those fish. The WEFTA Working Group of Analytical Methods is of the opinion that research on ciguatera and maito toxins in imported fish species should be included in a FP7 research project on imported fish species.

 

For more information see: www.fao.org/docrep