Ciguatéra : aspects écologiques, biologiques et toxicologiques

Ciguatera Fish Poisoning (CFP) is a human intoxication resulting from the consumption of marine products from coral reef environment contaminated by marine toxins, namely the ciguatoxins (CTXs), which are further concentrated and biotransformed through the food web in herbivorous and carnivorous fish and which act preferentially on the voltage gated sodium channels. This disease, highly prevalent in tropical and subtropical areas of the globe, is characterized by gastrointestinal, neurological, cutaneous, cardiovascular and respiratory disturbances of variable intensity, often complicated by the occurrence of chronic cases and the absence of an effective treatment, except perhaps by the resort to traditional remedies. The primary causative agent of CFP is a benthic dinoflagellate, Gambierdiscus spp., characterized by a high morphological and molecular diversity (up to 11 distinct species described to date) and a large geographical distribution. More recently however, the potential involvement of marine cyanobacteria in some atypical forms of ciguatera has also been documented. Environmental disturbances (e.g. increased sea temperature levels) and anthropogenic aggressions undergone by coral reef ecosystems are some of the factors likely to trigger ciguatera outbreaks. Only certain genetic strains of Gambierdiscus are capable of producing CTXs. These latter are distributed into 3 distinct toxin groups corresponding to the 3 geographical areas where CFP is endemic (i.e. the Pacific, the Caribbean and the Indian Ocean), which represent more than 40 different CTXs congeners. Despite the wide range of detection tests already available (including in vivo, in vitro and even traditional tests), there is currently no duly validated reference test which makes CFP a major impediment to the sustainable exploitation of fisheries.