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Vertebrates , Ciguatera fish poisoning

المؤلف:  Sue Jickells , Adam Negrusz (Editors)

المصدر:  Clarkes Analytical Forensic Toxicology

الجزء والصفحة:  126

2026-10-01

20

Vertebrates

Ciguatera fish poisoning

 Ciguatera fish poisoning (CFP) is caused by two groups of toxins, of which the principal one includes the lipid-soluble ciguatoxins (CTXs) (Fig. 1) and gambierol, produced by the epiphytic dinoflagellate Gambierdiscus toxicus. The other group comprises the water-soluble maitotoxin. CTXs are a group of heat-stable, lipid-soluble, highly oxygenated cyclic polyether molecules, which appear in the food chain through coral reef-fishes that have become toxic through their diet. CTX-containing dinoflagel lates live on solid surfaces of macroalgae and are consumed during fish grazing. The mechanism of CTX toxicity is through its direct effects on excitable membranes. Consumption of contaminated fish leads to gastrointestinal disturbances (nausea, vomiting and diarrhoea) within a few hours, followed by neurological symptoms. The latter include paraesthesias, tooth pain and reversal of hot/cold temperature sensation. The third symptom is pathognomonic for CFP. Paraesthesia and weakness may persist for months after the acute illness. CFP is the most common cause of poisoning with marine toxins. Of those who live in or visit subtropical and tropical areas, an estimated 10 000 to 50 000 people per year suffer from ciguatera. The fatality rate, however, is probably less than 1%. There is no specific therapy for CFP. Prevention of consumption of contaminated fish is essential. Analysis is difficult because of the low toxin level in fish and the complex structure of the CTX group of toxins. A method based on HPLC and tandem electrospray MS offers the required sensitivity (less than parts per billion; Lewis et al. 1999) and other LC-MS methods are available (Hamilton et al. 2002). A membrane immuno-bead assay appears to be a simple, rapid, sensitive and specific detection method for CTX and its related polyethers, but further validation of this test is required; for a review, see Quilliam (1999). A commercially available immunoassay-based test kit based is available but is not yet validated.

Figure 1 Ciguatoxin.