Identification of putative palytoxin as the cause of clupeotoxism

In 1994 in Madagascar a woman died after eating a sardine, Herklotsichthys quadrimaculatus. Two heads removed, respectively, from a toxic and a nontoxic fish before cooking were retrieved, kept frozen, and used for toxin analysis. The causative toxin was identified as palytoxin or its analogs based on its cytotoxicity, delayed hemolysis, neutralization with an anti-palytoxin antibody, chromatographic properties on different columns, and MS data. The gill and esophagus of the fish contained large amount of bottom sediments indicating that the fish had fed on the bottom and thus probably obtained the toxin from a benthic organism. The benthic dinoflagellate Ostreopsis siamensis that produces palytoxin and its analogs was inferred as the probable toxin source. This is the first study to shed light on clupeotoxism, a highly fatal form of human intoxication due to ingestion of clupeoid fish.