AN OUTBREAK OF TETRODOTOXIN POISONING FOLLOWING GASTROPOD MOLLUSK CONSUMPTION

Tetrodotoxin, a violent neurotoxin, is present in puffer fish and may occur in a variety of marine animals. Outbreaks of human tetrodotoxin poisoning, following consumption of marine organisms other than puffer fish, has been rare. We here report an outbreak of tetrodotoxin poiso ning following ingestion of gastropod molluscs and its clinical featur es are discussed. A 71-year-old woman was admitted with hypertension a nd other neurological symptoms developing after ingestion of some moll uscs. A further 16 cases were also found to have typical symptoms of t etrodotoxication after mollusc consumption. Clinical features in these 17 cases were similar to those conventionally found in tetrodotoxin p oisoning, except that there was hypertension in eight cases (47%). All except one case had mild poisoning and recovered well. The molluscs c onsumed comprised two different species: Nassarius castus and Nassariu s conoidalis, both of which were shown to contain various amounts of t etrodotoxin. It is concluded that tetrodotoxin poisoning following mol lusc consumption is a possibility. Hypertension, as an unusual feature in tetrodotoxication, is frequent in this outbreak, and should be loo ked for in future cases, The explanation of hypertension in tetrodotox ication may come either from an exaggerated response to sympathetic st imuli, or due to various responses of the vasomotor centre to a small dose of tetrodotoxin. Further studies are required to answer this ques tion.