Marine toxins are naturally occurring chemicals that can contaminate certain seafood. The seafood contaminated with these chemicals frequently looks, smells, and tastes normal. When humans eat such seafood, disease can result. The most common diseases caused by marine toxins in United States in order of incidence are scombrotoxic fish poisoning, ciguatera poisoning, paralytic shellfish poisoning, neurotoxic shellfish poisoning and amnesic shellfish poisoning. Marine toxins are naturally occurring chemicals.
Diagnosis of marine toxin poisoning is generally based on symptoms and a history of recently eating a particular kind of seafood. Laboratory testing for the specific toxin in patient samples is generally not necessary because this requires special techniques and equipment available in only specialized laboratories. If suspect, leftover fish or shellfish are available, they can be tested for the presence of the toxin more easily.
There is no specific antidote for ciguatoxin or maitotoxin poisonings. Treatment is generally for specific symptoms and includes supportive care. Intravenous mannitol has been reported in uncontrolled studies to reduce the severity and duration of neurologic symptoms, particularly if given within 48 hours of the appearance of symptoms.
Tetrodotoxin is a neurotoxin responsible for many human fatalities, most commonly following the consumption of pufferfish. Whilst the source of the toxin has not been conclusively proven, it is thought to be associated with various species of marine bacteria. Whilst the toxins are well studied in fish and gastropods, in recent years, there have been a number of reports of tetrodotoxin occurring in bivalve shellfish, including those harvested from the UK and other parts of Europe.