Facts on marine biotoxins


Marine biotoxins are naturally occurring chemicals caused by certain types of toxic algae. Exposure to marine biotoxins can occur through direct contact by swimming, breathing in aerosolised toxins in water droplets or eating toxin-contaminated seafood. Marine biotoxins can accumulate in seafood, and most human illnesses from marine biotoxins occur when people eat contaminated fish or shellfish.  Symptoms of food poisoning can vary depending on the type of toxin. The following diseases and symptoms caused by marine biotoxins have been identified.

Ciguatera fish poisoning (CFP) is the most common reported illness caused by marine biotoxin in food.  It is caused by eating fish that have  accumulated ciguatoxins (CTXs) due to feeding on toxic microalgae (Gambierdiscus spp. and Fukuyoa spp.) Traditional endemic regions for ciguatoxic fish include areas in the Caribbean Sea and the Pacific and Indian Oceans, but autochthonous outbreaks have also been reported in Europe (the Canary Islands and Madeira).

Neurotoxic Shellfish Poisoning (NSP) is caused by eating shellfish contaminated with brevetoxins produced by a species of dinoflagellate Karenia brevis. These toxins have been found in shellfish, including oysters, clams, and mussels from the Gulf of Mexico and mid-Atlantic waters. NSP usually presents as gastroenteritis, accompanied by neurologic symptoms. 

Paralytic Shellfish Poisoning (PSP) is a marine toxin disease with both gastrointestinal and neurologic symptoms reported worldwide. It is caused by eating shellfish contaminated with saxitoxin, a toxin produced by dinoflagellates of the genus Alexandrium. PSP toxins can be found in shellfish (such as mussels, cockles, clams, scallops, oysters, crabs and lobsters).

Amnesic Shellfish Poisoning (ASP) is caused by eating shellfish contaminated with domoic acid, a toxin produced by the diatoms Pseudo-nitzschia, Nitzschia, and Amphora. ASP differs from most other marine biotoxin poisonings in that it mainly causes neurological symptoms. High levels of toxin have been found in shellfish in areas such as the United States along the Pacific coast and northeast coast, the Gulf of Mexico and off the west coast of Scotland. 

Diarrhetic Shellfish Poisoning (DSP) is caused by eating shellfish contaminated with okadaic acid and dinophysistoxins, toxins produced by the dinoflagellates Dinophysis and Procentrum. DSP is a gastrointestinal illness without neurologic manifestation, and it is reported worldwide.

Azaspiracid Shellfish Poisoning (AZP) is the most recently discovered human illness with severe gastrointestinal symptoms related to shellfish contaminated with marine biotoxins. Azaspiracids are toxins that are produced by dinoflagellates Azadinium spinosum. The toxins have been found in shellfish from many coastal regions of western Europe, northwest Africa, Chile and eastern Canada.