ABSTRACT
Shellfish are a significant worldwide source of dietary protein. Bacterial and viral diseases are the most common causes of illness resulting from human consumption of shellfish, particularly raw specimens. The diagnosis may be missed when clinical symptoms are mild or when small numbers of people are involved and a link with shellfish ingestion is not established. Dinoflagellate toxins are passed through the food chain to humans via shellfish and, less frequently sea creatures such as crabs and some fish species. Crabs and fish become toxic by ingesting dinoflagellates directly or by feeding on affected shellfish. Prevention and investigation of outbreaks of toxicity from naturally harvested shellfish is best carried out by the same central regulatory authority which monitors commercial shellfish farms. Four main clinical syndromes are apparent: paralytic shellfish poisoning, neurotoxic shellfish poisoning, diarrhetic shellfish poisoning, and amnesic shellfish poisoning which has recently been described as a result of domoic acid toxicity.
