Well, I would say;
Infectious agents cause most shellfish-associated illness. Hepatitis A, Norwalk virus, Vibrio parahaemolyticus, and Vibrio vulnificus all have been transmitted through shellfish ingestion. Toxic illness caused by shellfish has been recognized for several hundred years.
Native Americans are known to have warned early settlers to avoid shellfish during the summer months. Since that time, at least 4 distinct shellfish-poisoning syndromes have been identified, as follows:
Paralytic shellfish poisoning (PSP)
Neurologic shellfish poisoning (NSP)
Diarrheal shellfish poisoning (DSP)
Amnestic shellfish poisoning (ASP)
All 4 syndromes share some common features and primarily are associated with bivalve mollusks (eg, mussels, clams, oysters, scallops). These shellfish are filter feeders and, therefore, accumulate toxins produced by microscopic algae in the form of dinoflagellates and diatoms.
Australian Blenny (Ecsenius australianus) anyone?