For reasons that are not clearly understood, when certain hydrographic and climatic conditions occur, the organisms undergo a dramatic population surge. These tiny organisms contain brown or reddish pigments, and depending on their density, the surrounding ocean waters take on a similar hue. In California, the main mollusk of concern for PSP and ASP are intertidal mussels. Since PSP was made a reportable disease in 1927, there have been 521 reported incidents, with 32 deaths. ASP in humans is characterized by nausea, vomiting, severe headache, and GI symptoms.
Severe cases can progress to persistent cognitive deficit, coma and death.
Symptoms of both PSP and ASP can occur within minutes to hours of eating affected mussels. Toxic algae blooms are uncontrollable, chronic conditions that are a constant component of our marine coastal environment. Toxicity in mussels can increase from safe to dangerous within a few days. The single most important activity to prevent PSP and ASP is an aggressive surveillance program. PHI mails quarantine orders to retail bait operations throughout the county, makes periodic, on-site inspections of each of these operations, and posts and maintains mussel warning signs.