Paralytic Shellfish Poisoning

Causative organisms: Alexandrium spp.,Gymnodinium catenatum, Pyrodinium bahamense

Toxins produced: Saxitoxins

Paralytic Shellfish Poisoning (PSP), like ASP, is a life threatening syndrome. Symptoms are purely neurological and their onset is rapid. Duration of effects is a few days in non-lethal cases. Symptoms include tingling, numbness, and burning of the perioral region, ataxia, giddiness, drowsiness, fever, rash, and staggering. The most severe cases result in respiratory arrest within 24 hours of consumption of the toxic shellfish. If the patient is not breathing or if a pulse is not detected, artificial respiration and CPR may be needed as first aid. There is no antidote, supportive therapy is the rule and survivors recover fully. PSP is prevented by large-scale proactive monitoring programs (assessing toxin levels in mussels, oysters, scallops, clams) and rapid closures of suspect or demonstrated toxic areas to harvest.

U.S. Finfish, Shellfish and Wildlife Affected by PSP
Harmful Algal Species
Geographic Area
Affected Organisms*
Alexandrium spp.

Northern Atlantic and Pacific Coast of North America

Mussels, surfclams, softshell clams, sea scallops, butterclams, ocean quahogs, oysters, gastropods, lobsters, crabs.

Herring, salmon, menhaden, sandlance, mackerel, and possibly other fish species.

Whales, sea lions+, sea otters+, sea birds.

Squid, zooplankton, and other benthic invertebrates.

*Found to contain algal toxins, or to be adversely affected by toxic or harmful marine algae.
+Causative algae implicated, not confirmed.

Medical Community
PSPParalytic Shellfish Poisoning
Additional Information on PSP including: Background, Clinical Presentation, Diagnosis, Management and Treatment, Chemical Structure, and Molecular Mechanism of Action.

Additional Resources
Non-Traditional Vectors for Paralytic Shellfish Poisoning
Jonathan R. Deeds, Jan H. Landsberg, Stacey M. Etheridge, Grant C. Pitcher, Sara W. Longan
    DOI: 10.3390/md20080015

Last updated: July 31, 2012