Paralytic shellfish poisoning

Paralytic shellfish poisoning (PSP) is one of the four recognized syndromes of shellfish poisoning (the others being neurotoxic shellfish poisoning, diarrhetic shellfish poisoning and amnesic shellfish poisoning). All four syndromes share some common features and are primarily associated with bivalve molluscs (such as mussels, clams, oysters and scallops). These shellfish are filter feeders and, therefore, accumulate toxins produced by microscopic algae, such as dinoflagellates and diatoms, and cyanobacteria.cite journal |author=Clark RF, Williams SR, Nordt SP, Manoguerra AS |title=A review of selected seafood poisonings |journal=Undersea Hyperb Med |volume=26 |issue=3 |pages=175–84 |year=1999 |pmid=10485519 |doi= |url=http://archive.rubicon-foundation.org/2314 |accessdate=2008-08-12] Human toxicity and mortality can occur after ingestion of these animals, but toxicity is also seen in wild animal populations.

Pathophysiology

The toxins responsible for most shellfish poisonings are water-soluble, heat and acid-stable, and are not inactivated by ordinary cooking methods. The main toxin responsible for PSP is principally saxitoxin. Most shellfish only store this toxin for six weeks after a red tide passes, but some such as butterclams are known to store the toxin for up to two years. Additional toxins are found such as neosaxiton and gonyautoxins I to IV. All of them act primarily on the nervous system.

PSP can be fatal in extreme cases (particularly in those who are already immuno-suppressed). Children are more susceptible. PSP affects those who come into contact with the affected shellfish by ingestion. Ten to thirty minutes after ingestion, symptoms can include nausea, vomiting, diarrhea, abdominal pain, and tingling or burning lips, gums, tongue, face, neck, arms, legs, and toes. Shortness of breath, dry mouth, a choking feeling, confused or slurred speech, and lack of coordination are also possible.

PSP in wild marine mammals

PSP has been implicated as a cause of sea otter mortality and morbidity in Alaska, as one of its primary prey items, the butterclam, ("Saxidonus giganteus"), bioaccumulates PSP as a chemical defense mechanism. In addition, ingestion of saxitoxin-containing mackerel has been implicated in the death of humpback whales.

Additional cases where PSP was suspected as the cause of death in Mediterranean Monk Seals ("Monachus monachus") in the Mediterranean Sea have been questioned due to lack of additional testing to rule out other causes of mortality.

See also

* Harmful algal bloom
* Cyanotoxin
* Algal bloom (see "toxic chemicals" in paragraph 3)
* Ciguatera
* Dinoflagellate (see "neurotoxins" and "red tide" under Ecology and fossils and see "phosphate" under Cautions)
* Red tide

References

External links

* [http://www.emedicine.com/EMERG/topic528.htm Toxicity, Shellfish]