View source for Amnesic shellfish poisoning

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==Overview==
''Amnesic shellfish poisoning'' (ASP) is one of the four recognized [[syndrome]]s of [[shellfish poisoning]], which are primarily associated with [[Bivalvia|bivalve mollusks]] (such as [[mussel]]s, clams, [[oyster]]s and scallops). These shellfish are filter feeders and, therefore, accumulate [[toxin]]s produced by [[microscopic]] [[algae]] in the form of [[dinoflagellate]]s and [[diatom]]s. 

ASP results from consumption of [[domoic acid]]. In the brain, domoic acid especially damages the [[hippocampus]] and [[amygdaloid]] nucleus. It damages the [[neuron]]s by activating [[AMPA]] and [[kainate]] [[receptor]]s, causing an influx of [[calcium]]. Although [[calcium]] flowing into cells is a normal event, the uncontrolled increase of [[calcium]] causes the cell to degenerate.

The chemical can [[bioaccumulation|bioaccumulate]] in marine organisms that eat [[phytoplankton]], such as shellfish, anchovies, and sardines. In [[mammal]]s, including [[human]]s, domoic acid acts as a [[neurotoxin]], causing permanent short-term [[memory]] loss, [[brain]] damage, and [[death]] in severe cases. [[Harmful algal bloom]]s are associated with the phenomenon of ASP. Cooking or freezing affected fish or shellfish tissue does not lessen the toxicity.
==Historical Perspective==
ASP was first discovered when, in late 1987, a serious outbreak of [[food poisoning]] occurred in eastern Canada. Three elderly patients died and other victims suffered long-term [[neurological]] problems. Because of the [[memory loss]] problem, the term [[amnesia|amnesic]] shellfish poisoning (ASP) is used to refer to this clinical [[syndrome]] [M. A. Quilliam, J. L. C. Wright, Anal. Chem., 61 (1989) 1053A]. The story made front-page newspaper headlines. 

[[Epidemiologist]]s from [[Health Canada]] quickly linked the illnesses to restaurant meals of cultured mussels harvested from one area in Prince Edward Island, a place never before affected by toxic [[algae]]. Mouse [[bioassay]]s on aqueous extracts of the suspect mussels caused death with some unusual [[neurotoxic]] [[symptom]]s very different from those of [[paralysis|paralytic]] shellfish poison and other known toxins. On December 12, 1987, a team of scientists was assembled at the National Research Council of Canada laboratory in Halifax, Nova Scotia. Integrating [[bioassay]]- directed fractionation with chemical analysis, the team identified the toxin on the afternoon of December 16, just 4 days after the start of the concerted investigation.

On June 22, 2006, a California brown pelican, possibly under the influence of domoic acid, flew through the windshield of a car on the Pacific Coast Highway.  The acid is found in the local seas.

Domoic acid poisoning may also have caused a 1961 invasion of thousands of frantic seabirds in Santa Cruz, California. Director [[Alfred Hitchcock]] heard about this invasion while working on his adaptation of Daphne du Maurier novella "The Birds" for his feature film ''The Birds'' (1963).

==Diagnosis==
===History and Symptoms===
[[Gastrointestinal]] [[symptom]]s appear within 24 hours of [[ingestion]] of molluscs contaminated with domoic acid. They may include [[vomiting]], [[nausea]], [[diarrhea]], [[abdominal]] [[cramp]]s and [[hemorrhage|hemorrhagic]] [[gastritis]]. In more severe cases, [[neurological]] [[symptom]]s develop after a delay of several hours or up to three days. These include [[headache]], [[dizziness]], [[disorientation]], vision disturbances, loss of [[short-term memory]], motor weakness, [[seizure]]s, profuse [[respiratory]] [[secretion]]s, [[hiccough]]s, unstable [[blood pressure]], [[cardiac arrhythmia]], and [[coma]]. 
==Treatment==
===Medical Therapy===
People poisoned with very high doses of the toxin or displaying risk factors such as old age and [[renal failure]] can die. Death occurred in 4 of the 107 confirmed cases. In a few cases, permanent [[sequela]]e included short-term memory loss and peripheral [[polyneuropathy]].

There is no [[antidote]] available for domoic acid and treatment is [[symptomatic]].
==References==
{{reflist|2}}

{{Poisoning and toxicity}}

[[Category:Emergency medicine]]
[[Category:Medical emergencies]]
[[Category:Foodborne illnesses]]

[[gl:ASP]]

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