Amnesic Shellfish



  • First Described in 1987 During an Outbreak Involving 107 Patients Who Consumed Contaminated Mussels Cultivated Off of the Coast of Prince Edward, Canada


  • Outbreaks Have Been Reported in Europe (Spain, Portugal, Scotland, Ireland, France, Belgium), South America (Chile), and Australia/New Zealand (Epidemiol Infect, 2010) [MEDLINE] and (Environ Int, 2012) [MEDLINE]
    • In Addition, Erratic Behavior and Death of Sea Lions, Pelicans, and Cormorants Has Been Attributed to Ingestion of Domoic Acid-Contaminated Anchovies in California


  • Ingestion of Contaminated Shellfish (Mussels, Scallops, Razor Clams, and Crustaceans)
    • Domoic Acid is Taken Up by the Shellfish During Phytoplankton Blooms


  • Domoic Acid
    • Domoic Acid is Synthesized by Single Cell, Algae-Like Organisms of the Pseudonitzschia Species
    • Domoic Acid is a Heat-Stable Compound Which is Structurally Related to Glutamate
    • Domoic Acid Acts as a Potent Excitatory Neurotransmitter and Can Result in Death of Neurons in the Amygdala and Hippocampus


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Clinical Manifestations

General Comments

  • Age: age >65 y/o is associated with more severe symptoms (memory loss, etc) (Food Chem Toxicol, 2004) [MEDLINE]

Gastrointestinal Manifestations

Neurologic Manifestations

Other Manifestations

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  • Limits on Domoic Acid Concentrations In Inspected Shellfish in Developed Countries: <20 μg/g of shellfish flesh (represents 10-fold less than the concentration in mussels known to cause clinical symptoms) (NEJM, 1990) [MEDLINE]


Supportive Care

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Activated Charcoal (see Activated Charcoal, Activated Charcoal)

  • Recommended to Bind Unabsorbed Food (Although Data is Lacking)

Lorazepam (Ativan) (see Lorazepam, Lorazepam)

  • Clinical Efficacy
    • Lorazepam Has Been Suggested to Prevent Neurologic Damage (Including Memory Loss)


  • May Be Fatal


  • An outbreak of toxic encephalopathy caused by eating mussels contaminated with domoic acid. N Engl J Med. 1990;322(25):1775 [MEDLINE]
  • Neurologic sequelae of domoic acid intoxication due to the ingestion of contaminated mussels. N Engl J Med. 1990;322(25):1781 [MEDLINE]
  • Amnesic shellfish poison. Food Chem Toxicol. 2004;42(4):545 [MEDLINE]
  • Neurobehavioral effects of harmful algal bloom (HAB) toxins: a critical review. J Int Neuropsychol Soc. 2005 May;11(3):331-8 [MEDLINE]
  • Neurotoxins from marine dinoflagellates: a brief review. Mar Drugs. 2008 Jun 11;6(2):349-71. doi: 10.3390/md20080016 [MEDLINE]
  • Shellfish toxicity: human health implications of marine algal toxins. Epidemiol Infect. 2010 Jul;138(7):927-40. Epub 2010 Apr 23 [MEDLINE]
  • Exposure to domoic acid through shellfish consumption in Belgium. Environ Int. 2012 Nov;49:115-9. Epub 2012 Sep 23 [MEDLINE]
  • Multidetection of paralytic, diarrheic, and amnesic shellfish toxins by an inhibition immunoassay using a microsphere-flow cytometry system. Anal Chem. 2013 Aug 20;85(16):7794-802. doi: 10.1021/ac401146m [MEDLINE]