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Amnesic Shellfish Poisoning

Confirmed Case

  • Gastrointestinal symptoms [1] within 24 hours OR neurological symptoms [1] within 48h of eating shellfish [2] or contaminated seafoods [3];
  • Laboratory confirmation through:
    • Detection of domoic acid in ingested shellfish [2] or contaminated seafoods [3] in edible tissues in excess of 10 mg/kg (10 ppm);
    • Detection of domoic acid in urine collected within 24h of exposure and illness.

Probable Case

  • Neurological symptoms [1] within 48 hours of eating shellfish [2] or contaminated seafoods [3];
  • Gastrointestinal symptoms [1] within 24h of eating shellfish [2] or contaminated seafoods [3] AND where the shellfish was:
    • also eaten by a confirmed case or a probable case with neurological symptoms;
    • from an area with domoic acid in excess of 10mg/kg (10ppm) in shellfish.


  1. Clinical illness defined as:
    1. Gastrointestinal symptoms (nausea, vomiting, abdominal cramps and/or diarrhea).
    2. Neurological symptoms (confusion and/or loss of memory). 
    Illness lasts hours to days. In severe cases: tachycardia, hypotension, arrhythmias, pulmonary edema, profuse respiratory secretions, mutism, unusual ocular movements with disconjugate gaze and grimacing, seizures, coma and/or death.
  2. At risk shellfish include filter feeding molluscan bivalve shellfish: clams, mussels, scallops (digestive tissue), oysters, cockles and whelks.  
  3. Seafoods at risk of being contaminated are any species that feeds on plankton, including crabs, prawns, squid and and plantiverous fish eaten whole (e.g., anchovies and sardines). Rarely, edible algae may be contaminated via contact with toxic phytoplankton.
SOURCE: Amnesic Shellfish Poisoning ( )
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