Amnesic shellfish poisoning


Amnesic shellfish poisoning

Amnesic shellfish poisoning (ASP) is a human illness caused by consumption of the marine biotoxin called domoic acid.[1] This toxin is produced naturally by marine diatoms belonging to the genus Pseudo-nitzschia and the species Nitzschia navis-varingica. When accumulated in high concentrations by shellfish during filter feeding, domoic acid can then be passed on to humans via consumption of the contaminated shellfish. Although human illness due to domoic acid has only been associated with shellfish, the toxin can bioaccumulate in many marine organisms that consume phytoplankton, such as anchovies, and sardines. Intoxication by domoic acid in non-human organisms is frequently referred to as "domoic acid poisoning" or "DAP". In mammals, including humans, domoic acid acts as a neurotoxin, causing permanent short-term memory loss, brain damage, and death in severe cases.

Contents

Symptoms and treatment

In the brain, domoic acid especially damages the hippocampus and amygdaloid nucleus.[1] It damages the neurons by activating AMPA and kainate receptors, causing an influx of calcium. Although calcium flowing into cells is a normal event, the uncontrolled increase of calcium causes the cell to degenerate.

Gastrointestinal symptoms can appear 24 hours after ingestion of affected molluscs. They may include vomiting, nausea, diarrhea, abdominal cramps and haemorrhagic gastritis. In more severe cases, neurological symptoms can take several hours or up to three days to develop. These include headache, dizziness, disorientation, vision disturbances, loss of short-term memory, motor weakness, seizures, profuse respiratory secretions, hiccoughs, unstable blood pressure, cardiac arrhythmia and coma.

People poisoned with very high doses of the toxin or displaying risk factors such as old age and renal failure can die. Death has occurred in 4 of 107 confirmed cases. In a few cases, permanent sequelae included short-term memory loss and peripheral polyneuropathy.

There is no known antidote available for domoic acid, so if symptoms fit the description, it is advised to go quickly to the hospital. Cooking or freezing affected fish or shellfish tissue does not lessen the toxicity.

Discovery

ASP was first discovered in humans late in 1987, when a serious outbreak of food poisoning occurred in eastern Canada.[1][2] Three elderly patients died and other victims suffered long-term neurological problems. Because the victims suffered from memory loss, the term "amnesic" shellfish poisoning is used.[3] The story made front-page newspaper headlines.

Epidemiologists 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 bioassays on aqueous extracts of the suspect mussels caused death with some unusual neurotoxic symptoms very different from those of paralytic shellfish poisoning toxins 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 [4].

Possible animal effects

On June 22, 2006, a California brown pelican, possibly under the influence of domoic acid [5], flew through the windshield of a car on the Pacific Coast Highway. The phycotoxin is found in the local coastal waters.

Since March 2007, marine mammal and seabird strandings and deaths off the Southern California coast have increased markedly. These incidents have been linked to the recent and dramatic increase of a naturally occurring toxin produced by algae. Most of the animals found dead tested positive for domoic acid.

According to the Channel Islands Marine and Wildlife Institute (CIMWI) [6], "It is generally accepted that the incidence of problems associated with toxic algae is increasing. Possible reasons to explain this increase include natural mechanisms of species dispersal (currents and tides) to a host of human-related phenomena such as nutrient enrichment (agricultural run-off), climate shifts or transport of algae species via ship ballast water."

In popular culture

In the "Bad Fish" episode of Get a Life (original air-date: February 2, 1992), Sharon and Gus get amnesia after eating bad shellfish, and Chris seizes the opportunity to convince them that they are his best friends.

Domoic acid poisoning may have caused an August 18, 1961 invasion of thousands of frantic seabirds in Capitola and 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), and asked the Santa Cruz Sentinel newspaper for any further news copy as "research for his new thriller".

See also

References

External links


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Look at other dictionaries:

  • amnesic shellfish poisoning — noun Severe, sometimes fatal, poisoning caused by the ingestion of domoic acid from contaminated shellfish • • • Main Entry: ↑amnesia …   Useful english dictionary

  • amnesic shellfish poisoning — a type of shellfish poisoning seen primarily in eastern Canada, caused by ingestion of shellfish that have consumed the diatom Nitschia pungens, which contains domoic acid. Symptoms include memory loss, sensorimotor neuropathy, diarrhea, and… …   Medical dictionary

  • Amnesic shellfish poisoning — Intoxication alimentaire Une toxi infection alimentaire (en langage courant, une intoxication alimentaire) est une maladie, souvent infectieuse et accidentelle, contractée suite à l ingestion de nourriture ou de boisson contaminées par des agents …   Wikipédia en Français

  • amnesic shellfish poisoning — (am ne sik) The disease arising in humans and animals that eat seafood such as mussels contaminated with domoic acid from diatoms. The disease produces short term memory loss in its victims …   Dictionary of microbiology

  • Shellfish poisoning — Infobox Disease Name = PAGENAME Caption = DiseasesDB = 32220 ICD10 = ICD10|T|61|2|t|51 ICD9 = ICD9|988.0 ICDO = OMIM = MedlinePlus = eMedicineSubj = emerg eMedicineTopic = 528 MeshID = There are four syndromes called shellfish poisoning, which… …   Wikipedia

  • shellfish poisoning — see PARALYTIC SHELLFISH POISONING * * * acute intoxication caused by ingestion of bivalve mollusks contaminated with neurotoxins. There are four different types: amnesic, diarrhetic, neurotoxic, and paralytic …   Medical dictionary

  • Neurotoxic shellfish poisoning — (NSP) is caused by the consumption of shellfish contaminated by breve toxins or brevetoxin analogs.[1] Symptoms in humans include vomiting and nausea and a variety of neurological symptoms such as slurred speech. No fatalities have been reported… …   Wikipedia

  • Diarrhetic shellfish poisoning — (DSP) is one of the four recognized symptom types of shellfish poisoning, the others being paralytic shellfish poisoning, neurotoxic shellfish poisoning and amnesic shellfish poisoning. As the name suggests, this syndrome manifests itself as… …   Wikipedia

  • 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… …   Wikipedia

  • Diarrheal shellfish poisoning — Diarrhetic shellfish poisoning (DSP) is one of the four recognised symptom types of shellfish poisoning, the others being paralytic shellfish poisoning, neurotoxic shellfish poisoning and amnesic shellfish poisoning.As the name suggests, this… …   Wikipedia


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