Amnesic shellfish poisoning (ASP) is an illness caused by consumption of

shellfish Shellfish, in colloquial and fisheries usage, are exoskeleton-bearing Aquatic animal, aquatic invertebrates used as Human food, food, including various species of Mollusca, molluscs, crustaceans, and echinoderms. Although most kinds of shellfish ...

that contain the marine biotoxin called

domoic acid Domoic acid (DA) is a kainic acid-type neurotoxin that causes amnesic shellfish poisoning (ASP). It is produced by algae and accumulates in shellfish, sardines, and anchovies. When sea lions, otters, cetaceans, humans, and other predators eat cont ...

. In

mammal A mammal () is a vertebrate animal of the Class (biology), class Mammalia (). Mammals are characterised by the presence of milk-producing mammary glands for feeding their young, a broad neocortex region of the brain, fur or hair, and three ...

s, including humans, domoic acid acts as a

neurotoxin Neurotoxins are toxins that are destructive to nervous tissue, nerve tissue (causing neurotoxicity). Neurotoxins are an extensive class of exogenous chemical neurological insult (medical), insultsSpencer 2000 that can adversely affect function ...

, causing permanent

short-term memory loss Amnesia is a deficit in memory caused by brain damage or brain diseases,Gazzaniga, M., Ivry, R., & Mangun, G. (2009) Cognitive Neuroscience: The biology of the mind. New York: W.W. Norton & Company. but it can also be temporarily caused by t ...

brain damage Brain injury (BI) is the destruction or degeneration of brain cells. Brain injuries occur due to a wide range of internal and external factors. In general, brain damage refers to significant, undiscriminating trauma-induced damage. A common ...

, and death in severe cases. This toxin is produced naturally by marine

diatom A diatom (Neo-Latin ''diatoma'') is any member of a large group comprising several Genus, genera of algae, specifically microalgae, found in the oceans, waterways and soils of the world. Living diatoms make up a significant portion of Earth's B ...

s belonging to the genus ''

Pseudo-nitzschia ''Pseudo-nitzschia'' is a marine planktonic diatom genus that accounts for 4.4% of pennate diatoms found worldwide. Some species are capable of producing the neurotoxin domoic acid (DA), which is responsible for the neurological disorder in humans ...

'' and the species '' Nitzschia navis-varingica''. When accumulated in high concentrations by shellfish during filter feeding, domoic acid can then be passed on to birds, marine mammals, and humans by consumption of the contaminated shellfish. Although human illness due to domoic acid has only been associated with shellfish, the toxin can

bioaccumulate Bioaccumulation is the gradual accumulation of substances, such as pesticides or other chemicals, in an organism. Bioaccumulation occurs when an organism absorbs a substance faster than it can be lost or eliminated by catabolism and excretion. Th ...

in many marine organisms that consume

phytoplankton Phytoplankton () are the autotrophic (self-feeding) components of the plankton community and a key part of ocean and freshwater Aquatic ecosystem, ecosystems. The name comes from the Greek language, Greek words (), meaning 'plant', and (), mea ...

, such as

anchovies An anchovy is a small, common forage fish of the family Engraulidae. Most species are found in marine waters, but several will enter brackish water, and some in South America are restricted to fresh water. More than 140 species are placed in 1 ...

and

sardine Sardine and pilchard are common names for various species of small, oily forage fish in the herring suborder Clupeoidei. The term "sardine" was first used in English during the early 15th century; a somewhat dubious etymology says it com ...

s. Intoxication by domoic acid in nonhuman organisms is frequently referred to as domoic acid poisoning.

Symptoms and treatment

In the brain, domoic acid especially damages the

hippocampus The hippocampus (: hippocampi; via Latin from Ancient Greek, Greek , 'seahorse'), also hippocampus proper, is a major component of the brain of humans and many other vertebrates. In the human brain the hippocampus, the dentate gyrus, and the ...

and amygdaloid nucleus. It damages the

neuron A neuron (American English), neurone (British English), or nerve cell, is an membrane potential#Cell excitability, excitable cell (biology), cell that fires electric signals called action potentials across a neural network (biology), neural net ...

s by activating

AMPA α-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid, better known as AMPA, is a compound that is a specific agonist for the AMPA receptor, where it mimics the effects of the neurotransmitter glutamate Glutamic acid (symbol Glu or E; kn ...

and kainate receptors, causing an influx of

calcium Calcium is a chemical element; it has symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar to it ...

. Although calcium flowing into cells is a normal event, the uncontrolled increase of calcium causes the cell to degenerate.

Discovery

ASP was first discovered in humans late in 1987, when a serious outbreak of food poisoning occurred in eastern

Canada Canada is a country in North America. Its Provinces and territories of Canada, ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, making it the world's List of coun ...

. 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. Epidemiologists from

Health Canada Health Canada (HC; )Health Canada is the applied title under the Federal Identity Program; the legal title is Department of Health (). is the Structure of the Canadian federal government#Departments, with subsidiary units, department of the Gove ...

quickly linked the illnesses to restaurant meals of cultured mussels harvested from one area in

Prince Edward Island Prince Edward Island is an island Provinces and territories of Canada, province of Canada. While it is the smallest province by land area and population, it is the most densely populated. The island has several nicknames: "Garden of the Gulf", ...

, a place never before affected by toxic algae. Mouse

bioassay A bioassay is an analytical method to determine the potency or effect of a substance by its effect on animal testing, living animals or plants (''in vivo''), or on living cells or tissues (''in vitro''). A bioassay can be either quantal or quantit ...

s on aqueous extracts of the suspect mussels caused death with some unusual neurotoxic symptoms very different from those of

paralytic shellfish poisoning Paralytic shellfish poisoning (PSP) is one of the four recognized syndromes of shellfish poisoning, which share some common features and are primarily associated with bivalve mollusks (such as mussels, clams, oysters and scallops). These shellfi ...

toxins and other known toxins. On December 12, 1987, a team of scientists was assembled at the

National Research Council of Canada The National Research Council Canada (NRC; ) is the primary national agency of the Government of Canada dedicated to science and technology research and development. It is the largest federal research and development organization in Canada. Th ...

laboratory in Halifax,

Nova Scotia Nova Scotia is a Provinces and territories of Canada, province of Canada, located on its east coast. It is one of the three Maritime Canada, Maritime provinces and Population of Canada by province and territory, most populous province in Atlan ...

. Integrating bioassay-directed fractionation with chemical analysis, the team identified the toxin on the afternoon of December 16, only four days after the start of the concerted investigation.

Possible animal effects

On June 22, 2006, a

California brown pelican The brown pelican (''Pelecanus occidentalis'') is a bird of the pelican family, Pelecanidae, one of three species found in the Americas and one of two that feed by diving into water. It is found on the Atlantic Coast from New Jersey to the mouth ...

, possibly under the influence of domoic acid, flew through the windshield of a car on the Pacific Coast Highway. The phycotoxin is found in the local coastal waters. According to the Channel Islands Marine and Wildlife Institute,

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

Domoic acid poisoning may have caused an August 18, 1961, invasion of thousands of frantic seabirds in Capitola and

Santa Cruz, California Santa Cruz (Spanish language, Spanish for "Holy Cross") is the largest city and the county seat of Santa Cruz County, California, Santa Cruz County, in Northern California. As of the 2020 United States census, 2020 census, the city population ...

. Director

Alfred Hitchcock Sir Alfred Joseph Hitchcock (13 August 1899 – 29 April 1980) was an English film director. He is widely regarded as one of the most influential figures in the history of cinema. In a career spanning six decades, he directed over 50 featu ...

heard about this invasion while working on his adaptation of the

Daphne du Maurier Dame Daphne du Maurier, Lady Browning, (; 13 May 1907 – 19 April 1989) was an English novelist, biographer and playwright. Her parents were actor-manager Gerald du Maurier, Sir Gerald du Maurier and his wife, actress Muriel Beaumont. Her gra ...

novelette " The Birds" for his feature film '' The Birds'' (1963), and asked the ''

Santa Cruz Sentinel The ''Santa Cruz Sentinel'' is a daily newspaper published in Santa Cruz, California, covering Santa Cruz County, California, and owned by Media News Group, which is controlled by Alden Global Capital. History The paper was owned by the McP ...

'' for any further news copy as "research for his new thriller."

References

External links

Amnesic Shellfish Poisoning
at

Woods Hole Oceanographic Institution The Woods Hole Oceanographic Institution (WHOI, acronym pronounced ) is a private, nonprofit research and higher education facility dedicated to the study of marine science and engineering. Established in 1930 in Woods Hole, Massachusetts, it i ...

Domoic acid and ''Pseudo-nitzschia'' references
at

Fisheries and Oceans Canada Fisheries and Oceans Canada (DFO; ) is a department of the Government of Canada that is responsible for developing and implementing policies and programs in support of Canada's economic, ecological and scientific interests in oceans and inland ...

Amnesic Shellfish Poisoning, Domoic Acid, and ''Pseudo-nitzschia'' links
at th
ISSHA
website

at

International Programme on Chemical Safety The International Programme on Chemical Safety (IPCS) was formed in 1980 and is a collaboration between three United Nations bodies, the World Health Organization, the International Labour Organization and the United Nations Environment Programme, ...

DOMOIC ACID — A MAJOR CONCERN TO WASHINGTON STATE’S SHELLFISH LOVERS
at

Washington Department of Fish and Wildlife The Washington Department of Fish and Wildlife (WDFW) is a department of the government of the state of Washington, United States of America. The WDFW manages over a million acres of land, the bulk of which is generally open to the public, an ...