From Monsoons to Microbes Understanding the Ocean's Role in Human Health (1999) / Chapter Skim
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3 Harmful Algal Blooms
3 Harmful Algal Blooms
Pages 59-70
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From page 59... ...
~ ..... Blooms of the single cell algae known as phytoplankton are sometimes called red tides, which have been recognized since biblical times.
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From page 60... ...
HARMFUL ALGAL BLOOM HAZARDS IN FOOD Filter-feeding bivalve molluscs accumulate and concentrate phycotoxins that can be further bioconcentrated as they move through the food chain to top carnivores (Shumway 1990~. Human intoxication follows ingestion of tainted shellfish or, in the case of ciguatera, finfish.
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From page 61... ...
61 ca .
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From page 62... ...
George Vancouver's crew succumbed to PSP while they explored the Pacific Northwest in 1798. A1though the toxin is initially accumulated by shellfish, marine mammal deaths have resulted from food chain concentration in mackerel following an unusual temporal passage from red tide to thread herring (Geraci et al., 1989~.
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From page 63... ...
breve are known to cause fish kills, shore bird deaths, and shellfish toxicity in Japan, New Zealand, and possibly South Africa. The Japanese and New Zealand species produce toxins similar to brevetoxin.
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From page 64... ...
Ciguatoxin, isolated from Pacific moray eel tissue, binds to the same site of voltage gated sodium channels as does brevetoxin. CFP was first recognized in the 1550s in the Caribbean (Martyr and Novo, 1912)
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From page 65... ...
Unlike the toxins that interact with nerve channel proteins, this toxin group inhibits protein phosphatases, a group of enzymes responsible for smooth muscle function, for regulation of cell division in vertebrates, and for overall phosphate metabolism. Diarrhea and tumor promotion are two toxic effects ascribed to okadaic acid.
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From page 66... ...
No acute lethal poisoning of humans by consuming foods containing freshwater cyanobacteria, such as occurs with paralytic shellfish poisoning, has been confirmed. There are no known food vectors, such as shellfish, to concentrate toxins of freshwater cyanobacteria in the human food chain.
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From page 67... ...
Depending upon the length of time in the airborne state, water can evaporate from the aerosol particles leaving dry salt with toxin coating the particle or entrapped within it. Only two types of toxic blooms are known to affect people by inhalation: Gynmodinium breve (Florida red tide)
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From page 68... ...
. RESEARCH REQUIREMENTS AIMED AT DIAGNOSTICS, THERAPEUTICS, AND PREVENTION The ecology of each harmful algal bloom organism is different.
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From page 69... ...
CONCLUSIONS Algal toxins in food, water, and the air affect the health of humans and ani mals. Also, harmful algal blooms disrupt the economies of coastal communities through the closure of fisheries affected by algal toxins.
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From page 70... ...
70 FROM MONSOONS TO MICROBES · determine the molecular mechanisms for the action of natural marine toxins on animals to help develop antidotes, to improve detection, and to understand the pharmacology of toxins, · ensure safety of seafood through development of cost-effective methods for detecting algal toxins in seafood, · document the incidence of toxin-related illness in coastal areas and among travelers to high risk areas. There is a need for comprehensive assessment and reporting of the temporal and geographic distribution of algal blooms and associated human illnesses, · train public health authorities in coastal states to recognize and respond to outbreaks of toxin-related illness.
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