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28 Cards in this Set

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What is the source of the cyanobacteria (blue-green algae) toxin?
Single- celled organisms found in fresh water
When is the cyanobacteria toxin released?
Upon death of cyanobacteria
Cyanobacteria produce toxins which can be _____toxic or _____toxic.
Neurotoxic or hepatotoxic
What are the 2 common neurotoxins produced by cyanobacteria?
Anatoxin a
Anatoxin a(s)
What is the mode of action of anatoxin a?
Nicotinic agonist at the cholinergic receptors
What is the mode of action of anatoxin a(s)?
Irreversible acetylcholinesterase inhibitor
What kind of toxin is microcystin?
Hepatotoxin produced by cyanobacteria
What is the mode of action of microcystin?
Alters the cytoskeleton of liver cells by inhibiting serine/threonine phosphatases type 1 and type 2A
How long does it take for the onset of neurotoxis produced by cyanobacteria?
Extremely poisonous and can kill w/in a few minutes
-so toxic animals are sometimes found next to contaminated water
What are the clinical signs of anatoxin-a?
Shows a rapid onset of rigidity and muscle tremors
Anatoxin-a causes acetylcholinesterase inhibition similar to ______________.
Organophosphorous/ carbamate insecticides
Do neurotoxins or hepatotoxins kill more rapidly?
Neurotoxins
Is death from anatoxin a(s) or microcystin more rapid?
Anatoxin a(s), the neurotoxins kill animal more rapidly
What are the clinical signs of microcystin toxicity?
-GI disturbances
-destruction of hepatocytes soon after ingestion
When does death occur from microcystin toxicity? How?
Death from liver failure often within 24 hours
How do you diagnose anatoxin-a or anatoxin-a(s) toxicity?
-History of exposure to blue-green algae
-clinical signs
-possible presence of algae in GI tract
-no gross or microscopic lesions
What do you find on postmortem examination in an animal with microcystin toxicity?
Liver often enlarged, swollen and dark red
-sometimes significant edema around gall bladder
What do you see on histology of an animal with microcystin toxicity?
Massive liver necrosis w/ severe intrahepatic hemorrhage
Is anatoxin-a or anatoxin-a(s) more toxic?
Anatoxin-a(s) is much more toxic
What is the LD50 for microcystin?
b/w 50 and 11,000 ug/kg depending on microcystin structure
How do you diagnose microcystin toxicity?
Gross & histologic liver lesions
What do you see on clinical pathology of anatoxins?
No significant findings
What do you see on clinical pathology of microcystins?
Increase in serum ALP, AST, ALT, bilirubin
What are the lesions present in an animal with anatoxicosis?
No lesions present
What are the lesions present in an animal with microcystin toxicity? (3)
1) Liver enlargement
2) Interhepatic hemorrhage
3) Progressive centrilobular hepatocyte rounding, dissociation & necrosis
Is there a treatment for cyanobacteria toxicity?
No antidote, rapid onset of clinical signs
-Need aggressive and intensive care
-Provide supportive care
What is the prognosis of cyanobacteria toxicity?
POOR
-animals usually found dead
How do you prevent cyanobacteria toxicity?
Deny access to water w/ visible algal blooms