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==Description==

==Description==

Blue-green algae is a type of phytoplankton found in ponds and other freshwater environments and toxic strains include ''Anacystis cyanea'', ''Microcystis aeruginosa''and ''Microcystis toxica''. The algae arise following long spells of hot dry weather and hence bloom in the summer but are also assosiated with high levels of phosphate and nitrate in the water. These algae can be extremely toxic and can poision livestock, birds and sometimes dogs.

Blue-green algae is a type of phytoplankton found in ponds and other freshwater environments and toxic species include ''Anabaena'' and ''Microcystis''. The algae arise following long spells of hot dry weather and hence bloom in the summer but are also assosiated with high levels of phosphate and nitrate in the water. These algae can be extremely toxic and can poision livestock, birds and sometimes dogs.

==Diagnosis==

==Diagnosis==

It is possible to test water for the presence of blue-green algae. This can be done by fixing fresh samples in a 1:10 dilution of formalin or frozen water samples can be evaluated for lethality using a mouse bioassay.

Based primarily on known ingestion, signs of poisioning or post mortem identification. Microscopic examination of the algae can be undertaken to confirm the presence of the toxigenic cyanobacteria. It is possible to test water for the presence of blue-green algae. This can be done by fixing fresh samples in a 1:10 dilution of formalin or frozen water samples can be evaluated for lethality using a mouse bioassay.

A biochemistry profile  may suggest hepatotoxicity with increases in Alanine transaminase (ALT), Aspartate transaminase (AST) and Alkaline phosphatase (ALP).

Additionally a biochemistry profile  may suggest hepatotoxicity with raised Alanine transaminase (ALT), Aspartate transaminase (AST) and Alkaline phosphatase (ALP) values.

==History and Clinical Signs==

==History and Clinical Signs==

History of drinking from stagnant water source.

History of drinking from stagnant water source.

Some genera produce hepatotoxic peptides called microcytins whilst others especially Anabaena , can produce both neuro and hepatotoxins. If a toxic waterbloom contains both types of toxins, neurological signs will be seen first as these toxins act quicker than the hepatotoxins. Clinical signs can be variable but in acute cases death can occur within a few hours. In less severe cases liver damage causing jaundice and photosensitisation may lead to death. Generalised signs may include severe abdominal pain, vomiting and bloody diarrhoea, muscle tremors, convulsions, hyperaesthesia, staggering, dullness, recumbency, ataxia, flaccid paralysis.

Clinical signs can be variable but in acute cases death can occur within a few hours. In less severe cases liver damage causing jaundice and photosensitisation may lead to death.Some genera produce hepatotoxic peptides called microcytins whilst others especially ''Anabaena'' , can produce both neuro and hepatotoxins. If a toxic waterbloom contains both types of toxins, neurological signs will be seen first as these toxins act quicker than the hepatotoxins. Signs may include severe abdominal pain, vomiting and bloody diarrhoea, muscle tremors, convulsions, hyperaesthesia, staggering, dullness, recumbency, ataxia, flaccid paralysis.

==Pathology==

==Pathology==

==Mechanism of toxicity==

==Mechanism of toxicity==

Blue green algae causes toxicity by metabolism into the cyclic peptide, microcystin. This causes dysfunctional phosphorylation of cellular keratins, leading to disruption of the normal cytoskeleton. This in turn leads to a "rounding up" effect of the hepatocytes, disruption of the hepatic sinusoids, separation of hepatocytes and excessive apoptosis, which all will result in liver failure.  

Blue green algae causes toxicity by metabolism into the cyclic peptide, microcystin. This causes dysfunctional phosphorylation of cellular keratins, leading to disruption of the normal cytoskeleton. This in turn leads to a "rounding up" effect of the hepatocytes, disruption of the hepatic sinusoids, separation of hepatocytes and excessive apoptosis, resulting in liver failure.  

 

Neuro toixns produced by certain blue-green algae include Anatoxin-a which is a potent post-synaptic depolarizing neuromuscular blocker and Anatoxin-a which is a potent acetylcholinesterase inhibitor.   

Neurotoxins anatoxin-a and anatoxin-a(s) are prodcued by other blue-green algae.  Anatoxin-a is a potent post-synaptic depolarizing neuromuscular blocker. Anatoxin-a(s) is a potent acetylcholinesterase inhibitor.   

==Treatment==

==Treatment==

==Prognosis==

==Prognosis==

Poor. Dependent on the degree of liver damage and quantity ingested. Prompt treatment is essential.

Poor. Dependent on the degree of liver damage and quantity ingested. Prompt treatment is essential.