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*Mostly non-pathogenic environmental organisms
 
*Mostly non-pathogenic environmental organisms
 
*''Bacillus anthracis'' causes anthrax
 
*''Bacillus anthracis'' causes anthrax
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*Anthrax is a severe disease affecting all mammals worldwide
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*Ruminants are highly susceptible to anthrax, dying of a septicaemic form
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*Pigs and horses are moderately susceptible, but carnivores are fairly resistant
 
*''Bacillus licheniformis'' may cause shoradic abortions in cattle and sheep
 
*''Bacillus licheniformis'' may cause shoradic abortions in cattle and sheep
 
*''Bacillus cereus'' causes food poisoning in humans and mastitis in cows
 
*''Bacillus cereus'' causes food poisoning in humans and mastitis in cows
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===''Bacillus anthracis''===
 
===''Bacillus anthracis''===
   −
*Saprophyte in soil
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*Capsule composed of homopolymer of D-isomer of glutamic acid allows survival in the body by resisting phagocytosis
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*Capsule stains mauve with polychrome methylene blue in the MacFadyean's reaction - identify anthrax in blood samples
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*Bacilli appear as chains of dark blue, square-ended rods surounded with the capsule
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*Extracellular toxin (holotoxin) composed of oedema factor, protective factor and lethal factor
   
*
 
*
 +
*Pathogenesis and pathogenicity:
 +
**Saprophyte in soil
 +
**Capsule composed of homopolymer of D-isomer of glutamic acid allows survival in the body by resisting phagocytosis
 +
**Capsule stains mauve with polychrome methylene blue in the MacFadyean's reaction - identify anthrax in blood samples
 +
**Bacilli appear as chains of dark blue, square-ended rods surounded with the capsule
 +
**Extracellular toxin (holotoxin) composed of oedema factor, protective factor and lethal factor
 +
**Oedema factor is an adenylate cyclase which increases intracellular cAMP concetrations, damaging phagocytes
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**Protective factor binds to the cell receptor to allow action of the other factors
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**The toxin kills phagocytes, increases capillary permeability and interferes with clooting cascade
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**Capillary thrombosis; leakage of fluid through damaged capillary endothelium
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**Systemic shock from circulatory collapse, haemorrhage and oedema lead to death of the animal
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*Clinical signs:
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**
     
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