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| − | <big><center>[[Infectious agents and parasites|'''BACK TO INFECTIOUS AGENTS AND PARASITES''']]</center></big>
| + | #REDIRECT[[:Category:Bacillus species]] |
| − | <big><center>[[Bacteria|'''BACK TO BACTERIA''']]</center></big>
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| − | [[Bacillus anthracis]]
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| − | *''CAR bacillus'' in [[Bacterial infections#CAR bacillus|URT infection in cattle]] and [[Bacterial infections#In Rabbits|URT infection in rabbits]]
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| − | * Can cause vascular fragility, leading to [[General Pathology - Haemostasis#Haemorrhagic Disease Due To Vascular Fragility|haemorrhagic disease]].
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| − | ===Overview===
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| − | *Mostly non-pathogenic environmental organisms
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| − | *''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
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| − | *''Bacillus licheniformis'' may cause shoradic abortions in cattle and sheep
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| − | *''Bacillus cereus'' causes food poisoning in humans and mastitis in cows
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| − | ===Characteristics===
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| − | *Large, Gram positive rods
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| − | *Produce endospores
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| − | *Aerobes or facultative anaerobes
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| − | *Grow on non-enriched media
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| − | *Motile
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| − | *Catalase positive, oxidase negative
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| − | *''Bacillus anthracis'' colonies are up to 5mm diameter, flat, dry, grey, with a ground-glass appearance; curled outgrowthsfrom the edge of the colony give a 'medusa head' appearance; non-haemolytic (differentiate from ''Bacillus cereus'')
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| − | *''Bacillus licheniformis'' forms dull, rough, wrinkled colonies, with hair-like outgrowths
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| − | *Biochemical tests for identification
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| − | *Can often tolerate adverse environmental conditions
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| − | ===''Bacillus anthracis''===
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| − | *
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| − | *Pathogenesis and pathogenicity:
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| − | **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
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| − | **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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| − | ===''Bacillus licheniformis''===
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| − | *Widespread in the environment
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| − | *Associated with food spoilage
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| − | *Abortion in cattle and sheep, possibly from spoiled silage or hay
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