Changes

*Epidemiology:

*Epidemiology:

**Endospore formation allows persistence and spread

**Endospore formation allows persistence and spread

**Endospores survive decades in the soil

**Endospores survive decades in the soil

**Infection usually by ingestion of spores

**Infection usually by ingestion of spores

*Pathogenesis and pathogenicity:

*Pathogenesis and pathogenicity:

**Saprophyte in soil

**Capsule and toxin (encoded by separate plasmids) required for virulence

**Capsule composed of homopolymer of D-isomer of glutamic acid allows survival in the body by resisting phagocytosis

**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

**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

**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

**Extracellular toxin (holotoxin) composed of oedema factor, protective antigen and lethal factor

**Oedema factor is an adenylate cyclase which increases intracellular cAMP concetrations, damaging phagocytes

**Oedema factor is an adenylate cyclase which increases intracellular cAMP concetrations, causing fluid accumulation and damaging neutrophils

**Protective factor binds to the cell receptor to allow action of the other factors

**The toxin kills phagocytes, increases capillary permeability and interferes with clooting cascade

**Protective antigen binds to the cell receptor to allow action of the other factors

**The toxin kills phagocytes, increases capillary permeability and interferes with clotting cascade

*Clinical signs:

*Clinical signs:

**Cattle:  

**Cattle: