*All are ''Mannheimia'' A biotypes (previously ''Pasterurella haemolytica''
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*All are ''Mannheimia'' A biotypes (previously ''Pasterurella haemolytica'')
*Strains often produce a cytotoxin, known as leukotoxin, which kills leukocytes of ruminants
*Strains often produce a cytotoxin, known as leukotoxin, which kills leukocytes of ruminants
*Leukotoxin is a member of the RTX group toxins, and is probably largely responsible for the pathogenicity of the bacteria in septicaemia and pneumonia
*Leukotoxin is a member of the RTX group toxins, and is probably largely responsible for the pathogenicity of the bacteria in septicaemia and pneumonia