Blackleg and Malignant Edema

Abstract

Blackleg is a relatively common disease of cattle which generally leads to rapid deterioration and death. It is usually considered to be due to infection by the anaerobic bacterium, Clostridium chauvoei although on occasion other organisms such as Cl. novyi and Cl. septicum may be implicated. Spores of Cl. chauvoei occur in the soil in problem areas most frequently as the result of contamination by the decomposing bodies of earlier cases. It is probable that infection takes place by ingestion, but how the organism reaches the musculature and why there may be a sudden stimulus for organismal proliferation is not understood. The pathological lesions arise as the result of the action of highly potent exotoxins which are produced and released by the bacterium. A severe inflammatory reaction takes place. rapidly progressing to gangrene. The animal usually dies within a few hours of first becoming ill. Treatment of established cases is usually unsuccessful and prevention rests upon the use of a monovalent or polyvalent vaccine.