Braxy

• Braxy, an abomasitis of sheep, is caused by the exotoxins of C. septicum.
• The disease, which occurs in winter during periods of heavy frost or snow, has been recorded.
• It has been suggested that ingestion of frozen herbage may cause local devitalization of abomasal tissue at its point of contact with the rumen, allowing invasion by C. septicum.
• The course of the disease is rapid and most animals die without premonitory signs.
• Anorexia, depression and fever may be evident immediately before death.
• Clostridium septicum found in the abomasal lesion by the fluorescent antibody technique.

Infectious necrotic hepatitis

• Infectious necrotic hepatitis (black disease) is an acute disease, caused by C. novyi type B replicating in liver tissue and affecting sheep and occasionally cattle.
• Rarely it also affects horses and pigs.
• The disease is associated with immature Fasciola hepatica or other migrating parasites.
• Death is rapid with no premonitory signs and the disease requires differentiation from acute fascioliasis.
• The term 'black disease' relates to the dark discolouration of the skin caused by the marked subcutaneous venous congestion observed at post-mortem examination. The fluorescent antibody technique may be used to demonstrate C. novyi type B in specimens from liver lesions.

Bacillary haemoglobinuria

• Bacillary haemoglobinuria occurs primarily in cattle and occasionally in sheep, caused by

C. haemolyticum.

• Its endospores are dormant in the liver, probably in Kupffer cells and its Beta toxin, a lecithinase, produced by vegetative cells, causes intravascular haemolysis in addition to hepatic necrosis.
• Haemoglobinuria, a major clinical feature of the disease, is a consequence of extensive red cell destruction.
• The aetiological agent may be demonstrated in specimens from hepatic lesions by the fluorescent antibody technique.

Treatment and control of histotoxic clostridial diseases

• Although treatment is usually ineffective, penicillin or broad-spectrum antibiotics administered to animals early in the disease may be of value.
• Vaccination, usually with bacterin and toxoid components in adjuvant, is the most effective method for preventing these diseases.
• Multicomponent vaccines which induce protection against several pathogenic clostridial species may be required on some farms.
• Animals should be vaccinated at 3 months of age and given a booster injection approximately three weeks later.
• Annual revaccination is recommended.