Systematic Veterinary Bacteriology and Mycology

DIAGNOSIS, CONTROL AND PREVENTION

• Based on history
• Direct Gram stained smears
  • Presence of characteristic liver lesions together with large number of Gram +ve rods in liver impression smears from a recently dead animal is suggestive of the disease.
• Flourescence Antibody Test is useful for the identification of C.novyi type B and C.haemolyticum in acetone fixed liver impression smears.
• Isolation of organism from affected tissue (as like other clostridial infections) and by characteristic cultural characters.
• Animal inoculation
  • Toxin in the liver can be demonstrated by intra muscular injection of homogenates into guinea pigs.
  • The pathogenicity is enhanced if the homogenate is added to an equal amount of 5% CaCl₂ solution before inoculation.
  • The guinea pigs die in 1-2 days with very extensive subcutaneous edema. Specific antitoxin is not readily available for neutralization tests.

Control and prevention

• Elimination of liver flukes through destruction of snail.
• Aluminum hydroxide adsorbed formalized whole culture vaccines are available.
• Outbreaks of the disease may be controlled by the prompt injection of hyper immune sera.