Clinical manifestations and lesions

CLINICAL MANIFESTATIONS

  • Incubation period one week. The disease has been arbitrarily divided into three forms.
  • Acute form
    • High rise of temperature, nasal discharge, salivation and lacrymation
    • Hyperemia, Petechiation and swelling of the buccal mucosa, dental pads and tongue. Later hyperaemic regions become "cyanotic" or "purplish blue"
    • Extensive necrosis of the dental pad
    • Muzzle turns dry show burnt appearance

    Blue tongue- Dry burnt muzzle

    • Cyanotic and bluish appearance of tongue
    • Blood stained diarrhoea occurs when the intestinal mucosa is involved which is always fatal.
    • There may be involvement of sensitive laminae and breaking of wool fibres
    • Heavy mortality occurs in early stages and chronically affected animals become thin and emaciated. Morbidity is 50%.  
  • Sub acute form or subclinical form
    • Common in cattle and generally passed unnoticed
  • Abortive form
    • Abortion of pregnant ewes, which results in the loss of entire breeding season. Young animals and Merino sheep are particularly susceptible.

Hyperemia and swelling of buccal mucosa and dental pad 

Lesions

  • Tongue : Blue and gangrenous
  • Leg : Coronary band show congestion and hemorrhage
  • Lungs : pneumonic changes
Last modified: Sunday, 3 June 2012, 8:14 AM