Caprine Arthritis Encephalitis Virus

CAEV

Antigenicity

• Serologically related to Visna-Maedi with antigenic and genetic envelope differences

Hosts

• Goats

Pathogenesis

• T cells induce immune complex disease
• Causes encephalitis of kids or insidious polyarthritis of adults
• Also causes pneumonia

Epidemiology

• Transfer via milk and colostrum, particularly batch-mixing
• Present in 10% of UK herds
• Clinical disease is rare

Diagnosis

• Visna-Maedi serology (ELISA) test can be used to remove positive stock

Control

• Separate kids from virus positive mothers at birth
• Treat mother's colostrum (56 deg for 1 hour)
• Rear on artificial milk

Caprine Arthritis-Encephalitis (CAE)

• Caused by retrovirus (lentivirus) similar to Maedi Visna in sheep described above
• Two forms:
  • Non-suppurative leukoencephalomyelitis in young goats and kids
  • Chronic, non-suppurative arthritis-synovitis in adult goats
• Also causes interstitial pneumonia which tends to be obscured by other clinical signs
• Gross pathology:
  • Mainly caudal lobes
  • Lungs are firm, grey-pink with grey-white focal lesions on cut surface
• Micro pathology:
  • Thickened alveolar wall
  • Lymphocyte infiltration and type II pneumocyte hyperplasia
• Can be confused with or coexisting with Parasitic pneumonia

• • Arthritis is commonly the main expression
  • Large limb joints are thickened
  • Carpal hygroma is often present
    • Subcutaneous cystic swelling on cranial surface of the knee, contains serous fluid
  • In advanced cases
    • Synovial villus hypertrophy
    • Necrosis
    • Mineralisation
    • Mononuclear cell infiltration
    • Pannus formation
    • Articular cartilage destruction