Equine Viral Arteritis

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  • Most cases are subclinical and only antibody positive


  • More common in thoroughbreds


  • Infects nasopharynx and spreads locally, causing:
    • Dyspnoea
    • Coughing
    • Diarrhoea
    • Colic
  • Spread to lymphoid tissue leads to leukopenia and immunosuppression
  • Typical medial necrosis of arteries causing:
    • Hemorrhage
    • Abortions occur after 10-30 days in 50% of pregnant mares (as opposed to Equine Herpes, which shows late abortions)
    • Oedema - particularly ocular, giving rise to "pink eye"
  • Other clinical signs include:
    • Pyrexia
    • Nettle rashes
    • Ocular and nasal discharge
    • Swelling of legs or scrotum
    • Stiffness of gait
  • Foal death caused by interstitial pneumonia
  • Stallions become intermittent or persistent shedders from accessory sex glands but may show no clinical signs


  • Controlled virus in the UK but AI and breeding schemes presents a real risk


  • Clinical symptoms, but may be variable
  • PCR on semen
  • ELISA for serum antibody


  • Vaccines:
    • Stallions: Live attenuated
    • Mares: Killed whole virus
  • Clinical disease is NOTIFIABLE
    • Seropositive stallions restricted from teasing, mating or AI unless PCR tested negative
    • Persistent shedders should be castrated
  • Serology on imported horses
  • Mares tested within 4 weeks of mating
  • In an outbreak, isolate and restrict movement until antibody-negative for one month

  • Causative agent: equine arterivirus (EVA)
  • Rhinitis, peripheral oedema, bronchitis/bronchiolitis, conjunctivitis, periorbital oedema
  • Replicates in macrophages and endothelial cells
  • Disseminates via the circulatory system causing necrotising arteritis
  • Interstitial pneumonia
  • Transmitted by respiratory and venereal routes through direct contact with infected horse or its secretions
  • Stallion are a reservoir of infection as they are chronic shedders