Difference between revisions of "Porcine Reproductive and Respiratory Syndrome"

From WikiVet English
Jump to navigation Jump to search
Line 55: Line 55:
 
[[Category:Arteriviridae]]
 
[[Category:Arteriviridae]]
 
[[Category:Pig]]
 
[[Category:Pig]]
[[Category:To_Do_-_Viruses]]
+
[[Category:To_Do_-_Clinical/Viruses]]
 
[[Category:Respiratory_Viral_Infections]]
 
[[Category:Respiratory_Viral_Infections]]

Revision as of 12:24, 30 July 2010



AKA PRRS

Antigenicity

  • Isolates vary in virulence
  • Some are subclinical

Hosts

  • Pigs: aka Blue Ear or Lelystad virus

Pathogenesis

  • Infects alveolar macrophages, followed by interstitial pneumonitis
  • Persistent infection of Monocytes followed by leukopenia and thrombocytopenia
  • Mostly affects piglets
  • In adults, cyanotic appearance due to vascular lesions
  • Transplacental spread leads to abortion, mummification, or resorption

Epidemiology

  • Discovered in Holland in 1990
  • Highly contagious
  • Survives well on fomites
  • Transfer may also be aerosol or via semen
  • Exacerbated by immunosuppression (eg by porcine circovirus 2)

Diagnosis

  • Clinical signs:
    • Thumping respiration
    • Abortions
    • Flushed skin
    • Eyelid oedema
    • Weak or dying piglets
  • ELISA for virus antibody
  • Rising antibody titres as a retrospective diagnosis (4X increase)

Control

  • Certified Specific Pathogen Free units exclude by quarantine
  • Management: all in/all out, screening AI semen
  • Vaccine available


Porcine reproductive and respiratory syndrome

  • The syndrome is caused by a small enveloped RNA virus which belongs to the new Arteriviridae group
  • Replicates in and destroys macrophages and endothelial cells causing vasculitis -> viraemia -> virus shedding (nasal secretions, faeces)
  • Clinical signs: respiratory and reproductive failure, weaned pigs, tachypnoea, eyelid oedema, conjunctivitis
  • Moderate to severe interstitial pneumonia in the cranial lobe
  • Superimposed bacterial infections are common
  • Infectious disease in swine that emerged 10 years ago
  • Today, PRRS is endemic in many if not all the pig-producing countries

PRRS Porcine reproductive and respiratory syndrome virus (Lelystad virus). There is abortion late in gestation with respiratory tract illness in live piglets (interstitial pneumonia).