Difference between revisions of "African Horse Sickness"

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*Once only found in Africa, but since 1987 has recurred in Spain and Portugal
 
*Once only found in Africa, but since 1987 has recurred in Spain and Portugal
 
*Not present currently in the UK but global warming may expand midge breeding grounds
 
*Not present currently in the UK but global warming may expand midge breeding grounds
[[Category:Orbiviruses]][[Category:Horse]]
+
[[Category:Orbiviruses]][[Category:Horse]][[Category:To_Do_-_Viruses]]

Revision as of 22:54, 26 June 2010



Antigenicity

  • 9 serotypes

Hosts

  • Clinical: horses, mules, donkeys
  • Subclinical: african donkeys, zebras

Pathogenesis

  • Virus oscillates between horses and midges
    • Replicates in the salivary glands of biting midges, and occurs where they breed
  • Pantropic virus: infects endothelium and myocardium
  • Peracute: causes sudden death with pyrexia before the onset of clinical signs
  • Two forms:
    • Acute cardac-pneumonic form:
      • Interlobular pulmonary oedema
      • Pericarditis
      • Hemorrhage and oedema of the viscera
      • Death within 5 days
    • Subacute cardiac form:
      • Milder clinical signs but still a high mortality rate

Diagnosis

  • Clinical signs
  • Differential: Equine Arteritis Virus (EAV)
    • EAV causes oedema in the legs, which AHS does NOT
  • Suckling mouse inoculation
  • Virus serotype identification
  • Serology
  • RT-PCR will be used in future outbreaks

Control

Control measures are largely preventative:

  • Slaughter or immediate isolation of sick animals
  • Mandatory and immediate vaccination with appropriate serotype
  • Restricted movement of susceptible animals
    • Protection zones and Surveillance zones set in place around outbreaks
  • Control of vector: ectoparasiticides, etc.

Current Relevance

  • Once only found in Africa, but since 1987 has recurred in Spain and Portugal
  • Not present currently in the UK but global warming may expand midge breeding grounds