Difference between revisions of "African Swine Fever"

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==Introduction==
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Also known as: '''''ASF — ASFV'''''
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African Swine Fever ocurs after infection by the Asfarviridae family of viruses. ASF is a serious exotic virus that should not be confused with [[Classical Swine Fever]].
  
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== Introduction  ==
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==Clinical Signs==
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[[File:African swine fever necropsy.jpg|thumb|200px|right|Swelling around kidneys and muscle haemorrhages. ''(Sourced from Wikimedia Commons)'']]
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''Acute Virus (Africa)''
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African Swine Fever ('''ASF''') occurs after infection by the [[:Category:Asfarviridae|Asfarviridae]] family of viruses. ASF is a serious exotic virus that should not be confused with [[Classical Swine Fever]] although the signs are similar for the two diseases.
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*Nasal discharge, diarrhoea, reddening of the skin
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*Death within 7 days
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*PM: widespread internal hemorrhage
  
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African Swine Fever is currently an exotic disease to the UK and is notifiable. The virus is spread either by direct contact with carrier pigs, by aerosol or from infected swill. It can also be transmitted by [[:Category:Soft Ticks - Overseas|soft ticks]] in Africa. The virus is relatively difficult to eliminate and can persist on infected premises for months. Sub-acutely infected recovered pigs become antibody - positive carriers.
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''Subacute Virus (Europe)''
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*Mortality: 30-70%
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*Survivors may lose body condition, have skin ulcers and joint swelling
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*PM: Petechial hemorrhages may be seen under kidney capsule
  
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== Clinical Signs  ==
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=Epidemiology=
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*Can persist on infected premises for months
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*Subacute recovered pigs become antibody-positive carriers
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*Transfer:
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**Africa: vertical transfer between '''soft ticks'''
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**Europe/Africa: '''direct contact''' with carrier pigs, '''aerosol''', infected swill, etc.
  
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In the '''acute form''' of the virus, that is usually seen in Africa, signs may include nasal discharge, diarrhoea, enlarged lymph nodes and reddening of the skin, especially around the ears. Death usually occurs within 7 days.
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=Diagnosis=
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*Mortalities with widespread hemorrhage, particularly in lymph nodes
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*Test to distinguish from  [[Classical Swine Fever]] and [[Porcine Circoviruses]]
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*Immunofluorescence
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*PCR
  
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In the '''subacute form''' of the virus that normally occurs in Europe, mortality is not as common, with only a 30 - 70% mortality rate. Survivors may lose body condition and have skin ulcers and joint swelling.
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=Control=
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*No vaccine is available
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Prevention:
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*Boiling swill
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*Isolation of sick pigs, domestic pigs from wild pigs
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*Keep pigs on concrete, not soil (to lessen tick contact)
  
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== Diagnosis  ==
 
  
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It is important to be able to distinguish ASF from Classical Swine Fever (CSF) and [[Porcine Circoviruses|Porcine Dermatitis and Nephropathy Syndrome (PDNS)]], as all three have similar clinical signs. Tests need to be performed to rule out the differentials.
 
  
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At post mortem there may be widespread internal haemorrhage, as well as petechial haemorrhages under the kidney capsule and in lymph nodes.
 
  
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Immunofluorescence and PCR test are available for confirmation.
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[[Category:Asfarviridae]]
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[[Category:Pig]]
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== Control  ==
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[[Category:To_Do_-_Clinical/Viruses]]
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No vaccine is available and in countries such as the UK, where infection is exotic, all animals with the disease must be humanely destroyed.
 
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Prevention control measures include boiling swill, isolation of sick pigs and domestic pigs from wild pigs. In Africa, a control mechanism is to keep pigs on concrete, not soil (to lessen tick contact).
 
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{{Learning
 
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|full text = [http://www.cabi.org/cabdirect/FullTextPDF/2009/20093263092.pdf '''Review of African swine fever: transmission, spread and control.''' Penrith, M. L.; Vosloo, W.; South African Veterinary Association, Pretoria, South Africa, Journal of the South African Veterinary Association, 2009, 80, 2, pp 58-62, 75 ref. - '''Full Text Article''']
 
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}}
 
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== References ==
 
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Straw, B.E. and Taylor, D.J. (2006) '''Disease of Swine,''''' Wiley-Blackwell
 
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Taylor, D.J. (2006) '''Pig Diseases''' (Eighth edition), ''St Edmunsdbury Press ltd''
 
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{{review}}
 
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{{OpenPages}}
 
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[[Category:Asfarviridae]] [[Category:Pig_Viruses]] [[Category:Expert_Review - Farm Animal]]
 

Revision as of 17:38, 18 October 2010

Introduction

African Swine Fever ocurs after infection by the Asfarviridae family of viruses. ASF is a serious exotic virus that should not be confused with Classical Swine Fever.

Clinical Signs

Acute Virus (Africa)

  • Nasal discharge, diarrhoea, reddening of the skin
  • Death within 7 days
  • PM: widespread internal hemorrhage

Subacute Virus (Europe)

  • Mortality: 30-70%
  • Survivors may lose body condition, have skin ulcers and joint swelling
  • PM: Petechial hemorrhages may be seen under kidney capsule

Epidemiology

  • Can persist on infected premises for months
  • Subacute recovered pigs become antibody-positive carriers
  • Transfer:
    • Africa: vertical transfer between soft ticks
    • Europe/Africa: direct contact with carrier pigs, aerosol, infected swill, etc.

Diagnosis

Control

  • No vaccine is available

Prevention:

  • Boiling swill
  • Isolation of sick pigs, domestic pigs from wild pigs
  • Keep pigs on concrete, not soil (to lessen tick contact)
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