Difference between revisions of "African Swine Fever"

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==Introduction==
+
== 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==
+
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]] although the signs are similar for the two diseases.<br>
''Acute Virus (Africa)''
 
*Nasal discharge, diarrhoea, reddening of the skin
 
*Death within 7 days
 
*PM: widespread internal hemorrhage
 
  
''Subacute Virus (Europe)''
+
African Swine Fever is currently an exotic disease to the UK and is notifiable.&nbsp; The virus is spread either by direct contact with carrier pigs, by aerosol or from infected swill. It can also be transmitted by 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.
*Mortality: 30-70%
 
*Survivors may lose body condition, have skin ulcers and joint swelling
 
*PM: Petechial hemorrhages may be seen under kidney capsule
 
  
=Epidemiology=
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== Clinical Signs  ==
The virus can persist on infected premises for months. Subacute recovered pigs become antibody-positive carriers.
 
* Viral transfer occurs as follows:
 
**Africa: vertical transfer between '''soft ticks'''
 
**Europe/Africa: '''direct contact''' with carrier pigs, '''aerosol''', infected swill, etc.
 
  
=Diagnosis=
+
In the acute form of the virus, that is usually seen in Africa, signs may include n<span style="font-style: italic;">a</span>sal discharge, diarrhoea, enlarged lymph nodes and reddening of the skin, especially around the ears. Death usually occus within 7 days.
*Mortalities with widespread hemorrhage, particularly in lymph nodes
 
*Test to distinguish from  [[Classical Swine Fever]] and [[Porcine Circoviruses]]
 
*Immunofluorescence and PCR test are available for confirmation
 
  
=Control=
+
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<br>
No vaccine is available.
 
  
Prevention control measures include:
+
== Diagnosis  ==
*Boiling swill
 
*Isolation of sick pigs and domestic pigs from wild pigs
 
*Keep pigs on concrete, not soil (to lessen tick contact)
 
  
==Literature Search==
+
It is important to be able to distinguish ASF from Classical Swine Fever (CSF) and Porcine Dermatitis and Nephropathy Syndrome (PDNS), as all three have similar clinical signs. Tests need to be performed to rule out the differentials.<br>
[[File:CABI logo.jpg|left|90px]]
 
  
 +
At post mortem there may be widespread internal haemorrhage, as well as petichael haemorrhages under the kidney capsule and in lymph nodes. <br>
  
Use these links to find recent scientific publications via CAB Abstracts (log in required unless accessing from a subscribing organisation).
+
Immunofluorescence and PCR test are available for confirmation
<br><br><br>
 
[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''']
 
  
[[Category:Asfarviridae]]
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== Control  ==
[[Category:Pig Viruses]]
+
 
[[Category:To_Do_-_Clinical/Viruses]]
+
No vaccine is available and in countries such as the UK, where infection is exotic, all animals with the disease must be humanely destroyed.<br>
 +
 
 +
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).
 +
 
 +
<br>
 +
 
 +
== References<br> ==
 +
 
 +
Straw, B.E. and Taylor, D.J. (2006) Disease of Swine Wiley-Blackwell<br>Taylor, D.J. (2006) Pig Diseases (Eighth edition) St Edmunsdbury Press ltd<br>
 +
 
 +
<br>
 +
 
 +
== Literature Search  ==
 +
 
 +
[[Image:CABI logo.jpg|left|90px]]
 +
 
 +
<br> Use these links to find recent scientific publications via CAB Abstracts (log in required unless accessing from a subscribing organisation). <br><br><br> [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''']
 +
 
 +
[[Category:Asfarviridae]] [[Category:Pig_Viruses]] [[Category:To_Do_-_Review]]

Revision as of 14:05, 16 March 2011

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 although the signs are similar for the two diseases.

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 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.

Clinical Signs

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 occus within 7 days.

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

Diagnosis

It is important to be able to distinguish ASF from Classical Swine Fever (CSF) and Porcine Dermatitis and Nephropathy Syndrome (PDNS), as all three have similar clinical signs. Tests need to be performed to rule out the differentials.

At post mortem there may be widespread internal haemorrhage, as well as petichael haemorrhages under the kidney capsule and in lymph nodes.

Immunofluorescence and PCR test are available for confirmation

Control

No vaccine is available and in countries such as the UK, where infection is exotic, all animals with the disease must be humanely destroyed.

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).


References

Straw, B.E. and Taylor, D.J. (2006) Disease of Swine Wiley-Blackwell
Taylor, D.J. (2006) Pig Diseases (Eighth edition) St Edmunsdbury Press ltd


Literature Search

CABI logo.jpg


Use these links to find recent scientific publications via CAB Abstracts (log in required unless accessing from a subscribing organisation).


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