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African swine fever

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African swine fever (ASF) is a viral infection of domestic and feral pigs (wild boar).

African swine fever (ASF) is a viral infection of domestic and feral pigs (wild boar). The virus may be transmitted by soft bodied ticks and can cause serious disease.

Signs of disease

The symptoms of African swine fever (ASF) and Classical swine fever (CSF) are almost identical and either may occur in chronic or acute form. A definitive diagnosis can only be obtained by laboratory tests as warthogs, bush pigs or giant forest hogs may not show any clinical signs of the disease. These animals act as reservoir hosts.

Ticks can spread the disease. The essential differences between ASF and CSF are the incubation period, the possibility of ASF virus replication, persistence in a tick vector and the lack of any vaccine to control ASF.

The incubation period for the swine fever virus is variable but is usually between five and ten days. In the acute form pigs develop a high temperature (40.5 degrees C or 105 degrees F) then become dull and go off their food. Other symptoms seen vary but will include some or all of the following:

  • Constipation followed by diarrhoea
  • Gummed-up eyes
  • Coughing
  • Blotchy discolouration of the skin
  • Abortion, still births and weak litters
  • Weakness of hindquarters
  • Nervous signs including convulsions and tremors in new born piglets.


The movement of infected pigs is a common method of spreading this disease. Pigs that appear to be healthy may be incubating disease and recovered pigs can excrete the virus for long periods of time.

The virus can exist outside the pig for a long time, so the movement of contaminated vehicles, clothing, footwear and equipment can also spread disease.


The African Swine Fever (Wales) Order 2003 (external link) 

African swine fever: Disease control strategy for Great Britain

This document outlines how an outbreak of African Swine Fever (ASF) in Great Britain (GB) would be managed.