Clinical signs of African swine fever can be very variable. Most outbreaks are of mild to severe disease. In severe outbreaks the incubation period is 5 to 7 days and pigs rapidly become feverish. Many die after 7 to 10 days of illness with a variety of non-specific clinical signs including haemorrhage. In "per acute" infections, the pigs die so rapidly that the only sign of disease is sudden death. Milder strains of the virus can cause less severe illness with a longer incubation period (5 to 19 days). The most serious “chronic” form is not usually seen in outbreaks - it is more likely to be found in areas where the disease is endemic.
Signs are variable but will include some or all of the following:
- Diarrhoea (sometimes bloody)
- Reddening or darkening of the skin, particularly ears and snout
- Gummed-up eyes
- Laboured breathing and coughing
- Abortion, still births and weak litters
- Weakness and unwillingness to stand
At the first sign of disease isolate sick animals and stop all livestock movement. If you suspect African swine fever you are required by law (The Diseases of Swine Regulations 2014) to notify your local Animal & Plant Health Agency (APHA) Office immediately.
The clinical signs of African swine fever are identical to those for Classical swine fever and laboratory diagnosis is necessary to distinguish between the two. The main differences are that African swine fever generally has a longer incubation period, may be transmitted by ticks and there is no vaccine to control African swine fever.