Occurrence
The origin of African swine fever is in Africa, where the virus also shows the highest genetic diversity. From there, it spread several times to Europe and Asia in the course of food transports.
Reservoir
In Africa, different types of pigs (bush pigs, forest pigs and warthogs), as well as ticks of the genus Ornithodoros are the main reservoir of pathogens. In Europe, wild boar serves as the main reservoir of the virus.
Mode of transmission
Pigs and boar become infected by the bite of infected ticks (currently this transmission route is not important in Europe), by direct contact of susceptible (wild) pigs with infected conspecifics, or via ingestion of virus-containing food waste. The virus is very resistant, it remains partly infectious even after drying or processing/maturing in raw meat products such as raw ham or salami.
Incubation period
4 to 19 days
Symptoms
The symptoms are strongly dependent on the strain of the virus. The strain currently present in Europe, known as genotype 2, usually leads to high fever, severe general illness in domestic and wild pigs of all ages, and can cause bleeding into the skin and internal organs. Affected animals usually die of the disease before they develop antibodies. However, there are also other virus strains that lead to milder disease progression.
Treatment
There is no treatment for the ASF virus.
Preventive measures
Although a vaccination against ASF is being worked on, it is not yet available. Prevention is therefore limited to early detection, separation and eradication of infected animals.