What causes ASF?

African Swine Fever (ASF) is a devastating disease affecting swine caused by a complex virus, the only member of the Asfarviridae family. 

Is ASF a problem only in Africa?

No. In 2007, ASF was reported in the EU country of Georgia. The introduction was believed to be related to swill feeding with the waste from a ship coming from south east Africa. ASF spread rapidly throughout the country and in the rest of the Caucasus region (Azerbaijan, Armenia) and the Russian Federation, with some outbreaks reported very near to the EU borders (including a single introduction in Ukraine and a recently declared outbreak in Belarus), making it a significant present threat to the swine industry across Europe and beyond.

How long does it usually take since an animal is infected until it develops the disease?

3-15 days (usual incubation period). In the acute form, 3-4 days. What does ASF look like? It is a highly contagious disease that can affect pigs of all ages, without sex predilection. There is not a specific sign that can make you certain that the problem is ASF, although unusual high mortality among pigs of all age groups should lead to a strong suspicion of ASF although it can be similar to CSF (Classical Swine Fever).

When apparent, the disease can take four forms:

  • Peracute
  • Acute
  • Subacute
  • Chronic

The peracute and acute forms can have the following signs:

  • Sudden death of animals, with few signs
  • high fever (40.5- 42°C)
  • reddening of the skin (visible only in pale-skinned pigs) – tips of ears, tail, distal extremities, ventral aspects of chest and abdomen
  • decreased appetite, listlessness, cyanosis and mobility incoordination within 24- 48 hours before death
  • vomiting, diarrhea (sometimes bloody) and eye discharges
  • death within 6 -13 days, or up to 20 days
  • abortion
  • mortality rate often approaches 100% (in domestic swine)

How is the virus transmitted?

  • Directly (via contact between sick and healthy animals) or indirectly via:
  • Feeding on garbage containing infected pig meat and /or pork products (ASFV can remain infectious for 3-6 months in uncooked pork products)
  • Biological vectors (soft ticks of the genus Ornithodoros) that previously fed on infected hosts
  • contaminated fomites (premises, vehicles, clothes, …).

Sources of the virus include:

  • Blood, tissues, secretions and excretions of sick and dead animals
  • Animals which have survived and recovered from the infection
  • Soft ticks of the genus Ornithodoros (a natural arthropod host), infected with the virus
  • The environment: ASFV can persist in pig feces over 6-10 days, in pork products for several months, and in frozen meat for years

If I see a suspected case, what should I do?

Contact your veterinarian and/or the official veterinarian in your region. 

Decreased appetite, listlessness, cyanosis and mobility incoordination within 24-48 hours before death Photo credit: FAO

For full article, click here.