African swine fever

African swine fever is prohibited matter.

Under Queensland legislation, if you suspect the presence of this disease in any species of animal, you must report it to Biosecurity Queensland on 13 25 23 or contact the Emergency Disease Watch Hotline on 1800 675 888.

African swine fever is a highly contagious viral disease affecting pigs. It has a variety of clinical signs but can appear similar to classical swine fever (hog cholera). Diagnosis can only be confirmed by clinical testing.

Cause

A virus that has not been classified.

Distribution in Queensland

There have been no occurrences in Australia.

Currently present in most of sub-Saharan Africa. The disease spread to Spain and Portugal over 50 years ago but is now mainly restricted to feral pigs in small areas of these countries. Other European countries have had incursions of the disease but all except for Sardinia in Italy were eradicated.

A number of African countries reported outbreaks during 1998. Some Central and South American countries have had the disease and eradicated it (Brazil 1981, Haiti 1984).

Life cycle

The course of this disease is from 1-7 days. In less acute forms of the disease, symptoms can last up to 3-4 weeks.

Affected animals

pigs

Hosts

Ticks

Symptoms

When severe, the animal:

  • becomes depressed
  • has a high temperature
  • loses appetite
  • shows incoordination
  • is reluctant to move and often lies down
  • often displays blue blotching of the skin on ears, nose and limbs
  • produces nasal and eye discharges
  • sometimes aborts a pregnancy.

Pigs vomit and develop bloody diarrhoea and often die a few days later.

Impacts

Forms of the disease range from severe to very mild. In its most severe form, up to 100% of pigs may be affected and die.

How it is spread

African swine fever virus occurs in the warthog population in Africa due to the soft argasid tick. Similar ticks are found associated with kangaroos in Australia.

The virus spreads by direct contact with infected pigs. It also spreads by contaminated material from the environment, and the feeding of infected swill or meat scraps to pigs. Most of the international spread has been associated with the swill feeding of garbage from international airports or seaports. All Australian states and territories have laws against feeding swill to pigs.

Risk period

The virus is very stable in a wide range of acid and alkaline levels (4-13 pH) and temperatures, including temperatures below freezing. It can survive in contaminated pig pens for at least 1 month and can survive for many months in raw unprocessed frozen meat. Pigs can remain carriers of the virus for long periods, perhaps for life. Heating to above 60°C appears to eliminate the virus.

Control

Call 13 25 23 if you find an animal you suspect may be infected with African swine fever to seek advice on control options.

The strategy in Australia is to eradicate the disease in the shortest possible time. This will involve:

  • stamping out, which involves isolation, slaughter of all infected and exposed susceptible animals, and sanitary disposal of destroyed animals and contaminated animal products to remove the source of infection
  • strict isolation and movement controls to prevent further spread of the virus by animals, people, products and equipment
  • decontamination to eliminate the virus on infected premises and equipment and to control the tick vector
  • tracing and surveillance to determine the extent of the infection
  • zoning to define infected and disease-free areas.

More information