African swine fever

African swine fever is a notifiable disease

Under Queensland legislation, if you suspect the presence of African swine fever in pigs, you must report it to Biosecurity Queensland.

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Emergency Disease Watch Hotline 1800 675 888

Overview

Cause

African swine fever (ASF) is caused by a virus that has not been classified.

Description

ASF is a highly contagious virus disease of pigs. It can only be distinguished from the similar disease classical swine fever (hog cholera) by laboratory testing.

Where the disease occurs

The disease is present in most of sub-Saharan Africa. The disease spread to Spain and Portugal over 30 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, except for Sardinia in Italy, they have now eradicated the disease.

A number of African countries reported outbreaks during 1998.

Some Central and South American countries have had the disease have eradicated it (Brazil 1981, Haiti 1984).

There have been no occurrences in Australia.

The disease in animals

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.

The disease has a variety of clinical forms, some more severe than others. The death rate is dependent on the severity of the symptoms, with up to 100% deaths with the more severe forms.

In the severe form the animal becomes depressed, has a high temperature, loss of appetite, shows incoordination, reluctance to move and often will lie down. Blue blotching of the skin of the extremities, such as ears, nose and limbs, often occurs. Nasal and eye discharges may occur. Pigs vomit and develop bloody diarrhoea and often die a few days later. The course of this disease is from 1-7 days. Abortions can occur. In less acute forms the symptoms are similar, though milder, and last longer (up to 3-4 weeks).

Spread of the disease

The virus is spread by direct contact with infected pigs. It is also spread by contaminated material from the environment and the feeding of infected swill or meat scraps to pigs. Most of the international spread of ASF has been associated with the swill feeding of garbage from international airports or seaports.

In Africa the soft argasid tick maintains ASF virus in the warthog population. Similar ticks are found associated with kangaroos in Australia.

The virus is very stable in a wide range of acid and alkaline levels (pH 4-13) and temperatures, including temperatures below freezing. It can survive in contaminated pig pens for at least one 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 of the disease

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

  • stamping out to remove the immediate source of virus
  • strict quarantine 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.

There is no vaccination for ASF.

Can people get the disease?

No.

Further information

Last updated 28 February 2014