Classical swine fever

Classical 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.

A highly contagious viral disease of pigs, it is capable of spreading rapidly in susceptible pig populations. It is clinically similar to African swine fever, but caused by a different virus.

Cause

A virus belonging to the pestivirus genus of the family Flaviviridae.

Other names

Hog cholera

Distribution in Queensland

The disease is not present in Australia. Outbreaks have occurred and been eradicated in the past, with the last one occurring in 1961.

It is widespread in Africa, South America and Asia, but has been eradicated from most countries in Europe.

Affected animals

pigs

Symptoms

There are 3 clinical forms of this disease. The acute illness shows the following symptoms:

  • fevers
  • depression
  • loss of appetite
  • convulsions
  • constipation in the early stages of the illness, progressing to vomiting and diarrhoea
  • red or purplish skin blotching on ears, snout, limbs and abdomen.

Symptoms of the chronic form of the illness include:

  • depression
  • loss of appetite
  • poor growth
  • fluctuating fevers
  • constipation and diarrhoea, with even periods of normality

The most common symptom of the mild form of the illness is poor growth but pregnant sows may abort, or give birth to stillborn piglets. Surviving piglets may be born with tremors or deformities.

Impacts

The death rate depends on the severity of the clinical signs. The very acute form results in very high death rates, while the mild and chronic forms may pass undetected and the pigs then die from secondary infections.

How it is spread

Transmission of the virus occurs by direct contact with infected pigs or contact with contaminated pens, trucks or clothing.

Swill feeding of pigs with infected meat scraps is also an important means of spread to new areas or countries. The outbreaks in Australia occurred in this way.

All Australian states and territories have laws against feeding swill to pigs.

The virus is killed by heat at 60°C for 10 minutes. The virus is very stable in a protein-rich environment. It can survive months in refrigerated meat and for years in frozen meat. The virus can be isolated from 'green' salami and pepperoni sausages, but not after the required curing period and final acid treatment. The virus survives casings processing.

Control

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

  • stamping out to remove the source of the infection
  • strict movement controls
  • strict decontamination
  • tracing and surveillance to determine the source and extent of the disease
  • zoning to define infected and disease-free areas.

Vaccination

A vaccine is available overseas and may be used in exceptional circumstances if the disease becomes widespread and selected strategies are not being effective.

More information