Classical Swine Fever - Fact Sheet

What is classical swine fever?

Classical swine fever (CSF), also known as hog cholera or swine fever, is a highly contagious viral disease affecting domestic and wild pigs.

The disease ranges from mild to severe and can be fatal, often causing a large number of deaths in affected herds.

The most common clinical signs include:

  • fever and redness of the skin;
  • a lack of coordination;
  • diarrhea; and
  • pneumonia.

Severe cases appear very similar to African swine fever.

Is CSF a risk to human health?

No. There is no human health risk associated with CSF.

What are the clinical signs of CSF?

The clinical signs depend on the virus strain.

With the most damaging strains there is severe disease, with clinical signs that include:

  • high fever;
  • depression;
  • loss of appetite;
  • conjunctivitis;
  • nasal discharge;
  • lack of coordination;
  • stiffness;
  • convulsions;
  • vomiting;
  • diarrhea;
  • laboured breathing; and
  • possible red or purplish skin blotching on the ears, snout, limbs and abdomen.

Mortality is 100 per cent, occurring within one to two weeks.

With less severe strains, the chronic form of the disease is seen. The clinical signs are milder and more irregular. Affected animals have a compromised immune system and poor growth. Infected pigs will die after one to three months.

Depending on the strain of the virus, CSF infection in pregnant pigs can result in:

  • abortions;
  • stillbirths;
  • the birth of weak piglets which may have tremors; or
  • the birth of healthy-looking piglets that are persistently infected and will shed the virus until they die several months later.

Where is CSF found?

CSF has been reported in most countries around the world.

Canada successfully eradicated CSF in 1963.

How is CSF spread?

CSF is most commonly transmitted through direct contact. The virus is present in the blood, tissues, secretions and excretions of infected animals.

Persistent CSF carriers may not show any signs of illness, but continue to spread the virus.

Fetuses can become infected in the uterus (congenital infection), and if they survive, they will shed the virus persistently.

The CSF virus can survive in pork and processed pork products. The virus can live for months when meat is stored in cool temperatures and for years when it is frozen. Pigs can become infected by eating infected pork. It is important to note that there is no food safety risk associated with CSF.

Contact with contaminated vehicles, pens, feed or clothing may spread the disease.

There is also some evidence of airborne transmission of the virus.

How is CSF diagnosed?

CSF may be suspected based on clinical signs and lesions.

The diagnosis must be confirmed by laboratory tests that detect the virus.

The tonsil is the most important organ for detecting the disease.

How is CSF treated?

There is no specific treatment for infected animals.

Vaccines are used by many countries to control CSF where eradication of the disease is not possible.

What is done to protect Canadian livestock from an outbreak of CSF?

The Canadian Food Inspection Agency (CFIA) imposes strict regulations on the import of animals and animal products from countries where CSF is known to occur. These regulations are enforced through port-of-entry inspections done either by the Canada Border Services Agency or the CFIA.

CSF is a "reportable disease" under the Health of Animals Act. This means that all suspected cases must be reported to the CFIA for immediate investigation by inspectors.

How would the CFIA respond to an outbreak of CSF?

Canada's emergency response strategy to an outbreak of CSF would be to:

  • eradicate the disease; and
  • re-establish Canada's disease-free status as quickly as possible.

In an effort to eradicate CSF, the CFIA would use its "stamping out" policy, which includes:

  • the humane destruction of all infected and exposed animals;
  • surveillance and tracing of potentially infected or exposed animals;
  • strict quarantine and animal movement controls to prevent spread;
  • strict decontamination of infected premises; and
  • zoning to define infected and disease-free areas.

Owners whose animals are ordered destroyed may be eligible for compensation.

Additional information

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