Classical Swine Fever

Classical swine fever is one of the most important viral diseases in pigs. It is a systemic disease and it is notifiable in most countries.

Alternative names: CSF

Information

Classical swine fever is caused by a pestivirus related with bovine viral diarrhea and with border disease. There are several strains with different virulence. Its clinical condition is very similar to the African Swine Fever and many common diseases, such as salmonella; therefore laboratory diagnosis is required. Its control involves stamping out or, as a last resort, vaccination. As African Swine Fever, these viruses survive for a long time in frozen carcasses.

 

Symptoms

Lactating piglets

  • Vomiting.
  • Diarrhea.
  • Lack of coordination.
  • Conjunctivitis.
  • High fever.
  • Sudden death.
  • Malformations.
  • Piglets very weak at birth (congenital tremor).

Sows

  • Loss of appetite.
  • High fever.
  • Abortion.
  • Increase of stillbirths.
  • Increase of mummified piglets.
  • Seizures.
  • Lack of coordination.
  • Diarrhea.
  • General reproductive failure.
  • Blue discoloration of the skin.

Nursery and fattening

  • Pigs with depression - Heads down.
  • They stop eating.
  • Diarrhea.
  • Eye discharges.
  • Persistent high fever.
  • Nervous signs.
  • Seizures.
  • Lack of coordination.
  • Blue discoloration of the skin.
  • High mortality.

Causes / Contributing Factors

  • The virus is transmitted from infected or carrier pigs through nasal and mouth discharges, urine and feces. It is very contagious.
  • It can enter a herd through contaminated meat (can be transmitted through uncooked pork meat or cured meat).
  • Mechanical transmission is common through boots, clothing, trucks, etc.
  • Co-infection with PRRS virus.

Diagnosis

  • They present typical post-mortem changes with hemorrhagic lymph nodes, dead zones in the spleen, multiple small hemorrhages in kidneys and so-called "button ulcers" in the intestine.
  • In all suspicious cases the diagnosis should be confirmed by laboratory analysis..
  • Laboratory analysis include the identification of viral antigen, virus isolation and the presence of antibodies in serum. In most countries, CSF is reportable.
  • Infections with bovine viral diarrhea and with border disease may give false positive.


Control/Prevention

  • Vaccination is effective in enzootic areas and in high risk areas may be mandatory.
  • Most countries free of the disease do not include vaccination in their national eradication programs of the CSF, and is usually prohibited.
  • In areas where the CSF's virus is endemic it is normal to vaccinate all pigs at two weeks of age. Piglets born from vaccinated sows would be vaccinated at the age of 8 weeks. This policy generally results in the elimination of the virus from that region.
  • Countries that are free of CSF prevent getting infected from abroad, controlling the importation of pigs and pig meat products, unless they are properly processed, if they come from countries with CSF. In addition, organic fraction of waste that may contain meat products must be sterilized by heat.