Weak and ataxic pig

Haemorrhage in lymph nodes of acutely infected pig

Splenic infarcts in acutely infected pig

Infected pigs huddle together

CSF is a highly contagious disease of pigs of all ages. It is caused by a RNA-virus belonging to the family Flaviviridae, genus Pestivirus. The virus is relatively stable in moist excretions of infected pigs, pig carcasses and fresh pig meat. It is readily inactivated by detergents, lipid solvents, proteases and common disinfectants. It is transmitted through direct contact, swill-feeding, transplacentally, and through mechanical transmission (such as needles during treatments). Only one serotype exists although strains with different virulence characteristics have been identified. CSF is not a threat to human health.

Clinical Signs: The incubation period varies from 2-14 days. Pigs may die after a short febrile illness and before other clinical signs develop. Pigs become depressed, recumbent, have difficulty breathing, stop eating, and huddle together. Acute: Fever (41°C), cyanotic skin haemorrhages (especially at extremities), conjunctivitis, anorexia, ataxia, paresis, convulsions, sometimes vomiting, diarrhoea or constipation. Death usually occurs within 5-15 days after clinical signs develop. Mortality depends on the virulence of strain and age of the animal, with young animals are more vulnerable than adults. Chronic: Initial signs are similar to acute infection and progress to non-specific signs (intermittent fever, chronic enteritis, wasting). Skin haemorrhages are absent. Death after several months of disease. Virus is constantly shed.Congenital: Transplacental transmission can result in abortion, resorption, mummification, and stillbirth of piglets. Surviving piglets may be clinically normal at birth but are consistently viraemic and shed the virus until death. Weakness, tremor and poor growth sometimes leading to death.

Classical Swine Fever

Pathological FindingsAcute: No lesions if death soon after infection. Enlarged and haemorrhagic lymph nodes, encephalomyelitis. Multi-focal infarctions along the margin of the spleen. Widespread haemorrhage in skin, lymph nodes, larynx, bladder, kidney, ileocaecal junction Chronic: Button ulcers in caecum and large intestines, generalized depletion of lymph tissue. Haemorrhagic lesions often absent.Differential DiagnosisAfrican Swine Fever, Porcine Dermatitis Nephropathy Syndrome, Bovine Viral Diarrhea virus: Similar gross pathology. Laboratory differential diagnosis is essential.Bacterial diseases such as erysipelas, salmonellosis, and pasteurellosis usually respond to antimicrobials and have lower morbidity and mortality rates.

Control of Classic Swine Fever

Disinfectants:Inactivated by cresol, sodium hydroxide (2%), formalin (1%), sodium carbonate (4% anhydrous or 10% crystalline, with 0.1% detergent), ionic and non-ionic detergents, strong iodophors (1%) in phosphoric acid

Samples: Label all samples and provide epidemiological information and history

-Tissue from tonsils, lymph nodes (pharyngeal, mesenteric, maxillary, renal), spleen, kidney and distal ileum collected aseptically and kept separate and chilled (never frozen).

-Aseptic blood samples in EDTA from live animals, serum from recovered and affected animals.

Humane killing and proper burial of infected pigs

Disinfecting boot bath at entrance to farm

Sentinel pigs contained in a sty with controlled entry

Prevention: ► Pig farmers and field personnel should know the dangers of CSF and be

able to suspect the disease.► Contain pigs within pig sties with controlled entry/exit points► Do not allow visitors in without changing their boots and clothes► Have a boot bath to wash and disinfect boots regularly► Control and monitor movement of pigs within the country and especially

across international borders► Swill should not contain remains of pigs and should be boiled for 30

minutes and allow to cool before feeding► Vaccines can be used to protect swine from disease (attenuated and

sub-unit).► Infected sows can transmit the disease to piglets during pregnancy and

should be eliminated from the herd. During an outbreak: ► infected and suspected infected farms must be placed under quarantine► -no movement of pigs or any products of pig origin should be allowed► -all infected and in-contact pigs must be humanely slaughtered ► -carcasses, animal products and bedding must be burnt or buried

deeply on site► -personnel should ensure that shoes, clothes vehicles and equipment

are disinfected between farms► -farms should not be restocked until after proper cleaning and

disinfection is completed. Sentinel pigs might be used.► If using vaccine, only healthy non-infected pigs should be vaccinated.

If the shipping of samples to an OIE or FAO reference laboratory is required, FAO may be able to assist in the shipment; offering IATA transport boxes and arranging the shipment with a specialized transport company. For requests, please contact: empres-shipping-service@fao.org

Reference Experts and Laboratory Contacts:Veterinary Laboratories Agency (VLA) – Weybridge New Haw, Addlestone, Surrey KT15 3NB, United Kingdom Tel: +44 (0) 1932 341111 Email: enquiries@vla.defra.gsi.gov.ukForeign Animal Disease Diagnostic Laboratory Plum Island Animal Disease Center USA Tel: +1 631 323 3256 Fax: +1 631 323 3366 Email: nvsl.concerns@usda.aphis.govInstitut für Virologie Tierärztliche Hochschule Bünteweg 17, D-30599 Hannover GERMANY Tel.: +49 511 953 8840 Fax: +49 511 953 8898 Email: moennig@viro.tiho-hannover.deFriedrich-Loeffler-Institut Bundesforschungsinstitut für Tiergesundheit Suedufer 10, D-17493 Greifswald-Insel Riems GERMANY Tel: +49 38351 7-0 Fax: +49 38351 7-219