ASF affects both domestic and feral pigs of all ages. Clinical signs depend on the virulence of the strain.

Clinical Signs

Peracute form

• Sudden death with no prior signs

Acute Form

• High Fever (40.5-42^oC)
• Depression, listlessness
• Anorexia
• Cyanosis and incoordination up to 48hrs before death
• Redness of the skin, especially ears, abdomen and legs
• Abortion in sows
• Vomiting, diarrhoea
• Death, usually within 14 days.
• Mortality rates up to 100%

Sub-Acute Form

• Slight fever
• Reduced appetite and weight loss
• Depression
• Abortion in sows
• Death between 15-45 days
• Mortality rates of between 30-70%

Chronic Form

• Weight loss
• Irregular peaks of fever
• Respiratory signs
• Necrosis of the skin and chronic ulcers
• Arthritis
• Joint swelling
• Low mortality rate

Post-mortem Signs

Peracute form

• May not show any post-mortem lesions

Acute/subacute Form

• Pronounced haemorrhages in the gastrohepatic and renal lymph nodes
• Petechiae of the renal cortex, medulla and pelvis
• Congestive splenomegaly
• Oedematous areas of cyanosis in hairless parts of the skin
• Cutaneous ecchymoses on legs and abdomen
• Excess of pleural, pericardial and or peritoneal fluid
• Petechiae in the mucous membranes of larynx and bladder and visceral surfaces of the organs
• Oedema in the wall of the gall bladder and mesenteric structures of the colon and adjacent to the gall bladder

Chronic form

• Focal caseous necrosis and mineralisation of the lings
• Enlarged lymph nodes

If you suspect ASF call your herd veterinarian, Local Land Services veterinarian on 1300 795 299 or the Emergency Animal Disease Hotline 1800 675 888.

You should move any pigs you have away from boundaries. If you have multiple sheds or units:

• do not mix pigs from multiple units
• implement strict biosecurity protocols between sheds. E.g. Change into freshly laundered overalls, specific gumboots for each unit and wash hands between sheds.

You, and anyone on the farm should not visit any other farms with pigs until a negative result is returned or you have thoroughly showered and changed into freshly laundered clothes.

ASF is clinically indistinguishable from Classical Swine Fever, another emergency animal disease. Diagnosis relies on laboratory confirmation. See ASF Investigation PDF, 248.71 KB for more information.

Samples to take

If you can, collect samples from 10 animals. This can be a combination of sick and dead animals.

Live Pigs:

• 10mL EDTA blood (purple top)
• 10ml Clotted Blood (red top)
• Swabs in viral transport media from mouth, tonsils and nose

Dead Pigs:

• 10mL EDTA blood- recently dead or euthanised animals
• Swabs in viral transport media from mouth, tonsils and nose
• Sterile tissue samples in individual sterile pots approximately 2g of each tissue (keep chilled, not frozen) from Tonsils, spleen, gastro-hepatic lymph node, mesenteric lymph node, lung, kidney, ileum.
• Samples in 10% neutral buffered formalin, can be one large pot from tonsils, spleen, liver, lymph nodes, lung, kidney, heart and brain as well as any lesions seen in any tissue.

Forward the samples to the NSW Animal and Plant Health Laboratories, Elizabeth McArthur Agricultural Institute (EMAI).  If you are submitting samples for ASF exclusion, please contact the lab during business hours (8:30am to 4:30pm Monday to Friday) on 1800 675 623 to ensure samples are tested promptly on arrival. The lab can also assist with couriers if needed.

Differential Diagnoses for ASF include:

• Classical swine fever
• Porcine reproductive and respiratory syndrome
• Erysipelas
• Salmonellosis
• Pasteurellosis
• Any septicaemic condition.

The incubation period is usually 5-15 days, however it may be up to 20 days. Within herds, ASF is primarily spread through direct contact. Indirect spread also occurs through feeding of contaminated feed, food waste (swill) and/or garbage.

Spread between units and properties may occur through movement of infected pigs, contaminated vehicles, equipment, people or animal products. As the virus remains viable for long periods in blood, faeces, secretions and tissues of infected pigs it can survive at least 30 days in pig pens and 300 days in some pork products.

Some pigs that survive infection can become persistently infected, secreting virus into the environment.

ASF is not known to infect humans.

There is currently no vaccine or effective treatment of ASF registered for use in Australia. Despite the identical clinical signs with Classical swine fever, they are unrelated.

ASF virus is a complex, large, enveloped DNA virus. The virus is stable at a wide range of pH levels and can remain viable for long periods in blood, faeces and tissues, particularly in chilled or frozen pork products. Disinfectants permitted for use against ASF include Virkon S (10g/L) Calcium Hypoochlorite (0.5% solution), F10 (105) Citric acid (30g/L), Virocid (10mL/L).

ASF Cleaning and disinfection of vehicles PDF, 139.27 KB

ASF Personal decontamination PDF, 226.46 KB

Resources

Recognising exotic disease in pigs PDF, 687.48 KB

Outbreak.gov.au- African Swine Fever

Animal Health Australia Training Courses- ASF Module

Animal Health Australia- African Swine Fever

Australian Pork Limited- African Swine Fever

AusVetPlan- African Swine Fever

World Organisation for Animal Health- African Swine Fever