African Swine Fever

Introduction

African Swine Fever ocurs after infection by the Asfarviridae family of viruses. ASF is a serious exotic virus that should not be confused with Classical Swine Fever.

Clinical Signs

Acute Virus (Africa)

• Nasal discharge, diarrhoea, reddening of the skin
• Death within 7 days
• PM: widespread internal hemorrhage

Subacute Virus (Europe)

• Mortality: 30-70%
• Survivors may lose body condition, have skin ulcers and joint swelling
• PM: Petechial hemorrhages may be seen under kidney capsule

Epidemiology

The virus can persist on infected premises for months. Subacute recovered pigs become antibody-positive carriers.

• Viral transfer occurs as follows:
  • Africa: vertical transfer between soft ticks
  • Europe/Africa: direct contact with carrier pigs, aerosol, infected swill, etc.

Diagnosis

• Mortalities with widespread hemorrhage, particularly in lymph nodes
• Test to distinguish from Classical Swine Fever and Porcine Circoviruses
• Immunofluorescence and PCR test are available for confirmation

Control

No vaccine is available.

Prevention control measures include:

• Boiling swill
• Isolation of sick pigs and domestic pigs from wild pigs
• Keep pigs on concrete, not soil (to lessen tick contact)

Literature Search

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Review of African swine fever: transmission, spread and control. Penrith, M. L.; Vosloo, W.; South African Veterinary Association, Pretoria, South Africa, Journal of the South African Veterinary Association, 2009, 80, 2, pp 58-62, 75 ref. - Full Text Article