African swine fever virus

African swine fever ears

Asfarviridae virion

African swine fever infected macrophage

African swine fever necropsy

Warnschild an einem Autobahnparkplatz in Baden-Württemberg bei Bickelberg 02

African Swine Fever Virus (ASFV) is a highly contagious and deadly virus that affects domestic and wild pigs. It is a large, double-stranded DNA virus, belonging to the family Asfarviridae and is the sole member of the genus Asfivirus. ASFV is responsible for African swine fever (ASF), a disease with significant economic impact on the swine industry due to its high mortality rates and the restrictions it imposes on international trade of pigs and pork products.

Etiology and Transmission

ASFV is transmitted through direct contact with infected animals, their bodily fluids, or contaminated materials such as feed, clothing, and equipment. The virus can also be spread by ticks of the genus Ornithodoros, which act as a biological vector. ASFV is highly stable in the environment and can survive for long periods in meat and meat products, facilitating its spread across international borders.

Clinical Signs and Diagnosis

The clinical signs of ASF can vary from acute, subacute, to chronic forms, depending on the virulence of the ASFV strain. Acute forms are characterized by high fever, depression, anorexia, hemorrhages in the skin (particularly the ears and abdomen), respiratory distress, and high mortality rates, often reaching 100% within 7-10 days. Subacute and chronic forms may present milder symptoms and lower mortality rates but can lead to long-term carrier states in surviving pigs.

Diagnosis of ASF is based on clinical signs, epidemiological information, and laboratory tests, including virus isolation, PCR, and serological assays to detect ASFV-specific antibodies.

Prevention and Control

Currently, there is no effective vaccine against ASFV, making prevention and control strategies crucial to managing the disease. These strategies include strict biosecurity measures, surveillance, early detection, and rapid response to outbreaks. Infected animals must be culled, and their carcasses, as well as all contaminated materials, must be safely disposed of to prevent further spread of the virus.

Control measures also involve restricting the movement of pigs and pig products from affected areas, thorough cleaning and disinfection of farms, and vector control programs to manage tick populations.

Impact

The impact of ASF is profound, affecting not only the swine industry but also food security and the livelihoods of farmers, especially in countries where pig farming is a major agricultural activity. Outbreaks of ASF can lead to significant economic losses due to the death of animals, culling operations, trade bans, and increased costs associated with disease control measures.

Research and Development

Research efforts are ongoing to develop effective vaccines and antiviral drugs against ASFV. Understanding the virus's complex interactions with its hosts and vectors is key to developing strategies for its control and eventual eradication. Advances in genetic engineering and immunology offer hope for the development of safe and effective vaccines in the future.