African Swine Fever
African Swine Fever (ASF) is a highly contagious and often lethal viral disease that affects domestic and wild pigs. Caused by the African Swine Fever Virus, ASF leads to severe economic losses in affected regions due to its impact on swine farming. The disease was first described in Kenya in 1921, and the first outbreak was retrospectively recognized as having occurred in 1907.
The Virus
The virus responsible for ASF is a large, double-stranded DNA virus classified in the Asfarviridae family. Unlike many other viruses affecting pigs, ASF does not pose a threat to humans and has no zoonotic potential. However, its impact on the pig population can be devastating, with mortality rates approaching 100%.
Transmission and Spread
ASF is primarily spread through direct contact with infected pigs or through consumption of contaminated feed or garbage. The virus can also be transmitted by soft ticks, such as those in the Argasidae family, with the species Ornithodoros moubata being a known vector. Once introduced into a pig population, the virus can spread rapidly.
Notable outbreaks have occurred in various parts of the world, including Catalonia, Spain in 2025 and in Belgium in 2018. The introduction of the virus into new regions can often be linked to the movement of infected animals or contaminated products.
Economic Impact
ASF outbreaks lead to significant economic losses due to the death of infected animals and the costs associated with containment and eradication efforts. Infected farms often face culling of entire herds to prevent further spread, as seen in the 2019 outbreaks in Bulgaria, where preventive slaughtering of 4,000 domestic pigs was carried out in response to an outbreak among wild boars.
Control and Prevention
Efforts to control ASF focus on strict biosecurity measures, restricting movement of pigs and pig products, and culling infected and exposed animals. Despite these efforts, the absence of a vaccine has posed challenges for long-term control. However, recent advancements have been made, such as the development of a vaccine by Vietnam in 2022 and ongoing research in the United States.
Historical Context
The spread of ASF has had geopolitical implications. In 1971, an outbreak in Cuba was controversially linked to allegations involving the Central Intelligence Agency as part of efforts to destabilize the country's economy.