African Swine Fever
African swine fever (ASF) is a highly contagious viral disease of domestic and wild pigs, whose mortality rate can reach 100%. It is not a danger to human health, but it has devastating effects on pig populations and the farming economy. (WOAH, no date).
Primary reference(s)
WOAH, no date. African swine fever. World Organisation for Animal Health (WOAH). Accessed 28 May 2025.
Annotations
Additional scientific description
African Swine Fever (ASF) is a highly contagious, generalized disease of pigs caused by an Iridovirus of the family Asfarviridae that exhibits varying virulence between strains and is very hardy to physical and chemical inactivation. The agent can remain viable for long periods in blood, faeces and tissues. It can also multiply in its vectors. In view of this, control of ASF is dependent on stamping-out policy and strict quarantine enforcement (FAO, 2019).
In the natural sylvatic cycle, the soft-bodied, eyeless Ornithodoros ticks (also known as tampans) are, together with African wild suids, the natural reservoir hosts of ASFV. They can transmit the virus through their bites. All members of the pig family (Suidae) are susceptible to infection, but clinical disease is only seen in domestic and feral pigs, as well as in the closely related European wild boar. Wild African suids are asymptomatic carriers of ASF and act as the reservoir of the virus in parts of Africa. These include warthogs (Phacochoerus africanus and P. aethiopicus), bushpigs (Potamochoerus porcus and P. larvatus) and giant forest hogs (Hylochoerus meinertzhageni) (FAO, 2019).
In domestic pigs, ASF is transmitted mainly through direct contact, via the oronasal route, through excretions from infected pigs, or from ingestion of pork or other contaminated products containing the virus (e.g. swill, waste, carcasses, etc.). Further transmission pathways are indirect contact through fomites or vector-borne transmission through bites from infected Ornithodoros soft ticks, where present.
It most commonly appears in the acute form of a haemorrhagic fever. Subacute and chronic forms of the disease also exist. Mortality is usually close to 100% and pigs of all ages are affected (FAO, 2019).
In subacute and chronic cases, pigs may show milder clinical signs, such as loss of appetite, weight loss, and fever (Sánchez-Vizcaíno et al., 2015; Sun et al., 2021).
ASF is present in wild and/or domestic pigs in regions of Asia, Europe and Africa (OIE, 2018). People can transport the virus over large distances through contaminated meat and other sub-products such as skins, skulls, tusks or other hunting trophies (OIE, 2018; FAO, OIE & EC, 2019).
There are no commercial vaccines available for ASF. Some vaccine trials have been implemented in the Philippines and Vietnam. Most countries maintain a list of approved veterinary vaccines for use. For specific regulations, consult the country's veterinary authorities.
ASF is one of the World Organisation for Animal Health (WOAH) listed diseases (WOAH, 2024b).
The disease is not a zoonosis, i.e. it does not infect humans.
Metrics and numeric limits
An estimated quarter of the global domestic pig population has been decimated by the disease, causing food insecurity and economic losses on an unprecedented global scale (Dixon et al., 2019).
Key relevant UN convention / multilateral treaty
WTO Agreement on the Application of Sanitary and Phytosanitary Measures (SPS Agreement) (WTO, 1994). Available from: https://www.wto.org/english/res_e/booksp_e/agrmntseries4_sps_e.pdf
UN Recommendations on the Transport of Dangerous Goods - UN Model Regulations Model Regulations (UNECE, 2023). Available from: https://unece.org/transport/dangerous-goods/un-model-regulations-rev-23
Drivers
Lack of biosecurity, swill feeding and transport of live pigs and uncooked port products, presence of the competent vector ticks of the genus Ornithodoros.
ASF easily spreads in areas experiencing storms, flooding, civil conflict, insecurity, displacement of people, or a greater need to remain mobile, due to difficulties in maintaining high biosecurity. Pork products for food aid may introduce ASF to ASF-free areas when uncooked food waste is fed to raise pigs
Impacts
Death of infected animals, spread of infection and trade ban. The disease is the cause of major economic losses, threatens food security and safe trade, and challenges sustained swine production in affected countries.
Multi-hazard context
Pork meat is one of the primary sources of animal proteins, accounting for more than 35% of the global meat intake. Hence, this disease poses a serious problem for food security worldwide (WOAH, no date).
ASF continues to spread worldwide, threatening pig health and welfare. The disease has reached multiple countries across Asia, the Caribbean, Europe, and the Pacific, affecting both domestic and wild pigs (WOAH, no date).
This disease is also a concern for biodiversity and the balance of ecosystems, as it affects not only domestic farmed pigs but also wild boars, including native breeds (WOAH, no date).
Risk Management
Measures include depopulate infected herds, movement control, improving biosecurity at farms. A One Health approach to risk management will help address interconnected factors contributing to risk and promoting collaboration across sectors while enhancing surveillance and early warning through integrating human, animal, and environmental health.
Monitoring
The section and the table below offer an overview of monitoring for African swine fever. This information can be used for forecasting within a national early warning system (EWS). Since EWS capacities and processes differ across countries, the most current and specific information regarding EWS should be obtained from the appropriate national or regional agency/authority responsible for disaster management.
| Which institution(s) produce(s) Disaster Risk Data/Information? | FAO Reference Centres, WOAH Reference Centres, |
| How is the Hazard Observed/Monitored/Forecast? | FAO empres-i+ https://empres-i.apps.fao.org/diseases WOAH WAHIS https://wahis.woah.org/#/event-management |
References
Dixon, L.K., Sun, H., Roberts, H., 2019. African swine fever. Antiviral Res.;165:34-41. doi: 10.1016/j.antiviral.2019.02.018. Epub 2019 Mar 2. PMID: 30836106. Accessed 28 May 2025.
Sánchez-Vizcaíno, J.M., Mur, L., Gomez-Villamandos, J.C., Carrasco L., 2015. An Update on the Epidemiology and Pathology of African Swine Fever. J. Comp. Pathol, 152:9–21. doi: 10.1016/j.jcpa.2014.09.003.
Sun, E., Huang, L., Zhang, X., Zhang, J., Shen, D., Zhang, Z., Wang, Z., et al., 2021. Genotype I African Swine Fever Viruses Emerged in Domestic Pigs in China and Caused Chronic Infection. Emerg. Microbes Infect, 10:2183–2193. doi: 10.1080/22221751.2021.1999779.
WOAH, no date. African Swine Fever. World Organisation for Animal Health (OIE). Accessed 1 January 2025.
WOAH, 2024a. Manual of Diagnostic Tests and Vaccines for Terrestrial Animals, 13th edition. World Organisation for Animal Health (WOAH). Accessed 1 January 2025.
WOAH, 2024b. Terrestrial Animal Health Code. 32nd edition. World Organisation for Animal Health (WOAH). Accessed 1 January 2025.
WTO, 1998. The WTO and the World Organization for Animal Health (WOAH). G/SPS/GEN/775. World Trade Organization (WTO). Accessed 1 September 2024.