African Swine Fever (ASF)

Key findings & statistics 

• African Swine Fever is a highly contagious haemorrhagic disease of pigs with case‑fatality rates approaching 95–100 % in acute outbreaks (asm.org). 

• Only suids are affected – ASF infects domestic pigs, wild boar and certain wild African suids (warthogs, etc.), with no risk to humans or other livestock (efsa.europa.eu). It is not a zoonotic threat. 

• ASF is now endemic in more than 50 countries across Africa, Europe, Asia and the Pacific, and since 2021 it has been re‑introduced to the Caribbean (Hispaniola) (fao.org), posing a global pig‑health crisis. 

• There are no cures or widely available vaccines for ASF at present – outbreaks are managed by culling and movement bans, making prevention through biosecurity crucial (efsa.europa.eu). 

• The 2018–2019 ASF pandemic in Asia devastated pig herds: China alone lost an estimated ≈ 225 million pigs (about 50% of its herd), meaning roughly one quarter of the world’s pigs died or were culled in that period (asm.org). 

• Europe recorded 12,121 ASF outbreaks in 2023, nearly double the 2022 count, with Poland hardest hit. ASF entered five new European countries in 2023 (e.g. Sweden, Greece), though some contained it quickly (avma.org). 

• The ASF virus is extremely resilient: it can survive for 5–6 months in contaminated pig pens or manure and up to 30 months in chilled or frozen pork products (huvepharma.com) – enabling long‑distance spread via meat. 

• The first ASF vaccines (live‑attenuated) were approved in Vietnam in 2022–23 with ~95 % efficacy in trials (pigprogress.net), but international animal‑health authorities (WOAH) warn against sub‑standard vaccines because of safety concerns and insufficient data (avma.org). This underscores cautious optimism versus caution in the ASF‑vaccine race. 

What is African Swine Fever (ASF)? 

African Swine Fever (ASF) is a highly contagious, haemorrhagic disease of domestic pigs and wild suids caused by African swine fever virus (ASFV), the sole member of the genus Asfivirus (family Asfarviridae). The virus has a large double‑stranded DNA genome (≈ 170–190 kb) and is currently divided into 24 p72 genotypes; only genotypes I and II circulate outside Africa, with genotype II driving the current pandemic across Europe, Asia and the Americas. 

ASF virus is not zoonotic and poses no risk to human health. 

Virus resilience & transmission of African Swine Fever

• Tough survivor: ASF virus persists > 1 year in chilled blood, months in boneless meat and years in frozen carcases; it survives 60 days in manure at 22°C. 

• Primary spread routes 

• Direct contact with infected pigs (blood, saliva, faeces). 

• Oral exposure to contaminated pork or swill. 

• Fomites – vehicles, boots, feed, needles. 

• Sylvatic cycle involving soft ticks (Ornithodoros species) in Africa and parts of Europe. 

• Wild boar movements and carcases sustaining virus in the environment. 

Clinical forms & pathology of African Swine Fever

Lesions are strain‑dependent; highly virulent isolates cause fulminant vascular damage and disseminated haemorrhages. 

Global occurrence of African Swine Fever

African Swine Fever is now established on four continents and remains one of the world’s fastest‑spreading transboundary animal diseases. Since its leap from Africa to the Caucasus in 2007, the virus has swept across large parts of Europe, Asia and the Caribbean, while remaining enzootic in much of sub‑Saharan Africa. 

• Europe – Outbreaks ebb and flow each year, concentrated in central and eastern regions where wild‑boar populations act as a reservoir. Several northern countries have shown that rapid fencing, whole‑carcass removal and hunter engagement can eliminate localised incursions within a single production cycle. 

• Asia–Pacific – The disease is entrenched in major pork‑producing nations such as China, Vietnam and the Philippines, and periodically re‑emerges in neighbouring countries despite intensified biosecurity and movement controls. 

• Africa – ASF remains enzootic in most sub‑Saharan states; multiple p72 genotypes circulate, making the region a continuing source of genetic diversity and risk. 

• Americas – The virus was detected in the Caribbean early in the decade; mainland North and South America remain free, but risk assessments rank ASF as the top emerging threat to regional pork trade, prompting unprecedented border vigilance. 

Take‑home: Wherever domestic pigs coexist with dense wild‑boar populations, porous borders or swill feeding, ASF persists. Conversely, countries that combine early detection with strict biosecurity and wildlife management have demonstrated that eradication is possible – even in open landscapes. 

Socio‑economic impact of African Swine Fever

• China’s 2018–19 epidemic led to the loss (death or culling) of ≈ 225 million pigs – roughly half its herd – triggering a global pork deficit and > €115 billion in economic losses. 

• Rabobank (Q2 2025) warns that disease risk remains the chief wildcard for pork‑market volatility despite improving feed margins. 

• Trade bans automatically follow new detections; the cost of a single ASF introduction in the United States is modelled at €2.3 billion to 230 billion depending on outbreak duration. 

Diagnosis & reporting of African Swine Fever

• Notifiable to WOAH; confirmation relies on PCR or virus isolation in a reference laboratory. 

• Field diagnostics advancing: a 2024 Vietnamese study validated a portable qPCR (LOD ≈ 13 copies) and an antigen LFIA with 100% specificity but lower early sensitivity. 

• Differentiation from Classical Swine Fever (CSF) is essential – serology cannot distinguish the two; molecular assays or sequencing are required. 

Prevention & control of African Swine Fever

1. Strict biosecurity – no swill feeding, controlled access, dedicated clothing, vehicle disinfection. 

2. Early detection & stamping‑out – cull, dispose, clean, disinfect and enforce a 40‑day fallow. 

3. Controlled wild‑boar population management – carcass search & removal, fencing where feasible. 

4. Movement controls & zoning under EU Regulation 2023/594 and WOAH Terrestrial Code Chapter 15.1. 

Comparing ASF and CSF at a glance 

Outlook 

ASF remains the transboundary threat to global pig production. The absence of a universally safe vaccine means biosecurity, surveillance and rapid response are still the only proven safeguards. Encouragingly, EU data show that intensive control can sharply reduce outbreaks. Collaborative vaccination R&D and information‑sharing (e.g. WOAH’s Standing Group of Experts) are vital to move from crisis management to long‑term resilience. 

FAQ on African Swine Fever

1. What is African Swine Fever and what causes it? 
   African swine fever is a highly contagious viral disease of pigs (domestic and wild). It is caused by the African swine fever virus (ASFv), a large DNA virus in the family Asfarviridae. Unlike Classical Swine Fever (hog cholera), ASFv is the only known DNA virus that affects pigs in this way. It does not infect humans, but in pigs it can be devastating, often causing high mortality. 

2. What are the symptoms of ASF in pigs? 
   In its acute form, ASF causes high fever (40–42 °C), loss of appetite, weakness and red blotches on the skin. Affected pigs often develop haemorrhages – for example bleeding on the ears, snout, belly or internal organs – and their extremities (ears, tail, legs) may turn bluish‑purple (cyanosis). Other common signs include laboured breathing, cough, vomiting or diarrhoea (sometimes bloody) and foamy discharge from the nose and eyes. Pregnant sows may abort their litters. Pigs can die suddenly within a week. Milder strains can cause chronic illness – survivors may be stunted, thin, have joint swelling or skin ulcers – but even chronic ASF is debilitating. 

3. How does African Swine Fever spread among pigs? 
   ASF spreads very easily between pigs through direct contact with bodily fluids (blood, saliva, faeces, etc.). It can also spread indirectly: pigs can catch ASF by eating contaminated pork products (uncooked or under‑cooked scraps). Farm equipment, vehicles or clothing/boots can carry the virus if not properly cleaned. In parts of Africa and Europe, certain soft ticks (Ornithodoros species) and biting flies can move the virus between pigs. The virus is extremely hardy – it survives for months in smoked or frozen pork – so movement of contaminated meat or feed is a major hazard. Good biosecurity and banning swill feeding are critical. 

4. Can ASF infect humans or other animals? 
   No. ASF does not infect humans. It is limited to members of the pig family (Suidae). Other farm animals and pets do not get ASF. Thus, ASF is exclusively a threat to pig health and the pork industry; pork from ASF‑infected pigs is not a food‑safety issue for people. 

5. Is there a vaccine or cure for African Swine Fever? 
   Currently, there is no cure and no commercially available vaccine with global approval. Experimental live‑attenuated vaccines show promise (e.g. in Vietnam) but are not yet in widespread use. Until a safe vaccine is available, controlling ASF relies on strict biosecurity, swift culling of infected herds and controlling pig and pork movements. 

6. How can pig farmers prevent ASF on their farm? 
   The best defence is biosecurity: prohibit swill feeding (or thoroughly cook any food waste), avoid bringing pork onto farms, enforce visitor and vehicle disinfection, provide farm‑specific clothing/footwear, quarantine new pigs, prevent contact with wild boar, control rodents/insects and report suspicious illness immediately to veterinary authorities.