African Swine Fever
LEVELS: Highly unlikely; No human illness; Extraordinary biosecurity required; Reference or research laboratory required; Substantial; Prolonged disruption; Little; Needed but not available
| Register id | african_swine_fever |
| Type | virus |
| Scientific name | African swine fever virus |
| NCBI taxid | 10497 |
| Evidence | 2 document(s) |
| Assigned | 2026-09-04, against criteria version 093366e352a2 |
Overview
African swine fever is the disease the whole industry organises itself around. The virus infects domestic pigs and wild suids and nothing else — it is not a threat to human health — but in its severe forms it causes a haemorrhagic disease that kills close to every pig it infects. Its danger lies in how it travels and how long it lasts. It spreads by direct contact between pigs, in pork and pork products, and on trucks, boots, equipment and clothing, and it survives for long periods in blood, tissue, carcasses and some cured or frozen pork. Once it establishes in a wild boar population it becomes very hard to remove, because infected carcasses in the environment keep the cycle going. There is no treatment, and although vaccine development has advanced, no vaccine is available for routine deployment in most of the world. Control therefore rests on rapid detection, movement standstills, stamping out and intensive biosecurity — and on keeping it out in the first place, which for the United States means feed, garbage feeding, imported pork products and international travel. It is a notifiable disease everywhere, and the trade consequences of a single confirmed case would dwarf the direct losses.
C1 Zoonotic potential
Likelihood of transmission from pigs to humans
Highly unlikely: Human infection with the agent has never been reported, or has been reported but is not attributed to pig or pork exposure
Basis. ch24 24.1.2, a Public Health section of one sentence: "ASFV IS NOT INFECTIOUS TO HUMANS AND DOES NOT DIRECTLY AFFECT PUBLIC HEALTH (Scientific Report on ASF, EFSA 2009)." What follows is about trade rather than people: "However, the disease has SERIOUS SOCIAL AND ECONOMIC IMPACTS ON THE TRADE OF SWINE, pig by-products, and FOOD SECURITY."
How this level was decided
Level 1. The chapter forecloses the question outright. NOTE HOW THE REST OF THE SENTENCE MUST NOT BE READ INTO THIS CELL: the serious human consequences of ASF are economic and nutritional, and they are scored in C5 and C6. C1 asks whether the agent moves from pigs to people, and it does not.
C2 Zoonotic impact
Severity of human illness caused by the agent
No human illness: Agent does not cause illness in people
Basis. ch24 24.1.2: "ASFV is not infectious to humans and DOES NOT DIRECTLY AFFECT PUBLIC HEALTH."
How this level was decided
Level 1, following C1. Pigs are not a source of human illness with this agent because it does not infect people. THE LABEL MUST BE PRINTED IN FULL WHEREVER THIS ENTRY IS EXCERPTED -- "No human disease from pigs" beside African swine fever will be misread as a claim that ASF does not matter, and this is the highest-scoring entry in the register on C5 and C6.
C3 Herd introduction risk
Effort required to keep the agent out of the herd
Extraordinary biosecurity required: Exclusion needs measures beyond the routine, such as air filtration, thermally treated feed and bedding, or repeated costly testing to find carriers, and may still fail
Standing note. NOT a bat-type case. Feral swine are established across the US and competent Ornithodoros ticks occur here, so the reservoir does follow the virus. L4 stands.
Basis. ch24 24.9: "Certain characteristics of ASFV are favorable for preventing both the entry of the virus into piggeries and its further spread... FIRST, UNDER NORMAL CIRCUMSTANCES, THE VIRUS SPREADS SLOWLY. SECOND, THE VIRUS IS ONLY AIRBORNE OVER SHORT DISTANCES IN A CONFINED SPACE -- THERE IS NO CONVINCING EVIDENCE FOR AIRBORNE SPREAD OUTDOORS. THIRD, owing to the lipid envelope, ASFV IS SENSITIVE TO HEAT, SUNLIGHT, AND DESICCATION AND IS DESTROYED BY A WIDE RANGE OF READILY AVAILABLE DISINFECTANTS... CONFINING PIGS, RESTRICTING ACCESS TO THE PIGS, ENSURING SAFE FEED, AND IMPLEMENTING MEASURES TO PREVENT INFECTION VIA CONTAMINATED OBJECTS, SUCH AS FOOTWEAR AND EQUIPMENT, IS SUFFICIENT TO PREVENT THE INTRODUCTION OF ASFV." Against that, 24.3 on the routes: in the dominant domestic pig cycle "the virus is transmitted between domestic pigs through contact between animals, through INGESTION OF INFECTED PORK or other contaminated materials, or through INDIRECT CONTACT WITH FOMITES SUCH AS CLOTHING, TRANSPORT VEHICLES, OR FEED SUPPLIES", with Ornithodoros ticks as biological vectors in two other cycles and stable flies shown experimentally to transmit mechanically. 24.9: "when susceptible wild pigs, especially Eurasian wild boar, are involved, CONTROL IS CHALLENGING, as these animals are efficient transmitters."
How this level was decided
Level 4, and it is the worked example at this level. THE CHAPTER ARGUES THE OTHER WAY AND THE LEVEL STILL HOLDS, which is worth saying plainly because the quotation above is the strongest counter-evidence any C3 cell in the register carries: the authors say confinement, restricted access, safe feed and fomite control are SUFFICIENT to prevent introduction. What puts it at level 4 is the feed pathway -- ingestion of infected pork and contaminated feed supplies is a named route, and excluding it means thermally treated feed and ingredient sourcing, which is a level 4 measure by enumeration, not by adjective. THE FRAMEWORK GIVES SOMETHING UP HERE AND YOU ACCEPTED IT KNOWINGLY on 2026-09-03: ASF and PRRSV now score the same on C3, and the permanence of a feral reservoir -- "once ASF is in feral pigs, it is there forever" -- has no home in any of the eight criteria. It shows up instead as consequence, in C5 and C6, and PAPRIKA adds the criteria so a second home would double it invisibly.
C4 Detection difficulty
Difficulty of recognizing and confirming infection
Reference or research laboratory required: A validated assay exists, but only at a national reference or research laboratory rather than at local or regional level
Basis. ch24 24.7: "RELIABLE TOOLS FOR THE DIRECT (DETECTION OF VIRUS) AND INDIRECT (DETECTION OF ANTIBODIES) DIAGNOSIS OF ASFV INFECTION ARE AVAILABLE for use with the appropriate samples from both domestic pigs and wild boar... The current ASF pandemic has led to improved diagnostics and brought NEW COMMERCIAL ELISAS, qPCR KITS, AND POINT-OF-CARE TESTS to the international market. MOST TESTS PROBABLY HAVE ADEQUATE PERFORMANCE, BUT PUBLISHED COMPARISONS ARE NOT ALWAYS AVAILABLE; IN WHICH CASE ADVICE SHOULD BE SOUGHT FROM ASF REFERENCE LABORATORIES." On the governing framework: "DUE TO INTERNATIONAL REPORTING OBLIGATIONS, LABORATORY DIAGNOSIS IS GUIDED BY RECOMMENDATIONS AND LEGAL STANDARDS. Detailed methods and procedures are available in the WOAH Manual... and through the EUROPEAN UNION REFERENCE LABORATORY FOR ASF." On the clinical picture, 24.5: the acute form is fever, lethargy, pigs lying in piles, hind limb paresis and red-blue skin discolouration -- and "IMPORTANTLY, NOT ALL ANIMALS REACH THE FINAL STAGE. That is, ANIMALS OFTEN DIE WITHOUT HEMORRHAGING or other ASFV-associated signs."
How this level was decided
Level 3, the worked example at this level, alongside classical swine fever and foot-and-mouth disease -- and the reason is the same for all three. A validated assay plainly exists and is good; WHERE IT MAY BE RUN IS THE POINT. Diagnosis is bound by international reporting obligations and legal standards, confirmation runs through designated reference laboratories, and the chapter tells the reader to seek reference-laboratory advice on test performance. That is the level 3 label. NOT LEVEL 2, even though commercial qPCR and point-of-care tests now exist: a regional laboratory may screen, but it does not confirm a foreign animal disease. NOTE THE CLINICAL TRAP FOR ANY BRIEF: the haemorrhagic signs everyone associates with ASF are often absent, and pigs die looking only febrile and dull.
C5 Production cost
Financial impact on the infected farm's cost of production
Substantial: Severe losses cause a major and potentially unsustainable increase in cost of production
Basis. ch24 24.5: "THE ACUTE FORM described above IS ASSOCIATED WITH A CASE FATALITY RATE OF WELL OVER 90% (even higher under experimental conditions). PERACUTE COURSES can also be seen, leading directly to death without the final stage (the animals die 4-5 days post infection)... Pregnant sows may abort at any stage of pregnancy." Naturally attenuated strains give "a fatality rate between 10 and 60%". 24.9 on what happens to the survivors: "CONVENTIONAL CONTROL MEASURES CONSIST OF QUARANTINE, MOVEMENT BANS, AND CULLING OF ALL PIGS ON INFECTED PREMISES (AND SOMETIMES ON ALL PREMISES IN A DEFINED RADIUS), with compensation for healthy pigs culled." 24.1.2 records the wider consequence: "serious social and economic impacts on the trade of swine, pig by-products, and FOOD SECURITY."
How this level was decided
Level 4, and it is the worked example at this level -- the entry the level was written around, and until this evening the only one in the register. A case fatality rate well over 90% in the acute form is a major and potentially unsustainable increase in cost of production by any reading. NOTE THAT THE CULLING IS NOT WHAT SCORES IT, and the distinction matters because it is the rule you accepted on swine vesicular disease: C5 scores the disease, and stamping out is a regulatory response to trade status scored at C6. ASF reaches level 4 on the virus alone, before any regulator arrives. STREPTOCOCCUS ZOOEPIDEMICUS NOW SITS BESIDE IT HERE at 50-90% mortality, which you ratified this evening.
C6 Market impact
Duration of material disruption to pork and pig markets
Prolonged disruption: Material negative effect on supply or demand lasting more than 6 months when disease occurs on one or more farms
Basis. ch24 24.1.2: the disease "has SERIOUS SOCIAL AND ECONOMIC IMPACTS ON THE TRADE OF SWINE, PIG BY-PRODUCTS, AND FOOD SECURITY, particularly in countries in which pigs are an important source of protein." 24.9: "Conventional control measures consist of QUARANTINE, MOVEMENT BANS, AND CULLING OF ALL PIGS ON INFECTED PREMISES (and sometimes on all premises in a defined radius)... These measures are only feasible for well-resourced countries and ARE CONSIDERED NECESSARY TO ENABLE INTERNATIONAL TRADE TO RESUME AS SOON AS POSSIBLE." 24.3 records that human activity drives long-distance translocation and that the epidemiology is "STRONGLY LINKED TO THE PROPERTIES OF THE LOCAL/REGIONAL PIG VALUE CHAIN."
How this level was decided
Level 4, the worked example at this level alongside foot-and-mouth disease. Material disruption lasting more than six months is not a projection here: the chapter frames the entire control programme as existing to get international trade RESUMED, which is a statement that trade stops. THE STANDING NOTE SCORING/market_impact NAMES THIS AS A SCOREABLE CASE rather than a null: "where a foreign precedent exists, use it -- African swine fever, classical swine fever and the 1998 Nipah cull of 1.1 million Malaysian pigs are all scoreable on it." There is no shortage of precedent; ASF has closed borders on three continents in the last decade.
C7 Treatment potential
Potential for treatment to improve outcomes
Little: Effective pathogen-directed treatment is available and works, or animals recover acceptably without it
Basis. No treatment for ASF is described anywhere in ch24. 24.9 gives the alternatives in full -- biosecurity, quarantine, movement bans, culling of all pigs on infected premises, and modified culling -- and 24.8 records what happens without intervention: "ANIMALS THAT SURVIVE ASFV INFECTION COMPLETELY CLEAR THE VIRUS AND DEVELOP IMMUNITY AGAINST CHALLENGE with similar strains and even against heterologous viruses in some cases." The acute form kills over 90% within about a week; a modified culling model showed that with early detection "IMPLEMENTING BIOSECURITY MEASURES COULD PREVENT VIRUS SPREAD AND SAVE UP TO 74% OF THE PIGS FROM DYING."
How this level was decided
Level 1, and it is scored on the same reasoning you gave for swine vesicular disease rather than on the absence of a product -- which your 2026-09-02 rule forbids. THE OBJECTIVE IS ERADICATION, NOT RECOVERY. An infected US herd is culled, so a pig that could be treated is killed regardless, and the intervention that saves pigs in the chapter's own model is biosecurity that prevents spread, not therapy. Level 3 would say outcomes would meaningfully improve if a treatment existed, and in a stamping-out response they would not: a treated survivor is still destroyed. NOTE THAT THIS CELL IS THE ONE PLACE ASF SCORES AT THE BOTTOM, which will look wrong in a table beside its C5 and C6 fours until the reason is read.
C8 Vaccine availability
Availability of effective vaccines or bacterins
Needed but not available: No effective vaccine is available in the US or has been developed, and the disease would justify vaccinating if one existed
Basis. ch24 24.9.1: "The lack of clear correlates of protection, the limited neutralizing capability of antibodies, and the complex nature of the virus all contribute to the NOTABLE CHALLENGE OF DEVELOPING EFFECTIVE VACCINES. Research efforts over many years have led to promising progress..., BUT COMMERCIALLY AVAILABLE VACCINES ARE STILL NOT WIDELY ACCESSIBLE AND PROBLEMS HAVE BEEN REPORTED AFTER THE USE OF THE CURRENT VACCINES IN THE FIELD, E.G. IN VIETNAM. Despite undergoing various testing conditions, INACTIVATED FORMULATIONS HAVE NOT BEEN SUCCESSFUL in providing immunity against disease and mortality... CONVINCING CANDIDATES FOR VECTORED OR SUBUNIT VACCINES ARE STILL LACKING." On the live candidates: several deletion mutants give "full or near-complete protection against challenge infections IN EXPERIMENTAL SETTINGS", with "AT LEAST TWO ALREADY LICENSED FOR THE VIETNAMESE MARKET", but "previous incidents involving the improper use of potentially illegal vaccines emphasize the need for caution."
How this level was decided
Level 3, the worked example at this level. Both halves hold without strain. No effective vaccine is available in the US -- none is licensed here, inactivated formulations failed outright, subunit and vectored candidates are still lacking, and the two products licensed in Vietnam have generated field problems. And the disease could not warrant one more clearly: over 90% case fatality, trade closure, and a control programme that consists of killing healthy pigs. THIS IS THE OPPOSITE OF THE "NOT NEEDED" CLAUSE and the clearest genuine gap in the register.
Levels and evidence are generated from data/assignments/african_swine_fever.yml; the overview is authored in data/overviews/african_swine_fever.md. Do not hand-edit this page — corrections go in data/assignments/CORRECTIONS.yml.
Quoted material marked Basis is from Zimmerman JJ, Karriker LA, Ramirez A, Schwartz KJ, Stevenson GW, Zhang J, eds. Diseases of Swine, 12th edition. Hoboken: Wiley Blackwell, 2025 — except where another source is named in the quotation itself.