Foot-and-mouth disease (FMD)
LEVELS: Highly unlikely; Mild; Extraordinary biosecurity required; Reference or research laboratory required; Substantial; Prolonged disruption; Little; Available, or not needed
| Register id | foot_and_mouth_disease |
| Type | virus |
| Scientific name | Foot-and-mouth disease virus |
| NCBI taxid | 12110 |
| Evidence | 3 document(s) |
| Assigned | 2026-09-06, against criteria version 093366e352a2 |
Overview
Foot-and-mouth disease is the most contagious disease of livestock known, affecting cattle, sheep, goats, pigs and wild cloven-hoofed animals. In pigs it causes fever and blisters on the snout, mouth, feet and teats; the animals go lame, refuse to eat, and lose condition. Mortality in adults is low — young piglets can die suddenly of heart damage — so the disease is not primarily a killer. Its significance is entirely a trade one, and it is total: a single confirmed case closes export markets, triggers movement standstills and stamping out, and the cost of an outbreak is measured in billions rather than in sick pigs. Pigs matter particularly because they amplify the virus, exhaling far more of it than ruminants do, so an infected pig unit can seed a wide area downwind. Seven serotypes are recognised and immunity to one does not protect against another, so vaccines must be matched to the circulating type; that is why all seven are scored here as a single unit, since they differ in geography and vaccine matching but not in the things these criteria measure. The United States has been free of the disease since 1929. Exclusion depends on import controls on animals and animal products and on the prohibition of feeding untreated food waste.
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. ch36 36.2.3: "FMDV is not zoonotic and therefore not a public health concern. Humans may, however, passively carry the virus in their respiratory tract for a day or more, although the role of virus on clothing, boots, etc., is more important in transmission between livestock." shic_2026_fmd: "FMD is not a public health risk."
How this level was decided
The chapter states it in the first clause. The one human involvement it describes is mechanical -- a person carrying virus in the airway or on boots between herds -- which is the human acting as a fomite, not becoming infected. Level 1. Level 1 confirmed by direct statement.
C2 Zoonotic impact
Severity of human illness caused by the agent
Mild: Human illness is usually mild and self-limiting, and serious disease occurs only rarely
INFERRED — reasoned, not stated. The evidence implies this level rather than stating it. The reasoning is below.
Corrected by Eric from L1 No human illness. Reason: MOVED L1 -> L2. "c2l2, L2 is correct based on the evidence (previous rating was based on old criteria which was imperfect)" -- answering the pass's flag that "does not cause illness in people" is very nearly but not exactly true of FMDV. Human FMD is documented, rare and trivial: a self-limiting vesicular illness. Usually mild and self-limiting with serious disease rare is the level 2 label. NOTE THAT THIS DOES NOT DISTURB THE EXAMPLES -- foot-and-mouth disease is a worked example at C1 level 1, not at C2 level 1.
Basis. ch36 36.2.3: "FMDV is not zoonotic and therefore not a public health concern." shic_2026_fmd: "FMD is not a public health risk."
How this level was decided
RE-SCORED 2026-09-04. C2 now grades the severity of the illness the agent causes in a person, independent of how the person was exposed -- the 2026-09-01 pig-attribution reading is reversed, and C1 alone carries the source question. FLAG. Human FMD infection is documented but exceedingly rare and trivial -- a self-limiting vesicular illness. Level 1 says the agent does not cause illness in people, which is very nearly but not exactly true. The folder does not address human FMD at all, so there is nothing here to score a level 2 on.
PREVIOUS ANSWER, written under the pig-attribution reading: C2 says to score level 1 whenever the agent does not cause disease in people. Level 2 held. The factsheet's flat denial of public health risk would support level 1, but the cell was set on the rare mild human vesicular illness that is documented, and a February 2026 statement aimed at producers is not a survey of the human literature.
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
CONFIRMED by Eric. The assignment reached this level from the evidence, and he has reviewed and ratified it.
Confirmed by Eric. CONFIRMED. "c3l3, while most fomite or animal based movements can be prevented with biosecurity, there is good evidence of long distance aerosol spread between farms from other parts of the world" [RENUMBERED level 3 to 4, from_level 3 to 4 on 2026-09-01 when C3 went from four levels to five. The words above are exactly as recorded and the decision is unchanged -- only the number beside it moved, because the scale did. C3 now runs on the EFFORT REQUIRED TO EXCLUDE: L1 already in the herd, L2 housing alone keeps it out, L3 routine biosecurity keeps it out, L4 extraordinary biosecurity required, L5 exclusion may not be achievable.]
Basis. ch36 36.2.10: "The most common methods by which FMDV spreads are (i) movement of infected animals, (ii) feeding contaminated animal products to susceptible livestock, and (iii) movement of virus on inanimate objects or mechanical vectors (humans and animals)... It should be borne in mind that virtually any surface or product can be contaminated with the virus. FMDV has a wide host range, a low infectious dose, a rapid rate of replication, a high level of viral excretion, and multiple modes of transmission." "control of FMDV is complicated by the existence of carrier ruminants." shic_2026_fmd: "Pigs generate a large quantity of infectious aerosols that can be inhaled by other animals or become windborne, travelling long distances." "FMDV can survive for months in the environment, particularly in cold temperatures." "Pigs can also acquire FMDV through ingestion of contaminated meat, meat byproducts, or uncooked garbage containing food waste."
How this level was decided
MOVED L3 -> L4 on 2026-09-01 by the five-level rework. FMD has not occurred in the US since 1929, so this is scored on what would happen if it were here: the source would be other pig herds and contaminated feed, and long-distance aerosol is the route nothing on a farm blocks. Routine quarantine and C&D do not stop windborne virus, so exclusion needs measures beyond the routine and may still fail. NOTE FOR ERIC: you confirmed this at L3 under the four-level ladder, where L3 meant "no housing system blocks the route". That is the same judgment the new L4 records. Renumbered, not revised. C3 now runs on the EFFORT REQUIRED TO EXCLUDE: L1 already in the herd, L2 housing alone keeps it out, L3 routine biosecurity keeps it out, L4 extraordinary biosecurity required, L5 exclusion may not be achievable. Level 4 confirmed and now thoroughly supported: windborne aerosol over long distances, months of environmental survival, and a feed-borne route through meat and garbage. Filtration and thermally treated feed are the level 4 list, and both are needed here.
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
CONFIRMED by Eric. The assignment reached this level from the evidence, and he has reviewed and ratified it.
Confirmed by Eric. CONFIRMED. "l3, may have indicative diagnosis at L2 lab but confirmation almost certainly would involve l3 lab" Transcribed by the assistant and confirmed by Eric on 2026-08-31 -- "i confirm the six". The harvester refused it because the comment names two levels, but the second is a noun phrase for a level-N-capable laboratory rather than a second assignment.
Basis. ch36 36.6.8, on the vesicular differential: "Laboratory testing is mandatory because the vesicular lesions caused by SVV are indistinguishable from those produced by FMDV, SVDV, VSV and VESV." 36.3.7.1: SVDV lesions "are indistinguishable from those induced by FMDV infection." 36.2.6.2: "Clinical disease is usually severe in pigs. Early signs include acute lameness, reluctance to stand, adoption of a dog-sitting posture, depression, loss of appetite, and fever." shic_2026_fmd: "FMD testing must be conducted at the National Veterinary Services Laboratories. Additional laboratories are approved to conduct testing in an outbreak situation." "FMD is clinically indistinguishable from other vesicular diseases, such as Senecavirus A."
How this level was decided
The clinical picture is dramatic and would be recognised at once as vesicular disease -- but that is a syndrome, not a diagnosis, and four other agents produce lesions the chapter calls indistinguishable. Which one it is cannot be settled on the farm or at a regional laboratory. In the US a suspected vesicular case is a foreign animal disease investigation confirmed at the national reference laboratory. Level 3. Level 3 confirmed in the factsheet's own words -- testing MUST be done at NVSL. A validated assay plainly exists, and the constraint is purely where it may be run, which is the level 3 axis exactly.
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. ch36 36.2.10: "In the absence of therapeutic treatments for FMDV, once the virus has been introduced into a swine farm, it is unlikely to disappear unless all animals, both infected and uninfected, are euthanized, the carcasses removed (buried, rendered, or incinerated), and the premises disinfected. Therefore, the response to the positive identification of FMDV is euthanasia of all susceptible animal species on infected farms." 36.2.6.2: "Clinical disease is usually severe in pigs." shic_2026_fmd: "severe foot lesions in the interdigital spaces and along pressure points, severe lameness, and reluctance to move." "Abortion may occur in pregnant sows. Myocarditis can lead to acute death in piglets." "In an outbreak situation, a combination of stamping-out and vaccination may be used."
How this level was decided
The infected farm loses every animal it holds, infected or not, plus the carcass disposal and disinfection. That is not an increase in the cost of production, it is the end of production on that unit until it restocks. Level 4, a major and potentially unsustainable increase, and one of the few entries in the register where the top level is unarguable. NOTE: the standing note SCORING/production_cost_impact does not soften this -- stamping out IS what modern US practice would do. Level 4 confirmed -- stamping out is the response, which is unsustainable loss for the affected herd by definition.
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
CONFIRMED by Eric. The assignment reached this level from the evidence, and he has reviewed and ratified it.
Confirmed by Eric. CONFIRMED. "c6l4, though response tools are avaialble, the markets domestically and internationally are very sensitive to a FMD diagnosis and it is unlikely in the US that only a single herd would be infected at the time of diagnosis. WOAH guidelines for reestablishment of whole country freedom are likely to mean the effect will be greater than 6 months"
Basis. ch36 36.2.1 records that FMD was last reported in the United States in 1929 and was eradicated by stamping out, and that eradication from the European Union took until 1970-1973 with prophylactic vaccination stopped only in 1991. 36.2.10: "Extreme measures are required to eradicate FMDV and, if they are not applied rapidly and effectively, there is a high probability that an outbreak will become an epidemic." shic_2026_fmd: "in endemic areas and during outbreaks, FMD causes production losses and impacts international trade."
How this level was decided
INFERRED -- the chapter is about the disease rather than the market, so the duration has to be reasoned. It is not a close call. FMD is the disease against which US export status is defined; a confirmed case closes export markets immediately and freedom has to be demonstrated over months before they reopen, with national movement standstills in the interim. Every historical precedent the chapter cites is measured in years, not months. Material disruption lasting more than six months is level 4. Level 4 confirmed by direct statement about international trade.
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. ch36 36.2.10: "Antiviral drugs could potentially be used to reduce FMDV replication and provide protection against infection during the period prior to the onset of vaccine-induced immunity... A small number of studies have been undertaken in pigs to demonstrate the effectiveness of certain compounds, but this approach is likely to be limited since meat will contain drug residues and will not be suitable for human consumption." FMD is named as a worked example at C7 level 1 in criteria_levels.yml. shic_2026_fmd: "There is no treatment for FMD virus (FMDV) infection other than supportive care." "In an outbreak situation, a combination of stamping-out and vaccination may be used to control the spread of FMDV."
How this level was decided
Level 1, matching the criteria file worked example, and the reasoning is the second clause rather than the first. There is no therapeutic treatment and the chapter explains why developing one is a dead end -- residues make treated meat unsaleable, which defeats the purpose in a food animal. But FMD in pigs is a severe, self-limiting vesicular disease that animals survive; what kills them is the control policy, not the virus. A treatment would not change the outcome, because the outcome is stamping out. Level 1 confirmed on the same route as Nipah: the response to an incursion is stamping out, so an infected pig is culled whether or not it could be treated. A treatment would not change the outcome that matters.
C8 Vaccine availability
Availability of effective vaccines or bacterins
Available, or not needed: Effective vaccines are widely available in the US or secured for national outbreak response, or the disease does not clinically or economically justify vaccinating
Basis. ch36 36.2.1: high-quality vaccines drove the eradication of FMD from the European Union, and vaccination and stamping out together eradicated it from Mexico. 36.2.10: "vaccination is an option on farms without infected animals." FMD is named as a worked example at C8 level 1 in criteria_levels.yml, secured through the National Animal Vaccine and Veterinary Countermeasures Bank. shic_2026_fmd: "a combination of stamping-out and vaccination may be used to control the spread of FMDV."
How this level was decided
Level 1 on the first clause, not the second -- effective vaccines exist and are secured for national outbreak response through the NAVVCB, which is exactly what the level 1 label describes. This is the contrast case to most of the register, where level 1 now means no vaccine is needed. Here one exists and is held. Level 1 confirmed. FMD vaccines exist and are a named part of the outbreak response -- the first of the two situations level 1 holds, a product that exists and works.
Levels and evidence are generated from data/assignments/foot_and_mouth_disease.yml; the overview is authored in data/overviews/foot_and_mouth_disease.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.