Definition and epidemiology
Foot-and-mouth disease (FMD) is a severe, highly contagious vesicular disease of cloven-hoofed animals caused by Aphthovirus, a genus within the Picornaviridae family. It is one of the most economically important livestock diseases worldwide and is endemic in parts of Africa, the Middle East, Asia, and South America, with many countries (including the US, Canada, and most of Western Europe) currently FMD-free.
Human infection is extremely rare and almost always occurs through direct contact with infected animals, their secretions, or contaminated animal products (milk, meat). It is not a food safety concern after normal cooking or pasteurization. Occupational groups at risk include farmers, veterinarians, abattoir workers, and livestock handlers in endemic areas. There is no significant human-to-human transmission.
Important distinction
FMD must not be confused with hand-foot-and-mouth disease (HFMD), a common pediatric exanthem caused by coxsackievirus A16 or enterovirus 71. HFMD is far more frequently tested on exams and is a completely different disease with a different virus family, host, and epidemiology.
- FMD is caused by Aphthovirus (Picornaviridae), not the same virus family as human HFMD
- Human infection is extremely rare, mild, and self-limited; it is primarily a disease of cattle, pigs, sheep, and goats
- Transmission to humans requires direct contact with infected animals or their products, not person-to-person spread
- Classic exam trap: FMD (animal, Aphthovirus) vs HFMD (children, coxsackievirus A16/enterovirus 71) — do not confuse them
- Diagnosis in confirmed/suspected cases uses RT-PCR, virus isolation, and ELISA; management is supportive only
- Animal FMD outbreaks are controlled by culling, movement restriction, and serotype-specific vaccination, coordinated by WOAH
- No cross-protection exists between the seven FMDV serotypes (O, A, C, Asia-1, SAT-1/2/3)
- Reporting any suspected case (animal or human) is mandatory in FMD-free countries due to trade and agricultural impact
Etiology and risk factors
- Causative agent: Aphthovirus (foot-and-mouth disease virus, FMDV), a non-enveloped, single-stranded RNA picornavirus
- Seven immunologically distinct serotypes (O, A, C, Asia-1, SAT-1, SAT-2, SAT-3) with no cross-protection between them
- Reservoir/host: cattle, pigs, sheep, goats, and other cloven-hoofed animals
- Transmission to humans: direct contact with infected animals, their saliva, vesicle fluid, or unpasteurized milk; occupational exposure (farming, veterinary work, meat processing)
- Risk factors: living or working in endemic livestock regions, lack of protective equipment during animal handling, outbreak settings with high viral load in the environment
Pathophysiology
FMDV infects epithelial cells, causing vesicle formation through cytolytic replication. In animals, the virus has strong tropism for the epithelium of the mouth, feet (coronary band, interdigital space), and mammary gland, producing characteristic vesicles and erosions.
In the rare human case, the virus is thought to enter through breaks in skin or mucous membranes after direct exposure, with a short incubation period (typically 2 to 6 days). Viral replication in oral and sometimes acral (hands, feet) epithelium produces small vesicles that rupture into shallow erosions. The human immune response typically clears the infection quickly, and the disease is self-limited without the systemic complications seen in affected livestock.
Clinical features
Human FMD is typically mild and short-lived:
- Low-grade fever and malaise
- Small vesicles or blisters on the lips, tongue, buccal mucosa, and occasionally the hands and feet
- Vesicles rupture to form shallow, painful ulcers
- Regional lymphadenopathy may occur
- Symptoms generally resolve within one to two weeks without scarring
There is no chronic carrier state in humans, and secondary bacterial infection of ulcers is uncommon. Severe or fatal human disease has not been convincingly documented in modern case reports.
Diagnosis
Diagnosis is largely clinical, supported by a history of direct animal contact in an outbreak or endemic setting.
Confirmatory testing (reference laboratory level)
- RT-PCR for FMDV RNA from vesicle fluid or epithelial tissue
- Virus isolation in cell culture
- ELISA for FMDV antigen or antibody (acute and convalescent serology)
- Serotyping is performed for epidemiologic tracing and outbreak control, not for individual patient management
Any suspected human or animal FMD case in a non-endemic country triggers mandatory reporting to animal health authorities, since livestock outbreaks have major trade and economic implications.
Note on coding: ICD-10 has no dedicated code for human FMD. It is typically captured under the nonspecific code B08.8 ('Other specified viral infections characterized by skin and mucous membrane lesions'), which is shared with several unrelated viral exanthems and is not FMD-specific.
Differential diagnosis
| Condition | Key distinguishing feature |
|---|---|
| Hand-foot-and-mouth disease (coxsackievirus/enterovirus) | Common in children, no animal exposure needed, classic oral + palm/sole lesions |
| Herpes simplex (herpetic gingivostomatitis) | Grouped vesicles, recurrent, HSV PCR/culture positive |
| Aphthous stomatitis (canker sores) | Recurrent, no systemic prodrome, no animal exposure |
| Herpangina | Posterior oropharynx vesicles, coxsackievirus, pediatric |
| Pemphigus/pemphigoid | Chronic, autoimmune, Nikolsky sign, biopsy with immunofluorescence |
| Erythema multiforme | Target lesions, drug or HSV trigger, not linked to animal contact |
The single most important differential point for exams: distinguishing true zoonotic FMD (animal contact history, Aphthovirus) from HFMD (pediatric, coxsackievirus/enterovirus, no animal contact required).
Management
In humans
- Supportive care only: analgesics, hydration, oral hygiene, and soft diet
- No antiviral therapy is approved or needed; the disease is self-limited
- Isolation of the patient is not required since human-to-human transmission is not a significant concern, but reporting to public health/animal health authorities is mandatory given the implications for livestock
In animals (context students should recognize)
- No treatment; management is through control and eradication: culling of infected and in-contact animals, movement restrictions, disinfection, and ring vaccination in some countries
- Inactivated vaccines exist and are serotype-specific; used in endemic regions and sometimes in outbreak control, though many FMD-free countries rely on a non-vaccination, stamping-out policy to preserve trade status
- WHO, WOAH (World Organisation for Animal Health, formerly OIE), and national veterinary authorities coordinate surveillance and outbreak response
Complications and prognosis
Human disease is almost always mild and self-resolving within one to two weeks, with full recovery and no long-term sequelae reported in confirmed cases. Secondary bacterial infection of oral ulcers is a rare complication.
The greater burden of FMD is agricultural and economic rather than medical: outbreaks in livestock cause significant production losses, trade restrictions, and large-scale culling programs, which is why rapid veterinary reporting and containment are prioritized over any direct human health concern.
Think "COW" for FMD: Cloven-hoofed hosts, Occupational animal contact, Weeks-long self-limited course in humans — vs HFMD, which is a Child's illness from Coxsackievirus with no animal link.
Practice questions
1. A 34-year-old cattle farmer in a region with an active livestock disease outbreak presents with low-grade fever and several small painful vesicles on his buccal mucosa and tongue that appeared three days after helping deliver a calf from a visibly ill cow. He has no contact with young children. Which of the following best describes the expected clinical course?
2. A veterinarian investigating a suspected foot-and-mouth disease outbreak on a pig farm wants to confirm the diagnosis and determine the viral serotype for epidemiologic tracing. Which test is most appropriate for both detecting the virus and determining its serotype?
3. A 6-year-old child develops fever, oral vesicles, and a vesicular rash on the palms and soles after attending daycare, where several classmates have similar symptoms. A medical student mistakenly tells the parents this is foot-and-mouth disease transmitted from a nearby petting zoo visit. Which statement best corrects this assumption?
Frequently asked questions
What causes foot-and-mouth disease?
Foot-and-mouth disease is caused by Aphthovirus, an RNA virus in the Picornaviridae family, which primarily infects cloven-hoofed livestock like cattle, pigs, sheep, and goats. Human infection is a rare zoonosis that occurs through direct contact with infected animals or their secretions, not from eating cooked meat or pasteurized dairy.
What are the first symptoms of foot-and-mouth disease in humans?
The first symptoms are usually mild fever and malaise, followed within a day or two by small painful vesicles on the lips, tongue, or inside the mouth, and occasionally on the hands and feet. Symptoms typically appear two to six days after direct contact with an infected animal and resolve on their own within one to two weeks.
How is foot-and-mouth disease diagnosed?
Diagnosis is based on a history of direct animal contact plus characteristic oral or acral vesicles, confirmed when needed by RT-PCR, virus isolation, or ELISA testing on vesicle fluid or blood samples. Confirmatory testing is usually done through veterinary or public health reference laboratories because of outbreak reporting requirements.
Is foot-and-mouth disease curable?
Yes, human foot-and-mouth disease is self-limited and resolves completely with supportive care alone, usually within one to two weeks, since no antiviral treatment exists or is needed. There is no chronic infection or carrier state in humans; the ongoing medical concern after an outbreak is almost entirely about livestock, not people.
Foot-and-mouth disease vs hand-foot-and-mouth disease — what is the difference?
Foot-and-mouth disease (FMD) is caused by Aphthovirus and mainly affects livestock, with human cases being rare and linked to direct animal contact. Hand-foot-and-mouth disease (HFMD) is caused by coxsackievirus A16 or enterovirus 71, is common in young children, spreads person-to-person, and has no connection to animal exposure.
Related conditions and differentials
Sources and further reading
StatPearls (NCBI Bookshelf)MedlinePlusWHO ICD-10: B08.8
Educational content for medical students, prepared by the WhiteCoat Pro editorial team with AI assistance; every page is reviewed by a second AI model for factual errors. It is not medical advice and does not replace the product label, local guidelines or a clinician.