What Is Foot-and-Mouth Disease (FMD)?
Foot-and-Mouth Disease (FMD) is a severe, highly contagious viral disease that affects cloven-hoofed animals. Caused by the Foot-and-Mouth Disease Virus (FMDV) — a member of the Aphthovirus genus within the Picornaviridae family — it is considered one of the most economically devastating animal diseases in the world. While rarely fatal in adult animals, FMD causes significant suffering, production losses, and can trigger international trade bans.
The Virus: Biology and Serotypes
FMDV exists in seven distinct serotypes:
- O – The most widespread globally
- A – Common in Asia, Africa, and South America
- C – Rarely reported in recent decades
- SAT 1, SAT 2, SAT 3 – Primarily found in sub-Saharan Africa
- Asia 1 – Historically present in Asia and the Middle East
Crucially, immunity to one serotype does not protect against others, which makes vaccination programs complex and requires careful matching of vaccine strains to circulating viruses.
Which Animals Are Affected?
FMD affects all cloven-hoofed (biungulate) animals. The most commonly affected species include:
- Cattle and buffalo
- Pigs
- Sheep and goats
- Deer and other wild ruminants
- Camels (less commonly)
Horses are not susceptible to FMD. Humans can very rarely contract a mild form, but FMD is not considered a significant public health threat.
Key Symptoms to Watch For
Symptoms typically appear within 2–14 days of exposure. Early and accurate recognition is critical for containment. Common clinical signs include:
- Fever (often the first sign, appearing before blisters)
- Blisters (vesicles) on the tongue, lips, mouth, nostrils, and between the toes
- Excessive salivation and drooling
- Lameness — animals may be reluctant to walk or stand
- Reduced milk production in dairy cattle
- Loss of appetite and weight loss
- In pigs: pronounced lameness and foot lesions
- In young animals: sudden death due to myocarditis is possible
How Does FMD Spread?
FMD is exceptionally contagious. Transmission occurs through multiple pathways:
- Direct contact – Animal-to-animal contact is the most common route.
- Aerosol transmission – The virus can travel on the wind for several kilometres under suitable weather conditions, especially from pigs.
- Contaminated materials – Feed, water, vehicles, equipment, clothing, and footwear can all carry the virus.
- Animal products – Improperly treated meat, milk, and other products can harbor live virus.
- Wildlife – Certain wild animal populations can act as reservoirs, complicating control efforts.
FMD vs. Other Vesicular Diseases
Several other diseases produce similar blister-like lesions and can be confused with FMD. These include Swine Vesicular Disease, Vesicular Stomatitis, and Vesicular Exanthema of Swine. Laboratory confirmation is always required to definitively diagnose FMD. This is why rapid reporting and professional veterinary assessment are essential when vesicular disease is suspected.
Why FMD Matters So Much
Even in regions where FMD is endemic, the disease imposes enormous costs — reducing livestock productivity, limiting trade access to disease-free markets, and undermining food security for farming communities. Countries that achieve and maintain FMD-free status gain significant advantages in international livestock and product trade, making disease control a high-stakes national and global priority.