You vaccinated your cattle in the spring, and in the autumn they start drooling, going lame, and showing blisters on the tongue and feet. The first thought is that the vaccine was “fake” or spoiled. That is sometimes true, but in our region today there is another, very real explanation that is simpler and more serious: the virus that infected the herd belongs to a serotype that was never in the vaccine.
Seven serotypes, and each needs its own vaccine
The World Organisation for Animal Health (WOAH) states that the foot-and-mouth disease virus comes in seven serotypes — A, O, C, SAT1, SAT2, SAT3 and Asia1 — and that each serotype requires its own vaccine to give a vaccinated animal immunity. The UK Department for Environment, Food and Rural Affairs (Defra) explains that immunity from infection or from vaccination is serotype-specific and does not protect against the other serotypes. In other words, a cow well protected against serotype O remains fully exposed to serotype SAT1.
Matching the serotype alone is not enough. According to WOAH, the strain or strains in the vaccine must antigenically match those circulating in the field, and the Center for Food Security and Public Health at Iowa State University (CFSPH) notes that protection against other strains within the same serotype varies with how similar they are. So a good vaccine can “fail” simply because it was made for a different strain from the one that arrived.
What is new in our region?
According to Defra, the serotypes circulating in the Near East and West Eurasia were mainly O, A and Asia1; then SAT2 entered in 2022–2023, affecting Bahrain, Jordan, Iraq, Oman and Türkiye with viruses originating in East Africa. SAT1, for its part, had not circulated widely in the region since 1962, when it appeared in countries including Syria, Iraq, Jordan, Lebanon and Türkiye. This means most of our present herds have never met this serotype and have no immunity against it.
Then the picture changed quickly. According to a WOAH article from August 2026, Iraq, Kuwait, Egypt and Azerbaijan reported SAT1 as a “first occurrence” in 2025; Israel, Cyprus, Palestine, China and Mongolia reported it for the first time in 2026; and after sixty years it was reported again in Türkiye, Lebanon and Greece between 2025 and 2026. The Food and Agriculture Organization (FAO) had warned in May 2025 that this serotype is exotic to the Near East and West Eurasia, and Defra’s assessment cites FAO as saying that until livestock are immunised with a suitable SAT1 vaccine, only rapid and effective biosecurity can limit its spread.
The question to ask your vet
Do not ask “did I vaccinate against foot-and-mouth?” but “against which serotypes did I vaccinate?”. Read the vaccine leaflet, and ask the official veterinary services which serotype is circulating in your area now, and whether the available vaccine covers it.
How to recognise it in the herd
Foot-and-mouth disease affects cattle, buffalo, sheep, goats, pigs and other cloven-hoofed animals. The incubation period — the time between infection and the appearance of signs — is 2 to 14 days according to WOAH, which describes the following signs:
- Blisters (vesicles) on the nose, tongue and lips, inside the mouth, between the claws and above the hooves, and on the teats.
- Fever, dullness, heavy drooling, loss of appetite and weight loss.
- Severe lameness and reluctance to move or eat once the blisters burst.
- A drop in milk yield; WOAH notes that chronically affected animals are reported to lose about 80% of their overall yield.
The disease rarely kills adult animals, where mortality is generally 1 to 5%, but it is harder on young calves, lambs and piglets, where mortality can reach 20% or more, according to WOAH. WOAH warns that an animal may die before any blister appears, because of inflammation of the heart muscle (myocarditis).
In sheep and goats you may not see the blisters
According to CFSPH, the disease in sheep and goats is often mild: the signs may be limited to fever and lameness in one or more legs, foot lesions can be missed, and any mouth lesions usually appear as shallow erosions. Ewes may abort or give birth to stillborn lambs. So do not wait for obvious blisters in a small-ruminant flock: sudden lameness in several animals at once is reason enough to call the vet.
Most important for understanding how fast it spreads: the virus is present in all excretions and secretions of an infected animal, is breathed out in large amounts, and can be in milk and semen for up to 4 days before signs appear. Some recovered animals can remain carriers and start new outbreaks. And because foot-and-mouth disease cannot be told apart by eye from other vesicular diseases, WOAH stresses that laboratory confirmation of any suspected case is urgent.
No drug for the virus: what does “treatment” mean here?
CFSPH states that there is no specific treatment for foot-and-mouth disease other than supportive care. Supportive care as WOAH describes it is simple: keep sick animals in the shade on a dry surface, observe them regularly, and give them soft feed and clean water — the animal stops eating because its mouth hurts, not because it is full.
Antibiotics, for their part, do nothing to the virus itself. But burst blisters are open wounds that can pick up a secondary bacterial infection, as WOAH notes, and it is the vet who decides — after examination — whether an animal needs an antibiotic and which one. Injecting the whole herd with an antibiotic “just in case” does not stop the outbreak; it adds residues to milk and meat and feeds resistance.
What to do when blisters appear
WOAH sums up the action plan for a suspected foot-and-mouth outbreak in steps any farmer can carry out, and we add what FAO recommends:
- Report the suspected case to the local veterinary services immediately; laboratory confirmation and tracing of the outbreak cannot happen without them.
- Separate sick animals from the rest of the herd with tethers, fences or a natural boundary, and have them examined by an animal health professional.
- Stop all animal movement and all shared grazing, and do not buy or sell any animal until the outbreak subsides.
- Do not share farm and shed equipment with your neighbours.
- Clean and disinfect all areas and contaminated material regularly: tools, vehicles and clothes. Among the disinfectants CFSPH lists as effective against the virus are sodium hydroxide, sodium carbonate, some acids such as citric acid, and sodium hypochlorite; the concentration and contact time are set by the product label and your vet.
- Handle and dispose of dead animals, their bedding, manure and contaminated products safely.
Watch the invisible routes too: WOAH lists milk, feed, hay, water, clothing, footwear, equipment and vehicles among the ways the virus is carried, and FAO advises preventing people, vehicles and potentially contaminated materials from moving from farm to farm. CFSPH notes that people who have handled infected animals may be asked to stay away from healthy animals for a period and to decontaminate their clothing. As for people themselves, the disease does not pass readily to humans and is not a public health risk, according to WOAH.
Prevention before it arrives
- Buy from reliable sources and avoid bringing in animals of unknown origin, as FAO recommends.
- Avoid mixing different consignments of animals during transport and at markets; FAO advises thoroughly cleaning and emptying markets, vehicles and transport hubs between sales, with rest days.
- Vaccinate within the official programme, with the vaccine the veterinary services specify for the circulating serotype. WOAH sets out the conditions for a successful campaign: coverage of at least 80% of the target animals, completion in the shortest possible time, scheduling that allows for interference from maternal immunity in young animals, the correct dose by the correct route, and an inactivated rather than live vaccine.
- Watch your herd daily and report any suspicion early; WOAH counts early detection and warning systems among the first steps in controlling the disease.
The vaccination decision is not yours alone
WOAH states that the decision to use vaccination against foot-and-mouth disease lies with national authorities, and FAO stresses that the vaccine must match the field strains and be given according to the manufacturer’s instructions. A vaccine bought on the market without knowing its serotype may give you false reassurance rather than immunity.
Antibiotics do not treat foot-and-mouth disease, and using them without need has a price the herd pays later. That article explains why.
Read: how resistance is made on the farm