Foot & mouth disease

AHVLA investigates all incidents of suspected notifiable disease. If you suspect signs of a notifiable disease, you must immediately notify your local AHVLA Field Services.

What is foot and mouth disease?

Foot and mouth disease (FMD) is caused by aphthovirus an acute infectious disease affecting cloven-hoofed animals, in particular cattle, sheep, pigs, goats and deer. It causes fever followed by the development of vesicles (blisters); chiefly in the mouth and on the feet. It is highly infectious and spreads rapidly if uncontrolled. In addition to farm stock, elephants, hedgehogs, rats and any wild cloven-footed animals can also contract FMD.

FMD is endemic in parts of Asia, Africa, the Middle East and South America, with sporadic outbreaks in disease-free areas.

How to recognise the disease

What to look for

The interval between exposure to infection and the appearance of symptoms varies between twenty-four hours and ten days, or even longer, but on average is three to six days.


  • In the early stage, a rise in temperature is noticed and the animal is dull, blowing slightly and off its food.
  • A cow in milk will show a sudden drop in yield.
  • Blisters begin to develop, usually within a few hours, most frequently on the upper surface of the tongue and the bulbs of the heels.
  • Feeding and cudding may cease and the animal is ‘tucked up’ with staring coat.
  • If at pasture, the animal will be away from the rest of the herd, and probably lying down.
  • There is quivering of the lips and uneasy movement of the lower jaw, with copius, frothy saliva around the lips that drips to the ground at intervals a smacking sound is produced by partial opening of the mouth.
  • Evidence of pain in the feet, such as the animal lying down constantly and, when forced to move, walking very tenderly, occasionally shaking a leg as if to dislodge some object wedged between the clays.
  • Loss of condition is marked, partly on account of the fever and partly because the mouth is so painful that the animal is afraid to eat.
  • Cows and heifers may develop blisters on the teats and resent any attempt at milking.
  • If the mouth is examined in the early stages, blisters on the dental pad, inside the lips, and sometimes on the muzzle, will be found, as well as those on the upper surface of the tongue.
  • At first the blisters are seen as small raised areas, whitish in colour and containing fluid: they quickly increase in size until they may be as big as half a walnut.
  • Two or more blisters may join to form a larger one, sometimes covering half the surface of the tongue. Later, the blisters burst and collapse, leaving the ‘skin’ loose and wrinkled, with a dead appearance. On handling, the ‘skin’ is easily removed, leaving a raw surface underneath. When the blisters have burst the temperature falls, pain decreases and the animal may start to eat again.
  • Blisters develop on the feet about the same time as in the mouth, or a little later; they rarely appear first. Most commonly they occur at the bulbs of the heels, at the front of the cleft of the hoof, and in the cleft itself. They usually burst fairly quickly through movement of the feet, and then appear as a ragged tear exposing a raw surface.

See Defra website for photographs of the clinical signs of FMD in cattle


  • The chief symptom is a sudden, severe lameness, affecting one or more legs.
  • The animal looks sick, lies down frequently and is very unwilling to rise.
  • Usually, the disease affects all four feet, and when the animal is made to rise, it stands in a half-crouching position, with the hind legs brought well forward, and seems afraid to move.
  • Mouth symptoms are not often noticeable. There are blisters on the feet at the top of the hoof, where the horn joins the skin in the cleft of the foot. They may extend all round the coronet, and when they burst the horn is separated from the tissues underneath, and the hair round the hoof is damp. Unless complicated by foot rot, the foot is clean and there is no offensive smell.
  • Blisters in the mouth, when they do develop, form on the dental pad and sometimes the tongue.

Special care is necessary with sheep where lameness is often the only symptom. Keepers of sheep should always be suspicious when one or more sheep become lame suddenly and the lameness starts to spread through the flock.

See Defra website for photographs of the clinical signs of FMD in sheep


  • The chief symptom in pigs is sudden lameness. The animal prefers to lie down and when made to move squeals loudly and hobbles painfully, though lameness may not be so obvious where the pigs are on deep bedding or soft ground.
  • The blisters form on the upper edge of the hoof, where the skin and horn meet, and on the heels and in the cleft. They may extend right round the hoof head, with the result that the horn becomes detached.
  • At a later stage new horn starts to grow and the old hoof is carried down and finally shed. The process resembles the loss of a fingernail following some blow or other injury.
  • Mouth symptoms are not usually visible, but blisters may develop on the snout or on the tongue.

Swine vesicular disease has identical symptoms to FMD. Therefore anyone who suspects vesicular disease in pigs must report the sighting and treat the condition as suspected FMD until laboratory tests prove otherwise.

Special care is necessary with pigs where lameness is often the only symptom. It must be remembered that pigs will ‘go off their legs’ for various reasons, and that foot-and-mouth disease is one of them. Keepers of livestock should always be suspicious when one or more pigs become lame suddenly and the lameness starts to spread through the herd.

See Defra website for photographs of the clinical signs of FMD in pigs.

Reducing the risk of disease

Defra information leaflet: Biosecurity – preventing the introduction and the spread of foot and mouth (PDFkb)

See our web page on biosecurity for advice on how to help prevention of disease.


Routine, preventative vaccination is banned under EU law, thus allowing the EU to maintain the highest FMD status under international trade rules of “countries free from foot-and-mouth disease without vaccination”.

For further information on Defra’s vaccination policy, see the Defra leaflet Vaccination as a control tool for exotic animal disease (PDF).

Reducing the impact of disease

Actions to take if you suspect FMD is present in animals

The success of disease control measures is dependent on the prompt reporting of all suspected cases of disease. Delay allows the disease to get a start that is very difficult to overtake.

Stock owners should therefore be constantly on the watch for any suspicious symptoms among their animals, even when the country is free from outbreaks of the disease.

If you suspect FMD report this to your local AHVLA office. AHVLA staff are available at all times, and no one should be tempted to wait and see if there is any change in the animal’s condition before calling AHVLA.

Lessing the risk of disease spread

Before an AHVLA vet arrives there are steps that keepers can take at once to lessen the risk of spreading the disease:

  • Isolate animals suspected of having FMD
  • Ensure that no one who has been in contact these animals is allowed to go among other stock.
  • If the suspected animal is in an outlying pasture and has been there for some days, it is better to leave it where it is, provided the fences are sound.
  • A suspected animal must not be moved on or across a public road.
  • No animals, vehicles, foodstuffs, milk etc., must be moved from the suspected premises and, if possible, no person should leave.
  • Anyone leaving for some essential purpose must first thoroughly cleanse and disinfect his boots, wash his hands and if practicable, change his clothing before leaving the premises. Special care should be taken to see that boots are really clean, and that no dirt or dung is left on the under-surface or in the grooves on the soles of rubber boots. Any disinfectant which indicates on the container label that it is approved for use against foot-and-mouth disease, or a solution of washing soda in hot water – one heaped double handful of soda in a two-gallon (nine litre) bucket of water – can be used.
  • Dogs, cats, and poultry must be shut in or tied up.
  • A notice with the words FOOT AND MOUTH DISEASE – KEEP OUT must be displayed at the main entrances.
  • Nobody must be allowed to enter the premises, neither should vehicles (for example milk tankers, milk lorries, cattle floats, and lorries with feeding stuffs) be allowed to enter. If there is no main gate that can be shut, a rope or chain could be strung across the entrance.

Confirmation of disease: Infected Areas

A Protection Zone will be imposed with a minimum radius of 3km around the Infected Premises and a Surveillance Zone with a minimum radius of 10km.

In the Protection Zone no animal movements will be allowed except for movement to emergency slaughter.

In both the Protection and Surveillance Zones, there will be requirements for increased levels of biosecurity on farms, cleansing and disinfection (C&D) of vehicles, people and machinery moving on/off farms. Movement of animals, animal products, feed and bedding will be prohibited, except under licence.

In exceptional circumstances restrictions have to be imposed over a much wider area.

Footpaths will only be closed on Infected Premises and within the 3km Protection Zone.

Animal products

Products from animals in these zones will be subject to treatment to ensure destruction of the FMD virus. Such treatments include the pasteurisation of milk (normal process for most milk produced in the UK), heat treatment or de-boning and maturation of meat in certain circumstances.

Slaughterhouses and knacker’s yards

No carcass or animal product (other than a carcass intended for human consumption) or manure, slurry or litter may be moved from a slaughterhouse or knacker’s yard unless authorises through a licence from AHVLA.

Artificial insemination

All Artificial Insemination services, including the servicing of farm storage flasks, within a restricted area must be immediately suspended and not resumed until appropriate licences allowing this are issued. These licences may impose particular conditions on the inseminators or semen delivery personnel, or limit the areas in which they may work. Inseminators’ field flasks which have been used on farms in the infected area may be placed under restrictions.

Under certain circumstances the Farm Gate Artificial Insemination Service will be permitted. This means that special insemination kits can be delivered to the farm gate on the condition that the semen must only be used by the owner or his full time employee and must not taken off the farm. Semen already on the farm in farm storage flasks may continue to be used by the licensee, but not by a visiting inseminator or veterinary surgeon.

Cull of livestock infected, or suspected of being infected, with FMD

As a disease control measure, all infected livestock, together with other animals which have been exposed to risk of infection such that it is reasonably probable that they would develop the disease if left alive, will be culled.


Export health certificates for animals and animal products will be withdrawn. Exports from Great Britain of susceptible animals during the risk period will be identified and notified to the importing countries.

Further information

Page last modified: 13 December 2012