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Foot and mouth

Foot and mouth disease (FMD) is an infectious disease affecting cloven-hoofed animals, in particular cattle, sheep, pigs, goats and deer. Other ruminants including deer and some zoo animals, camelids (camels, llamas, alpacas, guanaco and vicuña) and elephants can also be affected.

The disease is notifiable: if you suspect the disease, you must immediately notify the duty vet in your local Animal Health Veterinary Laboratories Agency (AHVLA) office.

The disease is serious for animal health and for the economics of the livestock industry.

While Foot and Mouth is not normally fatal to adult animals, it is debilitating and causes significant loss of productivity; for example milk yields may drop or the animals may become lame. In young animals it can be fatal on a large scale.

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About the disease

FMD is an acute infectious disease which spreads very quickly if not controlled. It causes fever, followed by the development of blisters, chiefly in the mouth and feet of cloven-footed animals, such as cattle, sheep, pigs and deer.

The disease is caused by a virus of which there are seven ‘types’, each producing the same symptoms, and distinguishable only in the laboratory. The interval between exposure to infection and the appearance of symptoms varies between twenty-four hours and ten days, or even longer. The average time, under natural conditions, is three to six days.

After being free of the disease for many years, this country had an outbreak in 2001, resulting in the slaughter of many animals, and an outbreak in 2007.  The virus responsible for the 2001 outbreak was the highly virulent pan-Asiatic O type. When animals recover from infection by one type of virus they have little or no protection against attacks by any one of the others.

Clinical signs

Cattle

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.

About the same time there is evidence of pain in the feet. The animal lies down constantly and, when forced to move, walks very tenderly, occasionally shaking a leg as if to dislodge some object wedged in the hoof. Lameness usually gets worse, until the animal can only hobble when moving on hard or uneven surfaces. 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.

The 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.

Sheep

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.

Pigs

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.

It is important to remember that the disease known as Swine Vesicular Disease, which first occurred in this country in 1972, has identical symptoms to Foot and Mouth disease. Therefore anyone who sees vesicular disease in pigs must report the sighting and treat the condition as suspected Foot and Mouth disease until laboratory tests prove otherwise.

Spread/transmission

The virus is present in great quantity in the fluid from the blisters, and it can also occur in saliva, milk and dung. Contamination of any objects with any of these discharges is a danger to other stock. At the height of the disease, virus is present in the blood. Infected animals begin by excreting the virus a few days before signs of the disease develop. Pigs in particular produce large numbers of virus particles.

Airborne spread of the disease can take place and under favourable weather conditions the disease may be spread considerable distances by this route. For example, circumstantial evidence strongly suggests that the outbreak on the Isle of Wight in 1981 resulted from the airborne spread of the virus from Brittany in northern France.

Animals pick up the virus either by direct contact with an infected animal or by contact with foodstuffs or other things which have been contaminated by such an animal, or by eating or coming into contact with some part of an infected carcase. In the past, outbreaks of the disease have been linked with the importation of infected meat and meat products.

The disease is spread mechanically by the movement of animals, people, vehicles and other things which have been contaminated by the virus. Trucks, lorries, market places, and loading ramps – in or over which infected animals have travelled – are dangerous until disinfected. Roads may also become contaminated and virus may be picked up and carried on the wheels of passing vehicles.

The boots, clothing and hands of a stockman who has attended diseased animals can spread the disease and dogs, cats, poultry, wild game and vermin may also carry infection.

Disease prevention

In countries like Great Britain, where the disease arises only as the result of imported infection, the accepted policy is to stamp it out by slaughtering all affected stock and any others which have been exposed to such risk of infection that it is reasonably certain that they would develop the disease if left alive. Compensation is paid for animals slaughtered.

The success of the slaughter policy depends 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.

Special care is necessary with sheep and pigs where lameness is often the only symptom. It must be remembered that pigs will ‘go off their legs’ for various reasons, and that FMD is one of them; also that sheep can be lame from foot rot and FMD at the same time. Owners of livestock should always be suspicious when one or more pigs or sheep become lame suddenly and the lameness starts to spread through the herd or flock.

The owner of a suspected animal or carcass must by law report the fact to their local AHVLA Office. The owner is not expected to diagnose the disease, but he ought to know enough about the disease to suspect it. All owners and stockmen should make themselves familiar with the symptoms, and call in a veterinary surgeon as early as possible; they should never ask another stock-owner to look at the suspected animal.

If the suspicion is strong it is better to report at once to the local AHVLA office for the area, who will immediately arrange, without cost to the owner, for the examination of the suspected animal.

Before the Veterinary Officer arrives there are steps that owners should take at once to lessen the risk of spreading the disease. The suspected animal must be isolated, and no one who has been in contact with it should be 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. Dogs, cats, and poultry must be shut in or tied up. 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.

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. In short, the aim should be “nothing in, nothing out’ until the Veterinary Officer arrives. Neighbouring owners who hear reports of disease should restrict movements of their stock as far as possible, and keep them off roads in the vicinity. It is better to leave outlying stock where they are, unless they can be moved further from the suspected premises without coming into contact with the main herd.

Disease Control Strategy

The Foot and Mouth Disease control strategy for Great Britain was developed with other GB administrations and in England with the core group of industry representatives.

It reflects existing knowledge and understanding and is consistent with the UK’s EU obligations and in line with Foot and Mouth Disease legislation which transposes Directive 2003/85/EEC. The Government’s primary objective in tackling any outbreak of FMD will be to eradicate the disease as quickly as possible and to regain the UK’s disease-free status. In doing so, the Government will act swiftly and decisively, in partnership with its operational partners and industry stakeholders:

  • to minimise overall cost of the outbreak and the burden on the taxpayer and public as well as the economic burden of the outbreak on the food, farming and tourism industries and the wider economy;
  • to protect the health and safety of the public and those directly involved in controlling the outbreak.

In delivering this objective, the disease control measures set out in this strategy will seek to:

  • minimise the number of animals that need to be culled either for disease control purposes or to safeguard animal welfare;
  • minimise adverse impacts on animal welfare, the rural and wider economy, the public, rural communities and the environment.

Vaccination

A decision to vaccinate can only be made by the Secretary of State once an outbreak has been confirmed using all the evidence available.

The Secretary of State is obliged under Regulations 9 and 10 of The Foot and Mouth Disease (Control of Vaccination) (England) Regulations 2006 (2006/183) to consider the case for vaccination for Foot and Mouth from the outset of a confirmed outbreak, and to publish the decision once it has been made. Any such decision will be based on a combination of expert veterinary and scientific advice, as well as the results of modeling, and economic analysis and stakeholder views. A very wide range of factors will be taken into account in assessing whether vaccination would have a beneficial impact on disease control, including the availability and efficacy of a suitable vaccine.

The domestic legislation transposes the Council Directive 2003/85/EEC on Foot and Mouth into law. Annex X to the Directive sets out the following criteria to influence the decision to vaccinate:

  • public reaction and acceptance of regionalisation
  • third-country reaction
  • availability of suitable vaccine
  • population density of susceptible animals
  • predominant species infected
  • movement of potentially infected animals out of PZ
  • risk of airborne spread from infected holdings
  • known origin of outbreak
  • incidence slope of outbreaks
  • distribution of outbreaks
  • economic assessments of slaughter/vaccination
  • ability to meet 24/48 hr deadlines
  • large intensive holdings in an otherwise low livestock density area.

Under our contingency plan, we have call off contracts in place with Genus PLC, to establish operational vaccination centres within 5 days of confirmation of a Foot and Mouth outbreak. The Government will rely on the substantially enlarged EU FMD vaccine bank if a decision were to be taken to use vaccination in an outbreak, and in the extremely unlikely event no suitable antigen was available through the EU vaccine bank, additional vaccine could be requested from FMD vaccine banks in other countries.

Regaining disease free status would take at least three months longer if the decision was made to vaccinate in the event of a Foot and Mouth outbreak, therefore increasing the time before the UK could resume exporting. All animals that had been vaccinated would also need serological surveillance based on the detection of Foot and Mouth Disease non-structural proteins demonstrates the absence of infection in the remaining vaccinated population.

Legislation

Control of FMD is also supported in England through the following orders and Regulations:

  • The Animal By-Products (Enforcement) Regulations 2011
  • The Transport of Animals (Cleansing and Disinfection) (England) (No3) Order 2003
  • The Animal Gatherings Order 2010
  • The Disease Control (England) Order 2003

There is also a contingency plan for exotic animal diseases which is published and reviewed annually.

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Page last modified: 8 February 2013