FAQ: Foot-and-mouth disease

Q: What causes foot-and-mouth disease?

A: Foot-and-mouth disease (FMD) is an acute infectious viral disease caused by a picornavirus. Symptoms are fever, followed by the development of vesicles (blisters) chiefly in the mouth and on the feet. It is probably more infectious than any other disease affecting animals and spreads rapidly if uncontrolled.

Q: Which animals are affected?

A: It affects cattle, sheep, pigs and goats. Wild and domestic cloven-hoofed animals and elephants, hedgehogs and rats are also susceptible.

Q: Can horses and ponies contract FMD?

A: No, horses and ponies definitely cannot contract foot-and-mouth disease.

Q: If horses cannot catch FMD, why are race meetings etccancelled or postponed?

A: The concern is that horses, humans, dogs, vehicles, etc can carry the virus and so spread it from one area to another. Cattle trucks, lorries, markets and loading ramps, anywhere infected animals may have been present, are sources of infection until effectively disinfected. Roads may also become contaminated and the virus picked up and carried on the wheels of passing vehicles such as delivery lorries and milk tankers. Any person who has attended diseased animals can spread the disease, so vets need to be very careful. Dogs, cats, poultry, birds, wild game and vermin may also carry infected material.

Q: Can human beings contract FMD?

A: Advice from the Department of Health is that the disease in man is very rare. The disease has no implication for the human food chain.

Q: How does the disease spread?

A: The virus spreads most effectively directly from one animal to another ¨ for example, one pig coughing droplets containingvirus on to another ¨ but it can also be spread:

• l Indirectly by carriers ¨ for instance, the virus may spread from an infected farm on a horse¨s hooves to a previously uninfected area.
• l Airborne spread of the virus can take place. Under favourable climatic conditions the disease may be spread considerable distances by this route ¨ up to at least 60km overland and 300km by sea.
• l The virus may be present in milk, dung and even carcasses. This is why disinfection is important and why meat and dairy products are being confiscated by customs on arrival in other countries.
• l Imported meat or dairy products, infected with the virus are a source of infection. Lamb bones brought in from South America were thought to have caused the outbreak in 1967.Q: How long does the virus stay in the environment?A: Under favourable conditions, the FMD virus can survive for long periods. It can persist in the environment and in contaminated fodder for up to one month,depending on the temperature and other conditions.Q: What conditions favour the virus?A: Heat, sunlight and disinfectants will destroy the virus, whereas cold and darkness tend to keep it alive. It is preserved by refrigeration and freezing and progressively inactivated by temperatures above 50øC.Q: How do I recognise FMD?A: You will see lameness and dribbling in more than one animal.Q: Is FMD fatal?A: If FMD is left to run its natural course, the majority of animals will survive the infection and recover in two to three weeks. Some, particularly young stock, will die, but most will get better.Q: So why does infected stock have to be destroyed?A: The problem is that they are unlikely to thrive thereafter and will not fatten as efficiently. Dairy cows, in particular, have long-lasting complications, such as reduced milk yields, abortion and lameness.Q: Do animals have any natural immunity to FMD?A: This strain of FMD has been shown to be the very infectious pan-Asiatic O type, which is one of seven main types of FMD virus. After having the infection, the animals will acquire some natural immunity to that strain of the virus; however, it is like colds and flu in that infection with one type of virus provides little or no protection against attacks by any of the others.Q: Do such animals carry the disease?A: Yes, FMD can persist in the throat of cattle for up to 30 months and nine months in sheep.Q: Is vaccination possible?A: Vaccination is available to control the disease using an inactivated virus and has been used effectively elsewhere in the world. A vaccination programme usually entails two doses one month apart and provides immunity for around six months, provided the vaccine involves the correct strain. In this respect, it is similar to the human flu vaccination. Vaccinated animals will have antibodies to FMD. If blood is taken and tested aftervaccination, it is not possible to distinguish whether they have immunity from the disease or the vaccine.The problem with vaccination is that exports would be limited if Britain could not maintain her disease-free status. Some countries insist on imports only from countries that are recognised to be FMD-free, both without disease and with no vaccination programme.Q: How did the disease reach the UK?A: The disease is present in many countries of the world. There was an outbreak in Greece within the EU last year. The big outbreak in the 1960s was thought to have originated in a lamb carcass brought in from South America. It is likely, but still unproven, that this outbreak may have started similarly.The smallholding in Northumberland at the centre of the current crisis was fattening pigs by swill feeding. Proper swill feeding requires the swill (food scraps) to be heated thoroughly before being fed to the pigs. If this was not done, it could have allowed the passage of disease to the animals.Q: If the disease is not fatal, why are infected animals slaughtered?A: The justification for the slaughter policy is economic in that, according to the MAFF website (www.maff.gov.uk), “widespread disease throughout the countryside would be economically disastrous”.