What is foot-and-mouth disease?
In 2001 the UK went through an epidemic of foot-and-mouth disease (FMD) which led to the slaughter of 6.5 million animals and a cost of £8 billion.1 What have we learned from it, and what has changed to stop it from happening again?
Foot-and-mouth disease is a viral disease of cloven-hoofed animals such as sheep, pigs and cattle. It is present all over the world and has had a large impact on agriculture for many years. It is highly infectious and can be spread in a variety of ways. This adds to the likelihood of epidemics and uncontrolled outbreaks. Although not usually fatal, FMD can cause health issues in animals which recover. This can be from increased chance of still-borns and damage to heart tissue2, to decreased milk yield in cows.3 As a result, this disease is of major economic and animal welfare importance.
In the UK, FMD is a notifiable disease. This means that if someone suspects or diagnoses the disease, they must immediately report it to the APHA. This helps to keep track of any outbreaks and allows Defra to quickly take measures to prevent widespread infection.
What are the signs of foot-and-mouth disease?
The disease typically presents as a high fever which declines after a few days, and blisters which form inside the mouth and on the feet which can then lead to lameness. In sheep and pigs, blisters in the mouth are less common, and the most obvious sign of FMD is sudden-onset lameness.4 For a more in-depth idea of how to spot FMD, go to Defra’s info sheet here.
There is currently no effective treatment for FMD. However, antibiotics can treat any secondary infections which arise. In much of the EU, where there is no endemic FMD, affected animals are usually culled immediately to prevent spread. Culling is usually extended to unaffected high risk animals.
How can we prevent foot-and-mouth disease?
There is a vaccine for FMD, which prevents symptoms of the disease and limits spread. However, there are issues around its use and the transport of vaccinated livestock. In areas of the world where FMD occurs naturally, farmers and vets use the vaccine to prevent major outbreaks among populations. Where the disease is not present, usually control and prevention of infection are more effective.
The best defence against FMD is strict biosecurity measures and monitoring. On the whole, prevention is better than cure. Stopping movement of any infected animals, equipment or meat is very important in limiting spread.
How did the 2001 UK foot-and-mouth outbreak occur?
The origin of the epidemic in the UK is now known to be a pig finishing unit in Northumberland. FMD was confirmed there in February 2001. The investigation revealed that most of the pigs on the farm had the disease. The incubation period of the disease in pigs is 2-14 days. As a result, it is possible that pigs infected with FMD before the diagnosis were sent to the abattoir. Studies concluded that the infection arrived on the farm through infected meat.
The disease then spread through movement of infected pigs to an abattoir in Essex. Airborne virus particles also spread directly to sheep kept on a nearby farm. Sixteen sheep from this farm then entered the marketing chain. They went on to infect other sheep, people and vehicles and subsequently spread FMD across the country. The virus is extremely virulent. It easily transferred between populations of animals and quickly spread once introduced.
How did it turn into an epidemic in 2001?
There are believed to be a number of contributing factors that came together to provide an opportunity for the disease to spread silently.
Defra reports the following factors were to blame for the outbreak:
- There were delays in the reporting of the disease in the pigs
- Movement of un-diagnosed infected sheep through markets spread the disease widely
- The virus emerged when the climate provided favourable conditions, enabling it to survive well
- It occurred at the peak sheep selling time, thus enabling wider spread
- Signs are not as clear in sheep than in other livestock animals
- Large sheep populations with reduced farm labour allowed the disease to infect whole flocks easily
- Producers gather sheep regularly for management such as shearing, treatment and housing in winter. This means the disease had more opportunity to spread
How was it stopped?
The primary control measure of the disease in 2001 was the widespread culling of animals. Teams of health officials implemented the immediate culling of any animals showing the disease. This included high risk healthy animals in the local area. While this did eventually get the disease under control, the costs were enormous. In total, around 6.5 million animals were culled. While farmers received compensation, the mental and emotional effects were far-reaching and vast.5
The UK government implemented a complete ban on movement of any livestock animals. People had to stick to very strict biosecurity measures when entering or leaving any agricultural premises. Many farming communities were put under tight movement bans. Social events were completely cancelled over fear of spreading the disease. Parks where there were deer were closed to visitors and trade of animals out of the UK was stopped.
The farming and wider community learnt many lessons from this epidemic. There are measures in place today that are solely due to it, such at the 6 Day Standstill Rule (6DSS). The rule stops animals from moving rapidly from one farm to another and helps to limit disease spread. With the current coronavirus pandemic still ongoing, perhaps it is time to take a look back at lessons learnt from previous epidemics and see what might apply now.
- The 2001 Outbreak of Foot and Mouth Disease – National Audit Office (NAO) Report. National Audit Office.
- Stenfeldt, et al. (2014). Acta Vet. Scand. 56, 42.
- Ferrari, et al. (2014) Transbound. Emerg. Dis. 61, e52-59.
- Foot and mouth disease: how to spot and report it. GOV.UK
- Mort, et al. (2005) BMJ 331, 1234.