Foot and Mouth Disease

What is Foot and Mouth Disease (FMD)?

Foot and Mouth Disease (FMD) is a severe, highly contagious viral disease of livestock with significant economic impact. The disease affects cattle and swine as well as sheep, goats, and other cloven-hoofed ruminants. All species of deer and antelope as well as elephant, and giraffe are susceptible to FMD. In a susceptible population, morbidity approaches 100%. Intensively reared animals are more susceptible to the disease than traditional breeds. The disease is rarely fatal in adult animals but there is often high mortality in young animals due to myocarditis or by lack of milk when the dam is infected by the disease.FMD is characterized by fever and blister-like sores on the tongue and lips, in the mouth, on the teats and between the hooves. The disease causes severe production losses and while the majority of affected animals recover, the disease often leaves them weakened and debilitated. The organism which causes FMD is an aphthovirus of the family Picornaviridae. There are seven strains (A, O, C, SAT1, SAT2, SAT3, Asia1) each one requiring a specific vaccine strain to provide immunity to a vaccinated animal. FMD is a disease listed in the World Organization for Animal Health (OIE) Terrestrial Animal Health Code and must be reported to the OIE (OIE Terrestrial Animal Health Code). FMD is the first disease for which the OIE established an official list of free countries and zones with or without vaccination. Member Countries can also ask the OIE to officially recognise their national programmes for FMD control.

Where is the disease found?

FMD is endemic in several parts of Asia, most of Africa and the Middle East. In Latin America, the majority of countries applied zoning and are recognized free of FMD with or without vaccination, and the disease remains endemic in only a few countries. Australia, New Zealand and Indonesia, Central and North America and continental Western Europe are currently free of FMD. However, FMD can occur sporadically in typically free areas.

How is the disease transmitted and spread?

FMD is found in all excretions and secretions from an infected animal. The virus may be present in milk and semen for up to 4 days before the animal shows clinical signs of disease. Animals that have recovered from infection may serve as carriers of the virus. Infected animals notably breathe out a large amount of aerosolized virus, which can infect other animals via the respiratory or oral routes. The significance of FMD is related to the ease of virus spread through any or all of the following:

  • new animals carrying the virus (saliva, milk, semen, etc.) may introduce the disease to a herd;

  • contaminated pens, buildings or vehicles used to house and move susceptible animals;

  • contaminated materials such as hay, feed, water, milk or biologics;

  • people wearing contaminated clothes or footwear, or using contaminated equipment;

  • meat or animal products, raw or improperly cooked food infected with the virus and fed to susceptible animals, and;

  • aerosol spread of virus from an infected property via air currents.

What is the public health risk associated with this disease?

FMD is not readily transmissible to humans.

What are the clinical signs of Foot and Mouth Disease ?

The severity of clinical signs will depend on the strain of virus, the age and species of animal. The signs can range from a mild infection to severe. Clinical signs are more severe in cattle and intensively reared pigs than in sheep and goats. The typical clinical sign is the occurrence of blisters (or vesicles) on the nose, tongue, lips, oral cavity, between the toes, above the hooves, teats and pressure points on the skin. Ruptured blisters can result in extreme lameness and reluctance to move or eat. Secondary bacterial infection of open blisters can also occur. Other symptoms often seen are fever, depression, hypersalivation, loss of appetite and weight, drop in milk production. Health of young calves, lambs, kids, and piglets may be compromised by lack of milk from infected dams. If infected with the FMD virus, death can occur in young animals before development of blisters due to damage to the heart muscle caused by the virus. Blisters usually heal within 7 days or longer, however the impact of the disease on growth or milk production rates may persist after recovery. Animals that have recovered from infection may sometimes carry the virus and initiate new outbreaks of disease.

How is the disease diagnosed?

The disease may be suspected based on clinical signs with confirmation made through prescribed laboratory tests (OIE Terrestrial Animal Health Code and OIE Manual of Diagnostic Tests and Vaccines for Terrestrial Animals).

What is being done to prevent or control this disease?

The initial measures in the global strategy for dealing with FMD are early detection and warning systems and prevention measures in place according to OIE Guidelines for the Surveillance of Foot and Mouth Disease (OIE Terrestrial Animal Health Code). This contributes to monitoring the occurrence, prevalence and characterisation of FMD viruses. Protection of FMD free countries, areas or zones is enhanced with stringent import and cross-border animal movement controls and surveillance. It is essential for livestock owners and producers to maintain sound biosecurity practices to prevent introduction/spread of the virus.Measures that are recommended at the farm levelinclude:

  • control over access to livestock by people and equipment;

  • control the introduction of new animals to existing stock;

  • maintain sanitation of livestock pens, buildings, vehicles and equipment ;

  • monitor and report illness;

  • appropriate disposal of manure and dead carcasses.

Contingency planning for potential outbreaks willidentify the elements included in a response effortto eradicate the disease, such as:

  • humane destruction of all infected, recovered and FMD-susceptible contact animals (OIE Terrestrial Animal Health Code);

  • appropriate disposal of carcasses and all animal products (OIE Terrestrial Animal Health Code);

  • surveillance and tracing of potentially infected or exposed livestock;

  • strict quarantine and controls on movement of livestock, equipment, vehicles, and;

  • thorough disinfection of premises and all infected material (implements, cars, clothes, etc.).

In endemic countries or zones, culling may be complemented by vaccination for susceptible livestock. Vaccines used must protect against the particular virus strain prevalent in the area.