F246
Foot-and-Mouth Disease (FMD)

Introduction: Foot-and-mouth disease (FMD) is a viral disease of cloven-hoofed animals such as sheep, goats, cattle, and deer. The United States has been free of FMD since 1929. However, many countries throughout the world are NOT considered FMD free. Because the disease spreads easily and rapidly, this is a major concern for areas and countries that are currently FMD-free. This disease is considered to be the most economically devastating livestock disease in the world. FMD is not contagious to humans and therefore is not considered a zoonotic disease.

Causative Agent: FMD is caused by a virus (there are at least seven different types and many subtypes of this virus). If an animal develops immunity to one type of the virus, this does NOT protect the animal against the other types. The virus can survive in the environment for up to one month, depending on the temperature and pH conditions.

Clinical Signs: FMD can cause the animal to have very thick, stringy saliva and a loss of appetite because of the painful mouth lesions. This disease causes a fever and blister-like lesions (vesicles) on the mouth, tongue, lips, teats, and between the hooves. These vesicles eventually rupture leaving a very painful, red ulcer or erosion. This problem can also cause weight loss, lameness, decreased milk production, and abortions. Most animals do NOT die because of the disease, but they often never return to normal production levels.

Disease Transmission: FMD is highly contagious and can be spread by animals, people, or contaminated materials (clothing, gloves, shoes, instruments, truck tires, etc.) that bring the virus into physical contact with susceptible animals. The following list contains some of the common ways of spreading the disease:

  1. When contaminated clothing or equipment is used when treating susceptible animals.
  2. When contaminated vehicles (vet and feed trucks) move from farm to farm or are used to haul susceptible animals.
  3. When infected animals are brought into contact with susceptible animals.
  4. Where contaminated facilities are used to hold or process animals.
  5. When raw or improperly cooked products that contain infected meat or animal products are fed, and when materials such as hay or other feedstuffs that are contaminated with FMD are used.
  6. When susceptible animals drink from a common water source that is contaminated by infected animals.
  7. When a susceptible female is inseminated with semen from an infected male, or when direct animal to animal contact occurs during natural sexual activity.
  8. Because the virus can survive in human nasal passages for as long as 28 hours, humans can spread the virus to animals. The virus does not cause disease in humans.

 

Ruptured vesicles and ulcers in the mouth

 

Vesicles on the teat end

 

A sore between the hooves resulting from a FMD vesicle

All pictures are of cattle and have been used by permission from the USDA.

Diagnosis: Because this disease can look like other conditions and diseases, diagnosing FMD based only on clinical signs is difficult. Laboratory analysis of blood, fluid, and tissue samples is required to confirm a diagnosis. Handling of these samples can be complicated; therefore, if a case of FMD is suspected, a local and state veterinarian should be contacted immediately.

Other diseases that look like FMD include bluetongue, footrot, and lesions of the mouth/tongue caused by plant material (grass awns) and equipment (balling guns, etc.).

Prevention: Because the United States’ sheep and goat populations have not been exposed to this disease, they are extremely vulnerable to infection. In the United States, preventing FMD centers around keeping the virus from entering the country and detecting the disease early if it happens to appear. The following are things that can and are being done to prevent this disease from entering the United States:

  1. Certain animals and animal by-products from areas known to be infected with FMD are prohibited from entering the United States.
  2. Human travel into the United States from areas with FMD is being strictly monitored. During times of FMD outbreaks, all international travelers must do the following:
    • State on their customs declaration form whether or not they have been on a farm or in contact with livestock. This includes any contact with livestock at zoos, circuses, fairs, and other animal facilities and events.
    • State on their customs declaration form if they are bringing any meat or dairy products back from these countries. (Failure to declare any items may result in delays and fines of up to $1,000.)
    • Disinfect any soiled shoes/clothing before and after coming to the U.S.A.
    • International travelers should shower and shampoo prior to and again after returning to the United States from any FMD-affected area.
    • If international travelers are around livestock in FMD areas, they should avoid contact with any livestock for at least 5 days after returning to the United States.
  3. All animals (dogs, cats, horses) returning to the United States that had contact with livestock or areas frequented by livestock must be bathed as soon as they reach the United States and have their bedding completely cleaned. Like humans, animals that have been around livestock should not have contact with livestock in the United States for at least 5 days after returning.
  4. A significant education program is being implemented by Animal and Plant Health Inspection Service (APHIS) to educate veterinarians, producers, and the general public about this disease.

The following actions are a must for every veterinarian, producer, and livestock owner to help prevent an outbreak of FMD in the United States:

  1. Watch for any of the clinical signs of FMD to appear in a flock, herd or individual animal.
  2. If signs of FMD do appear, immediately report this case to the local veterinarian, state or federal animal health officials, or to the local county extension agent.
  3. Should an outbreak occur, be aware that the virus itself can be killed by heat, low humidity, and some disinfectants. The following table contains the disinfectants that are currently approved by the EPA/APHIS for the control of FMD.
Product    Mixing Instructions   
Bleach    Add 3 gallons of bleach to 2 gallons of water -then mix thoroughly   
Virkon-S
(Antec)    		Follow label directions   
Oxycept-333
(Ecolab)  		Add 4 oz. to 8 gallons of water

Additional general biosecurity information can be found on page B76.

Vaccination: There is a vaccine for FMD; however, the vaccine is not currently used in the United States. This is mainly because of 3 reasons:

  1. The United States is currently considered a FMD-free country. If a FMD vaccine were to be used, the United States would lose its FMD free status. This would cause a significant increase in costs to producers and introduce many new restrictions for international trade.
  2. For animals to maintain immunity to FMD, annual re-vaccination is required. This would also be a great cost to producers and others involved in the livestock industry.
  3. There is a risk of spreading the disease to other flocks/herds and even other animal species. This is because the vaccine only helps to prevent clinical signs of disease and does not actually prevent the animal from being infected. Some vaccinated animals may harbor the FMD virus for years and then spread it to other unvaccinated animals and wildlife.

If an outbreak ever occurred in the United States, vaccination could play an important role in the control of the disease. USDA officials, along with local and state authorities, could design a vaccination program specific to the area and type of outbreak. This is important because there are so many different types and subtypes of FMD that no universal vaccine against the disease exists. Currently, the North American FMD Vaccine Bank stores the different types of inactivated FMD antigen (virus). Should an FMD outbreak occur, these antigens could be rapidly formulated into a vaccine specific to the type of virus causing the outbreak.