Foot-and-mouth disease is one of the most highly contagious animal diseases known. It is caused by a virus that can infect cattle, swine, sheep, goats, other cloven-hooved animals, elephants, hedgehogs, rats, and mice. Infections in humans are extremely rare and non-fatal when they occur. The United States has been free of foot-and-mouth disease since 1929. The disease is currently known to exist in Great Britain, France, Eastern Europe, South America, Asia, Africa, and the Middle East.

The Virus (FMDV)

The foot-and-mouth virus is extremely hardy. It can survive freezing, and has been shown to survive milk pasteurization at 72 degrees C for 15 seconds (Pirtle 1991). Live FMDV has been recovered from cattle stalls 14 days after removal of infected cattle, from urine after 39 days, from soil after 28 days in cool weather and 3 days in summer, and from dry hay in cool weather 20 weeks after storage. Sunlight, extremes in pH and high temperatures have been shown to kill the virus.

Transmission can occur by:

• Direct contact with carrier animals or those ill with the disease.
• Aerosols (airborne droplets) from ill animals can be carried up to 40 miles by air movement.
• Contaminated clothing (virus can survive for several weeks on clothes and shoes).
• Meat products and cheese (virus survival can be months).
• People (virus can live in the lungs and nasal passages of humans for 48 hours, in tonsils for 14 to 21 days.
• It only takes 10 virus particles to infect a cow!!

Signs of the Disease

Vesicles (blisters), followed by ulcers in the mouth or nose, on the feet or udder, and the resulting excessive salivation and/or lameness, are the best known signs of the disease. Often, blisters may not be observed before they have ruptured.

Some of these other signs may appear in affected animals during an FMD outbreak:

• Temperatures rise markedly, especially in young animals, then usually fall in about 48 hours.
• Ruptured vesicles discharge either clear or cloudy fluid and leave raw, eroded areas surrounded by ragged fragments of loose tissue.
• Sticky, foamy, stringy saliva is produced.
• Consumption of feed is reduced because of painful tongue and mouth lesions.
• Lameness with reluctance to move is often observed.
• Abortions often occur.
• Milk flow of infected cows drops abruptly.
• Conception rates may be low.

Meat animals do not normally regain lost weight for many months. Recovered cows seldom produce milk at their former rates. FMD can lead to myocarditis (inflammation of the muscular walls of the heart) and death, especially in newborn animals.

Confusion With Other Diseases

FMD can be confused with several similar but less harmful domestic diseases, such as vesicular stomatitis, bluetongue, bovine viral diarrhea, foot rot in cattle, vesicular exanthema of swine, and swine vesicular disease. Whenever blisters or other typical signs are observed and reported, laboratory tests must be completed to determine whether the disease causing them is FMD.

How It Spreads

FMD viruses can be spread by animals, people, or materials that bring the virus into physical contact with susceptible animals. An outbreak can occur when:

• People wearing contaminated clothing or footwear or using contaminated equipment pass the virus to susceptible animals. (Virus can survive for several weeks on clothes and shoes).
• Following exposure, people can shed the virus from oral and nasal secretions for several days to weeks.
• Animals carrying the virus are introduced into susceptible herds.
• Contaminated facilities are used to hold susceptible animals.
• Aerosols from infected animals are inhaled by susceptible animals which may be located a considerable distance from the infected individuals.
• Contaminated vehicles are used to transport susceptible animals.
• Raw or improperly cooked garbage containing infected meat or animal products is fed to susceptible animals.
• Susceptible animals are exposed to materials such as hay, feedstuffs, hides or biologics contaminated with the virus.
• Susceptible animals drink contaminated water.
• A susceptible cow is inseminated by semen from an infected bull.

What is the Government Doing to Prevent a U.S. Outbreak?

The U.S. Government has had regulations in place for years to protect against foreign animal diseases such as foot-and-mouth disease. These regulations are in place 24 hours a day, 7 days a week. Port inspectors and customs officials conduct regular, random inspections of cargo and the possessions of individuals entering or returning to the United States. They are supported in their efforts by USDA's "beagle brigade" of dogs trained to sniff for forbidden food and plant items.

USDA's Animal and Plant Health Inspection Service issued an interim rule, effective January 29, 2001, removing the United Kingdom from the list of FMD-free countries. This action prohibits the importation of all ruminants and swine and most products derived from ruminants and swine, unless those products were processed in such a manner as to inactivate the FMD virus. Inspections at ports and airports have been increased.

What Can I Do to Prevent a U.S. Outbreak?

If you travel to any country outside the United States, be sure to follow all USDA restrictions regarding importation of meats, cheeses, and other potentially hazardous products.

If you travel to the United Kingdom, avoid rural areas. If this isn't possible, buy an inexpensive pair of comfortable shoes that you can leave behind before you fly home. Limit the clothes you wear on or near farms in such areas to one or two outfits that you can launder before your return flight or leave behind. If neither of these options is possible, launder or dry clean your clothes as soon as you return home.

Avoid contact with susceptible animals for at least 14 days after visiting an infected farm.

Watch for salivation, lameness, and other signs of FMD in your herd; and immediately report any unusual or suspicious signs of the disease to your veterinarian, to State or Federal animal disease control officials, or to your county agricultural agent.

If FMD should appear in your animals, your report will set in motion an effective State and Federal eradication program.

Your participation is vital. Both the early recognition of disease signs and the prompt notification of veterinary officials are essential if eradication is to be carried out successfully. Your warning may prevent FMD from becoming established in the United States, or if it does spread, reduce the time, energy and money needed to wipe it out.

Sources of Additional Information:

USDA, APHIS, Veterinary Services
Emergency Programs
4700 River Road, Unit 41
Riverdale, MD 20737-1231
Telephone: (301) 734-8073
Fax: (301) 734-7817

Web Sites:
www.aphis.usda.gov
www.maff.gov.uk/animalh/diseases
www.guardian.co.uk

David R. Griswold, VMD
Extension Veterinarian/Field Investigator
The Pennsylvania State University
Department of Veterinary Science