Foot and Mouth Disease: Viral Infection in Animals

Foot and mouth (hoof and mouth) disease should not be confused with hand, foot and mouth disease, although both viruses belong to the same family (Picornaviridae).

Foot and mouth disease (hoof and mouth disease) is a viral infection affecting cloven-hoofed domestic and wild animals. Foot and mouth disease is extremely contagious: as few as 10 infectious particles is required to cause infection.

Domestic livestock most often affected include cattle pigs and sheep. Free-ranging deer, elk, moose, caribou, mountain goats and bighorn sheep may also become infected providing a reservoir for the virus.

Foot and mouth disease is not the same as hand, foot and mouth disease that infects humans, although the viruses that cause each of the diseases belong to the Picornaviridae family: foot and mouth disease is caused by Aphthovirus. Hand, foot and mouth disease is caused by one of a number of enteroviruses, most often Coxsackie A virus.

Apthovirus is endemic in some parts of Asia, Africa, the Middle East and South America.

Symptoms of foot and mouth disease:

  • Blisters on the lips, tongue and mouth
  • Blisters between hooves
  • High fever
  • Excessive salivation
  • Weakness
  • Decreased production

Complications of foot and mouth disease:

  • Lameness
  • Secondary bacterial infections
  • Decreased milk yields
  • Abortion
  • Sterility

It is possible for humans to become infected by the animal virus, but infection is rare even among people working with infected carcasses. When human foot and mouth does occur, it is very mild, often characterized by only a rash. Human cases result from drinking infected milk, direct contact with infected animals or contamination of skin lesions or cuts.

Humans are an important vector in the spread of infection to uninfected stock.

How is foot and mouth disease spread?

  • Aphthovirus is readily airborne and may also be spread through air currents.
  • Meat and dairy products made from infected animals and fed to livestock
  • Direct or close contact with infected animals
  • Indirect contact with infected animals through contaminated equipment and vehicles
  • Contact with footwear, clothing or equipment contaminated with the virus

Dogs and cats may also aid spread of infection: although dogs and cats are not susceptible to the virus that causes foot and mouth disease, the virus can be transmitted on their fur and paws.

Rapid outbreak control is essential to prevent spread in disease-free areas.

How do I help reduce the spread of foot and mouth disease?

  • Disinfect clothing by washing in hot water or having them dry cleaned.
  • Clean and disinfect footwear and other items
  • Wash hands thoroughly after direct and indirect contact with livestock.

What measures prevent foot and mouth disease from being introduced into domestic stocks?

Import controls

  • Only cooked or hermetically sealed meat allowed entry from countries that have FMD
  • Requirement that travellers entering a country declare all foods, plants, animals and their products
  • Detector dogs in airports to sniff out concealed food, plant, animal or fish products

Is foot and mouth vaccine available?

Foot and mouth vaccine is available; however, is not currently recommended:

  • current tests do not distinguish between infected and vaccinated stock
  • countries that are free of foot and mouth disease will not import vaccinated animals
  • numerous strains of the foot and mouth virus make it difficult to vaccinate against all ciculating strains
  • vaccine is not effective in all animals immunized
  • animals may become carriers of the virus if exposed to the virus immediately following vaccination
  • for most animals, two vaccinations at scheduled intervals is required
  • recognition of foot and mouth disease in imported animals and domestic livestock may be delayed
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