Foot and Mouth Disease (FMD )is a severe, highly contagious viral disease of cattle, sheep and swine. FMD also affects goats, deer, bison and other cloven-hoofed domestic and wild ruminants.
Risk to humans
Only a few human cases have been reported in spite of people's regular exposure to infected livestock. The cases that have occurred were due to close contact with infected animals, a virus in the laboratory or consumption of unpasteurized milk. In humans, the disease is mild and lasts for approximately one week.
Clinical signs
Following an incubation period lasting between two and eight days (up to 21 days), clinical signs become evident. The disease is characterized by:
- the presence of painful vesicles in the epithelium of the tongue, gums, lips, nostrils, coronary bands, inter-digital space and teats;
- salivation;
- depression;
- anorexia; and
- lameness.
When the vesicles rupture, they leave large denuded areas, which may become secondarily infected. Many animals recover, but the disease leaves them debilitated. Clinical signs and lesions in pigs, sheep and goats are milder than in cattle. Lameness is the predominant sign in sheep, goats and pigs.
Transmission
The virus is present in tissues, excretions and secretions, including milk, blood, semen, urine and feces before the onset of clinical signs. FMD virus spreads by direct contact between infected and susceptible animals, and by indirect contact with contaminated animal products (meat, raw milk, hides) feed, bedding and equipment. Airborne spread of the FMD virus occurs where large numbers of animals, especially pigs, are infected, and there is an appropriate relative humidity greater than 60 per cent. The virus spread is within 10 km of its source; however, with the right wind conditions the virus could spread as far as 250 km. Pigs are the most potent excretors of the airborne virus and cattle the most susceptible to airborne infection.
Preventing the spread of FMD
It is possible that human travellers can transmit Foot and Mouth Disease to animals. A study done by the United States Department of Agriculture in 1998 concluded that FMD is a moderate risk for mechanical transmission from humans to animals. Enhanced biosecurity on every producer's farm is also important to control this disease.
Canadian producers should:
- Avoid travelling to countries experiencing an acute outbreak of FMD until it is contained.
- If you must travel to areas experiencing an outbreak of FMD, do not visit farms or areas with livestock, including cattle, sheep, pigs, goats, deer, antelope, llamas, alpacas, elephants and hedgehogs. Remain in urban surroundings and avoid country walks or hikes, farm bed and breakfasts or other rural activities.
- Do not bring back any meat, dairy or other animal products.
- Disinfect all clothes (dry clean, or launder all clothes with bleach or washing soda and disinfect luggage), footwear (remove soil and disinfect your shoes), and equipment (e.g. camera) and take a thorough shower before arriving home. Take a disposable camera and have pictures developed before you leave.
- Answer all the questions on the Canada Customs form accurately and follow all the directions at the airport upon arrival in Canada.
- Stay away from Canadian farms for at least 14 days.
- Be aware of the latest information on which countries have FMD.
- Do not host any farm tours or allow visits to anyone who has recently visited or resides in a country with a current FMD outbreak. A special precaution should also apply to all countries that regularly detect FMD.
- Know who is visiting your farm and where they have been. Do not let anyone on your farm if they have arrived less than 14 days from a country with FMD.
- If visits are necessary, provide visitors with boots and coveralls to be worn during their visits. Insist that all visitors disinfect their footwear.
If this disease is suspected on a farm, contact the Canadian Food Inspection Agency district veterinarian immediately.
FMD in Canada
If FMD was identified in Canada, the border would be closed for export of:
- live ruminants and swine;
- fresh or frozen meat of ruminant or swine origin;
- semen;
- embryos;
- hides;
- raw wool; and
- all other products derived from ruminants and swine.
Other commodities such as horses, commercial poultry, dogs and cats may also be prohibited because of the chance they might indirectly carry the virus. The borders may be closed until Canada contains the disease, which may be longer than six months. If vaccination is used the waiting period would be even longer.
Outbreak of FMD in Canada
In the event of an FMD outbreak, the CFIA's strategy would be to eradicate the disease and re-establish Canada's disease-free status as quickly as possible.
In an effort to eradicate FMD, the CFIA would use its "stamping out" policy, which includes:
- humane destruction of all infected and exposed animals;
- tracing to identify locations of potentially infected or exposed animals;
- surveillance to detect newly infected animals;
- quarantine and animal movement controls to prevent spread;
- possible use of focused emergency FMD vaccine, as part of a quarantine and eradication program;
- decontamination of infected premises; and
- zoning to define infected and disease-free areas.
Causes of a potential outbreak of FMD
- People wearing contaminated clothes, footwear, or equipment pass the virus on to susceptible animals. The virus may survive in the nasal passages of people from 28 to 36 hours.
- Animals carrying the virus are introduced into susceptible herds. Infected animals shed the virus in breath, saliva, manure, urine, milk and semen.
- Contaminated facilities and vehicles are used to hold and move susceptible animals.
- Meat and animal products infected with the virus, or raw or improperly cooked food waste containing infected meat or animal products is fed to susceptible animals.
- Infected semen, embryos, biologics and hides.
History of FMD
The disease is currently present in many areas of the world. Canada, the U.S., North and Central America, Australia, New Zealand, Chile, and several other countries are considered free of FMD.
In North America, FMD was last reported in 1929 in the U.S., 1952 in Canada and 1954 in Mexico.
FMD is the world's most important animal disease, even though the mortality rate is low. The disease causes significant economic losses for the livestock industry. The most important economic effects result from loss of production, the expense of eradication, and the interference with the movement of livestock and livestock products between countries. If an outbreak of FMD occurred, the virus could spread rapidly throughout Canada, due to routine livestock movements. Unless detected early, eradicated immediately and extensive movement restrictions are implemented, the economic losses could be extensive. The potential role that wildlife such as deer, elk and bison could play as a reservoir for the virus is largely unknown.
The Canadian Food Inspection Agency (CFIA) is responsible under the Health of Animals Act, for eradication of FADs. Effective eradication requires resources and co-operation by all levels of government and livestock industries to minimize the impact of the disease. The Foreign Animal Disease Emergency Support (FADES) plan is intended to provide CFIA with the support it requires from federal, provincial and local agencies to ensure a coordinated, efficient and effective identification and eradication of a foreign animal disease in Saskatchewan.