Fact Sheet - Scrapie
What is scrapie?
Scrapie is a fatal disease that affects the central nervous system of sheep and goats. It belongs to the family of diseases known as transmissible spongiform encephalopathies (TSE). Other TSEs include bovine spongiform encephalopathy (BSE) in cattle, chronic wasting disease in deer and elk and Creutzfeldt-Jakob disease in humans.
While the exact cause of scrapie is still unknown, the disease is associated with the presence of an abnormal form of a protein called a prion.
Is scrapie a risk to human health?
According to Health Canada, there is no known link between scrapie and human health.
What are the clinical signs of scrapie?
Scrapie is a disease that develops slowly. Clinical signs are only seen in adult animals, typically between two and five years of age, and in some animals, the disease has taken up to eight years to develop. However, once an animal appears ill, it will die in one to two months.
Symptoms vary tremendously between cases of scrapie. An older animal can show changes in general behaviour such as aggression or apprehension, tremors, incoordination or abnormal gaits. However, a mature animal with a poor coat, or one that is found dead, can also be diagnosed with the disease.
The disease seems to present itself differently in different countries. Wasting and debility (weakness) appear to be more prominent clinical features in North America, while pruritus (intense itching) remains the most noted clinical feature in Europe.
Where is scrapie found?
Scrapie is found in countries all over the world. Diagnosed for the first time in sheep in 1938, it was made a reportable disease in Canada in 1945. There has been a control program in place since that time.
How is scrapie transmitted and spread?
Scrapie is spread from an infected female to her offspring at birth, or to other animals exposed to the birth environment, through fluid and tissue from the placenta.
Research shows that sheep with a particular genetic makeup are more at risk of developing scrapie. At this time, genetic profiles that can consistently predict a high risk of developing scrapie have not yet been developed for goats.
How is scrapie diagnosed?
Scrapie is diagnosed after death by examination of the brain tissue, lymph nodes or spleen. Biopsies of peripheral lymphoid tissue from live sheep can accurately identify certain animals that have scrapie. However, a negative lymphoid biopsy does not rule out that a particular animal has the disease.
How is scrapie treated?
There is no treatment or vaccine currently available for this disease.
What is done to protect Canadian livestock from scrapie?
The Canadian Food Inspection Agency (CFIA) imposes strict regulations on the import of animals and animal products from countries where scrapie is known to occur. These regulations are enforced through port-of-entry inspections done either by the Canada Border Services Agency or the CFIA.
Scrapie is a "reportable disease" under the Health of Animals Act. This means that all suspected cases must be reported to the CFIA for immediate investigation by inspectors.
Sheep with certain genetic types are less likely to become infected with scrapie. Blood tests can determine the genetic profile of a sheep. Producers who want to minimize the risk of scrapie in their sheep flock can consider selective breeding for genetic resistance to scrapie; however, even genetic resistant sheep can get the disease.
Alternatively, sheep producers and goat producers can eliminate or severely restrict the introduction of females and commence scrapie surveillance by having animals over 12 months of age that die on their farm tested for the disease. Specific efforts towards managing the risk of scrapie on individual premises can be recognized through formal participation in a scrapie flock certification program.
In the absence of adopting specific measures to minimize the risk of scrapie on their farm, a producer is encouraged to implement general good management and biosecurity practices such as:
- individual animal identification;
- record keeping;
- prompt isolation of sick animals;
- separation of females giving birth;
- increased cleanliness of birthing environment;
- disinfection of equipment between animals; and
- single use needles for injections.
How would the CFIA respond to an outbreak of scrapie in Canada?
In an effort to eradicate scrapie, the CFIA would use its "stamping out" policy, which includes:
- the humane destruction of all infected animals;
- surveillance and tracing of potentially infected or high risk animals;
- strict quarantine and animal movement controls to prevent spread;
- strict decontamination of infected premises; and
- zoning to define infected and disease-free areas.
Owners whose animals are ordered destroyed may be eligible for compensation.
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