Scrapie is a fatal disease that affects the central nervous system of sheep and goats. It is what is known as a transmissible spongiform encephalopathy (TSE). Other TSEs include bovine spongiform encephalopathy (BSE) in cattle, chronic wasting disease in deer and elk, and Creutzfelt-Jakob disease in humans. While the exact cause of Scrapie is still debated, the disease is associated with the presence of an abnormal form of a protein called a prion.
According to Health Canada, there is no known link between Scrapie and human health. Nevertheless, there is evidence to suggest that some TSEs -- such as mad cow disease or BSE -- that affect animals affect humans. Any animal known to be infected with Scrapie is currently kept out of the food chain.
There is no treatment or vaccine currently available for this disease.
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. Incidents of Scrapie are reported annually to the Office international des épizooties (the international standard setting organization for animal health). Scrapie was last diagnosed in goats in Canada in 1976.
Scrapie is slow to develop, usually takes more than a year and a half for clinical signs to appear in an infected animal, although it has been known to take up to eight years to develop. Typically, cases occur in animals between two and five years of age. Once an animal appears ill, however, it will die in one to two months.
Symptoms vary tremendously between cases of Scrapie. One may observe an older animal with changes in general behavior such as aggression or apprehension, tremors, in coordination or abnormal gaits. However Scrapie can also present as a mature doing animal with a poor wool coat or even simply as a found dead.
A difference in the predominant presentation of the clinical disease has been documented between countries. Wasting and debility appear to be more prominent clinical features in North America. Pruritis remains the most prominent clinical feature in Europe.
Scrapie is spread through fluid and tissue from the placentas of infected females. It can be transmitted from an infected female to her offspring at birth, or to other animals exposed to the same birth environment. Males can contract Scrapie, but they do not transmit the disease to other animals. A sheep's genes affect both its susceptibility to the disease and the length of the incubation period. At this time, a correlation between specific genetics and related Scrapie susceptibility has not been determined for goats.
Scrapie is diagnosed after death by microscopic examination of the brain tissue, tonsils, lymph nodes, or spleen that have been treated with a special stain. 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.
Canadian Food Inspection Agency (CFIA) Program
Scrapie is a reportable disease under the federal Health of Animals Act, and a control program exists to prevent its spread. As Scrapie is a reportable disease, any suspect Scrapie case must be reported to a CFIA veterinarian immediately. Canadian veterinarians and livestock producers have been alerted to the symptoms/ signs of Scrapie. When an animal is identified with Scrapie, all the animals that were exposed to the same birthing environment and are deemed at risk to developing the disease are ordered destroyed. Producers are compensated for the loss of their animals. The maximum amount of compensation paid for sheep ordered destroyed under the Health of Animals Act is $600. Sheep that are known to be infected with Scrapie are humanely destroyed, and their carcasses are burned or buried under CFIA supervision. Owners are compensated for their disposal costs.
Control Measures for Owners
Sheep with certain genetic types are less likely to become infected with Scrapie. Blood tests can determine the genetic profile of a sheep. Producers that want to minimize the risk of Scrapie in their sheep flock can consider selective breeding for genetic resistance to Scrapie. However it should be remembered that even genetic resistant sheep can get Scrapie.
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 Scrapie. 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.
Being enrolled in the Scrapie Canada program is a committment of time, resources, and finances. Our flock is inspected annually by a CFIA accreditted Scrapie Veterinarian. With the help of flock management software, I am able to keep detailed and exact records on each of my sheep, even recording family lineage as far back as 5 generations. I am required to submit a brain for testing in year 3, 4 & 5, and then annually after I become Certified, in order to maintain my status in the program. I am not allowed to bring any ewes into my flock, unless I get them from a Scrapie Enrolled breeder with an equivalent or higher standing in the program than myself.
(as taken from Canadian Food Inspection Agency)
SCRAPIE AS A THREAT TO SHEEP AND GOATS
I became Scrapie enrolled in October 2009. I didn't have much of a choice, though could have quit the program once we imported our flock from the USA. There are stringent rules to follow, meticulous record keeping to maintain, and the issue of the annual kill in years 3, 4, & 5 until Certification, and every year there after. I think the kill (as Scrapie can only be positively identified (at this time) through brain matter) is what has deterred many sheep and goat breeders in Canada from getting involved in the program. Once I started thinking "outside of the kill-one-of-your-rare-sheep" box, I decided I could successfully maintain my enrollment in the Scrapie Canada Program.
The good news is, that I came into this prepared and with the mind-set that this is just "normal" business. We have all of our ewes, and all of our rams and wethers, each of them perfect in their own ways, Scrapie-free, and Vet-approved healthy. Each one is more sweeter and gentle than the other. They are wooly and playful, productive little animals, each of them stars in our surrounding communities of people who have never seen a sheep more sweet. I am proud to be the first Babydoll sheep breeder in Canada enrolled in the Scrapie Program.
In June 2010 we introduced 3 little Pygmy Goats to our little flock. I knew this would result in a penalty with Scrapie Canada, and since the goats were not from a Scrapie enrolled property of the same level or higher than myself, I incurred a time penalty and my "enrollment" date was changed from the October 2009 quarter to the April 2010 quarter. I should therefore be Scrapie Certified by April 2015.
Below are the details of the program. More information can be found on the Scrapie Canada website.