Scrapie is an incurable, degenerative, neurological disease which affects goats and sheep. It is caused by a prion which is a rogue protein which unfolds in an undesirable way, once it enters the system though the intestines or the mucous membranes. The means of transmission of this disease is not known, although it is believed to be spread through the urine of animals. There is a lot of research going on in this aspect. The disease is not communicable to human beings.
As the name suggests, the initial symptom is itching, which causes the animal to persistently scrape its fleece against rough objects like fences, boulders and trees. Other symptoms include lip smacking, change in gait and convulsions resulting in collapse.
Initially, the symptoms are mild, restricted to a heightened rate of chewing. There is now a test in place which involves taking a sample of lymphatic tissue from the third eyelid. The main clue for effective diagnosis of scrapie is the presence of the prion which causes the disease. In 2010, a team from New York devised a test which can detect the presence of the prion even if only present in a ratio of one part per 100 billion, using a technology known as Surround Optical Fiber Immunoassay(SOFIA).
There is no effective treatment for scrapie, hence the best measures that can be taken is to quarantine the infected animals from the rest of the flock.
As mentioned earlier, there is no cure for this disease, so the end result of this disease is usually death. As scrapie is a reportable disease in most countries, humane destruction of the infected animals is usually recommended.
As it has been found that the prion can persist in the soil for years, regular soil analysis is recommended. Certain genetic strains of sheep are more susceptible to the disease than others, so these particular breeds should be closely monitored.
If detected at an early stage, the treatment cost can be kept to a bare minimum – within $1,000, maybe. But if the disease is allowed to spread, then it may cost up to ten times this amount for bringing the epidemic under control.