Scrapie Pathology
The nature, cause, origin, and progress of Scrapie.
Nature of the Disease
Scrapie is an infectious disease of sheep and goats which causes a degeneration of the central nervous system. Infected animals may display skin irritation, behavioral changes, posture and gait changes, and/or weight loss. The disease eventually results in death.
Scrapie is among a number of diseases classified as transmissible spongiform encephalopathies (TSE). TSEs are the subject of increased attention and concern because of the discovery of bovine spongiform encephalopathy (BSE) in cattle, the link between BSE and variant Creutzfeldt–Jakob disease (vCJD) in people, and feline spongiform encephalopathy (FSE) in cats in Europe.
Cause
The agent responsible for scrapie and other TSEs is smaller than the smallest known virus and has not been completely characterized. There are three main theories. The scrapie agent could be a :
- Prion, which is an abnormal form of a normal cellular protein
- Virus with unusual characteristics
- Virino, a very small piece of DNA that acts like a virus
The scrapie agent is extremely resistant to heat and to normal sterilization processes. It does not evoke any detectable immune response or inflammatory reaction in sheep and goats.
