Scrapies is the form of spongilitis ecephalitis that affects sheep. (BSE is the form that affects cattle and CJD is the form that affects humans.) Once cases have been confirmed in cattle the whole herd is slaughtered as a precaution to prevent the spread of the disease. This is because the route of infection was largely unknown until recently. Now it is known that infected material from an animal has to be ingested by another animal for that infection to spread. It is accepted that BSE originated as the brain and spinal cord material from infected sheep was fed to cows. Waste material from infected cows (ie the brain and spinal tissue) was then processed and put back into the feed given to cows. (Most "normal" people would see the feeding of any material from an animal source to vegetarian animals ludicrous and full of hidden dangers.....but what do we hippy tree huggers know?)
It has been confirmed that at least seven cases of CJD in this country can be directly linked to the victims eating tissue that was contaminated with brain and/or spinal tissue from cattle. It is accepted that this is the route of infection.

For sheep, I'm afraid I know little, although scrapies is an older form of the disease. I will see what I can find and get back to you.

We now have 501 cases of Foot and Mouth, the first in the Republic of Ireland was confirmed yesterday.
The Government has warned that if the disease is not under control soon then half the country's stock of susceptable animals will be culled.