1.   There are three human prion diseases and four main prion diseases of animals.

2.   There were examples of prion diseases, but the ones that afflicted humans were so rare as to be medical oddities.

3.   Animal prion diseases are therefore brain diseases.

4.   At the moment, prion diseases are incurable and lethal.

5.   BSE is a prion disease, not one caused by a virus or a bacterium.

6.   But in animals and people with prion diseases, one protein could not be broken down.

7.   But Legname said it would be prudent to test livestock known to carry prion diseases.

8.   Can humans get a prion disease by eating meat from infected cows?

9.   Could studying these irregularities suggest a pathway for blocking the general spread of prion diseases in humans, or for treating them before they become symptomatic?

10.   Dr. Bons said that she suspects the pattern is typical of most prion diseases, called spongiform encephalopathies, found in many mammalian species.