21.   In the new work, researchers looked at nerve tissue from marmosets with an experimental version of MS and from three human patients.

22.   Nerve tissue is among the material classified by the European Union as a high-risk for containing prions, the deformed proteins blamed for causing BSE in cattle.

23.   Scientists believe cattle got the disease from eating feed enriched with sheep protein, including organs and nerve tissue.

24.   Scientists believe that cattle became infected from eating feed enriched with ground up organs and nerve tissue from sheep.

25.   Some earlier studies have failed to find prions in the meat of infected cattle, although it was present in their brains and nerve tissue.