Here is some information relevant to transmissible spongiform encephalopathies - "A Case for the Role of Copper Deficiency in 'Mad-Cow' Disease and Human Creutzfeldt-Jakob Disease"

http://www.copper.org/innovations/2001/12/mad-cow.html

I think that another possible cause for Alzheimer's that needs further investigation is Lyme disease:

"In 1995 Dr. Mattman obtained positive cultures for Bb from 43 of 47 persons with chronic illness. Only 1 of 23 control patients had a positive Bb culture. Dr. Mattman has subsequently recovered Bb spirochetes form 8 out of 8 cases of Parkinson’s Disease, 41 cases of multiple sclerosis, 21 cases of amyotrophic lateral sclerosis and all tested cases of Alzheimer’s Disease."

http://www.digitalnaturopath.com/cond/C351537.html

This group found no association between Lyme and Alzheimer's:

http://www3.niaid.nih.gov/research/t...antibiotic.htm

This group did find an association between Lyme and Alzheimer's:

http://www.canlyme.com/alzjournal6.html