Can Alzheimers be caused by infection?

Newly published research is showing that Alzheimer's disease may arise from infectious prions. An experiment was performed where a normal mouse's brain was injected with a small amount of Alzheimer's human brain tissue. Over time, the mouse developed Alzheimer's, and the disease spread to other parts of the brain. A control group was also injected with disease-free tissue showed no signs of the disease.

http://www.sciencedaily.com/releases/2011/10/111004113757.htm