I describe the prion as a completely new infectious particle. It's not a virus, not a bacterium, not a fungus. Prusiner, of the University of California, San Francisco, won the Nobel prize in medicine for discovering the prion. It's a natural protein in mammals that can mysteriously deform itself, replicate, and concentrate in the brain. The end result of this accumulation of prions in the brain are these big holes in the brain.
Cannibalism is the link.
Mad cow disease, it seems, is caused by healthy cows eating the remains of infected cows in feed. And then, somehow, the infectious prions jump to humans who eat beef. The outbreak in Europe has launched a scientific race to find a blood test for prions. The idea is, if you can find the infection in cows, you can prevent it in people. Also working on a blood test is Dr. Robert Gallo at the University of Maryland.