Dr. Stanley Prusiner, a doctor at the University of California, San Francisco, identified the transmissible proteins responsible for the degenerative nerve disease, scrapie, in 1982. This discovery transformed our understanding of how diseases are transmitted. The disease, which affects sheep and goats, had previously been a mystery due to its complexity and tendency to pass on in families. Prusier began studying scrapie in mouse spleens and brains before focusing on hamsters' disease symptoms within 70 days, compared to one to two years for mice. He identified the chemical nature of the "infectious agent" driving the disease and proposed the name "prion" to describe the infectious protein. The discovery was later validated when people became infected after eating beef from cows with besbovine spongiform encephalopathy (BESB).