1. Prions Fact or Science Fiction?

2. Stanley Prusiner, 1982 Born in Des Moines, Ia. Suggested that spongiform encephalopathies in animals and humans are caused by proteinaceous infectious agents or prions. His colleagues thought he was crazy. Why was it considered heresy?

3. Prion Proteinacious infectious agents Large vacuoles develop in the brain Possible genetic cause Also transferred by eating infected tissue (usually nervous tissue only)

4. How does it happen? Prion genes are present on human chromosome #20 (also other animals) Some of these proteins fold abnormally and are called PrP proteins Prions cause adjacent proteins to change shape and become infectious.

5. Neurological diseases Mad cow disease (cattle) Creutzfeldt-jakob disease (human) Scrapie (sheep) Chronic wasting disease (elk, deer) Kuru (human) Fatal familial insomnia (human) Gertsmann-Straussler-Scheinker disease (human, a hereditary dementia disease) Alzheimer’s, Parkinson’s diseases???

6. Infection Control Eat only well-cooked meat Do not reuse surgical instruments Do not use infected animal meat in animal feed Avoid high-risk tissues (nervous tissue) for transplantation

7. Controversy It is neither a virus or an organism Contains no DNA, RNA They are amazingly resistant to modern sterilization techniques No known treatment

8. But some scientists still believe that there is more to the whole story, like a virus that causes these diseases!