Lecture on Prions and Related Diseases

Introduction to Prions

Definition: Prions (or prions) are short for proteinaceous infectious particles.
Structure: Made up of proteins; no DNA or RNA.
Discovery: Stanley Prusiner from UCSF discovered prions, winning a Nobel Prize in 1997.

Normal vs. Diseased Prions:
- Normal prions have structured secondary, tertiary, and quaternary forms.
- Misfolding occurs when prions develop incorrect beta helical structures.
- Misfolded prions cause other normal prions to misfold, creating a domino effect.
Consequences:
- Misfolded prions clump together in the brain causing damage.
- These aggregates form 'seeds' that spread from cell to cell.
- Results in spongiform encephalopathy (brain tissue destruction causing spongy holes).

Transmissibility: Prion diseases can spread from one person to another.
Spongiform Encephalopathies: Named for the characteristic sponge-like holes in the brain.
Associated Diseases:
- Animals:
  - Scrapie
  - Bovine spongiform encephalopathy (BSE or mad cow disease)
  - Chronic wasting disease in deer and elk in North America.
- Humans:
  - Kuru: Linked to funerary cannibalism.
  - Creutzfeldt-Jakob disease: Inherited and infectious forms; rapid progression post-symptom onset.
  - Concerns about transmission through BSE-infected beef.

Resistance to Sterilization:
- Prions are not alive and cannot be "killed" like bacteria or viruses.
- Require extreme heat (1112°F or 600°C) or incineration to ash to neutralize.
- Cannot be effectively autoclaved.
Medical Equipment:
- Equipment that comes into contact with prions must be disposed of or cleaned with strong chemicals.
- Historical cases of transmission through contaminated surgical tools and medical therapies.

Fear and Uncommon Nature:
- Prion diseases are rare but formidable due to their nature.
- Serve as real-life "zombie" particles.

Lecture covered viruses and prions, emphasizing the unique and concerning aspects of prion pathogens.