Prions are a special form of infectious proteins that can cause serious diseases without genetic material.
What are prions?
Prions are infectious protein particles. The term ‘prion’ comes from ‘proteinaceous infectious particles’. Unlike viruses, they do not need nucleic acids to cause an infection – only the protein itself.
Properties of prions
Prions are extremely resistant to sterilisation and irradiation. They consist of misfolded forms of a natural protein (PrP) that occurs on the surface of nerve cells, among other places.
How do prions work?
The altered PrP has a different amino acid sequence, which leads to abnormal folding. It can convert normal PrP proteins into the pathological form, resulting in a chain reaction.
Prion diseases
Prions are the cause of rare but serious diseases in animals and humans, e.g.:
- Scrapie (sheep/goats)
- BSE – Bovine Spongiform Encephalopathy (cattle)
- Creutzfeldt-Jakob disease (CJD) and new variant (vCJD)
- Kuru
- Gerstmann-Sträussler-Scheinker syndrome
- Fatal Familial Insomnia (FFI)
Course and diagnosis
These diseases have long incubation periods, are always fatal and are accompanied by movement disorders and dementia. Sponge-like damage, cell loss and protein deposits (plaques) develop in the brain.
Particular challenges
Diagnosis is difficult. vCJD is thought to be linked to BSE-infected food. Due to the high resistance of prions, strict hygiene measures are necessary.