Question

What is the smallest pathogen?

Answer 1

Smallest pathogen: prion
plus fact `->` smallest living organism: nanobe

Explanation:

Priones

• they are made of proteins
• size: 2-3 nm, 1 nanometre= 0.000000001 m
• pathogens for humans and animals
• human prion diseases: Creutzfeldt–Jakob disease, fatal familial insomnia, kuru known as "laughing sickness"....
  The last one is spread via cannibalism.
• All prion diseases in humans affect the brain.
• animal prion diseases: mad cow disease, scrapie...
• mortality: 100%

Plus fact:
Nanobe

• mostly found in sediments
• "smallest living organism" title is not completely sure, fore some scientists this is just a hypothesis
• about 20 nm long