answersLogoWhite

0

A prion is a small infectious particle that contains a misfolded protein. These contain no DNA or RNA. These cause Creutzfeldt-Jakob disease, Scrapie in sheep and Kuru. These are deadly and progressive nerve wasting diseases.

A plant pathologist discovered an infectious RNA particle smaller than a virus that causes diseases in plants. He called it a viroid. Millions each year are lost by these viroids. These contain only RNA.

These two are the smallest infectious particles. They are not called microorganisms because they are not alive any more than viruses are.

User Avatar

Wiki User

12y ago

What else can I help you with?