Prions
 

The knowledge of diseases causes has been spread out for the last few years, with the discovery of a new pathogen agent called prion. they were revealed by Stanley Prusiner, American scientific from the University of San francisco in 1982.

Prusiner believes that the prion is a proteinaceous infectious particle which is generated by organisms and which would be modified in spongiform encephalopathies Prions form "a group" of microorganisms which is out of ordinary. Prions have no genetic information and are composed by proteins of 250 amino-acids. They are responsible for several neurodegenerative diseases found in animals such as scrapie in sheep, spongiform encephalopathy in cattle and for some other symptoms found in human beings. In New Guinea, the Kuru disease caused by a prion is transmitted generation to generation because cannibals eat their dead parent brain.

In Europe the Creutzfeld-Jakob disease is also due to a prion and brings men to madness. The origin of this disease remains mysterious, nevertheless, it seems to be linked to the absorption of animals already infected.

But, it's too early to give more accurate information about the structure and origin of prions. We do not even know if prions belong to the microorganism familys. It could also be a sort of virus.