[Prion encephalopathies]

Abstract

Spongiform encephalopathies, also called prion encephalopathies, are characterized, in human as well as in animals, by (1) their clinical picture which indicates strict localisation in central nervous system, (2) their histological aspect: spongiform degeneration and neuronal loss, and (3) their transmissibility in the same animal species but also from man to animal. The nature of the pathogenic agent is still debated. This agent could be one isoform of the prion protein which, probably because of a modification of its tertiary structure, is partially resistant to proteolytic enzymes. Recent description of a bovine spongiform encephalopathy caused by meat flour absorption has raised again the question of the transmissibility of these animal diseases to human.