Encéphalopathies subaiguës spongiformes transmissibles ou maladies à prions

Abstract

Prions are responsible for transmissible subacute spongiform encephalopathies (TSE) in humans and animals. Human transmissible spongiform encephalopathies are Creutzfeldt-Jakob Disease (CJD), Fatal Insomnia, Kuru and Gerstmann-Sträussler-Scheinker syndrome. In animals, TSE are natural scrapie in sheep and goats, bovine spongiform encephalopathy (BSE), feline spongiform encephalopathy, transmissible mink encephalopathy, and chronic wasting disease. Prions are thought to be composed of an abnormal isoform of a host-encoded protein, the prion protein (PrP). In vivo, raise in infectivity titre is always associated with a proportional accumulation of PrP. PrP from TSE-affected individuals resists proteinase K digestion and its accumulation is post-translational. Prions resist almost all the procedures generally used to inactivate conventional viruses. Due to their biophysical properties, prions behave differently depending upon the biophysical and biochemical characteristics of their environment. TSE agents are capable to cross the species barrier. In March 96, British epidemiologists reported the appearance of 10 cases of a new variant of Creutzfeldt-Jakob disease (vCJD), which is caused by the exposure of the human population to the BSE agent. Public health consequences are mainly depending upon the incidence of this emerging disease in UK and in continental Europe.