Prion infections in Creutzfeldt-Jakob disease and its variants

Prions (PrPSC) are proteinaceous infectious particles that occur as sporadi c (85 percent), infectious (iatrogenic) (Ei percent) or hereditary (10 perc ent) diseases in humans and animals. These unique infectious agents produce a spongiform change in the central nervous system without any inflammation , inclusion bodies or apparent antibody response. A helper (X) protein and genetic predisposition appear to be required to establish the infection, wh ich seems associated with a post-translational change of a normal protein ( PrPC) encoded by a gene on human chromosome 20. Sporadic human prion diseas e (Creutzfeldt-Jakob disease) is the most common form of human transmissibl e spongiform encephalopathy. Nevertheless, it is undoubtedly under-recogniz ed as a result of both low autopsy rates and confusion with other dementing diseases like Alzheimer's disease. Although no therapy is currently availa ble for this infectious dementia,which has a prolonged incubation period, t hese unfortunate victims should be offered supportive care and postmortem e xaminations. Universal precautious will protect laboratorians from this inf ectious, but not. contagious, disease.