In spite of a long history of intense investigation the transmissible spongiform encephalopathies remain a poorly understood family of neurodegenerative diseases. This group of diseases has been described in a wide variety of animal species and includes kuru, Creutzfeldt-Jakob disease, and Gerstmann-Straussler syndrome in humans, and scrapie, bovine spongiform encephalopathy, and related syndromes in ruminants and rodents. In all cases spongiform degeneration and astrocytosis are seen in specimens of brain and a filterable transmissible agent is present in the brain and some other tissues of affected individuals. However, the precise nature of this agent remains unknown. Agent infectivity, which can so far only be assayed by serial transmission to new individuals, be remarkably resistant to inactivation has been shown to by heat, chemicals, and irradiation. These properties create significant biohazard possibilities during exposure to infected tissues. Transmission between humans was originally reco gnized in the unique epidemiology of kuru in New Guinea tribesmen, and concern about transmission from animals to humans has re-emerged as a result of the current epidemic of bovine spongiform encephalopathy in dairy cattle in Great Britain. Although interspecies transmission has often been achieved experimentally, its efficiency is highly variable. There fore, the possibility of spread of bovine spongiform encephalopathy from cattle to humans or various animal populations cannot be accurately predicted at this time. This volume presents a comprehensive update of know ledge concerning the transmissible spongiform encephalo pathies.
The Human Spongiform Encephalopathies: Kuru, Creutzfeldt-Jakob Disease, and the Gerstmann-Sträussler-Scheinker Syndrome.- Bovine Spongiform Encephalopathy.- Purification of Scrapie Agents: How Far Have We Come?.- The Scrapie Fibril Protein and Its Cellular Isoform.- Ultrastructural Studies of Prions.- In Vitro Expression and Biosynthesis of Prion Protein.- Prion Protein Genes: Evolutionary and Functional Aspects.- Scrapie Strain Variation and Its Implications.- Evidence for Biological and Structural Diversity Among Scrapie Strains.- Genetics of Prion Diversity and Host Susceptibility.- Natural Transmission and Genetic Control of Susceptibility of Sheep to Scrapie.- The Scrapie Agent In Vitro.- The Scrapie Agent: “A Virus by Any Other Name”.- Novel Properties and Biology of Scrapie Prions.- Identifying and Mapping Changes in Gene Expression Involved in the Neuropathology of Scrapie and Alzheimer’s Disease.- Search for a Transmissible Agent in Alzheimer’s Disease: Studies of Human Buffy Coat.