Small virus-like structure in fractions from scrapie hamster brain.

The scrapie model in hamsters has been used to search for the agents that cause Creutzfeldt-Jakob disease in man and similar transmissible encephalopathies in animals. We found structures that are extraordinarily small for a virus, but exhibit viral structural properties in negatively stained samples, by electron microscopy in fractions containing scrapie-associated fibrils.