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EXPERIMENTAL TRANSMISSION OF CREUTZFELDT‐JAKOB DISEASE TO GUINEA PIGS

Brain material used in this experiment was from a 47‐year‐old woman autopsied 5 hours after death. The brain was markedly atrophic weighing 750 g. Histopathologically, a spongy state was extensive from cortex to medulla with fibrous astrocytosis and neuronal loss. This brain tissue was aseptically removed at autopsy and a 20% emulsion was prepared. Intracranially 0.1 ml and intraperitoneally 0.2 ml of the emulsion were inoculated into each guinea pig. Five and three of them were killed 10 and 22 months later, respectively, nevertheless showing no clinical signs. The brains from these guinea pigs did not reveal any changes as seen in the human autopsy brain both macroscopically and microscopically. However, all the brains indicated ultrastructural changes characterized by vacuolation with curled membranes in dendrites and free membranes with cellular debris in extracellular space. These changes were not found in guinea pigs inoculated with material from normal guinea pig brain or uninoculated guinea pigs, but similar to those observed in the human autopsy brain used as inoculum. Therefore, it could be considered that Creutzfeldt‐Jakob disease was transmitted from man to guinea pig to present an early stage of the lesion. Several organs were observed ultrastructurally after whole bleeding in monkeys. Curled membranes were generated only in the vacuoles of dendrite from 2 1/2 hours after bleeding and not in those of other organs. This may explain at least a part of the pathogenesis of spongiform changes restricted in the central nervous system.