CREUTZFELDT-JAKOB DISEASE IN THE SQUIRREL-MONKEY

Abstract

Four different strains of Creutzfeld-Jakob disease [CJD] virus (2 primary and 2 passaged in primates or mice) were inoculated intracerebrally into squirrel monkeys implanted with continously-recording indwelling electrodes. Simultaneous EEG and videotape recordings were made on unrstrained animals. In addition EEG recordings were made of evoked visual potentials on restrained animals. EEG abnormalities appeared to every animal before the first clinical signs (6-20 mo. after inoculation) and included generalized slowing, epileptiform patterns and occasional episodes of pseudo-periodic activity. Abnormal evoked visual potentials and disturbances of consciousness were also noted. All viral strains produced similar disorders and the death of inoculated animals. The relative frequency of epilepsy seen in the CJD-inoculated squirrel monkey contrasts with its irregular occurrence in most other monkeys species, and its total absence in the spider monkey. This could be related to the lesser complexity of neo-cortical evolution in the squirrel monkey and a less pronounced development of inhibitory CNS mechanisms under the general control of GABAergic neurons.