Slow Virus Infections of the CNS

Abstract

After the initial discovery that human kuru could be transmitted to chimpanzees after an incubation period of 18–24 months, it was found that many species of primates developed both kuru and C-J disease after extraordinarily long, silent, asymptomatic incubation periods—lasting several years in some cases (Gibbs and Gajdusek 1973). These agents demonstrate unusual resistance to various chemical and physical agents that include formaldehyde, proteases, nucleases, heat (80°C) and are incompletely inactivated at 100°C. These properties separate them from all other microorganisms. In addition, the lack of infectious nucleic acids or antigenicity, and therefore the absence of antibody production or cytopathogenic effects in infected cells in vitro and no interferon production, further indicate the unusual nature of these agents (Gajdusek 1977). In sucrose gradients, these agents aggregate and are difficult to isolate. Kuru is regarded as a subviral agent. Cell-fusing activity has been demonstrated with brain suspensions from patients with C-J (Moreau-Dubois et al. 1979).