Slow viral infections of the nervous system and genetic disease.

Slow viral infections are characterized by a long incubation period, protracted clinical course, and limited host range. Scrapie of sheep and kuru and Creutzfeldt-Jakob disease of man are slow infections which have been regarded at one time or another as being of genetic etiology. The initial assumption that these represented hereodofamilial degenerative diseases came from their occurrence in families or in population aggregates, their chronic afebrile clinical courses and their histopathologic changes of noninflammatory degeneration. The role of genetics in these diseases is uncertain although in scrapie genetic susceptibility appears important in the natural infection. A more intimate virus-gene interrelationship in the form of a temperate infection has been postulated; however, little evidence exists at this time to support this hypothesis.