Slow virus infections.
D007562:Creutzfeldt-Jakob Syndrome / Q000635:transmission; D006801:Humans; D007968:Leukoencephalopathy, Progressive Multifocal / Q000209:etiology; D012897:Slow Virus Diseases / Q000209:etiology; D013344:Subacute Sclerosing Panencephalitis / Q000209:etiology