Slow Virus Diseases [Disease/Finding] Diseases of viral origin, characterized by incubation periods of months to years, insidious onset of clinical manifestations, and protracted clinical course. Though the disease process is protracted, viral multiplication may not be unusually slow. Conventional viruses produce slow virus diseases such as SUBACUTE SCLEROSING PANENCEPHALITIS, progressive multifocal leukoencephalopathy (LEUKOENCEPHALOPATHY, PROGRESSIVE MULTIFOCAL), and AIDS. Diseases produced by unconventional agents were originally considered part of this group. They are now called PRION DISEASES. Slow Virus Diseases M0019974 C5728 Slow Virus Diseases C0037341 N0000002775 D012897 1030191 Virus Diseases [Disease/Finding]