[Research progress in slow virus infections in Japan and the diagnostic points].

There have been many progresses of researches on slow virus infections including sub-acute sclerosing panencephalitis (SSPE), progressive multifocal leukoencephalopathy (PML) and prion diseases. In Japan, many researches were conducted in relation with the research group on prion disease and slow virus infection sponsored by the Ministry of Health, Welfare and Labor. Particularly in prion disease, the nation-wide surveillance has shown many important epidemiological and clinical results. However the elucidation of pathomechanisms and development of effective treatments of prion disease, SSPE and PML are far from contentment and we the mankind need further efforts to overcome these diseases.