Our laboratory was established in 1992 by Professor Hisashi Ogura, who was invited from Kanazawa University to teach and conduct research on virology. In 1998, when the current building was constructed, the Department of Virology became independent from the Department of Parasitology. Our main research interest is to understand the neuropathogenesis of the measles virus. We have been studying measles viruses isolated from patients with subacute sclerosing panencephalitis (SSPE). We identified some mutations responsible for enhanced fusogenicity, and reproduced biased hypermutation in the M gene in a nude mouse infection model. These mutations were characteristic of the SSPE strain and also responsible for the neurovirulence of the measles virus. Our results can provide useful insights for more effective therapy for SSPE.