Survey of subacute sclerosing panencephalitis in Japan.

Investigators conducted a retrospective epidemiological study of subacute sclerosing panencephalitis, a fatal disease caused by measles infection, over the past few years in Japan. Data on 118 cases obtained from a questionnaire sent to attending physicians were analyzed. The annual incidence of subacute sclerosing panencephalitis was approximately 0.03 cases per million from 2001 to 2005. Children infected with measles at a young age (<12 months) showed a high incidence of subacute sclerosing panencephalitis, and those infected before 6 months of age showed earlier onset. Because a positive correlation was found between the prevalence of measles and the onset of subacute sclerosing panencephalitis, particularly among children infected at an early age, it is vital to eradicate measles infection by vaccination.