The relationship between measles virus infection and subacute sclerosing panencephalitis (SSPE).

On theoretical grounds we propose that the essential step in the development of subacute sclerosing panencephalitis (SSPE) after measles virus infection involves a reverse transcriptase-mediated change to a DNA form, probably brought about by co-infection with a leukovirus at a critical point in time. We further suggest that this new DNA then replicates either as the core of a new slow virus or as a membrane-attached viroid exhibiting a form of non-structural integration with host cell DNA resembling that found with the herpes viruses.