PARTICLES RESEMBLING PAPOVA VIRUSES IN HUMAN CEREBRAL DEMYELINATING DISEASE.

Degenerated brain tissue obtained from a deceased patient who had progressive multifocal leukoencephalopathy had been fixed in formalin prior to processing for electron microscopy. In ultrathin sections virus-like particles resembling papova virions were frequently observed in glial nuclei. Correlation with light-microscopy findings suggests that demyelination resulted from the cytocidal effect of the virus on oligodendroglia.