PROGRESSIVE MULTIFOCAL LEUKOENCEPHALOPATHY

a rapidly progressing, often fatal brain disease believed to be caused by the Jacob-Creutzfeldt (JC) papovavirus. PML infects oligodendrocytes (support cells in the brain) and leads to dysfunctional nerve signal transmission. Symptoms include headaches, changes in mental status, speech and vision difficulties, limb weakness, seizures, partial paralysis and loss of coordination.