<prompt> Progressive multifocal leukoencephalopathy is caused byHIVMeaslesRubellaPapova virus  <response>: D Papova virus Progressive multifocal leukoencephalopathy is a viral encephalitis caused by a polyomavirus Papova virus or JC virus, totally unrelated to Creutzfeldt-Jakob disease because the virus preferentially infects oligodendrocytes, demyelination is its principal pathologic effect. Progressive multifocal leukoencephalopathy PML, also known as progressive multifocal leukoencephalitis, is a rare and usually fatal viral disease that is characterized by progressive damage -pathy or inflammation -His of the white matter leuko- of the brain -encephalo- at multiple locations multifocal. It occurs almost exclusively in people with severe immune deficiency, e.g. transplant patients on immunosuppressive medications, or AIDS patients. The cause of PML is a type of polyomavirus called the JC virus JCV. 