A 30-year-old AIDS patient with no history of cutaneous eruption, presented with rapidly progressive flaccid paraplegia, hypoesthesia, urinary retention, moderate psychomotor slowing and fever (39.8 degrees C), leading to death within 1 week. CD4 count was 290/mm3. Cerebrospinal fluid contained 210 white blood cells and 238 mg/100 ml protein. Neuropathology revealed HIV encephalitis and diffuse ventriculitis with Cowdry type A inclusions in the ependymal cells. Extensive necrotic and hemorrhagic changes with marked recrotizing vasculitis involved the entire spinal cord and spinal roots. Immunocytochemistry revealed numerous inclusion bodies positive for varicella-zoster virus (VZV) and negative for cytomegalovirus (CMV) and herpes simplex virus type 1 and 2, in ependymal cells, subpial glial cells, endothelial cells and Schwann cells. Electron microscopy confirmed herpes virus-like particles. In situ hybridization confirmed VZV genome in leptomeninges, brain, spinal cord and spinal roots. Comparable neuropathological findings and numerous VZV inclusion bodies were also found in the brain, spinal cord, and spinal roots of a 40-year-old AIDS patient who died from a fulminant ascending myeloradiculopathy previously reported as "necrotizing vasculitis of the nervous system". Direct infection of the brain by VZV, in AIDS patients, has been shown to cause leukoencephalitis and cerebral non-inflammatory vasculopathies. Our observations demonstrate that, in AIDS patients, VZV infection of the central nervous system may also be responsible for meningo-myelo-radiculitis possibly secondary to ventriculitis as in CMV infection. The role of VZV in the pathogenesis of some AIDS-related vasculitides seems also very likely.