<prompt> JC virus causesProgressive Multifocal Leukoencephalopathy PMLSubacute Sclerosing Panencephalitis SSPESubacute EncephalitisTropical spastic paraparesis  <response>: A Progressive Multifocal Leukoencephalopathy PML JC virus JCV: JCV is a type of human polyomavirus formerly known as papovavirus and is genetically similar to BK virus and SV40. It was discovered in 1971 and named after the two initials of a patient with progressive multifocal leukoencephalopa:hy PML. The virus causes PML and other diseases only in cases of immunodeficiency, as in AIDS or during treatment with drugs intended to induce a state of immunosuppression e.g. organ transplant patients. Subacute Sclerosing Panencephalitis SSPE is a rare progressive clinical syndrome characterized by cognitive decline, spasticity of limbs, and seizures and caused by early-age acute infection with measles. Subacute Encephalitis or HIV Meningoencephalitis or AIDS dementia complex ADC characterized by insidiously beginning dementia, with mental slowing, memory loss, and mood disturbances, such as apathy depression; with motor abnormalities, ataxia, bladder bowel incontinence, and seizure. Tropical spastic paraparesis or HTLV -1 associated myelopathy HAM or Vascular Myelopathy is a disorder of spinal cord is found in 20-30 of patients with AIDS histopathological findings resemble subacute combined degeneration, though serum levels of vitamin B12 are normal. 