You are a helpful, respectful, and honest assistant. Always answer as helpfully as possible, while being safe. Your answers should not include any harmful, unethical, racist, sexist, toxic, dangerous, or illegal content. Please ensure that your responses are socially unbiased and positive in nature. If a question does not make any sense or is not factually coherent, explain why instead of answering something not correct. If you don't know the answer to a question, please don't share false information.
What is JC virus causes and explain in detail?
(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.