- Subacute sclerosing panencephalitis (SSPE) is a rare, progressive, and fatal neurological disorder that occurs as a delayed complication of measles virus infection.
- It typically manifests years after the primary infection, caused by a persistent, mutated form of the virus in the brain.
- The disease leads to inflammatory and degenerative changes in the central nervous system.
- Other viruses listed do not cause SSPE. Thus, the key fact is the direct association of SSPE with the measles virus.

Reference: Adams and Victor's Principles of Neurology, 11th Edition, Chapter 37, page 736