This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General Considerations - Infectious Diseases, Subject name: Pediatrics
Subacute sclerosing panencephalitis is a late neurological complication associated with infection due to: 
Select and explain. 
A. Measles virus, B. Mumps virus, C. Rubella virus, D. Parainfluenza virus
A: Measles virus
Answer: A: Measles virus 
Explanation: a. Measles virus(Ref: Nelson's 20/e p 1542-1547', Ghai 8/e p 213-214)Subacute sclerosing panencephalitis (SSPE) is a chronic complication of measles with a delayed onset & fatal outcome.