panencephalitis

a rare chronic progressive encephalitis caused by the measles virus and occurring primarily in children and young adults; death usually occurs within three years; characterized by primary measles infection before the age of two years

a rare loss of mental and physical skills in adolescents; associated with the rubella virus

inflammation of the brain usually caused by a virus; symptoms include headache and neck pain and drowsiness and nausea and fever (`phrenitis' is no longer in scientific use)