Measles virus infection of the CNS

Measles is caused by the measles virus (MV), rubeola, a highly contagious human pathogen. Effective live vaccines have greatly reduced its morbidity and mortality, but measles is still prevalent in certain developing countries. It is characterized by fever, upper respiratory tract symptoms, and a morbilliform skin rash. Recovery is the normal outcome. Acute measles may involve the CNS in two ways: aseptic meningitis, which has a benign outcome, or acute disseminated encephalomyelitis or postinfectious encephalitis. MV infection causes two rare subacute encephalitides: subacute sclerosing panencephalitis (SSPE) and immunosuppressive measles inclusion body encephalitis (MIBE). SSPE is a rare, subacute or chronic, slowly progressive fatal inflammation of the CNS caused by persistent, aberrant MV infection. It occurs predominantly in males, particularly when primary infection develops younger than two years of age. MIBE develops within months of the initial infection in patients with depressed cell-mediated immunity, especially those with congenital or acquired T-lymphocyte deficiency.