Human cytomegalovirus is a member of the herpesvirus family. Cytomegalovirus is a very common infection with 80% of the adult population having evidence of infection. Once infected with cytomegalovirus, individuals are permanently infected with the virus. Fortunately, most infections do not result in disease although there are exceptions. Infrequently, cytomegalovirus can cause infectious mononucleosis in otherwise normal healthy adults. Much more commonly, cytomegalovirus is associated with disease in newborn infants or people that are immunocompromised including transplant recipients and people with AIDS.

Infection of newborn infants usually results from transmission of the virus to the fetus while in utero. Infection of newborn infants is associated with a range of presentations from asymptomatic infection to deafness to mental retardation to death. Infection of people undergoing bone marrow transplantation is associated with pneumonitis while cytomegalovirus infection in people with AIDS is associated with retinitis, gastroenteritis and encephalitis. For additional information about the virus please see links.