cytomegalovirus
noun(cy-to-meg-a-lo-vi-rus)
a herpesvirus (species Human herpesvirus 5 of the genus Cytomegalovirus) that in healthy individuals causes an infection that is asymptomatic or is accompanied by mild symptoms (such as fever or fatigue) but in immunocompromised individuals and newborns may cause an infection marked by serious, sometimes life-threatening symptoms (such as pneumonia, hepatitis, retinitis, brain inflammation, or seizures)