noun. Any of a group of herpesviruses that attack and enlarge epithelial cells. Such viruses also cause a disease of infants characterized by circulatory dysfunction and microcephaly.

noun. Any of several herpes viruses, of the genus Cytomegalovirus, that attack the salivary glands

noun. any of a group of herpes viruses that enlarge epithelial cells and can cause birth defects; can affect humans with impaired immunological systems

"In 2002, UCSF neurosurgeon Charles Cobbs published a novel finding in a prominent cancer journal: nearly all of the two-dozen brain tumors he had analyzed were teeming with a common herpes virus called cytomegalovirus, or CMV."