Cytomegalovirus (sometimes called Betaherpesvirinae) is a subfamily of viruses in the family Herpesviridae. The viruses of this group are characterized by a long replication cycle (equivalent to the life cycles of true living things) and a narrow range of hosts (per virus). The viruses infect the kidneys and salivary glands of a number of vertebrate species, including humans.

From the BioTech Dictionary at http://biotech.icmb.utexas.edu/. For further information see the BioTech homenode.