Human cytomegalovirus is a species of virus that belongs to the viral family known as Herpesviridae or herpesviruses. It is typically abbreviated as HCMV and is alternatively known as human herpesvirus-5 (HHV-5). Within Herpesviridae, HCMV belongs to the Betaherpesvirinae subfamily, which also in- cludes cytomegaloviruses from other mammals. Although they may be found throughout the body, HCMV infections are frequently associated with the salivary glands. HCMV infec- tion is typically unnoticed in healthy people, but can be life- threatening for the immunocompromised, such as HIV- infected persons, organ transplant recipients, or new born infants. After infection, HCMV has an ability to remain latent within the body over long periods. HCMV is found throughout all geographic locations and socioeconomic groups, and in- fects between 50% and 80% of adults in the United States (40% worldwide) as indicated by the presence of antibodies in much of the general population.Seroprevalence is age- dependent: 58.9% of individuals aged 6 and older are in- fected with CMV while 90.8% of individuals aged 80 and older are positive for HCMV. HCMV is also the virus most fre- quently transmitted to a developing fetus. HCMV infection is more widespread in developing countries and in communities with lower socioeconomic status and represents the most significant viral cause of birth defects in industrialized coun- tries. CMV "seems to have a large impact on immune pa- rameters in later life and may contribute to increased morbid- ity and eventual mortality.