Transmission Electron Micrograph (TEM) of cytomegalovirus virions. Cytomegalovirus (CMV) is a genus of viruses in the order Herpesvirales, in the family Herpesviridae, in the subfamily Betaherpesvirinae. Humans and monkeys serve as natural hosts. Cytomegalovirus is a double-stranded DNA (dsDNA) virus. There are currently eight species in this genus including the type species, human cytomegalovirus (HCMV, human herpesvirus 5, HHV-5), which is the species that infects humans. CMV is a common virus that infects people of all ages. Once CMV is in a person's body, it stays there for life and can reactivate. Most people infected with CMV show no signs or symptoms. However, CMV infection can cause health problems for babies infected before they are born, this is called congenital CMV infection. About one in five babies with congenital CMV infection get sick from the virus or have long-term health problems. |