Cytomegalovirus

Cytomegalovirus
Classification and external resources
ICD-10	B25
ICD-9	078.5
MeSH	D003586

Cytomegalovirus
CMV infection of a lung pneumocyte.
Virus classification
Group:	Group I (dsDNA)
Family:	Herpesviridae
Subfamily:	Betaherpesvirinae
Genus:	Cytomegalovirus
Species
see text

Cytomegalovirus (from the Greek cyto-, "cell", and -megalo-, "large") is a viral genus of the viral group known as Herpesviridae or herpesviruses. It is typically abbreviated as CMV: The species that infects humans is commonly known as human CMV (HCMV) or human herpesvirus-5 (HHV-5), and is the most studied of all cytomegaloviruses.^[1] Within Herpesviridae, CMV belongs to the Betaherpesvirinae subfamily, which also includes the genera Muromegalovirus and Roseolovirus.^[2] It is related to other herpesviruses within the subfamilies of Alphaherpesvirinae that includes herpes simplex viruses (HSV)-1 and -2 and varicella-zoster virus (VZV), and the Gammaherpesvirinae subfamily that includes Epstein–Barr virus.^[1] All herpesviruses share a characteristic ability to remain latent within the body over long periods. Although they may be found throughout the body, CMV infections are frequently associated with the salivary glands in humans and other mammals.^[2] Other CMV viruses are found in several mammal species, but species isolated from animals differ from HCMV in terms of genomic structure, and have not been reported to cause human disease.

Species

Classified Cytomegaloviruses

Scientific Name	Host	Common Name
Human herpesvirus 5 (HHV-5) Cercopithecine herpesvirus 5 (CeHV-5) Cercopithecine herpesvirus 8 (CeHV-8) Panine herpesvirus 2 (PaHV-2) Pongine herpesvirus 4 (PoHV-4) Aotine herpesvirus 1 (AoHV-1) - tentative classification Aotine herpesvirus 3 (AoHV-3) - tentative classification	Human African green monkey Rhesus monkey Chimpanzee Orangutan Night monkey "	Human CMV (HCMV) Simian CMV (SCCMV) Rhesus CMV (RhCMV) Chimpanzee CMV (CCMV) " Herpesvirus aotus 1 Herpesvirus aotus 3

Several species of cytomegalovirus have been identified and classified for different mammals.^[2] The most studied is human CMV (HCMV), which is also known as human herpesvirus-5 (HHV-5). Other primate CMV species include chimpanzee CMV (CCMV) that infects chimpanzees and orangutans, and simian CMV (SCCMV) and rhesus CMV (RhCMV) that infect macaques; CCMV is known as both panine herpesvirus-2 (PaHV-2) and pongine herpesvirus-4 (PoHV-4), SCCMV is also called cercopithecine herpesvirus-5 (CeHV-5) and RhCMV is also called cercopithecine herpesvirus-8 (CeHV-8). A further two viruses found in the night monkey are tentatively placed in the cytomegalovirus genus, and are called Herpesvirus aotus 1 and Herpesvirus aotus 3. Rodents also have viruses previously called cytomegaloviruses that are now reclassified under the genus muromegalovirus; this genus contains mouse CMV (MCMV) is also known as murid herpesvirus 1 (MuHV-1) and the closely related murid herpesvirus 2 (MuHV-2) that is found in rats. In addition, there many other viral species with the name cytomegalovirus identified in distinct mammals that are as yet not completely classified; these were predominantly isolated from primates and rodents.

HCMV

Main article: human cytomegalovirus

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).^[1] Within Herpesviridae, HCMV belongs to the Betaherpesvirinae subfamily, which also includes cytomegaloviruses from other mammals.^[2]

Although they may be found throughout the body, HCMV infections are frequently associated with the salivary glands.^[2] HCMV infection 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.^[1] 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 infects between 50% and 80% of adults in the United States (40% worldwide^[3]) as indicated by the presence of antibodies in much of the general population.^[1] Seroprevalence is age-dependent: 58.9% of individuals aged 6 and older are infected with CMV while 90.8% of individuals aged 80 and older are positive for HCMV.^[4] HCMV is also the virus most frequently 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 countries. CMV "seems to have a large impact on immune parameters in later life and may contribute to increased morbidity and eventual mortality."^[5]

References

1. ^ ^{a b c d e} Ryan KJ, Ray CG (editors) (2004). Sherris Medical Microbiology (4th ed.). McGraw Hill. pp. 556; 566–9. ISBN 0838585299. 
2. ^ ^{a b c d e} Koichi Yamanishi; Arvin, Ann M.; Gabriella Campadelli-Fiume; Edward Mocarski; Moore, Patrick; Roizman, Bernard; Whitley, Richard (2007). Human herpesviruses: biology, therapy, and immunoprophylaxis. Cambridge, UK: Cambridge University Press. ISBN 0-521-82714-0. 
3. ^ Offermanns S, Rosenthal W (2008). Encyclopedia of Molecular Pharmacology (2nd ed.). Springer. pp. 437–438. ISBN 978-3-540-38916-3. 
4. ^ Staras SA, Dollard SC, Radford KW, Flanders WD, Pass RF, Cannon MJ (November 2006). "Seroprevalence of cytomegalovirus infection in the United States, 1988–1994". Clin. Infect. Dis. 43 (9): 1143–51. doi:10.1086/508173. PMID 17029132. http://www.journals.uchicago.edu/doi/full/10.1086/508173. Retrieved 2009-12-04. 
5. ^ Caruso C, Buffa S, Candore G, et al. (2009). "Mechanisms of immunosenescence" (PDF). Immun Ageing 6: 10. doi:10.1186/1742-4933-6-10. PMC 2723084. PMID 19624841. http://www.immunityageing.com/content/pdf/1742-4933-6-10.pdf. Retrieved 2009-12-04.