Human cytomegalovirus (HCMV), also called human herpesvirus 5 (HHV-5), is a species of
virus
A virus is a submicroscopic infectious agent that replicates only inside the living Cell (biology), cells of an organism. Viruses infect all life forms, from animals and plants to microorganisms, including bacteria and archaea. Viruses are ...
in the genus ''
Cytomegalovirus
''Cytomegalovirus'' (CMV) (from ''cyto-'' 'cell' via Greek - 'container' + 'big, megalo-' + -''virus'' via Latin 'poison') is a genus of viruses in the order '' Herpesvirales'', in the family '' Herpesviridae'', in the subfamily '' Betaherp ...
'', which in turn is a member of the viral family known as ''
Herpesviridae
''Orthoherpesviridae'', previously named and more widely known as ''Herpesviridae'', is a large family of DNA viruses that cause infections and certain diseases in animals, including humans. The members of this family are commonly known as herp ...
'' or herpesviruses. It is also commonly called CMV.
Within ''
Herpesviridae
''Orthoherpesviridae'', previously named and more widely known as ''Herpesviridae'', is a large family of DNA viruses that cause infections and certain diseases in animals, including humans. The members of this family are commonly known as herp ...
'', HCMV belongs to the ''
Betaherpesvirinae
''Betaherpesvirinae'' is a subfamily of viruses in the order '' Herpesvirales'' and in the family ''Herpesviridae''. Mammals serve as natural hosts. There are 26 species in this subfamily, divided among 5 genera. Diseases associated with this su ...
'' subfamily, which also includes
cytomegalovirus
''Cytomegalovirus'' (CMV) (from ''cyto-'' 'cell' via Greek - 'container' + 'big, megalo-' + -''virus'' via Latin 'poison') is a genus of viruses in the order '' Herpesvirales'', in the family '' Herpesviridae'', in the subfamily '' Betaherp ...
es from other
mammal
A mammal () is a vertebrate animal of the Class (biology), class Mammalia (). Mammals are characterised by the presence of milk-producing mammary glands for feeding their young, a broad neocortex region of the brain, fur or hair, and three ...
s.
CMV is a
double-stranded DNA virus.
Although they may be found throughout the body, HCMV infections are frequently associated with the
salivary gland
The salivary glands in many vertebrates including mammals are exocrine glands that produce saliva through a system of ducts. Humans have three paired major salivary glands ( parotid, submandibular, and sublingual), as well as hundreds of min ...
s.
HCMV infection is typically unnoticed in healthy people, but can be life-threatening for the
immunocompromised
Immunodeficiency, also known as immunocompromise, is a state in which the immune system's ability to fight infectious diseases and cancer is compromised or entirely absent. Most cases are acquired ("secondary") due to extrinsic factors that affe ...
, such as
HIV
The human immunodeficiency viruses (HIV) are two species of '' Lentivirus'' (a subgroup of retrovirus) that infect humans. Over time, they cause acquired immunodeficiency syndrome (AIDS), a condition in which progressive failure of the im ...
-infected persons,
organ transplant
Organ transplantation is a medical procedure in which an organ (anatomy), organ is removed from one body and placed in the body of a recipient, to replace a damaged or missing organ. The donor and recipient may be at the same location, or org ...
recipients, or
newborn infants.
Congenital cytomegalovirus infection
Congenital cytomegalovirus (cCMV) is ''cytomegalovirus'' (CMV) infection in a neonate, newborn baby. Most have no symptoms. Some affected babies are small for gestational age, small. Other signs and symptoms include blueberry muffin baby, a rash, j ...
can lead to significant morbidity and even death. After infection, HCMV remains latent within the body throughout life and can be reactivated at any time. Eventually, it may cause
mucoepidermoid carcinoma
Mucoepidermoid carcinoma (MEC) is the most common type of minor salivary gland malignancy in adults. Mucoepidermoid carcinoma can also be found in other organs, such as bronchi, lacrimal sac, and thyroid gland.
Mucicarmine staining is one stain us ...
and possibly other malignancies such as
prostate cancer
Prostate cancer is the neoplasm, uncontrolled growth of cells in the prostate, a gland in the male reproductive system below the bladder. Abnormal growth of the prostate tissue is usually detected through Screening (medicine), screening tests, ...
,
breast cancer
Breast cancer is a cancer that develops from breast tissue. Signs of breast cancer may include a Breast lump, lump in the breast, a change in breast shape, dimpling of the skin, Milk-rejection sign, milk rejection, fluid coming from the nipp ...
,
ovarian cancer
Ovarian cancer is a cancerous tumor of an ovary. It may originate from the ovary itself or more commonly from communicating nearby structures such as fallopian tubes or the inner lining of the abdomen. The ovary is made up of three different ...
and
glioblastoma
Glioblastoma, previously known as glioblastoma multiforme (GBM), is the most aggressive and most common type of cancer that originates in the brain, and has a very poor prognosis for survival. Initial signs and symptoms of glioblastoma are nons ...
.
HCMV is found in all geographic locations and all socioeconomic groups, and infects between 60% and 70% of adults in the
first world
The concept of the First World was originally one of the " Three Worlds" formed by the global political landscape of the Cold War, as it grouped together those countries that were aligned with the Western Bloc of the United States. This groupin ...
and almost 100% in the
third world
The term Third World arose during the Cold War to define countries that remained non-aligned with either NATO or the Warsaw Pact. The United States, Canada, Taiwan, Japan, South Korea, the Southern Cone, NATO, Western European countries and oth ...
. Of all herpes viruses, HCMV harbors the most genes dedicated to altering (evading)