''Human alphaherpesvirus 1'' (HHV-1) is a species of virus in the genus ''

Simplexvirus ''Simplexvirus'' is a genus of viruses in the order ''Herpesvirales'', in the family ''Herpesviridae'', in the subfamily ''Alphaherpesvirinae''. Humans and mammals serve as natural hosts. Diseases associated with this genus include skin vesicles ...

'', subfamily ''

Alphaherpesvirinae ''Alphaherpesvirinae'' is a subfamily of viruses in the family ''Herpesviridae'', primarily distinguished by reproducing more quickly than other subfamilies in the ''Herpesviridae''. In animal virology the most important herpesviruses belong to ...

'', family ''

Herpesviridae ''Herpesviridae'' is a large family of DNA viruses that cause infections and certain diseases in animals, including humans. The members of this family are also known as herpesviruses. The family name is derived from the Greek word ''ἕρπειν ...

'', and order ''

Herpesvirales The ''Herpesvirales'' is an order of dsDNA viruses (Baltimore group I) with animal hosts, characterised by a common morphology consisting of an icosahedral capsid enclosed in a glycoprotein-containing lipid envelope. Common infections in humans c ...

''.

Evolution

The ''Human alphaherpesvirus 1'' virus can be classified into six

clade A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, ...

s. Four of these occur in

East Africa East Africa, Eastern Africa, or East of Africa, is the eastern subregion of the African continent. In the United Nations Statistics Division scheme of geographic regions, 10-11-(16*) territories make up Eastern Africa: Due to the historical ...

, one in

East Asia East Asia is the eastern region of Asia, which is defined in both geographical and ethno-cultural terms. The modern states of East Asia include China, Japan, Mongolia, North Korea, South Korea, and Taiwan. China, North Korea, South Korea and ...

and one in

Europe Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a Continent#Subcontinents, subcontinent of Eurasia ...

and

North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...

. This suggests that the virus may have originated in East Africa. The

most recent common ancestor In biology and genetic genealogy, the most recent common ancestor (MRCA), also known as the last common ancestor (LCA) or concestor, of a set of organisms is the most recent individual from which all the organisms of the set are descended. The ...

of the Eurasian strains appears to have evolved ~60,000 years ago.

Pathology

''Human alphaherpesvirus 1'' infects humans, most often as

cold sores Herpes labialis, commonly known as cold sores or fever blisters, is a type of infection by the herpes simplex virus that affects primarily the lip. Symptoms typically include a burning pain followed by small blisters or sores. The first attack ...

. It is very common and contagious; about 67% of the world population under the age of 50 has ''Human alphaherpesvirus 1''. It is often acquired orally during childhood. It may also be sexually transmitted, including contact with saliva, such as

kissing A kiss is the touch or pressing of one's lips against another person or an object. Cultural connotations of kissing vary widely. Depending on the culture and context, a kiss can express sentiments of love, passion, romance, sexual attraction, ...

and mouth-to-genital contact (

oral sex Oral sex, sometimes referred to as oral intercourse, is sexual activity involving the stimulation of the genitalia of a person by another person using the mouth (including the lips, tongue, or teeth) and the throat. Cunnilingus is oral sex per ...

). The virus tends to reside in the

trigeminal ganglia A trigeminal ganglion (or Gasserian ganglion, or semilunar ganglion, or Gasser's ganglion) is the sensory ganglion at the base of each of the two trigeminal nerves (CN V), occupying a cavity ( Meckel's cave) in the dura mater, covering the trige ...

. This species appears to be particularly damaging to the nervous system, and some research has attributed ''Human alphaherpesvirus 1'' infection to an increased risk of developing Alzheimer’s disease. The virus interacts with the components and receptors of

lipoproteins A lipoprotein is a biochemical assembly whose primary function is to transport hydrophobic lipid (also known as fat) molecules in water, as in blood plasma or other extracellular fluids. They consist of a triglyceride and cholesterol center, sur ...

, which may lead to the development of Alzheimer's disease. However, evidence for a relationship with Alzheimer’s disease is mixed. In 2011 Manchester University scientists showed that treating infected cells with antiviral agents decreased the accumulation of

β-amyloid Amyloid beta (Aβ or Abeta) denotes peptides of 36–43 amino acids that are the main component of the amyloid plaques found in the brains of people with Alzheimer's disease. The peptides derive from the amyloid precursor protein (APP), which is ...

and

tau protein The tau proteins (abbreviated from tubulin associated unit) are a group of six highly soluble protein isoforms produced by alternative splicing from the gene ''MAPT'' (microtubule-associated protein tau). They have roles primarily in maintaining ...

, and also decreased replication of the virus.

References

{{Taxonbar, from=Q24808667 Alphaherpesvirinae

Evolution

Pathology

See also

References