Herpesvirales

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Herpesvirales
Herpesvirales virion diagram.jpg
Simplified diagram of Herpesvirales virion structure in cross-section. (1) nucleoprotein, (2) DNA, (3) capsid, (4) tegument, (5) envelope, (6) glycoprotein. Click to enlarge.
Herpesviridae EM PHIL 2171 lores.jpg
Electron micrograph of various viruses from the Orthoherpesviridae family including Human alphaherpesvirus 3 (Chickenpox), Human alphaherpesvirus 1 , and Human alphaherpesvirus 2
Virus classification OOjs UI icon edit-ltr.svg
(unranked): Virus
Realm: Duplodnaviria
Kingdom: Heunggongvirae
Phylum: Peploviricota
Class: Herviviricetes
Order:Herpesvirales
Families

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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 caused by members of this order include cold sores, genital herpes, chickenpox, shingles, and glandular fever. Herpesvirales is the sole order in the class Herviviricetes, which is the sole class in the phylum Peploviricota.

Contents

Virology

Morphology

All members of the order have a virion structure that consists of a DNA core surrounded by an icosahedral capsid composed of 12 pentavalent and 150 hexavalent capsomeres (T = 16). The capsid has a diameter of ~110 nanometers (nm) and is embedded in a proteinaceous matrix called the tegument, which in its turn is enclosed by a glycoprotein-containing lipid envelope with a diameter of about 200 nm. The DNA genome is linear and double stranded, with sizes in the range 125–290 kbp. [1] The genome contains terminal and internal reiterated sequences, with their number and disposition varying depending on the different subclades.

Hosts

A cold sore Herpes(PHIL 1573 lores).jpg
A cold sore
Herpesviruses may be highly virulent in some species. This dying mallard infected with Anatid alphaherpesvirus 1 is emitting a bloody nasal discharge on the ice. Duck plague victim.JPG
Herpesviruses may be highly virulent in some species. This dying mallard infected with Anatid alphaherpesvirus 1 is emitting a bloody nasal discharge on the ice.

All species in this order have animal hosts. The Malacoherpesviridae infect molluscs (abalone and oysters), the Alloherpesviridae infect anamniotes (frogs and fish), and the Herpesviridae infect amniotes (reptiles, birds, and mammals). Within the family Herpesviridae, genera Iltovirus and Mardivirus , and genus Scutavirus of the subfamily Alphaherpesvirinae infect birds and reptiles, respectively. All other genera in the Herpesviridae infect mammals only. [2]

Taxonomy

As of 2020, the order is made up of three families, three subfamilies, 23 genera, and 130 species. The taxonomy is shown from family, to subfamily, to genus below. [3]

History

The herpesvirus was first isolated from the blue wildebeest in 1960 by veterinary scientist Walter Plowright. [4] The genus Herpesvirus was established in 1971 in the first report of the International Committee on Taxonomy of Viruses (ICTV). This genus consisted of 23 viruses and 4 groups of viruses. In the second ICTV report in 1976 this genus was elevated to family level - the Herpetoviridae. Because of possible confusion with viruses derived from reptiles this name was changed in the third report in 1979 to Herpesviridae. In this report the family Herpesviridae was divided into 3 subfamilies (Alphaherpesvirinae, Betaherpesvirinae and Gammaherpesvirinae) and 5 unnamed genera: 21 viruses were listed. In 2009 the family Herpesviridae was elevated to the order Herpesvirales. This elevation was necessitated by the discovery that the herpesviruses of fish and molluscs were only distantly related to those of birds and mammals. [5] Two new families were created - the family Alloherpesviridae which incorporates bony fish and frog viruses and the family Malacoherpesviridae which contains those of molluscs.

Phylogenetics

The only protein with widespread conservation amongst all members of the order, albeit only at the amino-acid level, is the ATPase subunit of the DNA terminase; [1] the latter is involved in the packaging of the DNA during virion assembly. [6]

Phylogenies constructed with the conserved regions of the ATPase subunit of the DNA terminase suggest that Alloherpesviridae is the basal clade of the order, and that Herpesviridae and Malacoherpesviridae are sister clades. [7] Given the phylogenetic distances between vertebrates and molluscs, this suggests that herpesviruses were initially fish viruses and that they have evolved with their hosts to infect other vertebrates.[ citation needed ]

Species nomenclature

The Herpesvirales naming system originated in 1973 and has been elaborated considerably since. All herpesviruses described since this system was adopted have been named in accordance with it. The recommended naming system specifies that each species name consists of three parts: a first word, a second word, and finally a number.

The first word should be derived from the taxon (family or subfamily) to which its primary natural host belongs. The subfamily name is used for viruses from members of the family Bovidae or from primates (the virus name ending in –ine, e.g. bovine), and the host family name for other viruses (ending in –id, e.g. equid). Human herpesviruses have been treated as an exception (human rather than hominid). Following the host-derived term, species in the family Herpesviridae, which are divided into subfamilies Alphaherpesvirinae, Betaherpesvirinae, and Gammaherpesvirinae, will have the word alphaherpesvirus, betaherpesvirus, or gammaherpesvirus added, respectively. Species in the Herpesviridae that have not been assigned to a subfamily, and species in Alloherpesviridae and Malacoherpesviridae will have herpesvirus following the host-derived term instead. Finally an Arabic number (1, 2, 3, and so forth) is appended. Numbers are assigned in order of naming and bear no implied meaning about the taxonomic or biological properties of the virus.

An example of such a name is Canid alphaherpesvirus 1 . From this name it can be ascertained that the virus' primary natural host is a canid (i.e. a member of the family Canidae; dogs etc.), that it is a member of the family Herpesviridae and subfamily Alphaherpesvirinae, and that it is the first herpesvirus named for which canids serve as primary natural hosts.

A number of virus names (e.g. Epstein–Barr virus, also known as Human gammaherpesvirus 4) are so widely used that it may be impractical to attempt to insist on their replacement. This has led to a dual nomenclature in the literature for some herpesviruses.

Related Research Articles

<i>Cytomegalovirus</i> Genus of viruses

Cytomegalovirus (CMV) is a genus of viruses in the order Herpesvirales, in the family Herpesviridae, in the subfamily Betaherpesvirinae. Humans and other primates serve as natural hosts. The 11 species in this genus include human betaherpesvirus 5, which is the species that infects humans. Diseases associated with HHV-5 include mononucleosis and pneumonia, and congenital CMV in infants can lead to deafness and ambulatory problems.

Roseolovirus is a genus of viruses in the order Herpesvirales, in the family Herpesviridae, in the subfamily Betaherpesvirinae. There are currently six species in this genus. Diseases associated with this genus include: HHV-6: sixth disease ; HHV-7: symptoms analog to the 'sixth disease'.

Rhadinovirus is a genus of viruses in the order Herpesvirales, in the family Herpesviridae, in the subfamily Gammaherpesvirinae. Humans and other mammals serve as natural hosts. There are 12 species in this genus. Diseases associated with this genus include: Kaposi's sarcoma, primary effusion lymphoma and multicentric Castleman's disease, caused by Human gammaherpesvirus 8 (HHV-8), also known as Kaposi's sarcoma-associated herpesvirus (KSHV). The term rhadino comes from the Latin fragile, referring to the tendency of the viral genome to break apart when it is isolated.

<i>Mardivirus</i> Genus of viruses in the family Herpesviridae affecting Chickens, turkeys, and quail

Mardivirus is a genus of viruses in the order Herpesvirales, in the family Herpesviridae, in the subfamily Alphaherpesvirinae. Chickens, turkeys, and quail serve as natural hosts. There are six species in this genus. Diseases associated with this genus include: Marek's disease, which causes asymmetric paralysis of one or more limbs, neurological symptoms, and development of multiple lymphomas that manifest as solid tumors. Gallid herpesvirus 2 is the only one of these viruses known to be pathogenic and due to the antigenic similarity between the three viruses the other two have been used to vaccinate against Marek's disease. These viruses have double stranded DNA genomes with no RNA intermediate.

<i>Alphaherpesvirinae</i> Subfamily of viruses

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 the Alphaherpesvirinae. Pseudorabies virus is the causative agent of Aujeszky's disease in pigs and Bovine herpesvirus 1 is the causative agent of bovine infectious rhinotracheitis and pustular vulvovaginitis. Mammals serve as natural hosts. There are currently 45 species in this subfamily, divided among 5 genera with one species unassigned to a genus. Diseases associated with this subfamily include: HHV-1 and HHV-2: skin vesicles or mucosal ulcers, rarely encephalitis and meningitis, HHV-3: chickenpox (varicella) and shingles, GaHV-2: Marek's disease.

<i>Herpesviridae</i> Family of DNA viruses

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, referring to spreading cutaneous lesions, usually involving blisters, seen in flares of herpes simplex 1, herpes simplex 2 and herpes zoster (shingles). In 1971, the International Committee on the Taxonomy of Viruses (ICTV) established Herpesvirus as a genus with 23 viruses among four groups. As of 2020, 115 species are recognized, all but one of which are in one of the three subfamilies. Herpesviruses can cause both latent and lytic infections.

<span class="mw-page-title-main">Duck plague</span> Disease caused by Anatid alphaherpesvirus 1

Duck plague is a worldwide disease caused by Anatid alphaherpesvirus 1 (AnHV-1) of the family Herpesviridae that causes acute disease with high mortality rates in flocks of ducks, geese, and swans. It is spread both vertically and horizontally—through contaminated water and direct contact. Migratory waterfowl are a major factor in the spread of this disease as they are often asymptomatic carriers of disease. The incubation period is three to seven days. Birds as young as one week old can be infected. DEV is not zoonotic.

<i>Gammaherpesvirinae</i> Subfamily of viruses

Gammaherpesvirinae is a subfamily of viruses in the order Herpesvirales and in the family Herpesviridae. Viruses in Gammaherpesvirinae are distinguished by reproducing at a more variable rate than other subfamilies of Herpesviridae. Mammals serve as natural hosts. There are 43 species in this subfamily, divided among 7 genera with three species unassigned to a genus. Diseases associated with this subfamily include: HHV-4: infectious mononucleosis. HHV-8: Kaposi's sarcoma.

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 subfamily include: human cytomegalovirus (HHV-5): congenital CMV infection; HHV-6: 'sixth disease' ; HHV-7: symptoms analogous to the 'sixth disease'.

<i>Lymphocryptovirus</i> Genus of viruses

Lymphocryptovirus is a genus of viruses in the order Herpesvirales, in the family Herpesviridae, in the subfamily Gammaherpesvirinae. This genus includes the human-infecting Human gammaherpesvirus 4, as well as viruses that infect both Old World monkeys and New World monkeys. Other names for the Lymphocryptovirus genus include Lymphocryptoviridae and gamma-1 herpesviruses. There are nine species in this genus. Diseases associated with this genus include: mononucleosis, Burkitt's lymphoma, and nasopharyngeal carcinoma.

Muromegalovirus is a genus of viruses in the order Herpesvirales, in the family Herpesviridae, in the subfamily Betaherpesvirinae. Rodents serve as natural hosts. There are three species in this genus. Diseases associated with this genus include: infected peritoneal macrophages, dendritic cells (DC) and hepatocytes, inducing significant pathology in both the spleen and the liver. Murid viruses Murid betaherpesvirus 1 (MuHV-1) and Murid betaherpesvirus 2 (MuHV-2), previously defined as mouse cytomegalovirus (MCMV) and rat cytomegalovirus (RCMV), belong to this genus.

Malacoherpesviridae is a family of DNA viruses in the order Herpesvirales. Molluscs serve as natural hosts, making members of this family the only known herpesviruses to infect invertebrates. There are currently only two species recognised in this family, both classified into separate genera. Disease associated with this family includes sporadic episodes of high mortality among larvae and juveniles. The family name Malacoherpesviridae is derived from Greek word 'μαλακός (malacos) meaning 'soft' and from Greek word 'μαλάκιον (malakion) meaning 'mollusc'.

Proboscivirus is a genus of viruses in the order Herpesvirales, in the family Herpesviridae, in the subfamily Betaherpesvirinae. Elephants serve as natural hosts. EEHV1 is apathogenic for African elephants but causes fatal haemorrhagic disease in Asian elephants. The name "Proboscivirus" comes from the Greek word προβοσκίς or "proboscis" meaning "the elephant trunk," for which the virus accordingly uses as its means of contraction and transmission to enter the elephant's body.

Scutavirus is a genus of viruses in the order Herpesvirales, in the family Herpesviridae, in the subfamily Alphaherpesvirinae. Turtles and tortoises serve as natural hosts. Diseases associated with this genus include fibropapillomatosis.

Aurivirus is a genus of viruses in the order Herpesvirales, and one of only two genera the family Malacoherpesviridae. Haliotid molluscs serve as natural hosts. There is only one species described in this genus, Haliotid herpesvirus 1 (AbHV-1), commonly known as abalone herpesvirus. A disease associated with this virus is acute ganglioneuritis.

Caprine alphaherpesvirus 1 (CpHV-1) is a species of virus known to infect goats worldwide. It has been shown to produce systemic and respiratory symptoms in kids and to cause abortions in adult goats.

Callitrichine gammaherpesvirus 3 (CalHV-3) is a species of virus that infects marmosets. It is in the genus Lymphocryptovirus, subfamily Gammaherpesvirinae, family Herpesviridae, and order Herpesvirales,.

Panine gammaherpesvirus 1 (PnHV-1), commonly known as chimpanzee lymphocryptovirus, is a species of virus in the genus Lymphocryptovirus, subfamily Gammaherpesvirinae, family Herpesviridae, and order Herpesvirales.

Ovine gammaherpesvirus 2 (OvHV-2) is a species of virus in the genus Macavirus, subfamily Gammaherpesvirinae, family Herpesviridae, and order Herpesvirales.

<i>Duplodnaviria</i> Realm of viruses

Duplodnaviria is a realm of viruses that includes all double-stranded DNA viruses that encode the HK97 fold major capsid protein. The HK97 fold major capsid protein is the primary component of the viral capsid, which stores the viral deoxyribonucleic acid (DNA). Viruses in the realm also share a number of other characteristics, such as an icosahedral capsid, an opening in the viral capsid called a portal, a protease enzyme that empties the inside of the capsid prior to DNA packaging, and a terminase enzyme that packages viral DNA into the capsid.

References

  1. 1 2 Davison, Andrew J.; Eberle, Richard; Ehlers, Bernhard; Hayward, Gary S.; McGeoch, Duncan J.; Minson, Anthony C.; Pellett, Philip E.; Roizman, Bernard; Studdert, Michael J. (2009). "The order Herpesvirales". Archives of Virology. 154 (1): 171–177. doi:10.1007/s00705-008-0278-4. ISSN   1432-8798. PMC   3552636 . PMID   19066710.
  2. ↑ McGeoch, Duncan J.; Davison, Andrew J.; Dolan, Aidan; Gatherer, Derek; Sevilla-Reyes, Edgar E. (2008). DOMINGO, ESTEBAN; PARRISH, COLIN R.; HOLLAND, JOHN J. (eds.). Origin and Evolution of Viruses (Second ed.). London: Academic Press. pp.  447–475. ISBN   9780123741530.
  3. ↑ "Virus Taxonomy: 2020 Release". International Committee on Taxonomy of Viruses (ICTV). March 2021. Retrieved 10 May 2021.
  4. ↑ O.A., Ryder; Byrd, M.L. (1984). One Medicine: A Tribute to Kurt Benirschke, Director Center for Reproduction of Endangered Species Zoological Society of San Diego and Professor of Pathology and Reproductive Medicine University of California San Diego from his Students and Colleagues. Berlin, Heidelberg: Springer. pp. 296–308. ISBN   978-3-642-61749-2.
  5. ↑ Duncan J. McGeoch, Andrew J. Davison, Aidan Dolan, Derek Gatherer, Edgar E. Sevilla-Reyes (2008). Origin and Evolution of Viruses (Second ed.). Academic Press. pp. Chapter 20: 447–475.{{cite book}}: CS1 maint: multiple names: authors list (link)
  6. ↑ Selvarajan Sigamani, Sundaresan; Zhao, Haiyan; Kamau, Yvonne N.; Baines, Joel D.; Tang, Liang (June 2013). "The structure of the herpes simplex virus DNA-packaging terminase pUL15 nuclease domain suggests an evolutionary lineage among eukaryotic and prokaryotic viruses". Journal of Virology. 87 (12): 7140–7148. doi:10.1128/JVI.00311-13. ISSN   1098-5514. PMC   3676077 . PMID   23596306.
  7. ↑ Rakus, Krzysztof; Ouyang, Ping; Boutier, Maxime; Ronsmans, Maygane; Reschner, Anca; Vancsok, Catherine; Jazowiecka-Rakus, Joanna; Vanderplasschen, Alain (2013). "Cyprinid herpesvirus 3: an interesting virus for applied and fundamental research". Veterinary Research. 44 (1): 85. doi: 10.1186/1297-9716-44-85 . ISSN   0928-4249. PMC   3850573 . PMID   24073814.
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