Orbivirus

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Orbivirus
Bluetongue virus.gif

Negative image of a " bluetongue virus " -like virion that causes cytopathic effects in BHK-21 cells . Scale bar = 50  nm

Systematics
Classification : Viruses
Area : Riboviria
Empire : Orthornavirae
Phylum : Duplornaviricota
Class : Resentoviricetes
Order : Reovirals
Subfamily : Sedoreovirinae
Genre : Orbivirus
Taxonomic characteristics
Genome : dsRNA segmented
Baltimore : Group 3
Symmetry : icosahedral
Cover : no
Scientific name
Orbivirus
Left
NCBI  Taxonomy: 10892
ViralZone ( ExPASy , SIB): 106
ICTV Taxon History: 201854879 (type species)

The genus Orbi virus is a member of the virus - the family Reoviridae , subfamily Sedoreovirinae . In contrast to the other reoviruses, orbiviruses are classified as arboviruses because they are transmitted by arthropods . The genus currently contains 22 types (species), Type species is the bluetongue virus ( English Bluetongue virus ). There are at least 130 different serotypes . Orbiviruses can infect and replicate in a wide variety of arthropod and vertebrate hosts . Orbiviruses are named after their characteristic donut- shaped capsomeres ( Latin orbis , circle, round, rounding ” ).

Many orbiviruses are transmitted by blood-sucking insect vectors , especially by ticks and mosquitoes - among the latter, sandflies (Psychodomorpha) and, above all, mosquitoes (Culicomorpha) such as mosquitoes and midges (genus Culicoides ).

They have a wide range of hosts, including cattle , goats (Caprini: goats and sheep ), wild ruminants , horses (Equidae family), camels (Camelidae family), large canine and feline carnivores, sloths , bats , marsupials , birds and primates such as embraces people.

The three economically most important orbivirus species are bluetongue virus , African horse sickness virus and epizootic hemorrhage virus , all of which are transmitted by species of Culicoides .

construction

The Vironen (virus particles) in the genus Orbivirus are not enveloped with a diameter of 70-80  nm . The virus particles are approximately spherical in their external appearance and have icosahedral symmetry. The genome is surrounded by an outer and an inner capsid layer with a triangulation number T = 13 (outside) or T = 2 (inside). So there are two concentric protein bowls ,

  • the inner subcore layer , which contains 120 copies of the protein VP3,
  • and the outer core-surface layer , which consists of 780 copies of the VP7 protein.

In addition, there are other smaller enzymatic proteins, VP1, VP4 and VP6 , which are packaged together with the 10 genome segments in the central space of the virus nucleus. On the outer capsid layer of the orbivirus there are two additional structural proteins (VP2 and VP5) that mediate the attachment to and penetration into the host cell during the onset of infection. The outer capsid proteins are more variable than the core proteins and most non-structural proteins, and the specificity of their reactions with neutralizing antibodies determines the particular serotype .

Genome

Orbiviruses have a double-stranded RNA genome and are therefore classified as Group III viruses in the Baltimore classification. Their genome is linear and divided into 10 segments of different lengths. One copy of each of these gene segments is packaged for each virus particle. In most cases, encodes each gene segment a single open reading frame ( English Open Reading Frame , ORF). The genome codes for seven major structural proteins (VP1-VP7) and three non-structural proteins (NS1-NS3). Exceptions to the one-gene-one protein rule are segment 9 (Seg-9) and segment 10 (Seg-10), both of which encode two almost identical proteins, (VP6 and VP6a encoded by Seg-9, NS3 and NS3a encoded by Seg-10).

An ORF spans almost the entire length of genome segment 9 and encodes VP6 (the viral helicase ). A second ORF (OrfX) is also present in this segment and encodes a fourth non-structural protein (NS4), as shown by the sequence analysis of various orbiviruses such as the Great Island virus , which has a long NS4 ORF (about 21  kDa ) contains. The existence of NS4 was experimentally confirmed in 2011 for various orbiviruses transmitted by collieries and other insects.

NS1 is the most abundant protein found in cells infected by bluetongue virus . It forms tubules that are thought to be involved in the transport (translocation) of the daughter virus to the cell membrane. NS2 is phosphorylated by cellular kinases and is an important matrix protein of the granular viral inclusion bodies that form in the cytoplasm of infected cells. These viral inclusion bodies act as centers of viral replication. The membrane glycoproteins NS3 and NS3a are produced ( expressed ) in large numbers in insect cells , but not in mammalian cells. They are involved in the eventual release of daughter viruses from the infected cells and should therefore be of crucial importance for virulence and for the suitability of a vector.

Replication

Many orbiviruses preferentially infect vascular endothelial cells . Orbiviruses enter the host cell through endocytosis , after which the outer capsid is removed. The entire cycle of virus replication then takes place in the host cell's cytoplasm. After the viral genome has been transcribed into mRNA , it is translated into proteins using the host cell's ribosomes . These viral proteins are synthesized 2-14 days after the initial infection. New virones assemble themselves in the cytoplasm ( self-assembly ) and are then released from the host cell by budding . During the budding process, they temporarily acquire a lipid shell that can be detected for a short time after its release, but is then lost again.

Clinical picture

Orbiviruses mainly cause disease in animals. The different orbivirus species have different host specificities. Orbiviruses are vector- borne pathogens. Suitable vectors are mosquitoes ( mosquitoes , midges , sand flies ) and ticks through which is transmitted between vertebrates. The bluetongue virus (BTV) is a orbivirus , one in sheep, cattle, goats and wild ungulates bluetongue caused. BTV has been at the forefront of molecular studies for three decades and is one of the best understood viruses today on a molecular and structural level. Other types of orbiviruses are responsible for other animal diseases such as African horse sickness and equine encephalosis .

classification

Systematics

The genus Orbivirus is classified in Baltimore Group 3 based on its dsRNA genome . With the classification as a genus Orbivirus within the family Reoviridae , the previous classification as an independent family Oribiviridae was revised by the International Committee on Taxonomy of Viruses (ICTV). With the Master Species List # 35 (ratified March 2020) the ICTV has classified the genus taxonomically as follows; the representatives of the individual virus species are taken from the National Center for Biotechnology Information (NCBI).

Range : Riboviria , Kingdom: Orthornavirae
Phylum: Duplornaviricota (representatives are dsRNA viruses), Class: Resentoviricetes

  • Genus: Orbivirus (obsolete: "Bluetongue virus" –like viruses , bluetongue virus-like viruses )
  • African horse sickness virus 1 to 9
  • Australian bluetongue virus
  • Bluetongue virus 1
  • Bluetongue virus 2 including Corsican bluetongue virus
  • Bluetongue virus 3 to 24 and 26
  • Bluetongue virus isolate Kol-2
  • Bukakata virus
  • Fomede virus
  • Epizootic hemorrhagic disease of deer virus
  • Epizootic hemorrhagic disease virus 1, 2, 4 to 8
  • Ibaraki virus
  • Equine encephalosis virus 1 to 7
  • Eubenengee virus
  • Tilligerry virus
  • Ngoupe virus
  • Tilligerry virus
  • Broadhaven virus
  • Kemerovo virus
  • Lipovnik virus
  • Muko virus
  • Nugget virus
  • Tribec virus
  • Kemerovo virus ( en.Kemerovo virus , KEMV)
  • Lipovnik virus ( Lipovnik virus , LIPV, vector: ticks)
  • Tribec virus (also Tribeč virus, en. Tribec virus , Tribeč virus , TRBV)
  • Bunyip Creek virus
  • Chuzan virus (en. Chuzan virus , CHUV)
  • CSIRO Village virus
  • D'Aguilar virus
  • Gweru virus
  • Marondera virus
  • Marrakai virus
  • Nyabira virus
  • Elsey virus
  • Koyama Hill virus
unclassified orbiviruses (selection)
  • Species " Aniva virus "
  • Species " Anopheles annulipes orbivirus "
  • Species " Anopheles hinesorum orbivirus "
  • Species " Arakonam virus "
  • Species " Baku virus "
  • Species " Bat orbivirus "
  • Species " Big Cypress orbivirus "
  • Species " California mosquito pool virus "
  • Species " CHeRI orbivirus 1 "
  • Species " Dnistrovskyi 408 orbivirus "
  • Species " Guangxi orbivirus "
  • Species " Heramatsu virus "
  • Species " Heramatsu virus KY-663 "
  • Species " Ife virus "
  • Species " Itupiranga virus "
  • Species " Japanaut virus "
  • Species " Kammavanpettai virus "
  • Species " Kasba virus "
  • Species " Letea virus "
  • Species " Matucare virus "
  • Species " Middle Point orbivirus " (" Middle Point virus ", proposed)
  • Species " Minnal virus "
  • Species " Mobuck virus "
  • Species " Morris orbivirus "
  • Species " Mudjinabarry virus "
  • Species " Mulberry orbivirus "
  • Species " Okhotskiy virus "
  • Species " Orbivirus JKT-8132 "
  • Species " Orbivirus PREDICT_Orbi-6 "
  • Species " Orbivirus SX-2017a "
  • Species " Parry's Lagoon virus "
  • Species " Pata virus "
  • Species " Rasqueado orbivirus "
  • Species " Sandy Bay Virus "
  • Species " Sathuvachari virus "
  • Species " Skunk River virus "
  • Species " " (" Stretch Lagoon virus ")
  • Species " Tibet orbivirus "
  • Species " Fengkai orbivirus "
  • Species " Tick ​​and insect-borne orbivirus "
  • Species " Vellore virus "
  • Species " Xinjiang tick orbivirus "

Serogroups

This genus has traditionally been divided into at least 14 serogroups. In some cases the serogroups are also subdivided into subgroups, some viruses still remained unassigned to a serogroup. The serogroups are differentiated using antibody-based tests. These tests include ELISA tests and complement fixation tests using the complement fixation reaction . The serogroups or - if available - the serogroups correspond to the species in modern taxonomy. But not all serotypes can be at NCBI a tribe ( English strain ) or assign an isolate.

  • Serogroup the African Pferdepestviren (species African horse sickness , en. African horse sickness virus )
  • African horse sickness virus 1-9 (AHSV 1-9)
  • Serogroup of bluetongue virus (species bluetongue virus , en. Bluetongue virus )
  • Bluetongue virus 1–26 (BTV 1–26)
  • Changuinola serogroup (species Changuinola virus )
  • Corriparta serogroup (species Corriparta virus )
  • Umatilla serogroup (species Umatilla virus )
  • Wallal serogroup (species Wallal virus )
  • Warrego serogroup (species Warrego virus )
  • Wongorr serogroup (species Wongorr virus )
  • Lebombo virus (LEBV, species Lebombo virus , not assigned to a group)
  • Pata virus (PATAV, species " Pata virus ", without groupassignment)

Vector groups

Orbiviruses are known to be transmitted by various groups of mosquitoes and ticks. The viruses transmitted by a certain type of vector often appear to be both genetically and serologically related, which of course requires confirmation by sequence analysis for recognition by the ICTV.

  • Culicoides vector group (midges vector group), en. Midge vector group - carriers are midges of the genus Culicoides
  • African horse sickness virus
  • Bluetongue virus
  • Palyam virus : Chuzan virus
  • Epizootic Hemorrhage Virus
  • Equine Encephalosis Virus
  • Eubenangee virus
  • Palyam virus
  • Wallal virus
  • Warrego virus
  • Mosquito vector group (biting fly vector group), en. Mosquito vector group - carriers are biting flies (Culicidae)
  • Corriparta virus
  • Peruvian horse sickness virus
  • Wongorr virus
  • Umatilla virus
  • Yunnan Orbivirus
  • Tick ​​vector group - the representatives of this group all belong to the species Great Island virus . The ancestors of the other groups could come from this group.
  • Great Island virus
  • Broadhaven virus
  • Kemerovo virus
  • Lipovnik virus
  • Tribeč virus

Research history

In 1719, African horse sickness virus (AHSV) caused the first major orbivirus epidemic, killing 1,500 animals. The historically most significant orbivirus outbreak occurred between 1854 and 1855 when AHSV infected 70,000 horses. AHSV was discovered as a virus in 1900, and bluetongue virus followed shortly after in 1905 . Further outbreaks occurred sporadically in the 20th and 21st centuries.

Individual evidence

  1. ↑ ICTV Master Species List 2018b v1 MSL # 34, Feb. 2019
  2. ↑ a b c d e f g ICTV: Bluetongue virus , EC 51, Berlin, Germany, July 2019; Email ratification March 2020 (MSL # 35)
  3. ↑ a b c Viral Zone . ExPASy. Retrieved June 12, 2020.
  4. ↑ orbis , on: POS online dictionary
  5. ↑ a b David M. Knipe: Fields Virology ( en ). Wolters Kluwer Health, June 17, 2013, ISBN 9781451105636 .
  6. ↑ M. Belhouchet, F. Mohd Jaafar, A. E. Firth, J. M. Grimes, P. P. Mertens, H. Attoui: Detection of a fourth orbivirus non-structural protein , in: PLoS One 6 (10) of October 12, 2011, e25697, doi : 10.1371 / journal.pone.0025697 , PMC 3192121 (free full text), PMID 22022432
  7. ^ P. Roy: Molecular Dissection of Bluetongue Virus . In: Animal Viruses: Molecular Biology . Caister Academic Press, 2008, ISBN 978-1-904455-22-6 .
  8. ^ P. Roy: Structure and Function of Bluetongue Virus and its Proteins . In: Segmented Double-stranded RNA Viruses: Structure and Molecular Biology . Caister Academic Press, 2008, ISBN 978-1-904455-21-9 .
  9. ↑ G. J. Viljoen, H. Huismans: The Characterization of Equine Encephalosis Virus and the Development of Genomic Probes . J. gen. Virol. 70, 2007-2015. August 1, 1989, doi: 10.1099 / 0022-1317-70-8-2007
  10. ↑ a b NCBI: Orbivirus (genus)
  11. ↑ NCBI: unclassified orbivirus
  12. ↑ NCBI: Middle Point orbivirus (species)
  13. ↑ NCBI: Pata virus (species)
  14. ↑ NCBI: Stretch Lagoon orbivirus (species)
  15. ↑ M. Dilcher, L. Hasib, M. Lechner, N. Wieseke, M. Middendorf, M. Marz, A. Koch, M. Spiegel, G. Dobler, F. T. Hufert, M. Weidmann: Genetic characterization of Tribeč virus and Kemerovo virus, two tick-transmitted human-pathogenic orbiviruses , Virology, Volume 423, Issue 1, February 5, 2012, pp. 68-76, doi: 10.1016 / j.virol.2011.11.020
  16. ↑ D.A. Warrell, T.M. Cox, J.D. Firth: Oxford textbook of Medicine. Oxford 20013
  17. ↑ CDC: Virus Name: Altamira , in: Arbovirus Catalog
  18. ↑ CDC: Virus Name: Almeirim , in: Arbovirus Catalog
  19. ↑ CDC: Virus Name: Caninde , in: Arbovirus Catalog
  20. ↑ CDC: Virus Name: Changuinola , in: Arbovirus Catalog
  21. ↑ Yasuo Miura, Shunkou Miyazato, Masanori Kubo, Yoshiyuki Goto, Yuji Kono: Kawanabe Virus, an Isolate from a Calf in Japan: A New Virus belonging to the New Jersey Serotype of the Epizootic Hemorrhagic Disease Serogroup of Genus Orbivirus , in: The Japanese Journal of Veterinary Science, Vol. 50, No. 4, 1988, pp. 942-945
  22. ↑ Belaganahalli MN, Maan S, Maan NS, Tesh R, Attoui H, Mertens PP (2011) Umatilla virus genome sequencing and phylogenetic analysis: identification of stretch lagoon orbivirus as a new member of the Umatilla virus species. PLoS One 6 (8): e23605.

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