dcsimg
Image of Phlebovirus

Bunyavirales

Bunyavirales

provided by wikipedia EN

Bunyavirales is an order of segmented negative-strand RNA viruses with mainly tripartite genomes. Member viruses infect arthropods, plants, protozoans, and vertebrates.[2] It is the only order in the class Ellioviricetes.[1] The name Bunyavirales derives from Bunyamwera,[3] where the original type species Bunyamwera orthobunyavirus was first discovered.[4] Ellioviricetes is named in honor of late virologist Richard M. Elliott for his early work on bunyaviruses.[5]

Bunyaviruses belong to the fifth group of the Baltimore classification system, which includes viruses with a negative-sense, single-stranded RNA genome. They have an enveloped, spherical virion. Though generally found in arthropods or rodents, certain viruses in this order occasionally infect humans. Some of them also infect plants.[6] In addition, there is a group of bunyaviruses whose replication is restricted to arthropods and is known as insect-specific bunyaviruses.[7]

A majority of bunyaviruses are vector-borne. With the exception of Hantaviruses and Arenaviruses, all viruses in the Bunyavirales order are transmitted by arthropods (mosquitos, tick, or sandfly). Hantaviruses are transmitted through contact with rodent feces. Incidence of infection is closely linked to vector activity, for example, mosquito-borne viruses are more common in the summer.[6]

Human infections with certain members of Bunyavirales, such as Crimean-Congo hemorrhagic fever orthonairovirus, are associated with high levels of morbidity and mortality, consequently handling of these viruses is done in biosafety level 4 laboratories. They are also the cause of severe fever with thrombocytopenia syndrome.[8]

Hantaviruses are another medically important member of the order Bunyvirales. They are found worldwide, and are relatively common in Korea, Scandinavia (including Finland), Russia, western North America and parts of South America. Hantavirus infections are associated with high fever, lung edema, and pulmonary failure. The mortality rate varies significantly depending on the form, being up to 50% in New World hantaviruses (the Americas), up to 15% in Old World hantaviruses (Asia and Europe), and as little as 0.1% in Puumala virus (mostly Scandinavia).[9] The antibody reaction plays an important role in decreasing levels of viremia.

Virology

Structure

 src=
Peribunyavirus virion structure

Bunyavirus morphology is somewhat similar to that of the Paramyxoviridae family; Bunyavirales form enveloped, spherical virions with diameters of 80–120 nm. These viruses contain no matrix proteins.[10]

Genome

Bunyaviruses have bi- or tripartite genomes consisting of a large (L) and small(s), or large (L), medium (M), and small (S) RNA segment. These RNA segments are single-stranded, and exist in a helical formation within the virion. Besides, they exhibit a pseudo-circular structure due to each segment's complementary ends. The L segment encodes the RNA-dependent RNA polymerase, necessary for viral RNA replication and mRNA synthesis. The M segment encodes the viral glycoproteins, which project from the viral surface and aid the virus in attaching to and entering the host cell. The S segment encodes the nucleocapsid protein (N).[11]

Most bunyaviruses have a negative-sense L and M segment. The S segment of the genus Phlebovirus,[12] and both M and S segment of the genus Tospovirus are ambisense.[13] Ambisense means that some of the genes on the RNA strand are negative sense and others are positive sense. The ambisense S segment codes for the viral nucleoprotein (N) in the negative sense and a nonstructural protein (NSs) in the positive sense. The ambisense M segment codes for glycoprotein (GP) in the negative sense and a nonstructural protein (NSm) in the positive sense.[13]

The total genome size ranges from 10.5 to 22.7 kbp.[14]

Life cycle

 src=
Nairovirus life cycle.

The ambisense genome requires two rounds of transcription to be carried out. First, the negative-sense RNA is transcribed to produce mRNA and a full-length replicative intermediate. From this intermediate, a subgenomic mRNA encoding the small segment nonstructural protein is produced while the polymerase produced following the first round of transcription can now replicate the full-length RNA to produce viral genomes.

Bunyaviruses replicate in the cytoplasm, while the viral proteins transit through the ER and Golgi apparatus. Mature virions bud from the Golgi apparatus into vesicles which are transported to the cell surface.

Transmission

Bunyaviruses infect arthropods, plants, protozoans, and vertebrates.[2] Plants can host bunyaviruses from the families Tospoviridae and Fimoviridae (e.g. tomato, pigeonpea, melon, wheat, raspberry, redbud, and rose). Members of some families are insect-specific, for example the phasmavirids, first isolated from phantom midges,[15] and since identified in diverse insects including moths, wasps and bees, and other true flies.

Taxonomy

 src=
Phylogenetic tree of Bunyavirales

There are 477 virus species recognised in this order.[1] The phylogenetic tree diagram provides a full list of member species and the hosts which they infect.[2] The order is organized into the following 12 families:[1]

Diseases in humans

Bunyaviruses that cause disease in humans include:

Bunyaviruses have segmented genomes, making them capable of rapid recombination and increasing the risk of outbreak.[16] The bunyavirus that causes severe fever with thrombocytopenia syndrome can undergo recombination both by reassortment of genome segments and by intragenic homologous recombination.[17][18] Bunyaviridae are transmitted by hematophagous arthropods including mosquitoes, midges, flies, and ticks. The viral incubation period is about 48 hours. Symptomatic infection typically causes non-specific flu-like symptoms with fever lasting for about three days. Because of their non-specific symptoms, Bunyavirus infections are frequently mistaken for other illnesses. For example, Bwamba fever is often mistaken for malaria.[19]

Prevention

Prevention depends on the reservoir, amplifying hosts and how the viruses are transmitted, i.e. the vector, whether ticks or mosquitoes and which animals are involved. Preventive measures include general hygiene, limiting contact with vector saliva, urine, feces, or bedding. There is no licensed vaccine for bunyaviruses. As precautions Cache Valley virus and Hantavirus research are conducted in BSL-2 (or higher), Rift Valley Fever virus research is conducted in BSL-3 (or higher), Congo-Crimean Hemorrhagic Fever virus research is conducted in BSL-4 laboratories.

Timeline

1940s: Crimean–Congo hemorrhagic fever is discovered in Russia

1951: 3,000 cases of Hantavirus were reported in South Korea in 1951, a time when UN forces were fighting on the 38th parallel during the Korean War

1956: Cache Valley virus isolated in Culiseta inornata mosquitoes in Utah

1960: La Crosse virus was first recognized in a fatal case of encephalitis in La Crosse, Wisconsin

1977: Rift Valley Fever virus caused approximately 200,000 cases and 598 deaths in Egypt

2017: Bunyavirales order is created

References

  1. ^ a b c d "Virus Taxonomy: 2020 Release". International Committee on Taxonomy of Viruses (ICTV). March 2021. Retrieved 19 May 2021.
  2. ^ a b c Herath, Venura; Romay, Gustavo; Urrutia, Cesar D.; Verchot, Jeanmarie (September 2020). "Family Level Phylogenies Reveal Relationships of Plant Viruses within the Order Bunyavirales". Viruses. 12 (9): 1010. doi:10.3390/v12091010. PMC 7551631. PMID 32927652.
  3. ^ "ICTV 9th Report (2011) Bunyaviridae". International Committee on Taxonomy of Viruses (ICTV). Retrieved 31 January 2019. Bunya: from Bunyamwera, place in Uganda, where type virus was isolated.
  4. ^ Smithburn, K. C.; Haddow, A. J.; Mahaffy, A. F. (March 1946). "A Neurotropic Virus Isolated from Aedes Mosquitoes Caught in the Semliki Forest". The American Journal of Tropical Medicine and Hygiene. s1-26 (2): 189–208. doi:10.4269/ajtmh.1946.s1-26.189. ISSN 1476-1645. OCLC 677158400. PMID 21020339.
  5. ^ Wolf, Yuri; Krupovic, Mart; Zhang, Yong Zhen; Maes, Piet; Dolja, Valerian; Koonin, Eugene V.; Kuhn, Jens H. "Megataxonomy of negative-sense RNA viruses" (docx). International Committee on Taxonomy of Viruses (ICTV). Retrieved 12 January 2019.
  6. ^ a b Plyusnin, A; Elliott, RM, eds. (2011). Bunyaviridae: Molecular and Cellular Biology. Caister Academic Press. ISBN 978-1-904455-90-5.
  7. ^ Elrefaey, Ahmed ME; Abdelnabi, Rana; Rosales Rosas, Ana Lucia; Wang, Lanjiao; Basu, Sanjay; Delang, Leen (September 2020). "Understanding the Mechanisms Underlying Host Restriction of Insect-Specific Viruses". Viruses. 12 (9): 964. doi:10.3390/v12090964. PMC 7552076. PMID 32878245.
  8. ^ Yu XJ, Liang MF, Zhang SY, et al. (April 2011). "Fever with thrombocytopenia associated with a novel bunyavirus in China". N. Engl. J. Med. 364 (16): 1523–32. doi:10.1056/NEJMoa1010095. PMC 3113718. PMID 21410387.
  9. ^ Walter Muranyi; Udo Bahr; Martin Zeier; Fokko J. van der Woude (2005). "Hantavirus Infection". Journal of the American Society of Nephrology. 16 (12): 3669–3679. doi:10.1681/ASN.2005050561. PMID 16267154.
  10. ^ "Bunyaviridae - Negative Sense RNA Viruses - Negative Sense RNA Viruses (2011)". International Committee on Taxonomy of Viruses (ICTV). Retrieved 2020-09-08.
  11. ^ Ariza, A.; Tanner, S. J.; Walter, C. T.; Dent, K. C.; Shepherd, D. A.; Wu, W.; Matthews, S. V.; Hiscox, J. A.; Green, T. J. (2013-06-01). "Nucleocapsid protein structures from orthobunyaviruses reveal insight into ribonucleoprotein architecture and RNA polymerization". Nucleic Acids Research. 41 (11): 5912–5926. doi:10.1093/nar/gkt268. ISSN 0305-1048. PMC 3675483. PMID 23595147.
  12. ^ Elliott, Richard M; Brennan, Benjamin (April 2014). "Emerging phleboviruses". Current Opinion in Virology. 5 (100): 50–57. doi:10.1016/j.coviro.2014.01.011. PMC 4031632. PMID 24607799.
  13. ^ a b Lima, R. N.; De Oliveira, A. S.; Leastro, M. O.; Blawid, R.; Nagata, T.; Resende, R. O.; Melo, F. L. (7 July 2016). "The complete genome of the tospovirus Zucchini lethal chlorosis virus". Virology Journal. 13 (1): 123. doi:10.1186/s12985-016-0577-4. PMC 4936248. PMID 27388209.
  14. ^ "00.011. Bunyaviridae". ICTVdB—The Universal Virus Database, version 4. 2006. Retrieved 2009-01-01.
  15. ^ Ballinger, MJ; Bruenn, JA; Hay, J; Czechowski, D; Taylor, DJ (2014). "Discovery and evolution of bunyavirids in arctic phantom midges and ancient bunyavirid-like sequences in insect genomes". J Virol. 88 (16): 8783–94. doi:10.1128/JVI.00531-14. PMC 4136290. PMID 24850747.
  16. ^ Horne, Kate McElroy; Vanlandingham, Dana L. (2014-11-13). "Bunyavirus-Vector Interactions". Viruses. 6 (11): 4373–4397. doi:10.3390/v6114373. ISSN 1999-4915. PMC 4246228. PMID 25402172.
  17. ^ Lv Q, Zhang H, Tian L, Zhang R, Zhang Z, Li J, Tong Y, Fan H, Carr MJ, Shi W. Novel sub-lineages, recombinants and reassortants of severe fever with thrombocytopenia syndrome virus. Ticks Tick Borne Dis. 2017 Mar;8(3):385-390. doi: 10.1016/j.ttbdis.2016.12.015. Epub 2017 Jan 3. PMID 28117273
  18. ^ He CQ, Ding NZ. Discovery of severe fever with thrombocytopenia syndrome bunyavirus strains originating from intragenic recombination. J Virol. 2012 Nov;86(22):12426-30. doi: 10.1128/JVI.01317-12. Epub 2012 Aug 29. PMID 22933273
  19. ^ Patrick R. Murray, Ken S. Rosenthal and Michael A. Pfaller (2008-12-24). Medical Microbiology, 6e (6 ed.). Philadelphia: Mosby. ISBN 9780323054706.

 title=
license
cc-by-sa-3.0
copyright
Wikipedia authors and editors
original
visit source
partner site
wikipedia EN

Bunyavirales: Brief Summary

provided by wikipedia EN

Bunyavirales is an order of segmented negative-strand RNA viruses with mainly tripartite genomes. Member viruses infect arthropods, plants, protozoans, and vertebrates. It is the only order in the class Ellioviricetes. The name Bunyavirales derives from Bunyamwera, where the original type species Bunyamwera orthobunyavirus was first discovered. Ellioviricetes is named in honor of late virologist Richard M. Elliott for his early work on bunyaviruses.

Bunyaviruses belong to the fifth group of the Baltimore classification system, which includes viruses with a negative-sense, single-stranded RNA genome. They have an enveloped, spherical virion. Though generally found in arthropods or rodents, certain viruses in this order occasionally infect humans. Some of them also infect plants. In addition, there is a group of bunyaviruses whose replication is restricted to arthropods and is known as insect-specific bunyaviruses.

A majority of bunyaviruses are vector-borne. With the exception of Hantaviruses and Arenaviruses, all viruses in the Bunyavirales order are transmitted by arthropods (mosquitos, tick, or sandfly). Hantaviruses are transmitted through contact with rodent feces. Incidence of infection is closely linked to vector activity, for example, mosquito-borne viruses are more common in the summer.

Human infections with certain members of Bunyavirales, such as Crimean-Congo hemorrhagic fever orthonairovirus, are associated with high levels of morbidity and mortality, consequently handling of these viruses is done in biosafety level 4 laboratories. They are also the cause of severe fever with thrombocytopenia syndrome.

Hantaviruses are another medically important member of the order Bunyvirales. They are found worldwide, and are relatively common in Korea, Scandinavia (including Finland), Russia, western North America and parts of South America. Hantavirus infections are associated with high fever, lung edema, and pulmonary failure. The mortality rate varies significantly depending on the form, being up to 50% in New World hantaviruses (the Americas), up to 15% in Old World hantaviruses (Asia and Europe), and as little as 0.1% in Puumala virus (mostly Scandinavia). The antibody reaction plays an important role in decreasing levels of viremia.

license
cc-by-sa-3.0
copyright
Wikipedia authors and editors
original
visit source
partner site
wikipedia EN

Bunyavirales

provided by wikipedia FR

Les Bunyavirales sont un ordre de virus de plus de 300 membres avec une enveloppe sphérique et hélicoïdale de diamètre d'environ 80 à 120 nanomètres. L'une des caractéristiques unificatrices de ces virus est la possession d'un génome à ARN simple brin tripartite et polarité négative. Les trois fragments appelés L (6300-12000 nucléotides), M (3500-6000 nucléotides) et S (1000-2200 nucléotides). La longueur totale du génome est comprise entre 10,5 et 22,7 kilobases, selon les espèces.Les trois segments du génome codent pour quatre protéines structurales, qui composent la particule virale, et peut-être une ou deux protéines non structurales (protéines accessoires nécessaires à la réplication).

Cette stratégie de codage nécessite que la particule virale infectieuse contienne sa propre ARN polymérase ARN dépendante pour transcrire le génome en ARNm, qui à leur tour sont traduits pour produire de nouvelles protéines virales. La multiplication du virus se produit dans le cytoplasme des cellules infectées et les particules virales mûrissent à l'intérieur de la cellule en bourgeonnant principalement au niveau des membranes de l'appareil de Golgi. Les virus de cette famille peuvent infecter une gamme variée d'hôtes, des moustiques aux marsupiaux et des thrips aux tomates. Plusieurs des Bunyaviridae provoquent des maladies graves chez l'humain, et ils sont reconnus comme représentant une menace croissante pour la santé humaine et sont de bons exemples des infections dites émergentes[1].

Taxonomie et biologie

L'ordre des Bunyavirales regroupe 12 familles.

L'ancienne nomenclature les classaient comme famille des Bunyaviridae qui était divisée en cinq genres sur la base des caractéristiques sérologiques et biochimiques. Quatre de ces genres - Bunyavirus, Hantavirus, Nairovirus et Phlebovirus - contenaient des virus infectant les vertébrés tandis que les membres du genre Tospovirus infectaient les plantes. Les membres de ces genres sont ainsi appelés bunyavirus, hantavirus, nairovirus, etc. Bien que tous les virus de la famille partagent les critères moins rigoureux décrits ci-dessus, une diversité considérable existe au niveau biologique en termes d'hôtes et de vecteurs infectés et au niveau moléculaire en termes de stratégies de codage et de réplication du génome[2].

  • La plupart des virus sont transmis par des arthropodes vecteurs (et sont donc connus sous le nom d'arbovirus,: En général, les bunyavirus sont transmis par des .moustiques ou des moucherons, les nairovirus par des tiques et les phlébovirus par des phlébotomes ou des tiques[2]. Les bunyavirus transmis par les moustiques appartiennent au genre Orthobunyavirus. Ce genre comprend environ 170 virus : 48 espèces et 19 sérogroupes. Dans deux de ces sérogroupes se trouvent quatre virus émergents qui sont de plus en plus reconnus comme des agents pathogènes pour les humains et les animaux[3]
  • Les tospovirus se propagent aux plantes[2].
  • Les hantavirus ne possèdent pas d'arthropodes vecteurs mais sont maintenus dans la nature sous forme d'infections persistantes de rongeurs (d'où le terme robovirus, transmis par les rongeurs) et sont transmis à l'humain via des sécrétions infectieuses aérosolisées de rongeurs[2].

Arbovirus appartenant au genre Orthobunyavirus

Sérogroupe California

Les virus du sérogroupe California circulent partout dans le monde. Ils comprennent le virus d'Inkoo en Europe, le virus de Tahyna en Europe, en Asie et en Afrique, et le virus de La Crosse, le virus snowshoe hare et le virus de Jamestown Canyon en Amérique du Nord[4],[5].

Ce sérogroupe comprend 17 virus :

  • Virus de l'encéphalite de Californie
  • Virus d'Inkoo
  • Virus de Jamestown Canyon
  • Virus de La Crosse
  • Virus snowshoe hare
  • Virus de Tahyna

Sérogroupe Bunyamwera

Ce sérogroupe comprend 23 virus :

  • Virus de Cache Valley circule partout en Amérique du Nord et en Amérique du Sud[6].

Sérogroupe Simbu

  • Virus Oropouche
  • Virus Ikitos

Codage du génome et réplication

Maladies causées par les Bunyavirales

Les virus de cette famille diversifiée causent des maladies chez les humains, les animaux domestiques et les plantes, ces derniers étant d'une importance économique considérable. En ce qui concerne les maladies humaines, cinq types de manifestations sont associés aux Bunyaviridae : fièvre, encéphalite, fièvre hémorragique, et un syndrome respiratoire mortel[7]. Un grand nombre de bunyavirsus sont associés à des fièvres , souvent accompagnée d'une éruption cutanée, chez l'humain, spontanément résolutives et rarement, voire jamais, mortel, l'incidence globale des infections à bunyavirus est inconnu[7].

En Europe Tahyna bunyavirus est largement distribué en Allemagne, en Italie, l'ex-Yougoslavie et la République tchèque ; dans la Moravie jusqu'à 20 % des patients hospitalisés pour maladies fébriles sont infectés par ce virus.

Oropouchele bunyavirus a provoqué des épidémies importantes, impliquant des milliers de patients au Brésil, et il est probablement répandu dans tout le Sud de l'Amérique.

La fièvre des phlébotomes et la fièvre de la vallée du Rift sont causés par les phlébovirus. Le premier est une courte, infection spontanément résolutive non mortelle. En revanche, la fièvre de la vallée du Rift présente une variété de manifestation clinique allant d'une simple fièvre à un syndrome hémorragique.

Notes et références

  1. (en-US) Stephen S. Morse, « Factors in the Emergence of Infectious Diseases », Emerging Infectious Diseases, Centres pour le contrôle et la prévention des maladies, vol. 1, no 1,‎ janvier 1995 (DOI , lire en ligne, consulté le 6 mars 2020)
  2. a b c et d Elliott, R.M. Emerging Viruses: The Bunyaviridae. Mol Med 3, 572–577 (1997). https://doi.org/10.1007/BF03401814
  3. King AMQ, Lefkowitz E, Adams MJ, Carstens EB. Family bunyaviridae. In: King AMQ, Adams MJ, Carstens EB, Lefkowitz EJ, editors. Virus Taxonomy: Ninth Report of the International Committee on Taxonomy of Viruses. San Diego: Elsevier; 2012. p. 725-741.
  4. Leduc JW. Epidemiology and ecology of the California serogroup viruses. Am J Trop Med Hyg. 1987;37(3) Suppl: 60S-68S.
  5. Putkuri N, Kurkela S, Levanov L, Huhtamo E, Vaheri A, Sironen T, Vapalahti O. Isolation and characterization of a California encephalitis serogroup orthobunyavirus from Finnish mosquitoes. Infect Genet Evol. 2014;22:164-73.
  6. Andreadis TG Armstrong PM, Anderson JF, Main AJ. 2014 Spatial-temporal analysis of Cache Valley virus (Bunyaviridae: Orthobunyavirus) infection in Anopheline and Culicine mosquitoes (Diptera: Culicidae) in the Northeastern United States, 1997-2012. Vector Borne Zoonotic Dis. 2014;14(10):763-773.
  7. a et b Swanepoel R. (1995) Bunyaviridae. In: Zuckerman AJ, Banatvala JE, Pattison JR (eds). Principles and Practice of Clinical Virology, 3rd ed. John Wiley & Sons, Chichester, pp. 517–554.

Articles connexes

license
fr
copyright
http://creativecommons.org/licenses/by-sa/3.0/
original
visit source
partner site
wikipedia FR

Bunyavirales: Brief Summary

provided by wikipedia FR

Les Bunyavirales sont un ordre de virus de plus de 300 membres avec une enveloppe sphérique et hélicoïdale de diamètre d'environ 80 à 120 nanomètres. L'une des caractéristiques unificatrices de ces virus est la possession d'un génome à ARN simple brin tripartite et polarité négative. Les trois fragments appelés L (6300-12000 nucléotides), M (3500-6000 nucléotides) et S (1000-2200 nucléotides). La longueur totale du génome est comprise entre 10,5 et 22,7 kilobases, selon les espèces.Les trois segments du génome codent pour quatre protéines structurales, qui composent la particule virale, et peut-être une ou deux protéines non structurales (protéines accessoires nécessaires à la réplication).

Cette stratégie de codage nécessite que la particule virale infectieuse contienne sa propre ARN polymérase ARN dépendante pour transcrire le génome en ARNm, qui à leur tour sont traduits pour produire de nouvelles protéines virales. La multiplication du virus se produit dans le cytoplasme des cellules infectées et les particules virales mûrissent à l'intérieur de la cellule en bourgeonnant principalement au niveau des membranes de l'appareil de Golgi. Les virus de cette famille peuvent infecter une gamme variée d'hôtes, des moustiques aux marsupiaux et des thrips aux tomates. Plusieurs des Bunyaviridae provoquent des maladies graves chez l'humain, et ils sont reconnus comme représentant une menace croissante pour la santé humaine et sont de bons exemples des infections dites émergentes.

license
fr
copyright
http://creativecommons.org/licenses/by-sa/3.0/
original
visit source
partner site
wikipedia FR