Bunyavirales

Source: Wikipedia, the free encyclopedia.
(Redirected from
Ellioviricetes
)
Bunyavirales
Crimean-Congo hemorrhagic fever virus
(CCHFV) virion and replication cycle
Virus classification Edit this classification
(unranked): Virus
Realm: Riboviria
Kingdom: Orthornavirae
Phylum:
Negarnaviricota
Subphylum: Polyploviricotina
Class: Ellioviricetes
Order: Bunyavirales
Families[1]

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

biosafety level 4 laboratories. They are also the cause of severe fever with thrombocytopenia syndrome.[8]

Puumala virus (mostly Scandinavia).[9] The antibody reaction plays an important role in decreasing levels of viremia
.

Virology

Structure

Peribunyavirus virion structure

Bunyavirus

nm. These viruses contain no matrix proteins.[10] Instead, the viral surface glycoproteins which form a continuous layer on the virion surface are thought to play a role in the formation of new virions by budding from a cell membrane.[11]

Genome

Bunyaviruses have bi- or tripartite

nucleocapsid protein (N).[12]

Most bunyaviruses have a negative-sense L and M segment. The S segment of the genus

ambisense.[14] 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.[14]

The total genome size ranges from 10.5 to 22.7

kbp.[15]

Life cycle

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.[citation needed]

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.[citation needed]

Transmission

Bunyaviruses infect

true flies
.

Taxonomy

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:[citation needed]

Bunyaviruses have segmented genomes, making them capable of rapid reassortment and increasing the risk of outbreak.

non-specific symptoms, Bunyavirus infections are frequently mistaken for other illnesses. For example, Bwamba fever is often mistaken for malaria.[21]

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.[citation needed]

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. ^
    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. 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.[dead link]
  6. ^
    ISBN 978-1-904455-90-5
    .
  7. PMID 32878245
    .
  8. PMID 21410387
    .
  9. 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. PMID 20219926.{{cite journal}}: CS1 maint: multiple names: authors list (link
    )
  12. PMID 23595147
    .
  13. PMID 24607799
    .
  14. ^
    PMID 27388209
    .
  15. ^ "00.011. Bunyaviridae". ICTVdB—The Universal Virus Database, version 4. 2006. Retrieved 2009-01-01.
  16. PMID 24850747
    .
  17. PMID 24074583
  18. PMID 25402172
    .
  19. PMID 28117273
  20. PMID 22933273
  21. ISBN 9780323054706
    .

External links