Influenza B virus

Influenza B virus is the only species in the genus Betainfluenzavirus in the virus family Orthomyxoviridae.

Influenza B virus
Virus classification
(unranked): Virus
Realm: Riboviria
Phylum: Negarnaviricota
Class: Insthoviricetes
Order: Articulavirales
Family: Orthomyxoviridae
Genus: Betainfluenzavirus
Species:
Influenza B virus
Synonyms
Species
  • Influenza type B virus[1]
  • Influenza virus B[2]
Genus
  • Influenzavirus B[3]

Influenza B virus is only known to infect humans and seals with influenza.[4] This limited host range is apparently responsible for the lack of associated influenza pandemics in contrast with those caused by the morphologically similar influenza A virus as both mutate by both antigenic drift and reassortment.[5][6][7] There are two known circulating lineages of Influenza B virus based on the antigenic properties of the surface glycoprotein hemagglutinin. The lineages are termed B/Yamagata/16/88-like and B/Victoria/2/87-like viruses.[8] The quadrivalent influenza vaccine licensed by the CDC is currently designed to protect against both co-circulating lineages and has been shown to have greater effectiveness in prevention of influenza caused by Influenza B virus than the previous trivalent vaccine.[9]

Further diminishing the impact of this virus, "in humans, influenza B viruses evolve slower than A viruses and faster than C viruses".[10] Influenzavirus B mutates at a rate 2 to 3 times slower than type A.[11] Nevertheless, it is accepted that Influenza B virus cause significant morbidity and mortality worldwide, and significantly impacts adolescents and schoolchildren.[12]

Morphology

The Influenza B virus capsid is enveloped while its virion consists of an envelope, a matrix protein, a nucleoprotein complex, a nucleocapsid, and a polymerase complex. It is sometimes spherical and sometimes filamentous. Its 500 or so surface projections are made of hemagglutinin and neuraminidase.[13]

Genome structure

The Influenza B virus genome is 14,548 nucleotides long and consists of eight segments of linear negative-sense, single-stranded RNA. The multipartite genome is encapsidated, each segment in a separate nucleocapsid, and the nucleocapsids are surrounded by one envelope.[13]

References
  1. ICTV 2nd Report Fenner, F. (1976). Classification and nomenclature of viruses. Second report of the International Committee on Taxonomy of Viruses. Intervirology 7: 1-115. p57 https://talk.ictvonline.org/ictv/proposals/ICTV%202nd%20Report.pdf
  2. ICTV 6th Report Murphy, F. A., Fauquet, C. M., Bishop, D. H. L., Ghabrial, S. A., Jarvis, A. W. Martelli, G. P. Mayo, M. A. & Summers, M. D.(eds)(1995). Virus Taxonomy. Sixthreport of the International Committee on Taxonomy of Viruses. Archives of Virology Supplement 10, p297 https://talk.ictvonline.org/ictv/proposals/ICTV%206th%20Report.pdf
  3. Smith, Gavin JD; et al. (8 June 2017). "Changing individual genus and species names in the family Orthomyxoviridae". International Committee on Taxonomy of Viruses (ICTV). Retrieved 22 March 2019.
  4. Osterhaus AD, Rimmelzwaan GF, Martina BE, Bestebroer TM, Fouchier RA (2000). "Influenza B virus in seals". Science. 288 (5468): 1051–53. Bibcode:2000Sci...288.1051O. doi:10.1126/science.288.5468.1051. PMID 10807575.
  5. Hay AJ, Gregory V, Douglas AR, Lin YP (2001). "The evolution of human influenza viruses". Philos. Trans. R. Soc. Lond. B Biol. Sci. 356 (1416): 1861–70. doi:10.1098/rstb.2001.0999. PMC 1088562. PMID 11779385.
  6. Matsuzaki Y, Sugawara K, Takashita E, Muraki Y, Hongo S, Katsushima N, Mizuta K, Nishimura H (2004). "Genetic diversity of influenza B virus: The frequent reassortment and cocirculation of the genetically distinct reassortant viruses in a community". J. Med. Virol. 74 (1): 132–40. doi:10.1002/jmv.20156. PMID 15258979.
  7. Lindstrom SE, Hiromoto Y, Nishimura H, Saito T, Nerome R, Nerome K (1999). "Comparative Analysis of Evolutionary Mechanisms of the Hemagglutinin and Three Internal Protein Genes of Influenza B Virus: Multiple Cocirculating Lineages and Frequent Reassortment of the NP, M, and NS Genes". J. Virol. 73 (5): 4413–26. PMC 104222. PMID 10196339.
  8. Klimov, Alexander I.; Garten, Rebecca; Russell, Colin; Barr, Ian G.; Besselaar, Terry G.; Daniels, Rod; Engelhardt, Othmar G.; Grohmann, Gary; Itamura, Shigeyuki; Kelso, Anne; McCauley, John; Odagiri, Takato; Smith, Derek; Tashiro, Masato; Xu, Xiyan; Webby, Richard; Wang, Dayan; Ye, Zhiping; Yuelong, Shu; Zhang, Wenqing; Cox, Nancy (October 2012). "WHO recommendations for the viruses to be used in the 2012 Southern Hemisphere Influenza Vaccine: Epidemiology, antigenic and genetic characteristics of influenza A(H1N1)pdm09, A(H3N2) and B influenza viruses collected from February to September 2011". Vaccine. 30 (45): 6461–71. doi:10.1016/j.vaccine.2012.07.089. PMC 6061925. PMID 22917957.
  9. Moa, Aye M.; Chughtai, Abrar A.; Muscatello, David J.; Turner, Robin M.; MacIntyre, C. Raina (July 2016). "Immunogenicity and safety of inactivated quadrivalent influenza vaccine in adults: A systematic review and meta-analysis of randomised controlled trials". Vaccine. 34 (35): 4092–102. doi:10.1016/j.vaccine.2016.06.064. PMID 27381642.
  10. Yamashita M, Krystal M, Fitch WM, Palese P (1988). "Influenza B virus evolution: co-circulating lineages and comparison of evolutionary pattern with those of influenza A and C viruses". Virology. 163 (1): 112–22. doi:10.1016/0042-6822(88)90238-3. PMID 3267218.
  11. Nobusawa E, Sato K (April 2006). "Comparison of the Mutation Rates of Human Influenza A and B Viruses". J Virol. 80 (7): 3675–78. doi:10.1128/JVI.80.7.3675-3678.2006. PMC 1440390. PMID 16537638.
  12. van de Sandt, Carolien E; Bodewes, Rogier; Rimmelzwaan, Guus F; de Vries, Rory D (September 2015). "Influenza B viruses: not to be discounted". Future Microbiology. 10 (9): 1447–65. doi:10.2217/fmb.15.65. PMID 26357957.
  13. Büchen-Osmond, C. (Ed) (2006). "ICTVdB Virus Description—00.046.0.04. Influenzavirus B". ICTVdB—The Universal Virus Database, version 4. New York: Columbia University. Retrieved 2007-09-15.CS1 maint: extra text: authors list (link)
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