According to the rules for taxon naming established by the International Committee on Taxonomy of Viruses (ICTV), the name Filoviridae is always to be capitalized, italicized, never abbreviated, and to be preceded by the word "family". The names of its members (filoviruses or filovirids) are to be written in lower case, are not italicized, and used without articles.[13][14]
Life cycleedit
The filovirus life cycle begins with virion attachment to specific cell-surface receptors, followed by fusion of the virion envelope with cellular membranes and the concomitant release of the virus nucleocapsid into the cytosol. The viral RNA-dependent RNA polymerase (RdRp, or RNA replicase) partially uncoats the nucleocapsid and transcribes the genes into positive-stranded mRNAs, which are then translated into structural and nonstructural proteins. Filovirus RdRps bind to a single promoter located at the 3' end of the genome. Transcription either terminates after a gene or continues to the next gene downstream. This means that genes close to the 3' end of the genome are transcribed in the greatest abundance, whereas those toward the 5' end are least likely to be transcribed. The gene order is therefore a simple but effective form of transcriptional regulation. The most abundant protein produced is the nucleoprotein, whose concentration in the cell determines when the RdRp switches from gene transcription to genome replication. Replication results in full-length, positive-stranded antigenomes that are in turn transcribed into negative-stranded virus progeny genome copies. Newly synthesized structural proteins and genomes self-assemble and accumulate near the inside of the cell membrane. Virions bud off from the cell, gaining their envelopes from the cellular membrane they bud from. The mature progeny particles then infect other cells to repeat the cycle.[12]
Family inclusion criteriaedit
A virus that fulfills the criteria for being a member of the order Mononegavirales is a member of the family Filoviridae if:[13][14]
it forms nucleocapsids with a central axial channel (≈10–15 nm in width) surrounded by a dark layer (≈20 nm in width) and an outer helical layer (≈50 nm in width) with a cross striation (periodicity of ≈5 nm)
The mutation rates in these genomes have been estimated to be between 0.46 × 10−4 and 8.21 × 10−4 nucleotide substitutions/site/year.[15] The most recent common ancestor of sequenced filovirus variants was estimated to be 1971 (1960–1976) for Ebola virus, 1970 (1948–1987) for Reston virus, and 1969 (1956–1976) for Sudan virus, with the most recent common ancestor among the four species included in the analysis (Ebola virus, Tai Forest virus, Sudan virus, and Reston virus) estimated at 1000–2100 years.[16] The most recent common ancestor of the Marburg and Sudan species appears to have evolved 700 and 850 years before present respectively. Although mutational clocks placed the divergence time of extant filoviruses at ~10,000 years before the present, dating of orthologous endogenous elements (paleoviruses) in the genomes of hamsters and voles indicated that the extant genera of filovirids had a common ancestor at least as old as the Miocene (~16–23 million or so years ago).[17]
Filoviruses have a history that dates back several tens of million of years. Endogenous viral elements (EVEs) that appear to be derived from filovirus-like viruses have been identified in the genomes of bats, rodents, shrews, tenrecs, tarsiers, and marsupials.[20][21][22] Although most filovirus-like EVEs appear to be pseudogenes, evolutionary analyses suggest that orthologs isolated from several species of the bat genus Myotis have been maintained by selection.[23]
Vaccinesedit
There are presently very limited vaccines for known filovirus.[24] An effective vaccine against EBOV, developed in Canada,[25] was approved for use in 2019 in the US and Europe.[26][27] Similarly, efforts to develop a vaccine against Marburg virus are under way.[28]
Mutation concerns and pandemic potentialedit
There has been a pressing concern that a very slight genetic mutation to a filovirus such as EBOV could result in a change in transmission system from direct body fluid transmission to airborne transmission, as was seen in Reston virus (another member of genus Ebolavirus) between infected macaques. A similar change in the current circulating strains of EBOV could greatly increase the infection and disease rates caused by EBOV. However, there is no record of any Ebola strain ever having made this transition in humans.[29]
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^Jahrling, P. B.; Kiley, M. P.; Klenk, H.-D.; Peters, C. J.; Sanchez, A.; Swanepoel, R. (1995). "Family Filoviridae". In 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.). Virus Taxonomy—Sixth Report of the International Committee on Taxonomy of Viruses. Archives of Virology Supplement. Vol. 10. Vienna, Austria: Springer. pp. 289–92. ISBN 3-211-82594-0.
^Netesov, S.V.; Feldmann, H.; Jahrling, P. B.; Klenk, H. D.; Sanchez, A. (2000). "Family Filoviridae". In van Regenmortel, M. H. V.; Fauquet, C. M.; Bishop, D. H. L.; Carstens, E. B.; Estes, M. K.; Lemon, S. M.; Maniloff, J.; Mayo, M. A.; McGeoch, D. J.; Pringle, C. R.; Wickner, R. B. (eds.). Virus Taxonomy—Seventh Report of the International Committee on Taxonomy of Viruses. San Diego, USA: Academic Press. pp. 539–48. ISBN 0-12-370200-3.
^ abFeldmann, H.; Geisbert, T. W.; Jahrling, P. B.; Klenk, H.-D.; Netesov, S. V.; Peters, C. J.; Sanchez, A.; Swanepoel, R.; Volchkov, V. E. (2005). "Family Filoviridae". In Fauquet, C. M.; Mayo, M. A.; Maniloff, J.; Desselberger, U.; Ball, L. A. (eds.). Virus Taxonomy—Eighth Report of the International Committee on Taxonomy of Viruses. San Diego, USA: Elsevier/Academic Press. pp. 645–653. ISBN 0-12-370200-3.
^ abcdeKuhn JH, Becker S, Ebihara H, Geisbert TW, Johnson KM, Kawaoka Y, Lipkin WI, Negredo AI, Netesov SV, Nichol ST, Palacios G, Peters CJ, Tenorio A, Volchkov VE, Jahrling PB (2010). "Proposal for a revised taxonomy of the family Filoviridae: Classification, names of taxa and viruses, and virus abbreviations". Archives of Virology. 155 (12): 2083–2103. doi:10.1007/s00705-010-0814-x. PMC3074192. PMID 21046175.
^ abcKuhn, J. H.; Becker, S.; Ebihara, H.; Geisbert, T. W.; Jahrling, P. B.; Kawaoka, Y.; Netesov, S. V.; Nichol, S. T.; Peters, C. J.; Volchkov, V. E.; Ksiazek, T. G. (2011). "Family Filoviridae". In King, Andrew M. Q.; Adams, Michael J.; Carstens, Eric B.; et al. (eds.). Virus Taxonomy—Ninth Report of the International Committee on Taxonomy of Viruses. London, UK: Elsevier/Academic Press. pp. 665–671. ISBN 978-0-12-384684-6.
^Carroll SA, Towner JS, Sealy TK, McMullan LK, Khristova ML, Burt FJ, Swanepoel R, Rollin PE, Nichol ST (March 2013). "Molecular evolution of viruses of the family Filoviridae based on 97 whole-genome sequences". J. Virol. 87 (5): 2608–16. doi:10.1128/JVI.03118-12. PMC3571414. PMID 23255795.
^Taylor, D. J.; Ballinger, M. J.; Zhan, J. J.; Hanzly, L. E.; Bruenn, J. A. (2014). "Evidence that ebolaviruses and cuevaviruses have been diverging from marburgviruses since the Miocene". PeerJ. 2: e556. doi:10.7717/peerj.556. PMC4157239. PMID 25237605.
^Melanie M. Hierweger, Michel C. Koch, Melanie Rupp, Piet Maes, Nicholas Di Paola, Rémy Bruggmann, Jens H. Kuhn, Heike Schmidt-Posthaus & Torsten Seuberlich (2021-11-22). "Novel Filoviruses, Hantavirus, and Rhabdovirus in Freshwater Fish, Switzerland, 2017". Emerging Infectious Diseases. 27 (12): 3082–3091. doi:10.3201/eid2712.210491. PMC8632185. PMID 34808081.{{cite journal}}: CS1 maint: multiple names: authors list (link)
^Biao He, Tingsong Hu, Xiaomin Yan, Fuqiang Zhang, Changchun Tu (2023-08-07). "Detection and characterization of a novel bat filovirus (Dehong virus, DEHV) in fruit bats". bioRxiv. doi:10.1101/2023.08.07.552227.{{cite journal}}: CS1 maint: multiple names: authors list (link)
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Further readingedit
Klenk, Hans-Dieter (1999). Marburg and Ebola Viruses. Current Topics in Microbiology and Immunology. Vol. 235. Berlin, Germany: Springer-Verlag. ISBN 978-3-540-64729-4.
Klenk, Hans-Dieter; Feldmann, Heinz (2004). Ebola and Marburg Viruses—Molecular and Cellular Biology. Wymondham, Norfolk, UK: Horizon Bioscience. ISBN 978-0-9545232-3-7.
Kuhn, Jens H. (2008). Filoviruses—A Compendium of 40 Years of Epidemiological, Clinical, and Laboratory Studies. Archives of Virology Supplement. Vol. 20. Vienna, Austria: Springer. ISBN 978-3-211-20670-6.
Ryabchikova, Elena I.; Price, Barbara B. (2004). Ebola and Marburg Viruses—A View of Infection Using Electron Microscopy. Columbus, Ohio, USA: Battelle Press. ISBN 978-1-57477-131-2.
External linksedit
Wikimedia Commons has media related to Filoviridae.
Wikispecies has information related to Filoviridae.
ICTV Report:Filoviridae
"Filoviridae". NCBI Taxonomy Browser. 11266.
"FILOVIR". Scientific resources for research on filoviruses. Archived from the original on 2020-07-30. Retrieved 2014-08-08.
Theoretical Evidence That The Ebola Virus Zaire Strain May Be Selenium-Dependent: A Factor In Pathogenesis And Viral Outbreaks?Taylor 1995
Can Selenite Be An Ultimate Inhibitor Of Ebola And Other Viral Infections?Lipinski 2015 Archived 2020-11-19 at the Wayback Machine
Many In West Africa May Be Immune To Ebola VirusNew York Times