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Published in final edited form as: Arch Virol. 2022 Nov;167(11):2429–2440. doi: 10.1007/s00705-022-05516-5

Recent changes to virus taxonomy ratified by the International Committee on Taxonomy of Viruses (2022)

Peter J Walker 1, Stuart G Siddell 2, Elliot J Lefkowitz 3, Arcady R Mushegian 4, Evelien M Adriaenssens 5, Poliane Alfenas-Zerbini 6, Donald M Dempsey 7, Bas E Dutilh 8,9, María Laura García 10, R Curtis Hendrickson 11, Sandra Junglen 12, Mart Krupovic 13, Jens H Kuhn 14, Amy J Lambert 15, Małgorzata Łobocka 16, Hanna M Oksanen 17, Richard J Orton 18, David L Robertson 18, Luisa Rubino 19, Sead Sabanadzovic 20, Peter Simmonds 21, Donald B Smith 22, Nobuhiro Suzuki 23, Koenraad Van Doorslaer 24, Anne-Mieke Vandamme 25,26, Arvind Varsani 27, Francisco Murilo Zerbini 28
PMCID: PMC10088433  NIHMSID: NIHMS1889503  PMID: 35999326

Abstract

This article reports the changes to virus taxonomy approved and ratified by the International Committee on Taxonomy of Viruses (ICTV) in March 2022. The entire ICTV was invited to vote on 174 taxonomic proposals approved by the ICTV Executive Committee at its annual meeting in July 2021. All proposals were ratified by an absolute majority of the ICTV members. Of note, the Study Groups have started to implement the new rule for uniform virus species naming that became effective in 2021 and mandates the binomial ‘Genus_name species_epithet’ format with or without Latinization. As a result of this ratification, the names of 6,481 virus species (more than 60 percent of all species names currently recognized by ICTV) now follow this format.

Introduction

Changes to virus taxonomy (the universal scheme of virus classification of the International Committee on Taxonomy of Viruses [ICTV]) take place annually and are the result of a multi-stage process. In accordance with the ICTV Statutes (https://ictv.global/statutes), taxonomic proposals (TaxoProps) submitted to the ICTV Executive Committee (EC) undergo a review process that involves input from the ICTV Study Groups (SGs) and Subcommittees (SCs), other interested virologists, and the EC. After final approval by the EC, proposals are presented for ratification to the full ICTV membership by posting on the ICTV website (https://ictv.global/) followed by an electronic vote.

The latest set of proposals approved by the EC was made available on the ICTV website in early 2022 (see https://ictv.global/proposal/MSL37/ for all proposals combined into a single zip file, and use the links provided in the References to this publication to access individual proposals). A list of proposals was then emailed on 6 th February 2022 to the 184 members of ICTV, namely the EC Members, Life Members, ICTV SC Members including the SG chairs and the Bioinformatics Expert Group members, and ICTV National Representatives. Members were then requested to vote on whether to ratify the taxonomic proposals. Voting closed on 11th March 2022.

Changes to virus taxonomy ratified in 2022

All 174 proposals were ratified by ICTV members, in every case receiving an absolute majority of votes; at least 68% of eligible voters approved each proposal. A summary of the taxonomy changes enacted by ratification of the proposals is provided in Table 1; there were no proposals to change ICTV Code or ICTV Statutes this year. Each proposal is cited and listed in the References to acknowledge the authors’ efforts and to provide links to the specific proposal on the ICTV website [1175]. These documents remain available for those who wish to see the full details of the proposals. TaxoProp 2020.002G, ratified in 2021 [175], specified a procedure for expedited correction of unintended errors that may occur during proposal writing but clearly do not reflect the intention of the proposers, as described in the submitted proposal documentation. Examples of such errors include assignment of a lower-rank taxon to an incorrect higher rank, inadvertent introduction of duplicate taxon names, or assignment of a misspelled taxon name. Since the changes ratified by ICTV take effect immediately, this mechanism was used to correct several proposals in the current cycle. The corrections are listed in proposals 2021.097B [101], 2021.014M [129], 2021.042M [150] and 2021.043M [151].

Table 1.

Summary of taxonomic changes approved in March 2022

Rank Total, MSL-36a New Moved Abolished Renamed Promoted Total, MSL-37b
Realm 6 0 0 0 0 0 6
Subrealm 0 0 0 0 0 0 0
Kingdom 10 0 0 0 0 0 10
Subkingdom 0 0 0 0 0 0 0
Phylum 17 0 0 0 0 0 17
Subphylum 2 0 0 0 0 0 2
Class 39 0 0 0 0 0 39
Subclass 0 0 0 0 0 0 0
Order 59 7 0 1 0 0 65
Suborder 8 0 0 0 0 0 8
Family 189 48c 11 4 1 0 233
Subfamily 136 37 32 2 0 3 168
Genus 2,224 390 571 8 5 0 2,606
Subgenus 70 14 0 0 0 0 84
Species 9,110 1,342 103 18 3,354 0 10,434
a

Total number of taxa in the ICTV Master Species List (MSL) prior to 2022 ratification

b

Total number of taxa now recognized and reported in the ICTV MSL

c

Includes three families promoted from subfamily

Another important change ratified in 2021 was the adoption of a uniform binomial format for naming of virus species [176]. The ICTV SGs have been charged with conversion of all existing virus species names to the new binomial format, and two groups of authors affiliated with ICTV have recently provided guidance on designing and writing virus species’ names [177]. With the ratification described here, 6,481 virus species out of 10,434 in the ICTV official Master Species List (MSL) adhere to the required binary format. The process of name conversion continues and is expected to be completed by the EC meeting planned for 2023. This system concerns only the names of virus species and does not affect the names of viruses [177].

Also of note, one proposal [107] established the family Polydnaviriformidae, the first high-order taxon comprising viriforms, the classifiable entities that were explicitly included in the ICTV remit in 2021. The list of all new orders and new families ratified in 2022 is provided in Table 2.

Table 2.

New orders and families ratified by ICTV in 2022

Lineage Taxon History Page
New orders
Duplodnaviria;Heunggongvirae;Uroviricota;Caudoviricetes;Crassvirales https://ictv.global/taxonomy/p/taxonomy-history?taxnode_id=202113057
Duplodnaviria;Heunggongvirae;Uroviricota;Caudoviricetes;Kirjokansivirales https://ictv.global/taxonomy/p/taxonomy-history?taxnode_id=202112155
Duplodnaviria;Heunggongvirae;Uroviricota;Caudoviricetes;Methanobavirales https://ictv.global/taxonomy/p/taxonomy-history?taxnode_id=202112156
Duplodnaviria;Heunggongvirae;Uroviricota;Caudoviricetes;Thumleimavirales https://ictv.global/taxonomy/p/taxonomy-history?taxnode_id=202112154
Monodnaviria;Shotokuvirae;Cressdnaviricota;Arfiviricetes;Rivendellvirales https://ictv.global/taxonomy/p/taxonomy-history?taxnode_id=202113282
Monodnaviria;Shotokuvirae;Cressdnaviricota;Arfiviricetes;Rohanvirales https://ictv.global/taxonomy/p/taxonomy-history?taxnode_id=202113293
Riboviria;Orthornavirae;Pisuviricota;Yadokarivirales https://ictv.global/taxonomy/p/taxonomy-history?taxnode_id=202112466
New families
Adnaviria;Zilligvirae;Taleaviricota;Tokiviricetes;Ligamenvirales;Ungulaviridae https://ictv.global/taxonomy/p/taxonomy-history?taxnode_id=202112214
Duplodnaviria;Heunggongvirae;Uroviricota;Caudoviricetes;Aggregaviridae https://ictv.global/taxonomy/p/taxonomy-history?taxnode_id=202113573
Duplodnaviria;Heunggongvirae;Uroviricota;Caudoviricetes;Methanobavirales;Anaerodiviridae https://ictv.global/taxonomy/p/taxonomy-history?taxnode_id=202112170
Duplodnaviria;Heunggongvirae;Uroviricota;Caudoviricetes;Assiduviridae https://ictv.global/taxonomy/p/taxonomy-history?taxnode_id=202113549
Duplodnaviria;Heunggongvirae;Uroviricota;Caudoviricetes;Casjensviridae https://ictv.global/taxonomy/p/taxonomy-history?taxnode_id=202112984
Duplodnaviria;Heunggongvirae;Uroviricota;Caudoviricetes;Crassvirales;Crevaviridae https://ictv.global/taxonomy/p/taxonomy-history?taxnode_id=202113058
Duplodnaviria;Heunggongvirae;Uroviricota;Caudoviricetes;Duneviridae https://ictv.global/taxonomy/p/taxonomy-history?taxnode_id=202113559
Duplodnaviria;Heunggongvirae;Uroviricota;Caudoviricetes;Kirjokansivirales;Flexireviridae https://ictv.global/taxonomy/p/taxonomy-history?taxnode_id=202112168
Duplodnaviria;Heunggongvirae;Uroviricota;Caudoviricetes;Forsetiviridae https://ictv.global/taxonomy/p/taxonomy-history?taxnode_id=202113569
Duplodnaviria;Heunggongvirae;Uroviricota;Caudoviricetes;Thumleimavirales;Hafunaviridae https://ictv.global/taxonomy/p/taxonomy-history?taxnode_id=202112161
Duplodnaviria;Heunggongvirae;Uroviricota;Caudoviricetes;Kirjokansivirales;Haloferuviridae https://ictv.global/taxonomy/p/taxonomy-history?taxnode_id=202112165
Duplodnaviria;Heunggongvirae;Uroviricota;Caudoviricetes;Thumleimavirales;Halomagnusviridae https://ictv.global/taxonomy/p/taxonomy-history?taxnode_id=202112164
Duplodnaviria;Heunggongvirae;Uroviricota;Caudoviricetes;Helgolandviridae https://ictv.global/taxonomy/p/taxonomy-history?taxnode_id=202113556
Duplodnaviria;Heunggongvirae;Uroviricota;Caudoviricetes;Crassvirales;Intestiviridae https://ictv.global/taxonomy/p/taxonomy-history?taxnode_id=202113059
Duplodnaviria;Heunggongvirae;Uroviricota;Caudoviricetes;Kyanoviridae https://ictv.global/taxonomy/p/taxonomy-history?taxnode_id=202113665
Duplodnaviria;Heunggongvirae;Uroviricota;Caudoviricetes;Methanobavirales;Leisingerviridae https://ictv.global/taxonomy/p/taxonomy-history?taxnode_id=202112169
Duplodnaviria;Heunggongvirae;Uroviricota;Caudoviricetes;Madisaviridae https://ictv.global/taxonomy/p/taxonomy-history?taxnode_id=202112160
Duplodnaviria;Heunggongvirae;Uroviricota;Caudoviricetes;Mesyanzhinovviridae https://ictv.global/taxonomy/p/taxonomy-history?taxnode_id=202112407
Duplodnaviria;Heunggongvirae;Uroviricota;Caudoviricetes;Molycolviridae https://ictv.global/taxonomy/p/taxonomy-history?taxnode_id=202113562
Duplodnaviria;Heunggongvirae;Uroviricota;Caudoviricetes;Naomviridae https://ictv.global/taxonomy/p/taxonomy-history?taxnode_id=202112771
Duplodnaviria;Heunggongvirae;Uroviricota;Caudoviricetes;Orlajensenviridae https://ictv.global/taxonomy/p/taxonomy-history?taxnode_id=202112790
Duplodnaviria;Heunggongvirae;Uroviricota;Caudoviricetes;Pachyviridae https://ictv.global/taxonomy/p/taxonomy-history?taxnode_id=202113536
Duplodnaviria;Heunggongvirae;Uroviricota;Caudoviricetes;Peduoviridae https://ictv.global/taxonomy/p/taxonomy-history?taxnode_id=202100225
Duplodnaviria;Heunggongvirae;Uroviricota;Caudoviricetes;Pervagoviridae https://ictv.global/taxonomy/p/taxonomy-history?taxnode_id=202113545
Duplodnaviria;Heunggongvirae;Uroviricota;Caudoviricetes;Kirjokansivirales;Pyrstoviridae https://ictv.global/taxonomy/p/taxonomy-history?taxnode_id=202112166
Duplodnaviria;Heunggongvirae;Uroviricota;Caudoviricetes;Thumleimavirales;Queuoviridae https://ictv.global/taxonomy/p/taxonomy-history?taxnode_id=202112162
Duplodnaviria;Heunggongvirae;Uroviricota;Caudoviricetes;Saparoviridae https://ictv.global/taxonomy/p/taxonomy-history?taxnode_id=202112159
Duplodnaviria;Heunggongvirae;Uroviricota;Caudoviricetes;Kirjokansivirales;Shortaselviridae https://ictv.global/taxonomy/p/taxonomy-history?taxnode_id=202112167
Duplodnaviria;Heunggongvirae;Uroviricota;Caudoviricetes;Thumleimavirales;Soleiviridae https://ictv.global/taxonomy/p/taxonomy-history?taxnode_id=202112163
Duplodnaviria;Heunggongvirae;Uroviricota;Caudoviricetes;Crassvirales;Steigviridae https://ictv.global/taxonomy/p/taxonomy-history?taxnode_id=202113060
Duplodnaviria;Heunggongvirae;Uroviricota;Caudoviricetes;Straboviridae https://ictv.global/taxonomy/p/taxonomy-history?taxnode_id=202113666
Duplodnaviria;Heunggongvirae;Uroviricota;Caudoviricetes;Suolaviridae https://ictv.global/taxonomy/p/taxonomy-history?taxnode_id=202112158
Duplodnaviria;Heunggongvirae;Uroviricota;Caudoviricetes;Crassvirales;Suoliviridae https://ictv.global/taxonomy/p/taxonomy-history?taxnode_id=202113061
Duplodnaviria;Heunggongvirae;Uroviricota;Caudoviricetes;Vertoviridae https://ictv.global/taxonomy/p/taxonomy-history?taxnode_id=202112157
Duplodnaviria;Heunggongvirae;Uroviricota;Caudoviricetes;Vilmaviridae https://ictv.global/taxonomy/p/taxonomy-history?taxnode_id=202112658
Duplodnaviria;Heunggongvirae;Uroviricota;Caudoviricetes;Winoviridae https://ictv.global/taxonomy/p/taxonomy-history?taxnode_id=202113566
Duplodnaviria;Heunggongvirae;Uroviricota;Caudoviricetes;Zierdtviridae https://ictv.global/taxonomy/p/taxonomy-history?taxnode_id=202113388
Monodnaviria;Shotokuvirae;Cressdnaviricota;Arfiviricetes;Rivendellvirales;Naryaviridae https://ictv.global/taxonomy/p/taxonomy-history?taxnode_id=202113283
Monodnaviria;Shotokuvirae;Cressdnaviricota;Arfiviricetes;Rohanvirales;Nenyaviridae https://ictv.global/taxonomy/p/taxonomy-history?taxnode_id=202113294
Monodnaviria;Shotokuvirae;Cressdnaviricota;Arfiviricetes;Cirlivirales;Vilyaviridae https://ictv.global/taxonomy/p/taxonomy-history?taxnode_id=202113251
Varidnaviria;Bamfordvirae;Yaraviridae https://ictv.global/taxonomy/p/taxonomy-history?taxnode_id=202112528
Riboviria;Orthornavirae;Negarnaviricota;Polyploviricotina;Ellioviricetes;Bunyavirales;Discoviridae https://ictv.global/taxonomy/p/taxonomy-history?taxnode_id=202112952
Riboviria;Orthornavirae;Pisuviricota;Duplopiviricetes;Durnavirales;Fusariviridae https://ictv.global/taxonomy/p/taxonomy-history?taxnode_id=202113711
Riboviria;Orthornavirae;Pisuviricota;Hadakaviridae https://ictv.global/taxonomy/p/taxonomy-history?taxnode_id=202112463
Riboviria;Orthornavirae;Duplornaviricota;Resentoviricetes;Reovirales;Sedoreoviridae https://ictv.global/taxonomy/p/taxonomy-history?taxnode_id=202104872
Riboviria;Orthornavirae;Duplornaviricota;Resentoviricetes;Reovirales;Spinareoviridae https://ictv.global/taxonomy/p/taxonomy-history?taxnode_id=202104918
Riboviria;Orthornavirae;Negarnaviricota;Polyploviricotina;Ellioviricetes;Bunyavirales;Tulasviridae https://ictv.global/taxonomy/p/taxonomy-history?taxnode_id=202112959
Riboviria;Orthornavirae;Pisuviricota;Yadokarivirales;Yadokariviridae https://ictv.global/taxonomy/p/taxonomy-history?taxnode_id=202112467

Conclusion

All proposals submitted for ratification were ratified by an absolute majority of the ICTV, and the changes are now part of official ICTV taxonomy. An up-to-date list of all approved taxa, which now includes 10,434 virus species, can be found on the ICTV website: see https://ictv.global/msl/ for the MSL and https://ictv.global/vmr/ for the Virus Metadata Resource (VMR) that provides an exemplar virus isolate for each species along with the Gen-Bank accession number of the isolate.

Funding

E.M.A. gratefully acknowledges funding by the U.K. Biotechnology and Biological Sciences Research Council (BBSRC); this research was funded by the BBSRC Institute Strategic Programme Gut Microbes and Health BB/R012490/1 and its constituent projects BBS/E/F/000PR10353 and BBS/E/F/000PR10356. B.E.D. is supported by the European Research Council (ERC) Consolidator grant 865694: DiversiPHI and the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under Germany’s Excellence Strategy - EXC 2051 - Project-ID 390713860. This work was supported in part through Laulima Government Solutions, LLC prime contract with the US National Institute of Allergy and Infectious Diseases (NIAID) under Contract No. HHSN272201800013C. J.H.K. performed this work as an employee of Tunnell Government Services (TGS), a subcontractor of Laulima Government Solutions, LLC under Contract No. HHSN272201800013C. A.R.M. is a Program Director at the U.S. National Science Foundation (NSF); the statements and opinions expressed herein are made in a personal capacity and do not constitute endorsement by NSF or the government of the United States. H.M.O. was supported by the University of Helsinki and Academy of Finland by funding for FINStruct and Instruct Centre FI, part of Biocenter Finland and Instruct-ERIC. D.L.R. is supported by the U.K. Medical Research Council (MC_UU_1201412). R.J.O. and D.B.S. were supported by the Wellcome Trust (WT108418AIA). S.S. acknowledges support from the Mississippi Agricultural and Forestry Experiment Station (MAFES), USDA-ARS project 58-6066-9-033 and the National Institute of Food and Agriculture, U.S. Department of Agriculture, Hatch Project, under Accession Number 1021494. E.J.L, D.M.D. and R.C.H were supported by the National Institute of Allergy and Infectious Diseases of the National Institutes of Health under Award Number U24AI162625. Except for Donald M. Dempsey, R. Curtis Hendrickson, Richard J. Orton and Donald B. Smith, the authors were members of the ICTV Executive Committee during the relevant period. The views and conclusions contained in this document are those of the authors and should not be interpreted as necessarily representing the official policies, either expressed or implied, of the US Department of Health and Human Services, or of the institutions and companies affiliated with the authors. The findings and conclusions in this report are those of the authors and do not necessarily represent the official position of their affiliates, including the Centers for Disease Control and Prevention. For the purpose of open access, the authors have applied a Creative Commons Attribution (CC BY) licence to any Author Accepted Manuscript version arising from this submission.

Footnotes

Conflict of interest The authors declare no conflicts of interest.

Ethical approval None of the work reported involved research on human participants or animals.

References

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