Frequently Asked Questions about the ICTV

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Taxon names are written differently from virus names

A document containing this information can be downloaded here.

Names of viruses (the physical things you work with in the lab or that make you sick) are written differently than the names of species and other taxa (logical constructs that help us categorize viruses).

A species name* is written in italics with the first word beginning with a capital letter. Other words only begin with a capital if they are proper nouns (including host genus names but not virus genus names**) or alphabetical identifiers. A species name should not be abbreviated. Examples:

  • The genus Iflavirus includes the species Deformed wing virus.
  • Members of the species West Nile virus are arboviruses.
  • The species Sandfly fever Naples phlebovirus has many diverse member viruses.
  • The etiological agents of poliomyelitis (poliovirus types 1, 2 and 3) are members of the species Enterovirus C.
  • Anadyr virus, Batai virus, Birao virus, and many more, are members of the species Bunyamwera orthobunyavirus.
  • A new bacteriophage, belonging to the species Salmonella virus SP6, has been isolated.
  • Rattus norvegicus polyomavirus 1 is a species in the family Polyomaviridae.

Some host genus names may also be considered common nouns in English and can be written in lower case where they are not the first word of the species name. Example:

  • Indian citrus ringspot virus

A virus name should never be italicized, even when it includes the name of a host species or genus, and should be written in lower case. This ensures that it is distinguishable from a species name, which otherwise might be identical. The first letters of words in a virus name, including the first word, should only begin with a capital when these words are proper nouns (including host genus names but not virus genus names) or start a sentence. Single letters in virus names, including alphanumerical strain designations, may be capitalized. In most texts, virus names are used much more frequently than species names and may, therefore, be abbreviated. Examples:

  • Isolates of dengue virus 2 were obtained ....
  • Detection of West Nile virus in human serum ....
  • Salmonella phage SE1 was isolated ....
  • Sida ciliaris golden mosaic virus (SCGMV) causes ....
  • Aphids transmit potato virus Y (PVY).

A higher taxon name (i.e. above the rank of species) is written as a single word with a taxon-specific suffix. Examples:





























Like a species name, a higher taxon name is written in italics and begins with a capital letter. This differs from the convention in botany and zoology, in which taxon names above the level of genus are not italicized. Taxon names are often preceded by a taxon level identifier. Examples:

  • ... a new species in the genus Fabavirus
  • ... members of the subfamily Comovirinae
  • .... members of the family Secoviridae
  • The order Picornavirales includes viruses infecting hosts of a range of species.

A collective name for a group of viruses belonging to a higher-level taxon is neither italicized nor capitalized, even if it was derived from a proper noun. The first letter of a collective name may be capitalized if it begins a sentence.

  • ourmiaviruses, ourmiavirus
  • Guernseyviruses are distributed worldwide.
  • The guernseyviruses are distributed worldwide.
  • aparaviruses
  • the aparavirus polymerase

Note that if taxa have the same stem (e.g. Flavivirus and Flaviviridae), this may lead to ambiguity because both groups of viruses could be referred to as flaviviruses. Some virologists use the terms stem + virads, stem + virids, stem + virins, and stem + virus to distinguish members of orders, families, subfamilies and genera, respectively.

Complex example sentences

  • Ebola virus (species Zaire ebolavirus; genus Ebolavirus; family Filoviridae; order Mononegavirales) can cause disease in humans and nonhuman primates.
  • Infection of larvae of the silkworm, Bombyx mori(family Bombycidae) with the baculovirus Bombyx mori nucleopolyhedrovirus (BmNPV) (species Bombyx mori nucleopolyhedrovirus) is often lethal.
  • In the family Podoviridae, the subfamily Autographivirinae groups together all podoviruses that contain an RNA polymerase gene in their genome, including Escherichia phage T7 (species Escherichia virus T7; genus Teseptimavirus) and Klebsiella phage F19 (species Klebsiella virus F19; genus Drulisvirus).
  • Artoviruses form a family in the haploviricotine order Mononegavirales.

*The complete rules for naming virus taxa  can be found in the ICTV Code:

** A proper noun is a name used for an individual person, place, or organization. A common noun denotes a class of objects or a concept. Host genus names are normally considered as proper nouns because they refer to a group of unique entities but some, for example "citrus", have become common nouns because they can also describe intergeneric hybrids. Virus genus names are not considered as proper nouns when used as part of a species or virus name because they refer to a subset of the genus and not the genus as a whole.

Translating taxon names

  • Virus taxon names (species, genus, subfamily, family, and order names) have been formally approved using a defined process established by the ICTV and approved by the International Union of Microbiological Societies as specified in the International Code of Virus Classification and Nomenclature (Code of Virus Classification and Nomenclature). These names represent universal identifiers and as such, they should be written in the form in which they were approved, and not translated into other languages or alphabets. A list of all current virus taxon names can be downloaded from the ICTV web site at ICTV Master Species List.
  • Virus names, such as those assigned to virus strains or isolates, are different from taxon names in that they have not been universally assigned nor approved using any defined process. Therefore these virus names may, in contrast to taxon names, be translated as desired into local languages and alphabets.

Citing the ICTV Taxonomy

There are several ways that the ICTV taxonomy can be cited. The following should be the most useful:

  1. Direct citations of the web site “International Committee on Taxonomy of Viruses (ICTV):
  2. Citation of the ICTV Database using our manuscript in Nucleic Acids Research: 
    "Virus taxonomy: the database of the International Committee on Taxonomy of Viruses (ICTV)". Lefkowitz EJ, Dempsey DM, Hendrickson RC, Orton RJ, Siddell SG, Smith DB. Nucleic Acids Res. 2017 Oct 13. PubMed PMID: 29040670.
  3. For the most recent taxonomy release, you can use the following Archives of Virology manuscript:
    Walker PJ, Siddell SG, Lefkowitz EJ, Mushegian AR, Adriaenssens EM, Dempsey DM, Dutilh BE, Harrach B, Harrison RL, Hendrickson RC, Junglen S, Knowles NJ, Kropinski AM, Krupovic M, Kuhn JH, Nibert M, Orton RJ, Rubino L, Sabanadzovic S, Simmonds P, Smith DB, Varsani A, Zerbini FM, Davison AJ. Changes to virus taxonomy and the Statutes ratified by the International Committee on Taxonomy of Viruses (2020). Arch Virol. 2020 Nov;165(11):2737-2748. PMID: 32816125.

Submitting Proposals

  • Who can make proposals for new taxonomy to the ICTV?
    • Any virologist can do this. You don't need to have any position in the ICTV or be a member of any ICTV Study Group.
  • By what date should I make proposals?
    • The deadline for consideration of proposals at the next Executive Committee meeting (summer, 2021) will most likely be sometime in June or July, 2021. The earlier, the better!
  • How do I make proposals?
  • Where should I send proposals?
  • What happens after I submit proposals?
    • The Subcommittee chair will read them, and advise on any amendments. Your proposals will be discussed at the Executive Committee meeting, which takes place a few weeks after the submission deadline. The subcommittee chair will let you know the outcome.