ICTV Orthography

ICTV Rules of Orthography

How to write virus names


Below, we provide a brief guide on how to write the names of viruses and virus taxa.


  • In formal taxonomic usage, the accepted names of virus orders (e.g., Mononegavirales), families (e.g., Picornaviridae), subfamilies (e.g., Parvovirinae), and genera (e.g., Hepacivirus) are printed in italics and the first letters of the names are capitalized.
  • Species names are printed in italics and have the first letter of the first word capitalized (e.g., Mumps virus). Other words are not capitalized unless they are proper nouns (e.g., West Nile virus), parts of proper nouns (Enterobacteria phage MS2) or alphabetical identifiers (e.g., Enterovirus A).
  • Names of virus strains, on the other hand, are not italicized. The first letter of the first word is not capitalized (e.g., herpes simplex virus) unless it is a proper noun, typically based on the binomial name of the species it infects; e.g.:
  • Species name: Saccharomyces cerevisiae virus L-A
    Virus strain name: Saccharomyces cerevisiae virus L-A (ScV-L-A)

    • Species names are in italic script; strain names are in Roman script.
    • Please note that even though the virus name includes the host fungal name, it is not italicized because it is a virus name. Thus the designation Saccharomyces cerevisiae virus L-A is erroneous because the fungal name is italicized even though this is not a fungal name.
  • Since it is virus names that are used repeatedly in a text, they are the names that need to be abbreviated. Species names should never be abbreviated.
  • The formal taxon designation of each classified virus referred to in a manuscript should be identified at least once, preferably in the ‘Introduction’ or ‘Materials and Methods’ section, using formal family, genus, and species terms, e.g. “The replication of echovirus 7 (species Enterovirus B, genus Enterovirus, family Picornaviridae, order Picornavirales) was investigated in three cell lines.
  • Formal terms used for virus families, genera, and species should be those approved by the International Committee on Taxonomy of Viruses (ICTV):
  • Virus taxonomy: classification and nomenclature of viruses: Ninth Report of the International Committee on Taxonomy of Viruses. (2012) Ed: King, A.M.Q., Adams, M.J., Carstens, E.B. and Lefkowitz, E.J. San Diego: Elsevier.

    Up-to-date information on virus taxonomy can be found on the ICTV web site under Current Taxonomy Release.

  • Once formal taxonomic names have been given in a paper, vernacular terms may be used, e.g. “echovirus 7 is typical of enteroviruses and other picornaviruses in replicating rapidly in vitro“.
  • Additional information on the formal rules for orthography of virus taxa names can be found in section IX of the ICTV Code of Virus Classification and Nomenclature (see Code of Virus Classification and Nomenclature). The following references might also be helpful:

  1. Mayo MA. Constructing and writing the names of virus species–an editorial note. Arch Virol. 2000;145(2):427-8. PubMed PMID: 10752564.
  2. Van Regenmortel MH. How to write the names of virus species. Arch Virol. 1999;144(5):1041-2. Erratum in: Arch Virol 1999;144(8):1667. PubMed PMID: 10447501.