Introduction

The current species names approved by the ICTV are written in italics and capitalized but are otherwise the same as the English vernacular names of viruses written in Roman. This has resulted in considerable confusion among virologists who must differentiate in their writing, only on the basis of typography, between a species (a taxonomic construct created by taxonomists) and a virus (a molecular genetic parasite usually causing a disease) [1–4].

It is important not to confuse a virus species (which is a taxonomic construct or concept which does not have a sequence and cannot be isolated, transmitted to a host or otherwise manipulated) with a virus (a physical entity) that can be isolated and manipulated experimentally and always exists in the form of many mutants, variants and strains possessing different genome sequences. For the same reason, other taxonomic constructs such as a family or a genus also cannot be transmitted to a host or be sequenced. It is incorrect to write, as is often done, that the species Measles virus (italics) or Cucumber mosaic virus (italics) has been isolated, transmitted to a host or sequenced.

In biology, many animals, plants and microorganisms do not have vernacular names in English or other languages. As a result scientists will write that Escherichia coli (the italicized species name) has been infected by a bacterial virus, falsely implying that a taxonomic entity could be infected. In virology this undesirable practice can be avoided since all viruses have vernacular names and these names (in Roman) can therefore be used if one wants to refer to the infectious agent rather than to the species into which it has been placed. Unfortunately at present many virologists do not use available correct typography and write that a virus species (italicized typography) can be transmitted or sequenced [5].

Rationale for introducing non-Latinized binomial species names

Binomial Latin names have been proposed for virus species [6, 7] although virologists have traditionally been opposed to the introduction of Latin names [8–10]. This would require the creation of new Latin names for more than 2,000 virus species and reaching agreement on such names is unlikely to be easy [11]. In contrast, introducing non-Latinized binomial species names would be simple since they are obtained by combining existing English virus names with accepted genus names without involving the creation of new names.

Very few virus species are not yet assigned to a genus and are therefore excluded from the proposed system [12]. Only in a small number of cases will it be necessary to change existing genus names, mostly because these names do not follow the ICTV rule that genus names must end in “virus” [13–15]. For instance the species Enterobacteria phage T1 is currently placed in a genus called “T1-like viruses” in the family Siphoviridae and a proper genus name would have to be introduced to make the binomial system applicable. However, the need to create proper genus names in such cases is already recognized by the ICTV. In the case of bacterial viruses, the word “phage” could be deleted from the species name altogether. For instance, the virus enterobacteria phage M13 which is a member of the genus Inovirus could be placed into a species with the name Enterobacteria M13 inovirus.

Since the species name, which is written in italics with a capital initial, would be obtained by replacing the terminal word “virus” in the virus name with the genus name to which the species belongs, it would be appropriate to have species names such as Human papilloma 32 alphapapillomavirus and Influenza A alphainfluenzavirus. If the species name contains “-virus” as a suffix as in Rotavirus A, the suffix can be removed to avoid repeating “virus” twice in the binomial species name which then becomes Rota A rotavirus. Such word repetition is also frequent in the species names of organisms, for instance Rattus rattus (roof rat), Ciconia ciconia (white stork) and Gorilla gorilla gorilla (Western Lowland Gorilla).

The current proposal does not aim to provide a solution for these cases which should be addressed by the relevant ICTV Study Groups, once the principle of binomial species names has been accepted. However, these few problems are not a valid reason for rejecting the proposal.

Adopting the proposed binomial species names implies that a name change would have to occur when species are moved from one genus to another. However, by drawing attention to a new taxonomic placement this is probably a clarifying advantage rather than an alleged disadvantage [12]. Such changes are common in animal, plant and bacterial taxonomy.

Since all species names of animals, plants and microorganisms are binomials that always include a genus designation, virus species binomials will be easily recognizable as species names. The vernacular virus names in different languages (measles virus; virus de la rougeole; Masernvirus, etc.) will be recognized as virus names rather than species names and this will make it easier to distinguish between the two.

A major advantage of the proposed system is that inclusion of the genus affiliation in the species name indicates relationships with other viruses and provides additional information about the properties of members of the species. The advantage of a binomial name exists also when the genus affiliation appears at the end of the binomial species name instead of at the beginning. For instance, it would be immediately obvious that hepatitis A, B and C viruses are very different infectious agents belonging to different genera if the corresponding species names were Hepatitis A hepatovirus, Hepatitis B orthohepadnavirus and Hepatitis C hepacivirus. Since all such binomial names for virus species end with the suffix -virus present in the genus name, they also clearly indicate that the names refer to viral entities. This is an advantage compared to the Latin names used in biology which do not indicate to the uninitiated whether the organism referred to is an animal, a plant or a microorganism.

The proposed binomial system is not a new idea. The system was used to index the viruses in the 2nd, 3rd and 4th ICTV reports published in 1976, 1979 and 1982, respectively [16–18], because the benefits of referring to entries like bluetongue orbivirus and West Nile flavivirus must have been obvious already at the time. In the 5th ICTV report published in 1991 [19] the binomials were retained only for the indexing of plant viruses. In the 6th ICTV report [20], the binomials were dropped altogether because certain animal virologists, for no declared reason, were opposed to their use. Binomial names for referring to viruses rather than to species have always been popular with plant virologists and they have been used in many books [21–24]. Some animal virologists also find it helpful to use binomials to refer to viruses such as Bunyamvera orthobunyavirus [25]. When coining new virus names, the ICTV plant virus Study Groups have always been careful to avoid redundancies between virus names and genus names and, as a result, the proposed binomial species names would lead to very few problems with plant viruses [11, 14, 15].

When the proposal was first made in 1998, most members of the ICTV Executive Board who actually were not plant virologists, were opposed to the introduction of non-Latinized binomial species names [10]. By 2004, half the ICTV Executive Board no longer objected to the system, but when asked about their opinion on binomial names, only a minority of the 80 Study Groups responded [26]. Although in the past, the ICTV often has ratified decisions by accepting that a no answer vote was a vote in favor, this practice was not followed in this case. Surveys conducted in 2002 among laboratory virologists showed that more than 80% of those who responded were in favor of the binomial system [10, 12, 15, 27].

Species names in biology are never abbreviated in the form of acronyms. Since virus species names are used sparingly, they also do not deserve abbreviations. Abbreviations are useful for virus names but these are not affected by the present proposal. Although the ICTV is not responsible for devising appropriate abbreviations, it has published several lists of recommended virus name abbreviations [28–31]. Although one list [31] refers to abbreviations of virus species, these recommendations do all pertain to abbreviations of virus names.

Some non-Latinized binomial species names for vertebrate viruses are shown in Table 1. Many examples of possible binomial species names together with the unchanged current virus names are provided as a guideline in Table 2. In this list, the species names are grouped by family and genus. All family, genus and species names are written in italics. Unchanged virus names are written in Roman without capitals except for proper names. This list compiled by Claude Fauquet does not include all the species, genera and families presently recognized by the ICTV since the list only serves to illustrate that the binomial system is widely applicable. Although in many cases such as the ssRNA plant viruses these species names will not be controversial, in a limited number of cases the relevant ICTV Study Groups will have to decide which binomial species names should be adopted.

Table 1 Examples of non-Latinized binomial species names for vertebrate viruses
Full size table
Table 2 Examples of possible virus non-Latinized binomial species names
Full size table