The first bacteriophage known to science was the Bacteriophagum intestinale described by Félix d'Hérelle (3), an enterobacterial phage or a mixture of phages that was considered by d'Hérelle as a single virus with many races. In 1961 Eisenstark published the first list of phages, which included 111 phages with tailed, cubic or filamentous morphology (4). A second phage list, published by Fraenkel-Conrat in 1974, included 411 bacterial viruses and the dimensions and physicochemical properties of many of them (5). Unfortunately, phage names with the Greek letter f were reported without this letter. At present, over 5000 bacteriophages have been studied by electron microscopy and can be attributed to 11 virus families * (1). Our purpose is to give a (nearly) complete list of the phage names in existence, to help thereby other scientists in constructing phage names, and to document this aspect of the extraordinary efforts that have gone into phage research.
During 80 years, phage names have been constructed in the absence of any system and usually reflect little more than their author's imagination (or lack thereof). Phage nomenclature is therefore in a primitive and confusing state. Phage names may:
- Be single letters or numerals in any combination, even names of individuals or cities.
- Include the Greek letter f or the Latin letter P to indicate phage status.
- Include special types (superscript or infrascript characters, dots, dashes).
- Vary between authors, studies, even printer conventions.
As a result, (i) phage names do not reflect basic phage properties, (ii) synonyms and homonyms abound, and (iii) some designations are unduely complicated and a printer's nightmare. Certain synonyms of enterobacterial phages are even willful creations of investigators who published one and the same virus up to six times under different designations. Further ambiguities are created by the identity of some Roman letters and numerals (I, V), or are the product of odd printer conventions (witness, for the latter, the ambiguous numeral subscript status of the original T phages of Escherichia coli B; 2). However, one notes that quite numerous phage names have been constructed from host names and therefore reflect host ranges, and that names of temperate phages often comprise two elements, one for the phage and another for the host strain.
The list presented here includes over 5000 negatively stained phages or defective phages studied by electron microscopy since 1960 (though sometimes discovered years or even decades earlier): 5112 separate (though not always unique) names, as many as 5024 presumably unique phage isolates (4613 of which have names, many of which are homonyms), 351 phage family-host taxon (typically genus) combinations (e.g., family Myoviridae of genus Escherichia is one such family-host combination), and 411 phages that we know of that were propagated and studied by electron microscopy but were not named. Defective phages are indicated as such. Shadowed phages, prophages, mutants and phages without hosts (e.g., phages observed in water or rumen and not propagated) are omitted.
Hosts are listed in alphabetical order regardless of their taxonomical position. Host names do not reflect an endorsement of any system of taxonomy. An effort is made to replace obsolete host names. However, because the reclassification of Rhizobium-like bacteria is not completed the general term "rhizobia" is used. In addition, enterobacterial phages are generally polyvalent and not genus-specific; their listing here by host genera is solely for retrieval purposes.
Phage names are listed by family, host genus, and in alphabetical and numerical order. Roman letters are followed by Greek letters and Arabic numerals. Synonyms and spelling variants are indicated in parentheses. Homonyms are repeated as often as they occur (e.g., D, D, d). Unnamed phages are indicated by "NN" beside their genus and their numbers are given in parentheses. References may be obtained upon request.
Eighty years after the discovery of phages, it it clearly too late to construct a nomenclature system that reflects basic phage properties such as nucleic acid or particle shape. The most that can be done is to limit the amount of synonyms and homonyms. The practice of constructing phage names from host names should be continued as it gives at least a clue to the phage. We suggest the following:
- To use the first two letters of the host genus and the host species names, respectively (e.g., Esco for Escherichia coli).
- To complement the above constructs with any letters or numerals (e.g., Esco1).
- To avoid the over-used letters f and P.
- To avoid superscript or infrascript characters, parentheses, or dashes.
- To check this or similar phage-name lists for naming precedent.
- To avoid the invention of new names for old phages.
- To click here for a description of ICTV nomenclature rules.
- To obtain rules on virus genera and families see Van Regenmortel, M.H.V., Fauquet, C.M., Bishop, D.H.L. (eds.-in-chief). 2000. Virus Taxonomy. Classification and nomenclature of Viruses. Seventh Report of the International Committee on Taxonomy of Viruses. Academic Press, San Diego, 1065-1069.
- Ackermann, H.-W. 2001. Frequency of morphological phage descriptions. Arch. Virol., 146, 843-857.
- Demerec, M., and Fano, U. 1945. Bacteriophage-resistant mutants in Escherichia coli. Genetics 30, 119-136.
- D'Hérelle, F. 1918. Technique de la recherche du microbe filtrant bactériophage (Bacteriophagum intestinale). C.R. Soc. Biol. 81, 1160-1162.
- Eisenstark, A. 1967. Bacteriophage techniques. In: Maramorosch, K., Koprowski, H. (eds.), Methods in Virology, vol. 1. Academic Press, New York, pp. 449-525.
- Fraenkel-Conrat, H., 1974. Descriptive catalogue of viruses. In: Fraenkel-Conrat, H., Wagner, R.R. (eds.), Comprehensive Virology, vol. 1, Plenum Press, New York, pp. 121-156.
* Note that the list of phage families includes their descriptions which may be accessed by enlarging the displaying frame. To do this, simply place your cursor over the bar to the right of this frame until the cursor takes on a double arrow form ("<===>"). Then click down with your (left) mouse button and pull the now-grabbed bar as far as you like to right, thus enlarging the frame. Reverse to reduce the size of the frame. Refreshing/reloading the page may also accomplish this size reduction.
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