The International Committee on Taxonomy of Viruses (ICTV) is a committee which authorizes and organizes the taxonomic classification of viruses. Taxonomy is the practice and science of classification The word comes from the Greek, taxis (meaning 'order' 'arrangement' and, nomos A virus (from the Latin virus meaning Toxin or Poison) is a sub-microscopic infectious agent that is unable They have developed a universal taxonomic scheme for viruses and aim to describe all the viruses of living organisms. Members of the committee are considered to be world experts on viruses. The committee formed from and is governed by the Virology Division of the International Union of Microbiological Societies.
The committee also operates an authoritative database (ICTVdB) containing taxonomic information for over 1,500 virus species, as of 1999. It is open to the public and is searchable by several different means.
The official objectives of the ICTV are:
The ICTV's essential principles of virus nomenclature are:
The ICTV's universal virus classification system uses a slightly modified version of the standard biological classification system. It only recognises the taxa below kingdom: those of order, family, subfamily, genus, and species. A taxon (plural taxa) or taxonomic unit, is a name designating an organism or a group of Organisms In Biological nomenclature according to When it is uncertain how to classify a species into a genus but its classification in a family is clear, it will be classified as an unassigned species of that family. Many taxa remain unranked.
Proposals for new names, name changes, and the establishment and taxonomic placement of taxa are handled by the Executive Committee of the ICTV in the form of proposals. All relevant ICTV subcommittees and study groups are consulted prior to a decision being taken.
The name of a taxon has no status until it has been approved by ICTV, and names will only be accepted if they are linked to approved hierarchical taxa. A taxon (plural taxa) or taxonomic unit, is a name designating an organism or a group of Organisms In Biological nomenclature according to If no suitable name is proposed for a taxon, the taxon may be approved and the name be left undecided until the adoption of an acceptable international name, when one is proposed to and accepted by ICTV. Names must not convey a meaning for the taxon which would seem to either exclude viruses which are rightfully members of that taxa, exclude members which might one day belong to that taxa, or include viruses which are members of different taxa.
A species name shall consist of as few words as practicable but must not consist only of a host name and the word virus. A species name must provide an appropriately unambiguous identification of the species. Numbers, letters, or combinations thereof may be used as species epithets where such numbers and letters are already widely used. An epithet (from Greek ἐπίθετον - epitheton, neut of ἐπίθετος - epithetos, "attributed added" is a However, newly designated serial numbers, letters or combinations thereof are not acceptable alone as species epithets. If a number or letter series is in existence it may be continued.
A virus genus is a group of related species that share some significant properties and often only differ in host range and virulence. A genus name must be a single word ending in virus. Approval of a new genus must be accompanied by the approval of a type species. In Taxonomy, a type species is the species that originally defined a genus.
A subfamily is a group of genera sharing certain common characters. The taxon shall be used only when it is needed to solve a complex hierarchical problem. A subfamily name must be a single word ending in virinae.
A family is a group of genera, whether or not these are organized into subfamilies, sharing certain common characters. A family name must be a single word ending in viridae.
An order is a group of families sharing certain common characters. An order name must be a single word ending in virales.
Rules concerned with the classification of viruses shall also apply to the classification of viroids. The formal endings for taxa of viroids are the word viroid for species, the suffix -viroid for genera, the suffix -viroinae for sub-families, should this taxon be needed, and -viroidae for families.
Retrotransposons are considered to be viruses in classification and nomenclature. Satellites and prions are not classified as viruses but are assigned an arbitrary classification as seems useful to workers in the particular fields.
The ICTV classification uses an eight position decimal code to represent order, family, subfamily, genus, species, subspecies, serotype or subtype, and strain or isolate. Each position in the code uses 1, 2, or 3 numerical digits. The decimal code identifies a virus to the level of strain or isolate. Two examples are shown in the table below.
|Subfamily||00. 052. 0.|
|Species||00. 052. 0. 01. 007.||Poliovirus 1|
|Subspecies||00. 052. 0. 01. 007. 00.|
|Serotype||00. 052. 0. 01. 007. 00. 001.||Poliovirus 1|
|Strain or Isolate||00. 052. 0. 01. 007. 00. 001. 001.||PV-1 Brunhilde|
|Influenza A virus, A/Puerto Rico/8/34 (H1N1) isolate|
|Subfamily||00. 046. 0.|
|Species||00.046.0.01.001.||Influenza A virus|
|Subspecies||00. 046. 0. 01. 001. 00.|
|Serotype||00. 046. 0. 01. 001. 00. 001.||H1N1|
|Strain or Isolate||00. 046. 0. 01. 001. 00. 001. 001.||A/Puerto Rico/8/34|
The development of ICTVdB has been supported by the ICTV since 1991 and was initially intended to aid taxonomic research. The database classifies viruses based primarily on their chemical characteristics, genomic type, nucleic acid replication, diseases, vectors, and geographical distribution, among other characteristics. In classical genetics the genome of a Diploid Organism including Eukarya refers to a full set of chromosomes or genes in a Gamete, thereby A nucleic acid is a Macromolecule composed of chains of monomeric Nucleotides In Biochemistry these Molecules carry Genetic information In Epidemiology, a vector is an Organism that does not cause Disease itself but which transmits Infection by conveying Pathogens from
The database was developed at the Australian National University with support of the US National Science Foundation, and sponsored by the American Type Culture Collection. The Australian National University, commonly abbreviated to ANU, is a public Research university situated in Canberra, Australia. The National Science Foundation (NSF is a United States Government agency that supports fundamental Research and Education in all the non-medical The American Type Culture Collection (ATCC is a private not-for-profit biological resource center whose mission focuses on the acquisition authentication production preservation It uses the Description Language for Taxonomy (DELTA) system, a world standard for taxonomic data exchange, developed at Australia's Commonwealth Scientific and Industrial Research Organisation (CSIRO). DELTA (DEscription Language for TAxonomy is a data format used in taxonomy, for recording descriptions of living things The Commonwealth Scientific and Industrial Research Organisation ( CSIRO) is the national government body for scientific research in Australia. DELTA is able to store a wide diversity of data and translate it into a language suitable for traditional reports and web publication. For example, ICTVdB does not itself contain genomic sequence information but can convert DELTA data into NEXUS format. It can also handle large data inputs and is suited to compiling long lists of virus properties, text comments, and images.
ICTVdB has grown in concept and capability to become a major reference resource and research tool, in 1999 it was receiving over 30,000 combined online hits per day from its main site at the Australian National University, and two mirror sites based in the UK and USA. The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom, the UK or Britain,is a Sovereign state located The United States of America —commonly referred to as the