Group Group IV ((+)ssRNA) Higher classification Flaviviridae | Family Flaviviridae Rank Genus | |
Similar Flaviviridae, Hepacivirus, Pestivirus, Ugandan red colobus, Bovine viral diarrhea | ||
Pegivirus is the approved name for a new genus of single positive stranded RNA viruses in the family Flaviviridae. The name is derived one: "Pe" stands for "persistent" and "g" provides an historical reference to the former names of the human viruses ("G"B virus or hepatitis "G" virus).
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Taxonomy
There are two named species within the Pegivirus genus. Isolates termed "Pegivirus A" are monophyletic and show < 50% nucleotide (55% amino acid) sequence divergence between aligned sequences from the polyprotein from each other. However all differ by >50% nucleotide (>55% amino acid) divergence from other members of this genus. Pegiviruses to be assigned to this species (Pegivirus A) originate from primate host species (humans, chimpanzees and several New World monkey species). The sequence U22303 has been assigned the type member of the species as this was the first pegivirus to be described for this species. Terminology to describe viruses with different hosts has not been approved by the International Committee on Taxonomy of Viruses (ICTV); however, Pegivirus A viruses have been called HPgV for human pegivirus, SPgV for new world simian pegiviruses, and SPgVcpz for chimpanzee simian virus. This remains an area requiring further clarification.
A second species within the Pegiviruses is termed Pegivirus B. Only one virus was included in the naming proposal, which was a complete genome of a virus found in the bat species Pteropus giganteus. This sequence differs by >50% nucleotide (>55% amino acid) divergence from all proposed members of the primate-derived Pegivirus A species that originate from primate host species (humans, chimpanzees and several New World monkey species). The sequence GU566734 has been assigned the type member of the species as this was the first pegivirus to be described for this species. However, the use of deep sequencing technologies has identified additional viruses that differ from this bat species by >50% nucleotide (>55% amino acid) and primate viruses in rodents, horses, and in different bat species, indicating the need to expand the number of species of Pegiviruses. Additional primate pegiviruses have also been recently discovered in old world monkeys, thus the host range for Pegiviruses is much broader than previously realized, and a system to name the different species is needed.
History
In 1967 it was reported that experimental inoculation of serum from a surgeon (G. Barker) with acute hepatitis into tamarins resulted in hepatitis.
In 1995, two new members of the family Flaviviridae (GBV-A and GBV-B) were identified in tamarins that developed hepatitis following inoculation with the 11th GB passage. GBV-B has been assigned to the Hepacivirus genus, whereas GBV-A may be assigned to the new Pegivirus genus. A number of GBV-A variants were later identified in wild New World monkeys that were captured.
Subsequently a human virus was identified [GBV-C or hepatitis G virus (HGV)].
A more distantly related virus (GBV-D) was later discovered in the bat (Pteropus giganteus). Another virus—rodent pegavirus—has been isolated from the white throated woodrat (Neotoma albigula). A pegivirus (equine pegivirus) has also been isolated from a horse.
Theiler's disease—a form of equine hepatitis—also appears to be caused by a pegivirus—Theiler's disease-associated virus.
Human hepegivirus 1 is a virus isolated from 2 multiply transfused hemophiliacs and two transfused patients. This virus appears to belong to a new clade in the Pegiviruses.