The GB viruses: a review and proposed classification of GBV-A, GBV-C (HGV), and GBV-D in genus Pegivirus within the family Flaviviridae

In 1967, it was reported that experimental inoculation of serum from a surgeon
(G.B.) with acute hepatitis into tamarins resulted in hepatitis. In 1995, two new
members of the family Flaviviridae, named GBV-A and GBV-B, were identified in
tamarins that developed hepatitis following inoculation with the 11th GB
passage. Neither virus infects humans, and a number of GBV-A variants were
identified in wild New World monkeys that were captured. Subsequently, a related
human virus was identified [named GBV-C or hepatitis G virus (HGV)], and
recently a more distantly related virus (named GBV-D) was discovered in bats.
Only GBV-B, a second species within the genus Hepacivirus (type species
hepatitis C virus), has been shown to cause hepatitis; it causes acute hepatitis in
experimentally infected tamarins. The other GB viruses have however not been
assigned to a genus within the family Flaviviridae. Based on phylogenetic
relationships, genome organization and pathogenic features of the GB viruses, we
propose to classify GBV-A-like viruses, GBV-C and GBV-D as members of a
fourth genus in the family Flaviviridae, named Pegivirus (pe, persistent; g, GB or
G). We also propose renaming ‘GB’ viruses within the tentative genus Pegivirus to
reflect their host origin.