HCV, which is the causative agent of the hepatitis C in humans and the type species of the genus, was discovered in 1989.
GBV-B virus (also known as GB virus B) discovered in 1995 is capable of infecting New World monkeys, in particular tamarins. Like HCV it is transmitted by the blood-borne route and similar to HCV it is associated with the viral hepatitis. However GBV-B has never been identified in wild animals and its natural host is not known.
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