SEXUAL TRANSMISSION OF GB-VIRUS-C HEPATITIS-G VIRUS

Although it is established that infection with GB virus C (GBV-C) or h epatitis G virus (HGV) can be transmitted parenterally, the prevalence of GBV-C/HGV viremia in the general population (2-5%) is relatively h igh compared with other parenterally borne viruses such as hepatitis C virus. To investigate the possibility of sexual transmission of GBV-C /HGV, we determined the frequency of viremia by the polymerase chain r eaction and serological reactivity to the E2 protein by ELISA in sampl es collected from individuals at risk for sexually transmitted disease s attending a city genitourinary medicine clinic. GBV-C/HGV viremia wa s detected in 27 of 87 male homosexuals (31%) and 9 of 50 prostitutes (18%), frequencies significantly greater than those in matched control s (2/63) and local blood donors (2.3%). Among nonviremic individuals, a high frequency of serological reactivity to the E2 protein of GBV-C/ HGV was also observed in the risk groups (male homosexuals: 14/60; pro stitutes: 11/41), although these figures are likely to be underestimat es of the frequency of past infection as detectable anti-E2 reactivity may attenuate rapidly over time following resolution of infection. In fection with GBV-C/HGV was more frequent among those coinfected with h uman immunodeficiency virus type 1. Among male homosexuals from whom r etrospective samples were available, evidence for de novo infection wa s found in 9 of 22 individuals over a mean sampling time of 2.9 years, predicting an annualized incidence of GBV-C/HGV infection of approxim ately 11% in this group. The high prevalence and incidence of GBV-C/HG V infection in these individuals and prostitutes provides strong evide nce for its spread by sexual contact. Further studies are required to investigate the mechanism of its transmission and the clinical signifi cance of acute and persistent infection in these risk groups. (C) 1998 Wiley-Liss, Inc.