Prevalence of infection and genotypes of GBV-C/HGV among homosexual men

Since the discovery of GB virus-C (GBV-C) and hepatitis G virus (HGV), many studies have been performed. These viruses are now known to be parenterally, as well as sexually transmitted. A phylogenetic analysis also revealed that GBV-C has five major genotypes: type 1 predominates in West Africa, type 2 in Europe and the United States, type 3 in parts of Asia, type 4 in Southeast Asia, and type 5 in South Africa. Despite the number of reports so far, there have been few large-scale surveys of homosexual men to determine the prevalence of the GBV-C/HGV infections. We examined the levels of GBV-C/HGV viremia in 297 homosexual men who attended the Nagoya Lesbian and Gay Revolution held in Nagoya, Japan. Reverse transcription-polymerase chain reaction (RT-PCR)/nested PCR of the GBV-C/HGV 5'-non-coding region (NCR), and base sequence analyses showed that the infection rate was 12.5%, and genotypes in this population were classified into type 2 (32%) and type 3 (68%). None were classified as types 1, 4, or 5 in this study. Our results indicate that the GBV-C/HGV type 2 seen mainly in Europe and the US is spreading widely in Japan, especially in the Nagoya district.