RISK ANALYSIS OF THE EXPOSURE TO GB-VIRUS-C HEPATITIS-G VIRUS AMONG POPULATIONS OF INTRAVENOUS-DRUG-USERS, COMMERCIAL SEX WORKERS AND MALE OUTPATIENTS AT STD CLINIC IN CHIANG-MAI, THAILAND - A CROSS-SECTIONAL CASE-CONTROL STUDY

An exposure to GB virus C/hepatitis 6 virus (GBV-C/HGV) was studied am ong populations at risk for blood and sexual exposure to analyze risk factor of the transmission of the virus. Blood samples were drawn from 98 intravenous drug users (IVDU), 100 female high-class commercial se x workers (CSW) and 50 male outpatients (MOP) at a sexually transmitte d diseases (STD) clinic in Chiang Mai, Thailand. These blood samples w ere analyzed for GBV-C/HGV RNA; antibodies against second envelope pro tein of GBVC/HGV (anti-E2); anti-hepatitis C virus antibody (HCV-Ab); hepatitis B core antibody (HBcAb); and antibodies against human immuno deficiency virus (HIV-Ab). Prevalences of GBV-C/HGV RNA, anti-E2, HCV- Ab, HBcAb and HIV-Ab were 27.6%, 16.3%, 84.7%, 76.5% and 45.0% in IVDU ; 0%, 21.5 %, 2.0%, 72.0 % and 11.0 % in CSW; 6.0%, 13.6%, 0%, 64.0% a nd 14.0 % in MOP. While the prevalence of GBV-C/ HGV RNA was higher in IVDU than in CSW and MOP, comparable prevalences of anti-E2 among the three populations were found. Intravenous drug injection showed assoc iation with GBV-C/ HGV RNA, while history of STD associated with anti- E2. In conclusion, intravenous drug injection and STD were found to be risk factors for the previous exposure to GBV-C/HGV, but STD did not increase the risk of the GBV-C/HGV viraemia.