Exposure rates to HGV/GBV-C (hepatitis G) virus in adults and children

Objectives: 1. To assess the extent of exposure to the GBV-C virus in population groups with low and high risk of exposure to blood-borne agents. 2. To identify factors associated with exposure to the virus in populations at low risk for parenteral blood exposure. Methods: Exposure rates to GBV-C were assessed for blood donors, children, pregnant women, haemophiliacs, haemodialysis patients, hepatitis C antibody positive donors and injecting drug users. Exposure to GBV-C was assessed by testing for markers indicative of current infection and of past infection. GBV-C RNA, a measure of current infection, was detected using a reverse transcriptase PCR method (Abbott Laboratories). PCR reactive samples were further tested by Inhouse PCR and sequencing. Antibody to GBV-C envelope protein, anti-E2, a marker for past infection with clearance, was detected by an ELISA at Abbott Laboratories, Chicago and confirmed by immunoassays. All blood donors were invited to fill questionnaires designed to identify factors which could be associated with exposure to GBV-C. Results: Combined GBV-C RNA and anti-E2 prevalances ranged from 6.5% in children, 13.3% in blood donors, 14% in pregnant women, 22.5% in haemodialysis patients, 80% in anti-HCV positive donors and 88.6% in IVDUs and 85.7% in adult haemophiliacs. Children had the lowest antibody rate, 1.1%, compared with 10.8% for blood donors rising to 45.7% for IVDUs and to 74.6% for haemophiliacs. In contrast current infection rates were comparable for children, blood donors and pregnant women at 5.4%, 2.6% and 6%. These rates rose to 11.1% for haemophiliacs, 24.3% for anti-HCV donors and 48.6% for IVDUs. Ten of 12 donors had persistent vireamia while two had recent infections, one with apparent resolution. 47% of donors who had lived in the Pacific Islands had GBV-C exposure compared to 16% who had not lived in the Pacific. (P<0.01). Spending evening outdoors was also associated with HGB exposure. Conclusions and comments: Exposure to this virus is occurring at an early age in the population. However ongoing exposure continues into adulthood amongst groups at low risk of parenteral exposure to blood. We postulate that arthropod vector transmission may play a role in the transmission of this virus.