Epidemiology of hepatitis C virus infection among blood donors in northern Thailand

Objectives. To determine the potential risk factors for HCV infection, HCV genotype distribution, and the relationship between HCV genotypes and the routes of transmission among blood donors in northern Thailand.; Population. The donors and spouses aged at least 18 years at the time of donation or recruitment who resided in the north and donated blood during January, 2001 to June 2002 were eligible for the study.; Methods. A single masked matched case-control study was conducted. The confirmed cases were eligible cases who were EIA-3 with any positive for HCV of the following confirmatory test; PCR, RIBA-3, or high cut-off repeat EIA-3 from different companies.; Results. 157 of 175 cases were PCR positive. There were 166 confirmed cases and 329 matched controls. IDU was strongly associated with HCV infection (OR: 107.57). Based on multivariate analysis among non-IDU (107 matched sets), the major statistically significant were history of blood transfusion (22.77), immediate blood relatives ever had hepatitis/jaundice (4.37), having at least 6 lifetime sexual partners (2.66), and previous blood donation (0.89). Six of 45 case-spouses but none of 44 control-spouses had HCV infection. 156 could be identified the genotypes. Consensus phylogenic tree showed clustering of sequences within subtypes with high bootstrap values. The genotypes distribution was comprised of type 3 (36.5%), 6 (34.7%) and 1 (28.8%). Participants infected with type 3 had significantly higher ALT level than other types. Type 6 was more diverse than other types were. The highest prevalence of genotype among IDU who reported the last injecting drugs within the past 5 years, 5–9 years, and at least 10 years were type 3, 1 and 6, subsequently (p-value 0.045). No particular genotype was statistically associated with any route of infection.; Conclusion. History of IDU and prior blood transfusion were the important risk factors associated with HCV infection. Repeat blood donors were significantly less likely to have HCV infection. Improved process for self-deferral of blood donors with a history of IDU and transfusion of unscreened blood and active recruitment of repeat donors who have previously tested negative for HCV could reduce the number of HCV positive donor and improve transfusion safety. The possibility of the more recent introduction of genotype 3 and induced liver enzymes in donors infected with type 3 should be further evaluated. (Abstract shortened by UMI.)...