ABSTRACT
Objective To infer its transmission origin and route through studying the feature of molecular epidemiology of an HCV outbreak in Guangzhou.Methods Serum samples 192 cases in an HCV outbreak incident were analyzed for 2a and 6a subtypes.Appropriate genotypes were selected as control group.Informatics software were used in the evolutionary analysis to construct time scale trees and infer the origin time of HCV infection.Results Of 119 patients in the HCV outbreak,66 cases were 2a and 110 cases were 6a subtype.No other genotypes were found.The evolutionary analysis indicated the isolates of 2a group and 6a group both originated from 2 ～ 5 years ago.Both of 2a group and 6a group were in line with the characteristics of iatrogenic infection.Conclusion 2a and 6a were the main sub-genotypes in the Guangdong HCV outbreak investigation and they were originated from 2 to 5 years ago,which were in line with the characteristics of iatrogenic transmission.With the extension of time,a large number of cases accumulated and led to outbreak.