FEATURES OF CIRCULATION OF HEPATITIS C VIRUS IN KHABAROVSK REGION

Aim. Study the intensity of circulation of HCV in Khabarovsk Region and genetic variants of the virus circulating in the region. Materials and methods. 940 sera samples obtained from individuals with unestablished risk factors for HCV infection in polyclinic of the Far-Eastern Regional Centre for Prophylaxis and Control of AIDS (Khabarovsk) were studied. Individuals of the following age groups were included into the study: 1 - 4, 5 - 9,10 - 14,15 - 19,20 - 29, 30 - 39, 40 - 49, 50 - 59, older than 60 years; each group included approximately 100 individuals. Anti-HCV was determined in all the samples, HCV RNA was determined in samples positive for anti-HCV. Phylogenetic analysis with a time scale for the detected genovariants of HCV was carried out for reconstruction of the history of prevalence of HCV in Khabarovsk Region. Trees were constructed using BEAST vl.8.2 program by 2 genome sequences - core (1043 bp) and NS5B (389 bp). Results. The mean prevalence of anti-HCV among the examined individuals was 9.3% (87/940). The proportion of individuals with a current HCV-infection (presence of HCV RNA) was 4.2% (39/940). A sharp increase of HCV prevalence was observed beginning from the age group 20 - 29, where frequency of anti-HCV was 13.1% (13/99) that is 6 times higher compared with the previous age group of 15 - 19 (2,2%, p<0.01). The highest frequency of detection of HCV markers was observed in the age group 40 - 49 (20.8 and 9.4% for anti-HCV and HCV RNA, respectively). The frequency of detection of anti-HCV and HCV RNA in the 30-39 group was 20.2 and 8.9%, respectively, and among individuals older than 60-16.8 and 7.4%, respectively. Genotype lb was determined for 64.2% of HCV isolates, 28.3% of isolates belonged to genotype 3a, and 3 isolates were similar to genotype la, 2a and 2c members. Genotype lb was introduced into Khabarovsk Region around 55 - 65 years ago from Japan and the USA, around 15 years later - genotype 3a. Importation of novel HCV genotype 3a strains from Europe took place many times, these strains are present across the whole Russia. Conclusion. The data obtained have demonstrated high prevalence of HCV in the Khabarovsk Region, that has formed due to a prolonged circulation of the virus in the region.

hepatitis C virus (HCV), anti-HCV, age cohorts, population studies, HCV genotypes