Hepatitis C virus subtype 3a was introduced in the USSR in the early 1980s.

A total of 2120 nucleotide sequences of the NS5b region of HCV subtype 3a were analysed, including 310 strains derived from former republics of the USSR (Azerbaijan, Estonia, Lithuania, Russia, Tajikistan and Uzbekistan). Among the viral isolates collected from former regions of the Soviet Union, 294 strains formed 3 sustained phylogenetic clusters, with each having a common origin. Phylodynamic analysis demonstrated that the most recent common ancestors of the current strains inside the three clusters were introduced into the USSR population in 1981±1, 1984±2 and 1985±2, respectively (the confidence intervals were calculated using Student's t-distribution, P<0.05). The time estimation obtained for HCV subtype 3a correlated well with the historical and epidemiological context of this period, and in particular with the start of widespread injection drug use in the USSR in the first half of the 1980s.

Genetic Diversity and Possible Origins of the Hepatitis B Virus in Siberian Natives.

A total of 381 hepatitis B virus (HBV) DNA sequences collected from nine groups of Siberian native populations were phylogenetically analyzed along with 179 HBV strains sampled in different urban populations of former western USSR republics and 50 strains from Central Asian republics and Mongolia. Different HBV subgenotypes predominated in various native Siberian populations. Subgenotype D1 was dominant in Altaian Kazakhs (100%), Tuvans (100%), and Teleuts (100%) of southern Siberia as well as in Dolgans and Nganasans (69%), who inhabit the polar Taimyr Peninsula. D2 was the most prevalent subgenotype in the combined group of Nenets, Komi, and Khants of the northern Yamalo-Nenets Autonomous Region (71%) and in Yakuts (36%) from northeastern Siberia. D3 was the main subgenotype in South Altaians (76%) and Buryats (40%) of southeastern Siberia, and in Chukchi (51%) of the Russian Far East. Subgenotype C2 was found in Taimyr (19%) and Chukchi (27%), while subgenotype A2 was common in Yakuts (33%). In contrast, D2 was dominant (56%) in urban populations of the former western USSR, and D1 (62%) in Central Asian republics and Mongolia. Statistical analysis demonstrated that the studied groups are epidemiologically isolated from each other and might have contracted HBV from different sources during the settlement of Siberia.

Single nucleotide polymorphism rs1800872 in the promoter region of the IL10 gene is associated with predisposition to chronic hepatitis C in Russian population.

Previously, we studied an association of two IL28B gene single nucleotide polymorphisms (SNPs) and three IL10 gene SNPs with predisposition to tick-borne encephalitis in a Russian population. In this study, a possible involvement of these SNPs in the development of predisposition to chronic hepatitis C (caused by structurally similar, related virus from the Flaviviridae family) was investigated in the same population. Only the IL10 promoter rs1800872 SNP was associated with predisposition to chronic hepatitis C. This SNP seems to be a common genetic marker of predisposition to two diseases caused by hepatitis C and tick-borne encephalitis viruses in Russian population.

Association between polymorphisms in OAS2 and CD209 genes and predisposition to chronic hepatitis C in Russian population.

Chronic hepatitis C is a severe liver disease caused by positive-strand RNA virus. Previously, we reported an association between seven single nucleotide polymorphisms (SNPs) in four innate immunity genes (OAS2, OAS3, CD209, and TLR3) and human predisposition to tick-borne encephalitis, caused by a virus from the same Flaviviridae family, in a Russian population. Currently, genotype and allele frequencies for these SNPs were analyzed in 75 chronic hepatitis C patients and compared with the population control (269 Novosibirsk citizens). Data obtained suggest that the OAS2 rs1293762 and CD209 rs2287886 SNPs are associated with predisposition to chronic hepatitis C in Russian population.

Molecular epidemiology and interferon susceptibility of the natural recombinant hepatitis C virus strain RF1_2k/1b.

BACKGROUND: Hepatitis C virus (HCV) genotype is an important determinant of virological response to antiviral therapies. Currently, there are no data available on the molecular epidemiology and interferon susceptibility of the natural intergenotypic recombinant RF1_2k/1b (RF1) strain. METHODS: Genotyping and RF1-PCR screening were performed on samples from 604 HCV RNA-positive individuals from 7 countries. uPA/SCID mice carrying human hepatocytes (chimeric mice) were infected with the RF1_2k/1b strain, and the susceptibility of the strain to interferon and ribavirin was compared with the susceptibilities of 2 different strains of genotype B, used as references. RESULTS: Six new RF1 cases were identified in this study; 5 (2%) of 281 in Russia and 1 (1%) of 90 in Uzbekistan. Phylogenetic analyses based on Core/E1 and NS5b indicated that all RF1 representatives share a common evolutionary ancestor. Infection with RF1 was established in chimeric mice. Reduction of RF1 viral load was observed in response to 3 injections of 3 microg/kg pegylated-interferon alpha-2a alone or in combination with 50 mg/kg of ribavirin (0.5 or 1.4 log-copies/mL). CONCLUSIONS: All identified RF1-type strains appear to be introduced from a single source, suggesting that intergenotypic recombination in HCV is sporadic and not associated with cocirculation of different genotypes in a population. The RF1 strain in this study was responsive to interferon in vivo.