title: Genetic characterization of hepatitis C virus strains in Estonia: fluctuations in the predominating subtype with time.
abstract: During the last decade, there has been a dramatic increase in intravenous drug use in young adults in Estonia with an increased incidence of both hepatitis B and C as a consequence. Since genetic data are limited regarding hepatitis C virus (HCV) strains in Estonia, the aim of the study was to characterize HCV strains in different risk groups to determine their relatedness to strains from other geographical regions. Three hundred fifty-three anti-HCV positive sera collected during 1994-2004 from hospitalized patients, blood donors and health care workers were used as source of HCV RNA. Two hundred nine (59%) of the sera were positive for HCV RNA by PCR directed to the 5'-UTR region. For 174 strains the HCV subtype was determined by analyses of the NS5B and/or the 5'UTR-core regions. 1b (71%) was the most common subtype followed by 3a (24%), 2c (2%), 1a (1%), and 2a (1%). The 1b and 3a strains were similar to strains from other regions of the former USSR. Within genotype 1b there were several HCV lineages. However, for 3a there seemed to be two separate introductions into Estonia. There was a relative shift from subtype 1b to 3a in 1999-2000 with a further replacement of 3a with 1b in intravenous drug users in 2001 and onwards (P < 0.05). However, both subtypes were found to co-circulate in the community independent of risk factors. One patient was infected with the 2k/1b recombinant presumed to originate from St. Petersburg being the first isolate of this recombinant recovered outside Russia.
authors.affiliation: Department of Virology, National Institute for Health Development, Hiiu 42, 11619 Tallinn, Estonia.
authors.forename: Tatjana
authors.initials: T
authors.lastname: Tallo
authors.forename: Helene
authors.initials: H
authors.lastname: Norder
authors.forename: Valentina
authors.initials: V
authors.lastname: Tefanova
authors.forename: Tõnu
authors.initials: T
authors.lastname: Krispin
authors.forename: Jelena
authors.initials: J
authors.lastname: Schmidt
authors.forename: Madis
authors.initials: M
authors.lastname: Ilmoja
authors.forename: Karen
authors.initials: K
authors.lastname: Orgulas
authors.forename: Kaije
authors.initials: K
authors.lastname: Pruunsild
authors.forename: Ludmilla
authors.initials: L
authors.lastname: Priimägi
authors.forename: Lars O
authors.initials: LO
authors.lastname: Magnius
mesh_terms: D020121:5' Untranslated Regions / Q000235:genetics; D000293:Adolescent; D000328:Adult; D001782:Blood Donors; D004957:Estonia / Q000453:epidemiology; D005260:Female; D016174:Hepacivirus / Q000145:classification / Q000235:genetics*; D006526:Hepatitis C / Q000453:epidemiology*; D006761:Hospitals; D006801:Humans; D008297:Male; D017720:Molecular Epidemiology; D008969:Molecular Sequence Data; D010361:Patients; D010564:Personnel, Hospital; D012367:RNA, Viral / Q000145:classification; D012307:Risk Factors; D013045:Species Specificity; D015819:Substance Abuse, Intravenous; D014758:Viral Core Proteins / Q000235:genetics; D017361:Viral Nonstructural Proteins / Q000235:genetics; D012324:RNA-Dependent RNA Polymerase
chemical_list: D020121:5' Untranslated Regions; D012367:RNA, Viral; D014758:Viral Core Proteins; D017361:Viral Nonstructural Proteins; C069130:nucleocapsid protein, Hepatitis C virus; C087036:NS-5 protein, hepatitis C virus; D012324:RNA-Dependent RNA Polymerase