Shift in predominating subtype of HCV from 1b to 3a in St. Petersburg mediated by increase in injecting drug use*

Abstract

The genotypes of 149 HCV strains from St. Petersburg were determined by limited sequencing and phylogenetic analysis within the NS5B region. One hundred two strains derived from patients that attended infectious disease clinics, of whom 48 admitted injecting drug use, and 47 derived from dialysis patients. Subtype 3a was predominant in the patients from infectious disease clinics, both in patients that admitted injecting drug use (56%) and in those with unknown source of infection (46%). However, 89% of the strains from dialysis patients belonged to subtype 1b. Eleven of twelve characterised strains from recent cases of hepatitis C at these units were at phylogenetic analysis shown to be related to strains already circulating there, demonstrating that within the dialysis units nosocomial transmission is the most important route of HCV infection. The predominance of subtype 1b strains in dialysis patients indicates that these strains have been circulating for a long time in dialysis units. The predominance of subtype 3a also among patients who did not admit drug use and that their strains were intermixed with the strains from injecting drug users in the phylogenetic analysis shows that the increase in injecting drug use is the major factor that explains the recent spread of HCV in the St. Petersburg population. This supports the concept that injecting drug use remains the major route for HCV infection in developed countries and that the control of drug abuse is the most important measure to prevent its spread.

Identification of HCV genotypes in HCV infected blood donors

“…The distributions were similar for Subtypes 1a (53.1% versus 51.5%), 3a (25% versus 37.9%) in patients and donors respectively. Subtypes 1a and 3a most often infect injecting drug users and appear to be increasing in prevalence [18,19]. At present, injection drug use is the most common risk factor for contracting the infection.…”

A Natural Intergenotypic Recombinant of Hepatitis C Virus Identified in St. Petersburg

“…Two of the investigated strains showed discordant results of genotyping within the 5ЈUTR-core and the NS5B regions. Therefore, the 5ЈUTR-core regions of four additional strains were sequenced, since these strains formed a cluster with the two previously mentioned strains in a dendrogram based on the NS5B region (10). In addition, the NS5B and the 5ЈUTR-core regions of one subtype 2k strain, from a patient with chronic hepatitis C, sampled among 17 other patients in St. Petersburg during January 2001, were sequenced.…”

“…An ABI PRISM 3100 genetic analyzer (Applied Biosystems) was used for electrophoresis and data collection. The sequences obtained were edited, assembled, and analyzed as described previously (10). Similarity and bootscanning analyses were performed with the SimPlot program (version 1.2.2 for Windows 95/NT; available from the author, S. C. Ray, online [http://www.welch.jhu.edu/ϳsray /download])and a bootscanning program package using the PHYLIP package for phylogenetic analysis (22).…”

“…In a previous study, we subtyped 149 HCV strains from St. Petersburg by limited sequencing within the NS5B region (10). In order of decreasing frequency, subtypes 3a, 1b, 1a, 2a, 2c, and 4a were found.…”

Controversies in and challenges to our understanding of hepatitis C

“…One of these relates to the reported changing www.wjgnet.com genotype profiles in a number of countries [12][13][14][15] . This confronts clinicians and virologists with the reality that we are dealing with a very adaptive infectious agent and false steps taken in haste may leave the medical field carrying the consequences of poorly thought through strategies for a long time to come.…”