Summary:
Hepatitis C is a serious liver disease with worldwide spread. According to the
World Health
Organisation (WHO), 150 million people have been infected with hepatitis C
virus (HCV) and
suffer from the chronic form of the disease, while 350,000 people per year die
from adverse HCV related sequelae. HCV is transmitted through blood-to-blood
contact via injections with unsterilized equipment or transfusion of infected
blood in the developing world and the majority of new cases in the developed
countries are among people who inject drugs (PWID). In Greece, most of new HCV
cases are diagnosed among PWID and several programmes for the prevention and
treatment of the disease have been implemented in this specific risk group. HCV
is a genetically diverse RNA-virus and is classified into 7 genotypes and 67
subtypes. Genotype distribution varies
among geographic regions and risk groups. Molecular epidemiology methods have
been used to understand the evolution of the epidemic and study the route of
transmission of the disease
especially in PWID. In the present study, phylogenetic methods were applied in
HCV sequences isolated from PWID in Attica and subtype prevalence was evaluated
among them. Phylogenetic trees for the most prevalent sybtypes, 1a and 3a, were
constructed. According to tree topology, several monophyletic clusters were
formed revealing multiple introductions of HCV through
transmission networks in the population under study. Phylogenetic tree of
subtype 3a had more and larger monophyletic clusters than that of 1a. Moreover,
3a sequences were less genetically diverse with smaller genetic distances than
1a sequences. PWID who belonged in a transmission network had less years of
injecting career indicative of a more recent spread of HCV. The results of our
study in conjunction with data coming from classic epidemiology address the
need of targeted
intervention in PWID communities in order to prevent HCV epidemic and reduce
the burden
disease.
Keywords:
Hepatitis C, HCV, Intravenous drug users, Molecular epidemiology, Phylogenetics
