Molecular epidemiology of hepatitis C infection in Cyprus within the general population and high-risk cohorts

Abstract

Background: Initial data on the molecular epidemiology of HCV infection in Cyprus showed a highly polyphyletic infection and multiple points of introduction into the general population. The continuation and expansion of this investigation is presented here including high risk groups.

Findings: The samples include additional subjects from the general population, a group of inmates and HIV/HCV coinfected individuals, whose strains were amplified by RT-PCR and sequenced in partial Core-E1 and NS5B regions. The results confirm the broad genotype distribution and polyphyletic infection on the island, and no new subtypes were found. Monophyletic clusters between strains of the prisoners and the injecting drug users imply sharing of infected equipment, and highlight the risk of widespread transmission in these cohorts, although no spill-over to the general population was observed.

Conclusions: The results of this study underline the impact of population movements and high-risk population groups on the changing molecular epidemiology of HCV, with strains moving to Europe from Asia, Africa and Eastern Europe by means of immigration and modern transmission routes.

Figure 1

Maximum likelihood tree of partial Core-E1 sequences. Phylogenetic ML tree showing the genotype distribution of the HCV samples discovered in Cyprus sequenced in the Core-E1 genomic regions. HCV subtypes are designated with brackets on the right of each tree. U denotes unclassified strains. The samples are represented with different symbols for each cohort: grey circles denote samples from the general population from 2005-2008, yellow circles the general population from 2008-2010, red squares the incarcerated population, blue triangles the intravenous drug users, and green rhombus the HIV/HCV coinfected individuals. The general population 2005-2008 and the intravenous drug users have been previously described [14,15], and the rest are described in this study. Asterisks at branch nodes indicate bootstrap values of 70 and above. The genetic distance between any two sequences is denoted by the scale at the lower left side of each tree.

Figure 2

Maximum likelihood tree of partial NS5B sequences. Phylogenetic ML tree showing the genotype distribution of the HCV samples discovered in Cyprus sequenced in the NS5B genomic regions. HCV subtypes are designated with brackets on the right of each tree. U denotes unclassified strains. The samples are represented with different symbols for each cohort: grey circles denote samples from the general population from 2005-2008, yellow circles the general population from 2008-2010, red squares the incarcerated population, blue triangles the intravenous drug users, and green rhombus the HIV/HCV coinfected individuals. The general population 2005-2008 and the intravenous drug users have been previously described [14,15], and the rest are described in this study. Asterisks at branch nodes indicate bootstrap values of 70 and above. The genetic distance between any two sequences is denoted by the scale at the lower left side of each tree.