title: Reconstruction of the evolutionary dynamics of the hepatitis C virus 1b epidemic in Turkey.
abstract: Worldwide, 12.5% of the more than 170 million people infected by hepatitis C virus (HCV), live in Eastern Mediterranean countries. In Turkey, the prevalence of HCV infection ranges from 0.3% to 0.4% of the general population. We investigated the distribution of HCV subtype 1b in Turkey by analysing the NS5b viral genomic region, using a Bayesian coalescent-based framework and phylogeographical analysis to estimate the origin of the HCV 1b subtype epidemic and the genetic diversification of the virus in Turkey. The dataset consisted of 24 NS5b sequences obtained from patients chronically infected with HCV subtype 1b admitted to the different health districts of Ankara hospital plus the reference sequences for phylogenetic analysis. An independent dataset including the same 342-nt NS5b fragment from all over the world (203 sequences) was used to calibrate the evolutionary rate. Using the relaxed clock model, we estimated a mean evolutionary rate of 0.84 × 10(-3) sub/site/year (95% highest posterior density interval HPD 0.16-1.5 × 10(-3)). The results of the phylogeographical analysis suggested that the HCV epidemic probably originated in Greece during the first decade of 1900 and, a few years later (in the 1920s or 1930s), successfully spread to neighboring countries such as Turkey and Cyprus. The clustering of the majority of the Turkish strains in a single monophyletic group suggests the subsequent segregated circulation of the virus in the country during the years 1940-1999, which was probably due to unsafe medical parenteral procedures, with drug addiction playing a relatively negligible role. The Bayesian skyline plot (BSP) showed a growth in the number of effective infections between the 1940s and the 1990s, when the curve reached a plateau that still remains today, suggesting a partial success of improved transfusional policies. A coalescent-based approach to population dynamics can improve our understanding of the origin and spread of epidemics in a limited geographical area.
authors.affiliation: Department of Infectious, Parasitic and Immunomediated Diseases, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy. ciccozzi@iss.it
authors.forename: Massimo
authors.initials: M
authors.lastname: Ciccozzi
authors.forename: Anna-Rita
authors.initials: AR
authors.lastname: Ciccaglione
authors.forename: Alessandra
authors.initials: A
authors.lastname: Lo Presti
authors.forename: Tulay
authors.initials: T
authors.lastname: Yalcinkaya
authors.forename: Zeynep Pinar
authors.initials: ZP
authors.lastname: Taskan
authors.forename: Michele
authors.initials: M
authors.lastname: Equestre
authors.forename: Angela
authors.initials: A
authors.lastname: Costantino
authors.forename: Roberto
authors.initials: R
authors.lastname: Bruni
authors.forename: Erica
authors.initials: E
authors.lastname: Ebranati
authors.forename: Marco
authors.initials: M
authors.lastname: Salemi
authors.forename: Rebecca
authors.initials: R
authors.lastname: Gray
authors.forename: Giovanni
authors.initials: G
authors.lastname: Rezza
authors.forename: Massimo
authors.initials: M
authors.lastname: Galli
authors.forename: Gianguglielmo
authors.initials: G
authors.lastname: Zehender
mesh_terms: D001499:Bayes Theorem; D005075:Biological Evolution; D058872:Epidemics / Q000706:statistics & numerical data*; D016174:Hepacivirus / Q000235:genetics*; D006526:Hepatitis C / Q000453:epidemiology* / Q000821:virology*; D016013:Likelihood Functions; D010802:Phylogeny; D058974:Phylogeography; D013997:Time Factors; D014421:Turkey / Q000453:epidemiology