Characterization of HCV genotype 4d infections in Kayseri, Turkey*

Background/aim: The frequency of genotype 4 hepatitis C virus (HCV) infections is significantly higher in Kayseri compared to other provinces in Turkey. We aimed to characterize genotype 4 infections in Kayseri by analyzing the demographic and laboratory data of 218 HCV RNA-positive, treatment-naive patients admitted to the Kayseri Training and Research Hospital in 2010 and 2011. Materials and methods: The distributions of sex, age, and viral loads of these patients with respect to HCV genotypes were analyzed. We also characterized the type 4 sequences at the subtype level. Randomly selected sera from 32 of the 72 genotype 4 patients from this cohort were subjected to PCR amplification in the NS5B region and further characterized by sequencing and phylogenetic and molecular clock analysis. Results: Distribution rates of HCV genotypes 1, 4, and 2 in the 218 patients were 62.4%, 33.0%, and 4.6%, respectively. Most of the patients infected with types 1 and 4 were over the age of 40 and female. The NS5B sequences of 32 Kayseri genotype 4 isolates were closely related with type 4d sequences but formed a separate cluster. Conclusion: The introduction of type 4d HCV into the Kayseri region probably took place 30–75 years ago, as predicted by molecular clock analysis.