[Changes in Hepatitis C Virus Genotype Distribution: The Impact of Migration and Epidemiological Trends]

Hepatitis C virus (HCV) is a virus that can cause hepatitis, hepatic steatosis, cirrhosis and hepatocellular carcinoma. The distribution of HCV genotypes and subtypes varies according to geographical regions. The choice and duration of treatment for hepatitis C infection are influenced by genotype. This study aimed to investigate the distribution of HCV genotypes in chronic hepatitis C patients who admitted to a university hospital in Diyarbakır and to evaluate the impact of migration on this distribution. This crosssectional retrospective study included patients who tested positive for HCV RNA between January 2011 and December 2020. One sample per patient was included in the study. Genotype determination was performed by sequencing the HCV genome obtained after amplification in serum samples containing HCV RNA. Of the 815 samples included in the study, genotype 1 was detected in 768 (94.2%), genotype 2 in five (0.6%), genotype 3 in 27 (3.3%), genotype 4 in 14 (1.7%) and genotype 5 in one (0.12%). It was determined that the sample in which genotype 5 was detected, belonged to a Syrian patient. It was determined that the prevalence of genotype 1 decreased over the years, while the prevalence of genotype 4 increased. An increase in genotype 3 was observed in the last two years of the study (2019- 2020). The majority of patients with genotype 3 were male (88.8% male, 11.2% female). The study suggests that the increase in genotype 4 rates over the years and the identification of genotype 5 indicate that migration from Syria has altered the genotype distribution. Furthermore, the increasing prevalence of genotype 3, known to be more common in intravenous drug users, highlights the involvement of various factors influencing genotype distribution. While cure rates have increased with the use of directly effective antiviral drugs, the presence of rare mutations means that regular monitoring of genotype determination and molecular epidemiological data can contribute to the development of treatment modalities.