Determination of HCV genotypes and viral loads in chronic HCV infected patients of Hazara Pakistan

Hepatitis C virus (HCV) is a principal cause of chronic liver diseases including liver fibrosis, liver cirrhosis and hepatocellular carcinoma [1,2]. Nearly 170-200 million individuals infected globally including 10-17 million persons in Pakistan [1,3-5]. HCV is an enveloped virus having positive single stranded RNA as its genome that was firstly discovered in 1989 belonging to a virus family Flaviviridae [3,6,7]. HCV genome is approximately 9.6 kb in length with single open reading frame and encodes a polypeptide of 3000 amino acids [8,9]. Total six major HCV genotypes and multiple subtypes have been identified from around the world [10]. Identification of HCV genotype/subtype is extremely important clinically before prescribing therapy because genotypes 1 & 4 show more resistance as compared to genotypes 2 and 3 to PEG-IFN plus ribavarin therapy, therefore different types of HCV genotypes require different duration and dose of anti viral therapy [11]. Treatment durations for genotypes 1 and 4 are 48 weeks where as for 2 and 3 is 24 weeks with PEG-IFN plus ribavarin therapy [12]. Prevalence of viral genotypes has been documented in three different patterns to date [1]. First pattern differentiate by high genetic heterogeneity involves different geographical regions of West Africa with types 1 and 2 [13], Central Africa with type 4 [14] and Asia with types 3 and 6 [15]. Second pattern entails regions with a few subtypes circulating in an intravenous drugs abusers groups, e.g., subtype 3a [16]. The last pattern involves areas where a single subtype is circulate, such as in Egypt with subtype 4a [17] and South Africa with subtype 5a [18].Beside HCV genotypes, pre-treatment viral load has also been shown to be prognostic indicator of response to antiviral therapy [19] as increased pre-treatment viral load has been linked with low rates of response to standard interferon therapy [20-22]. Several studies have shown that patients with lower pre-treatment viral load (< 80,0