HCV genotype 4 - an emerging threat as a cause of chronic liver disease in Indian (South) patients

Abstract

Background: Hepatitis C virus (HCV) genotyping is relevant for the delivery of effective antiviral therapy. HCV genotypes are geographically restricted with genotype 4, which is resistant to therapy, traditionally considered to be confined to the Middle East and Africa. We report here on the occurrence of HCV genotype 4 in Indian (South) patients. Objectives: (1)To highlight the occurrence of HCV genotype 4 in the patient population attending a tertiary care hospital in south India. (2)To ascertain the difference in HCV viral loads and alanine aminotransferase (ALT) values between patients infected with HCV genotype 4 and those infected with the other two most commonly detected genotypes in this patient population viz., HCV genotypes 1 and 3. (3)To assess the genetic relatedness of the Indian strains to Genbank sequences, which we report for the first time. Study design: The study group consisted of 125 HCV infected, untreated patients who had been genotyped using type specific primers. Eight of the nine samples classified as HCV genotype 4 by this technique were subjected to nucleotide sequencing. Viral load estimations were carried out. Information on possible risk factors and ALT values were obtained from hospital records. Statistical analyses were carried out to compare viral loads and ALT values across genotypes. A phylogenetic tree was constructed and the genetic relatedness of the strains was assessed through sequence analysis. Results: HCV genotype 4 was detected in nine of 125 (7.2%) patients. Eight of the nine were subjected to nucleotide sequencing and all strains were confirmed as HCV genotype 4. Six of the eight strains were closely related, with two strains being phylogenetically diverse. Conclusions: HCV genotype 4 is detected in a significant minority of HCV infected patients in India. This finding should be considered in designing strategies prior to initiation of therapy in Indian patients infected with HCV.