Hepatitis C virus genotypes among population with reported risk factors in Assam, north-east India: Emergence of genotype-8.

Background & objectives Hepatitis C virus (HCV) exhibits extensive genetic diversity in infected hosts. There are few published reports of HCV genotype (GT) distribution from the north-east Indian States lying close to the 'Golden Triangle' known for illicit drug trafficking. Real-time knowledge of HCVGT distribution is important for studies on epidemiologic aspects and virus evolution and for the development of new target-specific, direct-acting antiviral drugs. This study aims to examine the distribution of HCVGTs and their subtypes in different risk groups from Assam, north-east India. Methods It is a hospital-based cross-sectional study. Plasma samples reactive for anti-HCV antibody in enzyme-linked immunosorbent assay (ELISA) were subjected to viral load test and genotyping by real-time Reverse Transcription-Polymerase Chain Reaction (RT-PCR) or characterization of non-structural protein NS5B region by nested PCR. Nucleotide sequences were subjected to phylogenetic analysis. Results The most common HCVGT detected was GT-3 (95.89%), followed by GT-1 (3.42%), GT-6xa (0.34%) and GT-8 (0.34%). The mean age of subjects was 30.24 yr, and males outnumbered females. The most commonly associated risk factor was injecting drug use (IDU) (74.31%), followed by tattooing and/or piercing (33.22%), transfusion of blood/blood products (10.27%), and haemodialysis (9.25%). Co-infection with human immunodeficiency virus (HIV) was found in 17.8 per cent, and with Hepatitis B virus (HBV) in 3.42 per cent of the cases. Interpretation & conclusions The detection of HCVGT-8 makes this the first report from Assam and the second from India as per the authors' knowledge. This may indicate strain's endemic nature in India. The increasing trend of HCV infection among young IDUs and HCV-HIV co-infection indicates the need for enhancing surveillance and intensified prevention efforts among young adults.