Distribution of hepatitis C virus genotypes in patients with chronic hepatitis C infection in India.

Background & Objectives: Hepatitis C virus (HCV), an important cause of chronic hepatitis, cirrhosis and hepatocellular carcinoma, shows a considerable genetic heterogeneity among hepatitis C virus isolates from all over the world. At least six main groups of sequence variants are recognized. The natural history of disease and response to treatment may be related to the genotype of HCV in a particular patient. Antigenic differences between genotypes also have implications for optimal design of serological sequencing and confirmatory assays for HCV. The present study was undertaken with the objective to find out various genotypes of hepatitis C virus prevalent in Indian patients with chronic hepatitis C infection.

Methods: Thirty six consecutive newly diagnosed patients with chronic hepatitis C infection were included in the study. HCV RNA was extracted from the serum by standard guanidinium thiocyanate method. Following reverse transcription and amplification, the HCV genotypes were determined by line probe assay (INNO-LiPA HCV II).

Results: Of the 36 patients, genotype 3 was found in 24 (66.6%). Of these 24 patients, 3a was seen in 5 patients (13.8%), 3b in two (5.5%) and mixed subtype 3a and 3b in 17 patients (47.2%). Genotype 1 was found in 5 patients (13.8%), with 1b in 1 and 1a in rest four cases. Two patients (5.5%) were infected with genotype 2 (subtype 2a and mixed subtype 2a, 2b respectively). One (2.7%) was infected with genotype 4 (4a). Mixed genotype infection was found in 4 patients (11.1%).

Interpretation & Conclusion: The present findings showed that genotype 3 of hepatitis C virus was the most prevalent genotype in patients with chronic hepatitis C in this part of India.