HEPATITIS-C VIRUS VARIANTS FROM NEPAL WITH NOVEL GENOTYPES AND THEIR CLASSIFICATION INTO THE 3RD MAJOR GROUP

Five isolates of hepatitis C virus (HCV) RNA from patients with chroni c liver disease in Nepal were not classifiable into the known genotype s I/1a, II/1b, III/2a, IV/2b or V/3a using PCR with type-specific prim ers deduced from the HCV core gene. Their nucleotide sequences were de termined for the 5'-terminal 1.5 kilobases and 3'-terminal 1.2 kilobas es, covering 30% of the entire genome, and compared with each other an d with reported sequences of HCV isolates of various genotypes. They w ere more similar to a reported HCV isolate (NZL1) of genotype V/3a (in 81.6 to 84.1% of their nucleotides and 85.7 to 88.7% of the deduced a mino acid sequence) compared with the genotypes I/1a to IV/2b (in 69.3 to 74.7% and 72.3 to 77.4%, respectively). Hence they were considered to be variants of the third major group (group 3). The five HCV isola tes shared 81.3 to 85.2% of nucleotide sequence and 85.4 to 89.3% of d educed amino acid sequence. Thus they were substantially different fro m each other. One of them was classified as genotype VI/3b due to an 8 8.2% similarity in nucleotide sequence to that of the reported HCV iso lates of this genotype, whereas the remaining four were classified int o provisional genotypes 3c, 3d, 3e and 3f. These HCV variants have evo lved and remained in Nepal, and have not been observed in the other ar eas of the world.