Identification and characterization of novel hepatitis B virus subgenotype C10 in Nusa Tenggara, Indonesia.

Six novel subgenotypes (B7, B8, C6, C8, C9, and D6) within three hepatitis B virus (HBV) genotypes (B-D) were recently identified in Indonesia. To further characterize HBV in this country, 18 HBV-viremic samples obtained from blood donors in Nusa Tenggara, Indonesia, were subjected to phylogenetic analysis of an 1.6-kb partial or full-length sequence. Thirteen HBV isolates were classified into genotype B with four distinct subgenotypes [B3 (n = 2), B5 (n = 1), B7 (n = 4), and B8 (n = 6)], followed by 4 HBV isolates of genotype C (HBV/C); the remaining one isolate was of D (D1). As for the four HBV/C isolates, one isolate segregated into subgenotype C1, and two into C2. The remaining HBV/C isolate [C0901177(NT3)] differed from reported HBV/C isolates (C1-C9) by 4.6-7.7% over the entire genome and did not show evidence of recombination with any of the known HBV genotypes/subgenotypes, justifying its conclusive assignment into a novel subgenotype (C10) within genotype C.

A nationwide molecular epidemiological study on hepatitis B virus in Indonesia: identification of two novel subgenotypes, B8 and C7.

Upon phylogenetic analysis of a partial S gene sequence [396 nucleotides (nt)], 928 hepatitis B virus (HBV) strains obtained from 899 viremic subjects in 28 major cities on 15 islands of Indonesia in 1989-2007 segregated into four HBV genotypes. Genotype B was predominant (66%), followed by genotype C (26%), genotype D (7%), and genotype A (0.8%). Comparative and phylogenetic analyses of the 396-nt S gene sequence of 928 HBV isolates and whole genomic sequences of 25 selected HBV isolates revealed a total of 14 subgenotypes within genotypes A-D: two (A1 and A2) in genotype A (HBV/A), five (B2, B3, B5, B7, and a novel subgenotype, tentatively designated B8) in HBV/B, five (C1, C2, C5, C6, and another novel subgenotype, C7) in HBV/C, and two (D1 and D3) in HBV/D. The distribution of HBV genotypes/subgenotypes, including B8 and C7, seems to be associated with ethnological origins in Indonesia.