Possible new hepatitis B virus genotype, southeast Asia

Abstract

We conducted a phylogenetic analysis of 19 hepatitis B virus strains from Laos that belonged to 2 subgenotypes of a new genotype I. This emerging new genotype likely developed outside Southeast Asia and is now found in mixed infections and in recombinations with local strains in a geographically confined region.

Figure 1

A) Phylogenetic comparison of all complete genotype I genomes (n = 15) obtained and compared to sequences of all known genotypes and subgenotypes. Non–genotype I genotypes identified in Lao People’s Democratic Republic in the present study are shown as full triangles. Numbers indicate bootstrap values of important nodes. B–D) Phylogenetic comparison of positions 400–1400 (left), 1400–3000 (middle), and 3000–400 (right), of all genotype I strains with all known genotypes and subgenotypes. Percentages indicate average genetic distances between genotype I and G, C, or A, respectively. Scale bars indicate number of substitutions per site.

Figure 2

Bootscan analysis of genotypes I, A, B, C, and G compared with genotypes A–H. Data points correspond to the center of sequence windows of 800 bp. For the analysis of the first 400 nt, the beginning of the genome was duplicated at the end of the sequence: nt 3200–4000 represent positions 0–800.