Full genome analysis of hepatitis B virus genotype E strains from South‐Western Africa and madagascar reveals low genetic variability

Abstract

The eight genotypes of hepatitis B virus (HBV), A–H, have a characteristic geographical distribution. The high prevalence of genotype E within a wide expanse of Africa makes it important to characterize this genotype. Although the preS/S region of a large number of genotype E isolates has been sequenced, to date only eight complete genotype E genomes have been published. The aim of this study, therefore, was to sequence and characterize the complete genome of genotype E isolates obtained from geographically distinct regions in Africa, including Namibia, Angola, and Madagascar. The nine newly sequenced genotype E isolates were closely related with an intra-group nucleotide divergence of 1.2%, reflecting their close geographical origin. All genotype E strains have the same characteristics, an in-frame deletion of three nucleotides (one amino acid) in the 5′ pre-S1, a signature pattern of amino acids in the pre-S1 region and the serological subtype ayw4. In addition, we have identified another unique attribute of genotype E strains, the introduction of another start codon Met⁸³ in the pre-S1 region that may result in the translation of an elongated middle hepatitis B surface protein (MHBs). J. Med. Virol. 77:47–52, 2005.