title: Molecular epidemiology and genetic diversity of hepatitis B virus in Ethiopia.
abstract: Although hepatitis B virus (HBV) infection is hyperendemic in Ethiopia and constitutes a major public health problem, little is known about its genetic diversity, genotypes, and circulation. The aim of this study was to determine the molecular epidemiology and genetic diversity of HBV in Ethiopia, using 391 serum samples collected from HBsAg-positive blood donors living in five different geographic regions. The HBV S/pol gene was amplified, sequenced, and HBV genotypes, subgenotypes, serotypes, and major hydrophilic region (MHR) variants were determined. Phylogenetic analysis of 371 samples (95%) revealed the distribution of genotypes A (78%) and D (22%) in Ethiopia. Further phylogenetic analysis identified one subgenotype (A1) within genotype A, and 4 subgenotypes within genotype D (D1; 1.3%, D2; 55%, D4; 2.5%, and D6; 8.8%). Importantly, 24 isolates (30%) of genotype D formed a novel phylogenetic cluster, distinct from any known D subgenotypes, and two A/D recombinants. Analysis of predicted amino-acid sequences within the HBsAg revealed four serotypes: adw2 (79%), ayw1 (3.1%), ayw2 (7.8%), and ayw3 (11.6%). Subsequent examination of sequences showed that 51 HBV isolates (14%) had mutations in the MHR and 8 isolates (2.2%) in the reverse transcriptase known to confer antiviral resistance. This study provides the first description of HBV genetic diversity in Ethiopia with a predominance of subgenotypes A1 and D2, and also identified HBV isolates that could represent a novel subgenotype. Furthermore, a significant prevalence of HBsAg variants in Ethiopian population is revealed.
authors.affiliation: Department of Viroscience, Erasmus Medical Center, Rotterdam, The Netherlands.
authors.forename: Gadissa Bedada
authors.initials: GB
authors.lastname: Hundie
authors.affiliation: Department of Viroscience, Erasmus Medical Center, Rotterdam, The Netherlands.
authors.forename: V Stalin
authors.initials: VS
authors.lastname: Raj
authors.affiliation: National Blood Bank Services, Ministry of Health, Addis Ababa, Ethiopia.
authors.forename: Daniel Gebre
authors.initials: DG
authors.lastname: Michael
authors.affiliation: Department of Viroscience, Erasmus Medical Center, Rotterdam, The Netherlands.
authors.forename: Suzan D
authors.initials: SD
authors.lastname: Pas
authors.affiliation: Department of Viroscience, Erasmus Medical Center, Rotterdam, The Netherlands.
authors.forename: Albert D M E
authors.initials: AD
authors.lastname: Osterhaus
authors.affiliation: Department of Viroscience, Erasmus Medical Center, Rotterdam, The Netherlands.|Division of Virology, Centre for Infectious Diseases Research, Diagnostics and Screening, National Institute for Public Health and the Environment, Bilthoven, The Netherlands.
authors.forename: Marion P
authors.initials: MP
authors.lastname: Koopmans
authors.affiliation: Department of Viroscience, Erasmus Medical Center, Rotterdam, The Netherlands.
authors.forename: Saskia L
authors.initials: SL
authors.lastname: Smits
authors.affiliation: Department of Viroscience, Erasmus Medical Center, Rotterdam, The Netherlands.
authors.forename: Bart L
authors.initials: BL
authors.lastname: Haagmans
mesh_terms: D000293:Adolescent; D000328:Adult; D000595:Amino Acid Sequence; D000914:Antibodies, Viral / Q000097:blood; D001483:Base Sequence; D004279:DNA, Viral / Q000097:blood; D005002:Ethiopia / Q000453:epidemiology; D005260:Female; D014644:Genetic Variation; D005838:Genotype; D006509:Hepatitis B / Q000453:epidemiology* / Q000821:virology*; D006514:Hepatitis B Surface Antigens / Q000097:blood / Q000235:genetics; D006515:Hepatitis B virus / Q000235:genetics*; D019694:Hepatitis B, Chronic / Q000453:epidemiology* / Q000821:virology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009154:Mutation; D010802:Phylogeny; D015995:Prevalence; D017422:Sequence Analysis, DNA; D065288:Serogroup; D055815:Young Adult
chemical_list: D000914:Antibodies, Viral; D004279:DNA, Viral; D006514:Hepatitis B Surface Antigens
keywords: Ethiopia; HBV; epidemiology; genetic diversity; genotype; mutation