title: Molecular characterization of the hepatitis B virus in autochthonous and endogenous populations in the Western Brazilian Amazon.
abstract: BACKGROUND
  Hepatitis B virus (HBV) infection is a serious public health issue worldwide. Hepatitis B virus is classified into eight genotypes, varying from A to H, with distinct geographical distributions. In Brazil, the most frequent genotypes are A, D, and F.
  
  
  METHODS
  This study aimed to characterize the HBV genotypes in cases of hepatitis B virus and hepatitis D virus (HDV) co-infections in an endemic area in the Western Brazilian Amazon. We analyzed 86 serum samples reactive for HBsAg from indigenous and non-indigenous populations obtained from previous serological surveys.
  
  
  RESULTS
  Of the 86 reactive serum samples, 39 were found to be HBV-DNA-positive by semi-nested PCR. The genotypes were established by sequencing the amplified S gene region. We obtained 20 sequences classified into three genotypes: A, D, and F. Genotype A was the most frequent (60%), followed by D (35%) and F (5%).
  
  
  CONCLUSIONS
  The distribution of the HBV genotypes reflected the pattern of historical occupation of the region.
authors.affiliation: Universidade do Estado do Amazonas, Manaus, AM.
authors.forename: Adila Liliane Barros
authors.initials: AL
authors.lastname: Dias
authors.forename: Cintia Mara da Costa
authors.initials: CM
authors.lastname: Oliveira
authors.forename: Márcia da Costa
authors.initials: Mda C
authors.lastname: Castilho
authors.forename: Maria do Socorro Pontes da
authors.initials: Mdo S
authors.lastname: Silva
authors.forename: Wornei Silva Miranda
authors.initials: WS
authors.lastname: Braga
mesh_terms: D001938:Brazil / Q000453:epidemiology; D003430:Cross-Sectional Studies; D004279:DNA, Viral / Q000097:blood*; D019353:Endemic Diseases; D005838:Genotype; D006509:Hepatitis B / Q000453:epidemiology / Q000821:virology*; D006514:Hepatitis B Surface Antigens / Q000097:blood*; D006515:Hepatitis B virus / Q000145:classification / Q000235:genetics* / Q000276:immunology; D006801:Humans; D007199:Indians, South American; D010802:Phylogeny; D016133:Polymerase Chain Reaction
chemical_list: D004279:DNA, Viral; D006514:Hepatitis B Surface Antigens