title: Molecular epidemiology of hepatitis B virus among the indigenous population of the Curuçá and Itaquaí Rivers, Javari Valley, State of Amazonas, Brazil.
abstract: BACKGROUND
  Hepatitis B virus (HBV) infection is one of the most serious public health problems in the world. In Brazil, HBV endemicity is heterogeneous, with the highest disease prevalence in the North region.
  
  
  METHODS
  A total of 180 samples were analyzed and subjected to polymerase chain reaction (PCR) and semi-nested PCR of the HBV S-gene, with the aim of determining the prevalence of HBV-DNA (deoxyribonucleic acid) in indigenous groups inhabiting the areas near the Curuçá and Itaquaí Rivers in the Javari Valley, State of Amazonas, Brazil.
  
  
  RESULTS
  The prevalence of the HBV-DNA S-gene was 51.1% (92/180). The analysis found 18 of 49 (36.7%) samples from the Marubo tribe, 68 of 125 (54.4%) from the Kanamary, and 6 of 6 (100%) from other ethnic groups to be PCR positive. There was no statistically significant difference in gender at 5% (p=0.889). Indigenous people with positive PCR for HBV-DNA had a lower median age (p<0.001) of 23 years. There was no statistical difference found in relation to sources of contamination or clinical aspects with the PCR results, except for fever (p<0.001). The high prevalence of HBV-DNA of 75% (15/20) in pregnant women (p=0.009) demonstrates an association with vertical transmission.
  
  
  CONCLUSIONS
  The results confirm the high prevalence of HBV-DNA in the Javari Valley, making it important to devise strategies for control and more effective prevention in combating the spread of HBV.
authors.affiliation: Laboratório de Virologia Tropical, Coordenação de Pesquisas em Ciências da Saúde, Instituto Nacional de Pesquisas da Amazônia, Manaus, AM, Brasil. crvcosta@inpa.gov.br
authors.forename: Cristóvão Alves
authors.initials: CA
authors.lastname: da Costa
authors.forename: Lucinete Okamura
authors.initials: LO
authors.lastname: Kimura
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001938:Brazil / Q000453:epidemiology; D002648:Child; D003430:Cross-Sectional Studies; D004279:DNA, Viral / Q000235:genetics*; D005260:Female; D006509:Hepatitis B / Q000453:epidemiology*; D006515:Hepatitis B virus / Q000235:genetics*; D006801:Humans; D007199:Indians, South American / Q000706:statistics & numerical data*; D008297:Male; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D011247:Pregnancy; D015995:Prevalence; D055815:Young Adult
chemical_list: D004279:DNA, Viral