title: Intrafamilial prevalence of hepatitis B virus in Western Brazilian Amazon region: epidemiologic and biomolecular study.
abstract: BACKGROUND
  Hepatitis B is endemic in the Amazon region.
  
  
  METHODS
  Serological markers for hepatitis B virus (HBV) were determined in 266 household members for hepatitis B surface antigen (HBsAg)-positive women (G1) and 395 household members for HBsAg-negative women (G2), randomly selected in Acre State Women's Medical Care Program, in order to evaluate the prevalence of HBV in this population. Before blood sample collection an epidemiological questionnaire was applied.
  
  
  RESULTS
  The overall prevalence of HBV carriers (HBsAg) and exposed individuals (anti-HBc, IgG) was, respectively, 21.1% and 60.5% in G1 and 2.8% and 27.4% in G2 (P < 0.0000001). The frequency of HBsAg was higher among siblings from group G1 (75%) compared to the absence of any HBsAg-positive sibling in G2 (P < 0.00006). The HBV markers in other family members was as follows: G1 parents, 27.3% vs 4.5% (P < 0.03), sexual partners, 21.1% vs 2.5% (P < 0.04), and offspring, 10.4% vs 1.5% (P < 0.04). A low prevalence of HBsAg and anti-HBc (IgG) was observed for the last offspring of G2 mothers compared to the high prevalence among children of G1 mothers (0% vs 18.2%, P < 0.01 and 2.3% vs 59.1%, P < 0.0000005, respectively), with children younger than 1 year being the most affected. The frequency of the habit of sharing toothbrushes and the presence of at least one HBsAg carrier were higher in G1 than in G2 (P < 0.0001 and P < 0.000002), respectively. Genotypes A, D and G were found to be predominant by Innolipa test. There were cases that reacted to more than one genotype.
  
  
  CONCLUSIONS
  Intrafamilial transmission of HBV is evident in the present study and is possibly associated with the presence of more than one HBV carrier in the family and the shared use of toothbrushes among household contacts. Genotype analysis confirms intrafamilial transmission.
authors.affiliation: CPgMS-State of Acre Cooperation Program with University of Bahia, Bahia, Brazil. unif@svn.com.br
authors.forename: Cirley
authors.initials: C
authors.lastname: Lobato
authors.forename: José
authors.initials: J
authors.lastname: Tavares-Neto
authors.forename: Márcio
authors.initials: M
authors.lastname: Rios-Leite
authors.forename: Christian
authors.initials: C
authors.lastname: Trepo
authors.forename: Ludmila
authors.initials: L
authors.lastname: Vitvitski
authors.forename: Parviz
authors.initials: P
authors.lastname: Parvaz
authors.forename: Fabien
authors.initials: F
authors.lastname: Zoulim
authors.forename: Argemiro
authors.initials: A
authors.lastname: D'Oliveira
authors.forename: Raymundo
authors.initials: R
authors.lastname: Paraná
mesh_terms: D000328:Adult; D001938:Brazil / Q000453:epidemiology; D003430:Cross-Sectional Studies; D005190:Family; D005260:Female; D006509:Hepatitis B / Q000453:epidemiology* / Q000276:immunology / Q000635:transmission; D006515:Hepatitis B virus / Q000276:immunology / Q000302:isolation & purification; D006801:Humans; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious / Q000453:epidemiology* / Q000276:immunology; D015995:Prevalence