title: Detection of Hepatitis B virus subgenotype A1 in a Quilombo community from Maranhão, Brazil.
abstract: BACKGROUND
  The Brazilian population is mainly descendant from European colonizers, Africans and Native Americans. Some Afro-descendants lived in small isolated communities since the slavery period. The epidemiological status of HBV infection in Quilombos communities from northeast of Brazil remains unknown. The aim of this study was to characterize the HBV genotypes circulating inside a Quilombo isolated community from Maranhão State, Brazil.
  
  
  METHODS
  Seventy-two samples from Frechal Quilombo community at Maranhão were collected. All serum samples were screened by enzyme-linked immunosorbent assays for the presence of hepatitis B surface antigen (HBsAg). HBsAg positive samples were submitted to DNA extraction and a fragment of 1306 bp partially comprising HBsAg and polymerase coding regions (S/POL) was amplified by nested PCR and its nucleotide sequence was determined. Viral isolates were genotyped by phylogenetic analysis using reference sequences from each genotype obtained from GenBank (n = 320). Sequences were aligned using Muscle software and edited in the SE-AL software. Bayesian phylogenetic analyses were conducted using Markov Chain Monte Carlo (MCMC) method to obtain the MCC tree using BEAST v.1.5.3.
  
  
  RESULTS
  Of the 72 individuals, 9 (12.5%) were HBsAg-positive and 4 of them were successfully sequenced for the 1306 bp fragment. All these samples were genotype A1 and grouped together with other sequences reported from Brazil.
  
  
  CONCLUSIONS
  The present study represents the first report on the HBV genotypes characterization of this community in the Maranhão state in Brazil where a high HBsAg frequency was found. In this study, we reported a high frequency of HBV infection and the exclusive presence of subgenotype A1 in an Afro-descendent community in the Maranhão State, Brazil.
authors.affiliation: Laboratory of Tropical Gastroenterology and Hepatology, São Paulo Institute of Tropical Medicine and Department of Gastroenterology, School of Medicine, University of São Paulo, São Paulo, Brazil. monica.viviana@usp.br
authors.forename: Mónica V
authors.initials: MV
authors.lastname: Alvarado-Mora
authors.forename: Livia
authors.initials: L
authors.lastname: Botelho
authors.forename: Michele S
authors.initials: MS
authors.lastname: Gomes-Gouvêa
authors.forename: Vanda F
authors.initials: VF
authors.lastname: de Souza
authors.forename: Maria C
authors.initials: MC
authors.lastname: Nascimento
authors.forename: Claudio S
authors.initials: CS
authors.lastname: Pannuti
authors.forename: Flair J
authors.initials: FJ
authors.lastname: Carrilho
authors.forename: João Rr
authors.initials: JR
authors.lastname: Pinho
mesh_terms: D001483:Base Sequence; D001499:Bayes Theorem; D044383:Black People; D001938:Brazil / Q000453:epidemiology; D016172:DNA Fingerprinting / Q000379:methods*; D004279:DNA, Viral / Q000097:blood / Q000235:genetics* / Q000276:immunology; D004797:Enzyme-Linked Immunosorbent Assay; D018703:Founder Effect; D005838:Genotype; D006509:Hepatitis B / Q000175:diagnosis* / Q000208:ethnology* / Q000235:genetics / Q000276:immunology; D006514:Hepatitis B Surface Antigens / Q000235:genetics* / Q000276:immunology; D006515:Hepatitis B virus / Q000235:genetics* / Q000276:immunology / Q000302:isolation & purification; D006801:Humans; D008969:Molecular Sequence Data; D010802:Phylogeny; D058974:Phylogeography; D017422:Sequence Analysis, DNA
chemical_list: D004279:DNA, Viral; D006514:Hepatitis B Surface Antigens