Open Access Research

Detection of Hepatitis B virus subgenotype A1 in a Quilombo community from Maranhão, Brazil

Mónica V Alvarado-Mora1*, Livia Botelho1, Michele S Gomes-Gouvêa1, Vanda F de Souza2, Maria C Nascimento2, Claudio S Pannuti2, Flair J Carrilho1 and João RR Pinho1

Author Affiliations

1 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

2 Laboratory of Virology, São Paulo Institute of Tropical Medicine, Department of Infectious and Parasitic Diseases, School of Medicine, University of São Paulo, Brazil

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Virology Journal 2011, 8:415  doi:10.1186/1743-422X-8-415

Published: 25 August 2011



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.


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.


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.


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.

Hepatitis B virus; Genotype A1; Quilombo community; Maranhão state; Brazil; Bayesian Analysis