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Open Access Research

Unusual presentation of hepatitis B serological markers in an Amerindian community of Venezuela with a majority of occult cases

Nathalia E Cardona1, Carmen L Loureiro2, Domingo J Garzaro2, María C Duarte1, Daisy M García1, Milian C Pacheco1, Isabelle Chemin3 and Flor H Pujol2*

Author Affiliations

1 Servicio Autónomo: Centro Amazónico para la Investigación y Control de enfermedades Tropicales, Simón Bolívar "CAICET", Puerto Ayacucho, Venezuela

2 Laboratorio de Virología Molecular, Centro de Microbiología y Biología Celular, Instituto Venezolano de Investigaciones Científicas, Apdo 20632, Caracas 1020-A, Venezuela

3 INSERM U1052 CRCL, Lyon I University, Villeurbanne, France

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Virology Journal 2011, 8:527  doi:10.1186/1743-422X-8-527

Published: 9 December 2011

Abstract

Background

Occult hepatitis B infection (OBI) is characterized by the presence of hepatitis B virus (HBV) DNA in the absence of HBsAg in the serum of patients. The aim of this study was to characterize HBV infection among a Piaroa community, an Amerindian group which exhibits significant evidence of exposure to HBV but relatively low presence of HBsAg, and to explore the presence of OBI in this population.

Results

Of 150 sera, with 17% anti-HBc and 1.3% HBsAg prevalence, 70 were tested for the presence of HBV DNA. From these, 25 (36%) were found positive for HBV DNA by PCR in the core region. Two of these 25 sera were HBsAg positive, indicating an overt infection. Of the remaining 68 sera tested, 23 exhibited OBI. Of these, 13 were HBV DNA out of 25 anti-HBc positive (52%) and 10 HBV DNA positive, out of 43 anti-HBc negative (23%), with a statistical significance of p = 0.03. Viral DNA and HBsAg were present intermittently in follow up sera of 13 individuals. Sequence analysis in the core region of the amplified DNA products showed that all the strains belonged to HBV genotype F3. The OBI isolates displayed 96-100% nucleotide identity between them. One isolate exhibited the co-circulation of a wild type variant with a variant with a premature stop codon at the core protein, and a variant exhibiting a deletion of 28 amino acids.

Conclusions

The frequency of OBI found in this Amerindian group warrants further studies in other communities exhibiting different degrees of HBV exposure.

Keywords:
Hepatitis B virus; Occult infection; Amerindians