Occult hepatitis B virus infection in an Amazonian community submitted to intense migratory flow, Pará State, Brazil

Abstract

INTRODUCTION:

Occult hepatitis B virus (HBV) infection (OBI) is defined as the presence of HBV DNA in liver, which may or not be detected in the serum with HBsAg-, and its possible clinical implications.

OBJECTIVE:

To investigate the OBI occurrence in the population of the municipality of Juruti, Pará State, Brazil, from February 2007 to November 2010.

MATERIALS AND METHODS:

Serum samples of 3,991 individuals were evaluated by immunoenzymatic techniques. The ones anti-HBc total+ isolated were selected, and from these the HBV DNA was investigated to identify OBI presence.

RESULTS:

In relation to HBV, the study showed 0.5% of carriers, 8.3% with a previous infection profile, 1.1% with a previous or current infection profile, and 33.6% with a vaccine response, characterizing that municipality as low endemicity for this virus. HBV DNA was detected in 66.7% of the HBsAg+ samples, with viral load between < 55 IU/mL and > 38,000 IU/mL; 69.2% of these samples were A1 subgenotype, 15.4% F2, and 15.4% F4. Of the total, 1.1% were samples from individuals anti-HBc total+ isolated whose molecular biology tests showed that 9.3% had HBV DNA, with viral load between < 15 IU/mL and 48 IU/mL.

CONCLUSION:

The findings of this study indicated the presence of OBI carriers in 0.1% of the Juruti population. The low prevalence of OBI found is probably related to the low endemicity of HBV in this population.