ABSTRACT The goal of this study was to investigate the prevalence of occult HBV infection in a reference center for the Northern Brazil from 2005 to 2015 and to identify mutations associated with occult hepatitis B. Molecular analysis was performed on 110 serum samples in which anti-HBc was the only positive serological marker. Regions of the HBV genome were amplified by polymerase chain reaction to detect HBV DNA. A prevalence of 4.1% (793/18,889) for anti-HBc alone was identified. Molecular analysis revealed a prevalence of occult HBV infection of 0.04%. HBV DNA detected were identified in individuals who underwent hemodialysis, infected with the hepatitis C virus and from area of high endemicity for HBV. Direct DNA nucleotide sequencing and phylogenetic analysis identified that genotypes A and D and mutations E164D, I195M, P217L and P120S were associated with occult HBV infection in the S gene. This study contributed with epidemiological and molecular information on Northern Brazil samples with a suggestive profile of occult HBV infection in addition to reinforcing the importanceof molecular diagnosis in this type of infection.

Abstract INTRODUCTION We evaluated the anti-hepatitis E virus (HEV) antibody prevalence and HEV-RNA in archived serum samples of non-A-C hepatitis, or suspected cases of HEV infection from the Eastern Brazilian Amazon from 1993 to 2014. METHODS Serum samples (n = 318) were tested using ELISA and immunoblotting, and screened for HEV-RNA by RT-qPCR. RESULTS Anti-HEV IgM and IgG were detected in 3.4% (11/318) and 5.9% (19/318) of the samples, respectively. All samples were HEV-RNA negative. CONCLUSIONS HEV was detected at a low prevalence. Broader serological and molecular evaluation of HEV infection in the Amazon region should be carried out.

Abstract INTRODUCTION The prevalence, public health impact, and epidemiological characteristics of hepatitis E virus (HEV) are poorly understood in Brazil. METHODS Serum samples from 535 individuals from three rural Afro-descendant communities located in eastern Brazilian Amazon were collected in October 2015 and tested for presence of anti-HEV IgM and IgG antibodies. Serologically positive samples were also tested for HEV-RNA. RESULTS Two cases were confirmed for anti-HEV IgM (0.3 %) and two cases for anti-HEV IgG (0.3 %). No sample was positive for HEV-RNA. CONCLUSIONS Results indicated low prevalence of HEV infection in Afro-descendant rural communities from the eastern Brazilian Amazon.