Genetic Diversity of the Hepatitis B Virus Subgenotypes in Brazil

First Detection of Hepatitis B Virus Subgenotype A5, and Characterization of Occult Infection and Hepatocellular Carcinoma-Related Mutations in Latin American and African Immigrants in Brazil

This study aims to characterize the molecular profile of the hepatitis B virus (HBV) among socially vulnerable immigrants residing in Brazil to investigate the introduction of uncommon HBV strains into the country. Serum samples from 102 immigrants with positive serology for the HBV core antibody (anti-HBc) were tested for the presence of HBV DNA by PCR assays. Among these, 24 were also positive for the HBV surface antigen (HBsAg). The full or partial genome was sequenced to determine genotype by phylogenetic analysis. Participants were from Haiti (79.4%), Guinea-Bissau (11.8%), Venezuela (7.8%), and Colombia (1%). Of the 21 HBV DNA-positive samples, subgenotypes A1 (52.4%), A5 (28.6%), E (9.5%), F2 (4.8%), and F3 (4.8%) were identified. Among the 78 HBsAg-negative participants, four were positive for HBV DNA, resulting in an occult HBV infection rate of 5.1%. Phylogenetic analysis suggested that most strains were likely introduced to Brazil by migration. Importantly, 80% of A5 sequences had the A1762T/G1764A double mutation, linked to an increased risk of hepatocellular carcinoma development. In conclusion, this study is the first report of HBV subgenotype A5 in Brazil, shedding new light on the diversity of HBV strains circulating in the country. Understanding the genetic diversity of HBV in immigrant communities can lead to better prevention and control strategies, benefiting both immigrants and wider society.

Genetic variability of hepatitis B virus in acute and in different phases of chronic infection in Brazil

The selection pressure imposed by the host immune system impacts on hepatitis B virus (HBV) variability. This study evaluates HBV genetic diversity, nucleos(t)ide analogs resistance and HBsAg escape mutations in HBV patients under distinct selective pressures. One hundred and thirteen individuals in different phases of HBV infection were included: 13 HBeAg-positive chronic infection, 9 HBeAg-positive chronic hepatitis, 47 HBeAg-negative chronic infection (ENI), 29 HBeAg-negative chronic hepatitis (ENH) and 15 acute infected individuals. Samples were PCR amplified, sequenced and genetically analyzed for the overlapping POL/S genes. Most HBV carriers presented genotype A (84/113; 74.3%), subgenotype A1 (67/84; 79.7%), irrespective of group, followed by genotypes D (20/113; 17.7%), F (8/113; 7.1%) and E (1/113; 0.9%). Clinically relevant mutations in polymerase (tL180M/M204V) and in the Major Hydrophilic Region of HBsAg (sY100C, T118A/M, sM133T, sD144A and sG145R) were observed. Our findings, however, indicated that most polymorphic sites were located in the cytosolic loops (CYL1-2) and transmembrane domain 4 (TMD4) of HBsAg. Lower viral loads and higher HBV genetic diversity were observed in ENI and ENH groups (p < 0.001), suggesting that these groups are subjected to a higher selective pressure. Our results provide information on the molecular characteristics of HBV in a diverse clinical setting, and may guide future studies on the balance of HBV quasispecies at different stages of infection.

Core Promoter and Pre-Core Variants of the Hepatitis B Virus (HBV) Are Frequent in Chronic Hepatitis B HBeAg-Negative Patients Infected by Genotypes A and D

In Brazil, hepatitis B virus endemicity is low, moderate, or high in some areas, such as Espírito Santo State in the southeast region. In this study, we intend to characterize the basal core promoter (BCP) and pre-core region (PC) variants and their association with clinical/epidemiological disease patterns in patients infected with genotypes A and D. The study included 116 chronic hepatitis B patients from Espírito Santo State, Southeast Brazil, infected with genotypes A and D. Basal core promoter (BCP) and pre-core mutations were analyzed in these patients. The frequency of BCP and PC mutations was compared with age, HBeAg status, HBV genotype and subgenotype, HBV-DNA level, clinical classification, and transmission route. HBeAg-negative status was found in 101 (87.1%) patients: 87 (75.0%) were infected with genotype A (A1 = 85; A2 = 2) and 29 (25.0%) were infected with genotype D (D3 = 24; D4 = 3; D2 = 2). BCP + PC variants altogether were more frequent (48.1%) in genotype D than in genotype A strains (6.0%) (p < 0.001). When this evaluation was performed considering the cases that presented only the A1762T and/or G1764A (BCP) mutations, it was observed that the frequency was higher in genotype A (67.5%) compared to genotype D (7.4%) (p < 0.001). On the other hand, considering the samples with mutations only in positions G1896A and/or G1899A (PC), the frequency was higher in genotype D (75.8%) than in genotype A (6.9%) (p < 0.001). Interestingly, HBV DNA was lower than 2000 IU/mL especially when both BCP/PC mutations were present (p < 0.001) or when only PC mutations were detected (p = 0.047), reinforcing their role in viral replication.

Genetic diversity of hepatitis B virus quasispecies in different biological compartments reveals distinct genotypes

The selection pressure imposed by the host immune system impacts hepatitis B virus (HBV) quasispecies variability. This study evaluates HBV genetic diversity in different biological fluids. Twenty paired serum, oral fluid, and DBS samples from chronic HBV carriers were analyzed using both Sanger and next generation sequencing (NGS). The mean HBV viral load in serum was 5.19 ± 4.3 log IU/mL (median 5.29, IQR 3.01-7.93). Genotype distribution was: HBV/A1 55% (11/20), A2 15% (3/20), D3 10% (2/20), F2 15% (3/20), and F4 5% (1/20). Genotype agreement between serum and oral fluid was 100% (genetic distances 0.0-0.006), while that between serum and DBS was 80% (genetic distances 0.0-0.115). Two individuals presented discordant genotypes in serum and DBS. Minor population analysis revealed a mixed population. All samples displayed mutations in polymerase and/or surface genes. Major population analysis of the polymerase pointed to positions H122 and M129 as the most polymorphic (≥ 75% variability), followed by V163 (55%) and I253 (50%). Neither Sanger nor NGS detected any antiviral primary resistance mutations in the major populations. Minor population analysis, however, demonstrated the rtM204I resistance mutation in all individuals, ranging from 2.8 to 7.5% in serum, 2.5 to 6.3% in oral fluid, and 3.6 to 7.2% in DBS. This study demonstrated that different fluids can be used to assess HBV diversity, nonetheless, genotypic differences according to biological compartments can be observed.

Hepatitis B virus-specific CD4 T cell responses differentiate functional cure from chronic surface antigen+ infection

BACKGROUND & AIMS

With or without antiviral treatment, few individuals achieve sustained functional cure of chronic hepatitis B virus (HBV) infection. A better definition of what mediates functional cure is essential for improving immunotherapeutic strategies. We aimed to compare HBV-specific T cell responses in patients with different degrees of viral control.

METHODS

We obtained blood from 124 HBV-infected individuals, including those with acute self-limiting HBV infection, chronic infection, and chronic infection with functional cure. We screened for HBV-specific T cell specificities by ELISpot, assessed the function of HBV-specific T cells using intracellular cytokine staining, and characterized HBV-specific CD4 T cells using human leukocyte antigen (HLA) class II tetramer staining, all directly ex vivo.

RESULTS

ELISpot screening readily identified HBV-specific CD4 and CD8 T cell responses in acute resolving infection compared with more limited reactivity in chronic infection. Applying more sensitive assays revealed higher frequencies of functional HBV-specific CD4 T cells, but not CD8 T cells, in functional cure compared to chronic infection. Function independent analysis using HLA multimers also identified more HBV-specific CD4 T cell responses in functional cure compared to chronic infection, with the emergence of CD4 T cell memory both after acute and chronic infection.

CONCLUSIONS

Functional cure is associated with higher frequencies of functional HBV-specific CD4 memory T cell responses. Thus, immunotherapeutic approaches designed to induce HBV functional cure should also aim to improve CD4 T cell responses.

LAY SUMMARY

Immunotherapy is a form of treatment that relies on harnessing the power of an individual's immune system to target a specific disease or pathogen. Such approaches are being developed for patients with chronic HBV infection, in an attempt to mimic the immune response in patients who control HBV infection spontaneously, achieving a so-called functional cure. However, what exactly defines protective immune responses remains unclear. Herein, we show that functional cure is associated with robust responses by HBV-specific CD4 T cells (a type of immune cell).

Genomic Variability of Hepatitis B Virus Circulating in Brazilian Western Amazon

The emergence of clinically relevant mutations in the hepatitis B virus (HBV) genome has been a matter of great debate because of the possibility of escape from the host’s immune system, the potential to cause more severe progression of liver diseases and the emergence of treatment-resistant variants. Here we characterized the circulating variants of HBV in Rondônia State, in the north of Brazil. Serum samples of 62 chronic HBV carriers were subjected to PCR assays and clinical data were collected. Mutations and genotypes were characterized through direct sequencing. The findings show the presence of subgenotypes A1 (54.83%, 34/62), D3 (16.13%, 10/62), F2 (16.13%, 10/62), A2 (4.84%, 3/62), D2 (3.23%, 2/62), D1 (1.61%, 1/62), D4 (1.61%, 1/62) and F4 (1.61%, 1/62). Deletions in the pre-S2 region were found in 13.79% (8/58) of the samples, mutations in the S gene in 59.68% (37/62) and RT mutations in 48.39% (30/62). We found a variable genotypic distribution in different locations and important mutations related to immune escape and drug resistance in Western Amazonia, which contributed to genetic surveillance and provided important information to help control the disease.

The unexpected high prevalence of HBV subgenotype D4 in patients with chronic hepatitis B in Galicia, a northwestern Spanish region, reflects strong links with Latin America

BACKGROUND

Hepatitis B virus (HBV) comprises 9 genotypes and multiple subgenotypes that depict differences in geographic distribution, clinical outcome and response to antiviral therapy. However, the molecular epidemiology of HBV geno/subgenotypes is globally scarce. In Spain, HBV genotype D seems to be more prevalent in the northwestern regions compared to the rest of the country for unclear reasons.

METHODS

HBV genotyping was performed using geno2pheno on a S gene fragment amplified from plasma collected from all chronic hepatitis B individuals attended at one reference hospital in Santiago de Compostela, the Galicia's capital town. Phylogenetic and phylogeographic analyses using a fragment of 345 bp were performed in all viremic specimens. To avoid misleading allocation as consequence of short fragment analysis, several bioinformatic controls were used.

RESULTS

A total of 320 individuals with persistent serum HBsAg+ and detectable HBV-DNA were seen between 2000 and 2016 (male 68.4%; median age, 52 years-old; native Spaniards 83.8%). HBV genotype distribution was as follows: A 15.3%; B 1.6%; C 2.5%; D 71.6%; E 3.1%; F 2.2%; G 3.1%; and H 0.6%. HBV genotype D was mostly represented by D4 and D2 subgenotypes (33.4% and 15% of total, respectively). Compared to chronic hepatitis B patients with genotypes B, C, E and G, HBV-D4 carriers tended to be older (54.2% had >50 years-old) and HBeAg-negative (85%). Moreover, 43% were female, 4.7% had cirrhosis, 10.2% hepatitis C and 6.4% HIV coinfection. Phylogenetic analyses could be performed on 82 HBV-D4 specimens; and 79 were confirmed as HBV-D4 using PhyML. Phylogeography using FasTree suggested at least two distinct introductions of HBV-D4 in Galicia, one from the Caribbean and South America, and another from India.

CONCLUSIONS

HBV subgenotype D4 is the most prevalent HBV variant in chronic hepatitis B patients living in the northwest of Spain, representing 33.4% (107/320) of all chronic hepatitis B infections. This rate of HBV-D4 is among the highest reported worldwide. Epidemiological and phylogenetic analyses suggest a strong association with historical migrant exchanges with Latin America, and especially with the Caribbean basin.

Hepatitis B Virus Infection among Japanese Immigrants and Descendants: The Need to Strengthen Preventive and Control Measures

This cross-sectional study aimed to investigate the prevalence and risk factors of Hepatitis B virus infection among Japanese immigrants and their descendants from São Paulo (SP), and to verify the occurrence of occult hepatitis B and coinfection with HCV, Delta, and HTLV. All samples (n = 2.127) were tested for HBV serological markers by electrochemiluminescence. HBsAg and/or total anti-HBc positive samples were tested for HBV DNA by real-time PCR, and genotyped by sequencing using the Sanger methodology. The prevalence rate of HBV exposure was 13.4% (CI 95%: 11.9–14.9%), and 22 (1.1%) were HBsAg positive. A high rate of susceptibility to HBV infection was found (67.4%; CI 95%: 65.4–69.4%). In contrast, only 19.2% (CI 95%: 17.6–20.9%) presented a serological profile analogous to that elicited by Hepatitis B vaccination. HBV isolates (n = 8) were classified as genotypes HBV/B1 (62.5%), HBV/C2 (12.5%), HBV/F1b (12.5%), and HBV/A1 (12.5%). Hepatitis B vaccination strategies and educational measures to control this infection should be considered.

Dried blood spot sampling for hepatitis B virus quantification, sequencing and mutation detection

Hepatitis B virus (HBV) diagnosis is performed on serum samples, but the access to this diagnosis is difficult in low-income regions. The use of dried blood spot (DBS) samples does not require special structure for collection, storage or transport. This study evaluates the use of DBS for detection, quantification and sequencing of HBV DNA using in-house techniques. Two study groups were included: 92 HBsAg + individuals and 49 negative controls. Serum and DBS samples were submitted to quantitative and qualitative in-house PCR for S/pol genes, sequencing and phylogenetic analyses. Total of 84 serum samples were successfully amplified. Of them, 63 paired DBS were also positive in qualitative PCR. Qualitative PCR in DBS presented a sensitivity of 75% and specificity of 100% (Kappa = 0.689). Quantitative PCR in DBS presented a detection limit of 852.5 copies/mL (250 IU/mL), sensitivity of 77.63% and specificity of 100% (Kappa = 0.731). A total of 63 serum samples and 36 DBS samples were submitted to sequencing, revealing the circulation of genotypes A (65.08%), D (4.8%), E (3.2%) and F (27%) with 100% of correspondence between serum and DBS. All sequenced samples displayed polymorphisms in HBsAg gene. An HIV-coinfected patient presented the rtM204V/I-rtL180M double resistance mutation in serum and DBS. In conclusion, DBS is an alternative to detect, quantify and characterize HBV DNA, being a possibility of increasing diagnosis in low-income settings, closing gaps in HBV control.

Hepatitis B virus genotypes and subgenotypes and the natural history and epidemiology of hepatitis B

INTRODUCTION AND OBJECTIVES

Espírito Santo state is considered a region with a higher frequency of hepatitis B virus infection. This study characterized demographic, epidemiological, laboratory, virological and clinical aspects of 587 chronic HBV carriers followed up at the University of Espírito Santo Hospital.

MATERIALS AND METHODS

Demographic, epidemiological, laboratory and clinical data were extracted from medical records during the entire follow-up period. Classification of the evolutionary phases of chronic hepatitis B was defined as immunotolerant; inactive carrier; chronic active hepatitis HBeAg (+)  and HBeAg (-). Characterization of HBV genotypes/subgenotypes was performed by sequencing of overlapping surface antigens and HBV DNA polymerase genes. Phylogenetic relationships were determined using BEAST 1.8.3 software.

RESULTS

and Conclusions: Genotypes found were A (132/65.3%) [A1 = 129 (63.9%) and A2 = 3 (1.5%)], D (66/32.7%) [D3 = 56 (27.7%), D4 = 8 (4.0%) and D2 = 2 (1.0%)] and F (4/2.0%) - all F2a. Subgenotypes A1 or D3 were not associated with age, sex, HIV/HCV co-infection, viral load, antiviral usage, HBeAg status or clinical stages of chronic hepatitis B. Mother -to-child-transmission (MTCT) was associated with the subgenotype A1 and intrafamilial transmission with subgenotype D3. Subgenotype A1 was more frequent than D3 among individuals born outside ES compared to those born in ES.

CONCLUSIONS

The most predominant clinical phases were HBeAg (-), inactive carrier and chronic active hepatitis HBeAg (-). Subgenotypes A1 and D3 were most frequent and were associated were MTCT and intrafamilial transmission of HBV, respectively.

Differences in prevalence of hepatitis B virus infection and genotypes between ethnic populations in Suriname, South America

Epidemiological data on hepatitis B virus (HBV) are needed to benchmark HBV elimination goals. We recently assessed prevalence of HBV infection and determinants in participants attending the Emergency Department in Paramaribo, Suriname, South America. Overall, 24.5% (95%CI = 22.7-26.4%) of participants had anti-Hepatitis B core antibodies, which was associated with older age (per year, adjusted Odds Ratio [aOR] = 1.03, 95%CI = 1.02-1.04), Afro-Surinamese (aOR = 1.84, 95%CI = 1.52-2.19) and Javanese ethnicity (aOR = 1.63, 95%CI = 1.28-2.07, compared to the grand mean). 3.2% of participants were Hepatitis B surface Ag-positive, which was also associated with older age (per year, aOR = 1.02, 95%CI = 1.00-1.04), Javanese (aOR = 4.3, 95%CI = 2.66-6.95) and Afro-Surinamese ethnicity (aOR = 2.36, 95%CI = 1.51-3.71). Sex, nosocomial or culturally-related HBV transmission risk-factors were not associated with infection. Phylogenetic analysis revealed strong ethnic clustering: Indonesian subgenotype HBV/B3 among Javanese and African subgenotypes HBV/A1, HBV/QS-A3 and HBV/E among Afro-Surinamese. Testing for HBV during adulthood should be considered for individuals living in Suriname, specifically with Javanese and Afro-Surinamese ancestry.

Cytokines profile in patients with acute and chronic hepatitis B infection

Hepatitis B virus (HBV) is one of the leading causes of acute and chronic hepatitis and represents a serious public health threat. Cytokines are important chemical mediators that regulate the differentiation, proliferation, and function of immune cells, with accumulating evidence indicating that the inadequate immune responses are responsible for the elimination or persistence of HBV. This study aimed to determine the cytokine profiles (IFN-γ, TNF-α, IL-2, IL-4, IL-6, IL-10, and IL-17A) during HBV infection and investigate their association with genotypes. A total of 66 plasma samples, 19 from patients with acute and 47 with chronic hepatitis B infection, were subjected to biochemical tests, nested-PCR, and real-time PCR, with cytokines evaluated using a commercial BD Cytometric Bead Array Human Th1/Th2/Th17 Cytokine Kit. Healthy controls (10 individuals) were selected from blood donors with no history of liver diseases. No correlation was found between genotypes, viral load, and cytokines analyzed. All cytokines showed higher levels of production among infected individuals when compared with the control group. A positive correlation classified as moderate to strong was found between cytokines IFN-γ, TNF, IL-10, IL-6, IL-4, and IL-2 through the Spearman correlation coefficient. TNF (P = 0.009), IL-10 (P < 0.001), and IL-6 (P < 0.001) levels were higher in acute individuals compared with chronic and control groups. Theses cytokines could be involved in the elimination of virus and protection against chronicity.

Hepatitis B virus genotypes prevalence in patients from hepatology services in Ceará, Brazil

INTRODUCTION

Hepatitis B virus (HBV) infection is a public health problem; therefore, we aimed to report HBV genotypes in Ceará, Brazil.

METHODS

A total of 103 HBsAg-positive samples were subjected to HBV genotyping and subgenotyping.

RESULTS

The following genetic compositions of samples were found: F-54% (F2-83.33%), A-40% (A1-65%), D-6%, C2-1%, E-1%, and G-1%.

CONCLUSIONS

Some genotypes are only prevalent in certain parts of the world; however, the State of Ceará is a hub for migration and has one of the most important liver transplantation centers in Brazil, which can explain the prevalence of the F genotype.

Temporal and geographic spreading of hepatitis B virus genotype A (HBV-A) in Brazil and the Americas

Hepatitis B virus genotype A (HBV-A) is disseminated in different countries around the world. It presents a high genetic diversity and is classified into seven subgenotypes (A1-A7). HBV-A1 and HBV-A2 are the most frequent and spread in almost all American countries. This study aimed to evaluate the molecular epidemiology of these two subgenotypes, with a special focus on the temporal and geographic spreading in the Americas and Brazil. Bayesian coalescent analyses with HBV-A1 and HBV-A2 whole-genome sequences were performed to study viral phylodynamic and phylogeography. HBV-A1 evolutionary history demonstrated that it was initially disseminated from Africa to other continents probably after the 1400s and mainly in the 17th-18th centuries. The whole viral population grew between the 1700s-1900s and then reached a stationary phase. In Brazil, HBV-A1 common ancestors dated back to the 1600s with successive introductions between the 17th-18th centuries. In contrast, HBV-A2 spread from Europe to other continents after the 1800s, with an increase in the viral population over decades. It was introduced in the 20th century in America and between the 1950s-1970s in Brazil, presenting a high increase in the viral population from the 1970s to the 1980s. The circulation continents for HBV-A1 are Africa and America, while for HBV-A2 are Europe and America. HBV-A is one of the predominant genotypes in America (including Brazil) because of the early introduction by human migration processes of the subgenotypes A1 and A2 between the 16th and 20th centuries and the continuous spreading inside the continent over time.

Applicability of oral fluid samples for tracking hepatitis B virus mutations, genotyping, and phylogenetic analysis

Little is known about the usefulness of saliva samples for hepatitis B virus (HBV) genotyping and mutation analysis. The aim of this study was to evaluate the usefulness of oral fluid samples to determine HBV genotype distribution, S/polymerase mutations, and HBV subpopulation diversity among chronically HBV-infected individuals. Serum and oral fluid samples were obtained from 18 individuals for PCR and nucleotide sequencing of the HBV surface antigen gene. Biochemical analysis of liver enzymes (ALT, AST, GGT) and HBV, HCV, and HIV serological tests were also performed. All serum samples were HBsAg (+), anti-HBc (+), and anti-HBs (-); 55.6% were HBeAg (+)/anti-HBe (-), and 11.1% were anti-HIV (+). The mean HBV DNA viral load was 6.1 ± 2.3 log IU/mL. The HBV genotype distribution was as follows: A, 72.2%; D, 11.1%; E, 5.6%; F, 11.1%. A concordance of 100% in genotype classification and 99.8% in sequence similarity between paired oral fluid and serum samples was observed. HBsAg mutations were detected in all samples, but no resistance mutations were found in the polymerase gene. This study demonstrates that oral fluid samples can be used reliably for tracking HBV mutations, genotyping, and phylogenetic analysis. This could be important for molecular epidemiology studies with hard-to-reach populations.

Drug-resistant and immune-escape hepatitis B virus mutants, occult hepatitis B infection and coinfections in public hospital patients from Argentina

Argentina exhibits low serological prevalence for Hepatitis B virus (HBV); however, occult hepatitis B infection (OBI) has been reported in blood donors, Amerindians and individuals coinfected with hepatitis C virus (HCV), and/or human immunodeficiency virus (HIV). The aim of this study was to analyze the genetic diversity of HBV and to evaluate serological marker associations and coinfections with HCV and HIV in patients attending and treated in a public hospital in the province of Buenos Aires, Argentina. A total of 189 HBV reactive samples (HBsAg and/or anti-HBc) were analyzed for HBV DNA characterization. All reactive samples were tested for anti-HCV and HIV-antigen/antibody using CMIA assays. Thirty-six samples exhibited detectable HBV DNA, 7 of which were OBI. HBV sequences were classified as subgenotypes A1, A2, B2, D3, F1b, F3 and F4. Mutations related to the ability to escape the host's immune response, resistance to antiviral therapy and progression to disease were found in patients, partly due to the variable sensitivity of HBsAg, the reverse transcriptase, the basal core promoter and the preCore. HCV and HIV prevalence was 10% and most of the genotypes found in the sequences were genotype 1 and B/F recombinant subtype, respectively. Of the total samples analyzed, 7 exhibited coinfections. This study shows the frequency of OBI, subgenotype distribution, HBV mutations and coinfections, which may have important clinical implications in public hospital patients. Planned prevention, detection and treatment adherence are needed to reduce transmission and morbidity in vulnerable populations.

Hepatitis B virus genotypes in Brazil: Introduction and dissemination

Hepatitis B is a viral infectious disease highly spread worldwide with a long evolutionary history associated with human migrations through the continents and countries. Hepatitis B virus (HBV) was disseminated probably from Africa and diverged into ten genotypes (HBV-A to HBV-J) distributed around the world. In Brazil, almost all HBV genotypes were already reported, with a predominance of three ones: A (52.1%), D (36.8%), and F (7.7%). This review aimed to evaluate the introduction and dissemination of the main HBV genotypes and subgenotypes in Brazil over the last centuries to explain the current epidemic scenario. The highest frequency of HBV-A is a consequence of the introduction and spreading of HBV-A1 in the 16th to 19th centuries due to the African slave trade, but the more recent introduction of HBV-A2 from Europe also contributed to the current situation. HBV-D is the second most frequent genotype because it was consecutively introduced by migrations from Europe (mainly subgenotype D3, but also D2) and the Middle East (D1) in the 19th to 20th centuries. On contrary, HBV-F (F1a, F1b, F2a, F2b, F3, and F4) was disseminated by the Amerindians in all South American countries, including Brazil, by migrations inside the continent for more than three centuries ago. Other HBV genotypes are rare and eventually frequent in some human groups because of the dissemination by very specific epidemiological routes. In conclusion, the current scenario of the HBV epidemics is a consequence of the introduction and dissemination of some subgenotypes from the three main genotypes A, D, and F over the last five centuries.

Cytokine, Genotype, and Viral Load Profile in the Acute and Chronic Hepatitis B

Several hepatitis B virus (HBV) factors, including viral load, genotype, genome mutations, and cytokine production, have been reported to be associated with different risks of progression of liver disease. The aim of this study was to verify if there is an association among the levels of cytokines (interleukin [IL]-35, IL-6, IL-17A, interferon [IFN]-γ) in the plasma, viral load, and the different genotypes of HBV in patients with acute or chronic hepatitis B. Methods: 49 serum samples, 20 from acute and 29 from chronic cases, were submitted to a real-time and nested-polymerase chain reaction to quantify, detect, and genotype HBV DNA. The cytokines IL-35, IL-6, IL-17A, and IFN-γ were detected by an enzyme-linked immunosorbent assay (ELISA). The median viral load was 3.15 log₁₀ IU DNA/mL and 2.90 log₁₀ IU DNA/mL for acute and chronic patients, respectively. Genotype A, D, E, and F were identified in chronic carriers of HBV infection, while only genotype A and F were identified in individuals with acute infection. IFN-γ (p = 0.024) and IL-17A (p = 0.046) levels were significantly increased in chronic patients and IL-6 and IL-35 were higher in patients with acute infection, however, without statistical difference. IL-17A and IFN-γ can be modulating proinflammatory effects and inducing hepatocellular damage, in chronic patients, and IL-6 and IL-35 may be involved in viral elimination and protection against chronicity during the acute phase of infection. These results can contribute to understanding of the complex regulatory mechanisms of the host antiviral response related to cytokine production during acute and chronic HBV infection.

Hepatitis B: changes in epidemiological features of Afro-descendant communities in Central Brazil

Hepatitis B virus (HBV) infection is still a concern in vulnerable populations. In a study performed by our team in 1999–2003 in two Afro-Brazilian communities, Furnas dos Dionísios (FD) and São Benedito (SB), high prevalence rates of HBV exposure (42.7% and 16.0%, respectively), high susceptibility to HBV (55.3% and 63.0%) and low HBV vaccination like profile rates (2.0% and 21.0%) were observed. In 2015–2016, we reassessed HBV epidemiological and molecular features in these two communities to verify the impact of health actions adopted in the last years. The prevalence rate of HBV exposure among the enrolled 331 subjects was 35.3% in FD and 21.8% in SB. HBV chronic infection (5.8% in FD, 4.9% in SB) remained high. The rate of HBV vaccination like profile increased from 10.7% to 43.5% (2.0% to 45.9% in FD, 21.0% to 39.5% in SB) while susceptible subjects declined from 58.9% to 26.3% (55.3% to 18.8% in FD, 63.0% to 38.7% in SB). Among 18 HBsAg positive samples, 13 were successfully sequenced (pre-S/S region). Phylogenetic analyses showed that all isolates belong to HBV subgenotype A1, clustering within the Asian-American clade. Despite the maintenance of high prevalence rate of HBV exposure over these 13 years of surveillance, significant improvements were observed, reinforcing the importance of facilitated HBV vaccination to difficult-to-access population to close gaps in prevention.

Epidemiology of hepatitis B and C virus infection in Central West Argentina

Little information is available regarding the prevalence of viral hepatitis in Central West Argentina. This study aims to give new information regarding HBV and HCV prevalence, genotypes, and risk factors in Central West Argentina and the suitability of dried blood spot (DBS) sampling for HBV and HCV screening.

METHODS

A total of 622 individuals were included; the mean age was 36.6 ± 14.3 years and 55.4% were females. HBV and HCV markers were detected using serological and molecular analysis, and risk factors were evaluated using statistical analysis.

RESULTS

Using serum samples, the HBsAg prevalence was 1.8%, the rate of HBV exposure (anti-HBc positivity) was 5.3%, and the rate of HBV immunity was 34.9%. HBV DNA was found in four out of 11 HBsAg⁺ samples, and the viruses in three of these samples were classified as genotypes A1, A2 and F2a. Multivariate analysis showed that anti-HBs positivity was associated with the level of schooling and history of HBV vaccination. The anti-HCV prevalence was 2.6%, and HCV RNA was found in 11 samples, seven of which contained viruses of genotypes 1a (n = 2), 1b (n = 3) and 2 (n = 2). The sensitivity of the DBS assay for HBsAg, anti-HBc, and anti-HCV was 100%, 66.6%, and 75%, respectively, and the specificity was above 98% for all markers when compared to serum.

CONCLUSION

A low rate of HBV immunity was observed, demonstrating the importance of HBV vaccination. High HCV prevalence was found, and HCV 1b was closely related to other Argentinian isolates. Finally, the performance of DBS testing in this population needs more optimization to increase its sensitivity and specificity.