High Prevalence of Hepatitis B Subgenotype D4 in Northeast Brazil: an Ancient Relic from African Continent?

High prevalence of hepatitis B virus and low vaccine response in children and adolescents in Northeastern Brazil

Children have an increased likelihood of becoming carriers of the chronic hepatitis B virus. A total of 1,381 children and adolescents were assessed in five municipalities of Maranhao State, Brazil, for detection of anti-HBc, HBsAg and anti-HBs serologic markers and sociodemographic and behavioral features. Among those who were HBsAg negative and anti-HBc negative, the proportion of anti-HBs positives was calculated after the individuals had completed the vaccination schedule. The robust variance of the Poisson's regression model was used in order to have adjusted tables and calculate the prevalence ratio. Multivariate analysis was performed to identify the factors associated with the prevalence of anti-HBc with or without HBsAg and the vaccine response. It was observed that 163 children were anti-HBc positive and nine individuals were HBsAg positive. The factors associated with the infection were: municipality of residence (residing in Morros municipality or Humberto de Campos municipality), residence in a rural area, aged between 13 and 15 years old, and illicit drug use. The percentage of individuals who were anti-HBc negative and received all three doses of the vaccine was 48.5%. Among these, only 276 (38.9%) had antibodies at protective concentrations. In an adjusted analysis, Morros municipality presented an increased positivity of vaccine response (p < 0.001), and the age ranging between 6 and 10 years old presented a reduced frequency of response. This study reveals a high prevalence of current and past HBV infection within the targeted age group which, in addition to the low vaccination coverage and serological responses, raises concerns about the management of prevention measures, especially the quality of vaccination in these locations.

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.

Unexpected findings of hepatitis B and delta infection in northeastern Brazil: A public health alert

INTRODUCTION AND OBJECTIVES

Research has shown that hepatitis B (HBV) and Delta virus (HDV) are a worldwide public health problem. This study aims to estimate the prevalence rates of HBV and HDV infection in five municipalities of Maranhão, Northeastern Brazil.

MATERIALS AND METHODS

A total sample between 3856 and 4000 individuals. Questionnaires were used to register sociodemographic characteristics and factors associated with transmission. Patients were tested for hepatitis B virus surface antigen (HBsAg), anti-hepatitis B core antigen (anti-HBc), and antibodies against hepatitis Delta virus (anti-HDV). Factors associated with HBV were detected by means of multivariate Poisson regression.

RESULTS

Overall, 3983 subjects were included. Ninety-two of the participants were HBsAg-positive (2.30%, 95% CI 1.80-2.80), and anti-HBc was detected in 1535 (38.50%, 95% CI 37-40). The factors associated with the presence of anti-HBc were: (1) Municipality (P<0.001); Age (P<0.001); School education (P<0.001); Illicit drug use (P=0.001); non-HBV vaccine (P=0.041). Among the HBsAg carriers, eight were anti-HDV-positive (8.69%, 95% CI 2.90-14.40). The most frequent HBV genotype was D4. The only HDV genotype was HDV-8.

CONCLUSION

HBV exhibited intermediate endemicity in the studied region. Traditional factors were associated with exposure to the virus. The presence of the HDV was confirmed. The most frequent HBV and HDV genotypes were unlike the ones currently described in Brazil.

Hepatitis B in the Northwestern region of Sao Paulo State: genotypes and resistance mutations

In Brazil, few studies on the molecular aspects of hepatitis B virus (HBV) infection have been conducted in the interior regions of Sao Paulo State. This study aimed to identify HBV genotypes and evaluate strains with resistance mutations for nucleoside analogues in the Administrative Region (AR) of the municipality of Sao Jose do Rio Preto. We performed nested PCRs of 127 samples from the Health Care Services of the AR to amplify, sequence and analyze fragments of the HBV DNA, in order to identify genotypes and resistance mutations. The HBV S/Pol regions of 126 samples were successfully amplified and sequenced. Five different genotypes were found, and the main ones were A, D and F; a greater number of samples contained the subgenotypes A1 (n = 51; 40.5%), D3 (n = 36; 28.6%), A2 (n = 14; 11.1%) and F2a (n = 9; 7.1%). Resistance mutations (rtM204V/I/S) associated or not with compensatory mutations (rtL180M, rtV173L) were identified in 13.9% (5/36) of patients undergoing viral treatment and 1.1% (1/90) of naïve patients. The diversity of genotypes/subgenotypes found is probably due to the intense migration occurring in the region. These data can complement epidemiological and clinical surveillance, and can be used for a more effective management of chronic HBV patients.

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.

Genetic Diversity of the Hepatitis B Virus Subgenotypes in Brazil

Hepatitis B virus (HBV) subgenotypes may be related to clinical outcomes and response to antiviral therapy. Most Brazilian studies on HBV subgenotypes are restricted to some regions and to specific population groups. Here, we provide an insight about genetic diversity of HBV subgenotypes in 321 serum samples from all five geographical regions, providing a representative overview of their circulation among chronic carriers. Overall, HBV/A1 was the most prevalent subgenotype, being found as the major one in all regions except in South Brazil. Among HBV/D samples, subgenotype D3 was the most prevalent, found in 51.5%, followed by D2 (27.3%) and D4 (21.2%). D2 and D3 were the most prevalent subgenotypes in South region, with high similarity with European strains. D4 was found in North and Northeast region and clustered with strains from Cape Verde and India. For HBV/F, the most frequent subgenotype was F2 (84.1%), followed by F4 (10.1%) and F1 (5.8%), closely related with strains from Venezuela, Argentina and Chile, respectively. Phylogeographic analyses were performed using an HBV full-length genome obtained from samples infected with genotypes rarely found in Brazil (B, C, and E). According to Bayesian inference, HBV/B2 and HBV/C2 were probably introduced in Brazil through China, and HBV/E from Guinea, all of them mostly linked to recent events of human migration. In conclusion, this study provided a comprehensive overview of the current circulation of HBV subgenotypes in Brazil. Our findings might contribute to a better understand of the dynamics of viral variants, to establish a permanent molecular surveillance on the introduction and dispersion patterns of new strains and, thus, to support public policies to control HBV dissemination in Brazil.

Phylogenetic analysis and genotype distribution of Hepatitis B Virus (HBV) in Roraima, Brazil

Hepatitis B virus (HBV) infection is a serious global health problem. HBV has a high viral genetic diversity, with 10 genotypes recognized. In Brazil, the Roraima State is the third in the Northern region regarding the number of hepatitis B cases. On the other hand, few data on HBV genotyping and phylogenetic analysis are available. The purpose of this study is to characterize the HBV genotypes circulating in Roraima State. Of the 113 chronic hepatitis B patients enrolled in this study, 40 were HBV-DNA positive. A fragment of 280 bp (S gene) was amplified by PCR and submitted to nucleotide sequencing. A dataset containing the viral sequences obtained in this study, plus 130 obtained from GenBank was used for genotyping by phylogenetic analysis. The HBV subgenotype distribution found was A1 (62.5%), A2 (7.5%), D2, D3, D4 (2.5%), F2a (12.5%), and F3 (10%). We characterized the genotypes and subgenotypes of HBV circulating among patients in the State of Roraima. In addition, our study shows for the first time the HBV/F3 genotype circulating in Brazil. In conclusion, our findings showed a high diversity of HBV genotypes in Roraima, which is also found in other Brazilian geographical regions.