Characterization of the Genotypic Profile of Hepatitis Delta Virus: Isolation of HDV Genotype-1 in the Western Amazon Region of Brazil

Epidemiology and Genetic Diversity of Hepatitis B Virus and Hepatitis Delta Virus Infection in Indigenous Communities in Colombia

Despite the universal vaccination program, there are still regions and territories with a high prevalence of Hepatitis B Virus infection (HBV), such as the Amazon basin, where several indigenous communities live. Additionally, Hepatitis Delta Virus (HDV) is a defective that requires the hepatitis B surface antigen (HBsAg) for the assembly and release of de novo viral particles. Therefore, hepatitis D could be the result of HBV/HDV coinfection or HDV superinfection in individuals with chronic hepatitis B. Among the high prevalence HDV populations are indigenous communities of America. This study aims to describe and characterize the frequency of HBV and HDV infection, viral genotypes and HBV immune escape mutants in indigenous populations from different regions of Colombia. The diagnosis of hepatitis B and hepatitis D was confirmed by serological markers. Moreover, the HBV and HDV genome were amplified by PCR and RT-PCR, respectively, and, subsequently, the phylogenetic analysis was performed. We characterized 47 cases of chronic hepatitis B, 1 case of reactivation and 2 cases of occult hepatitis B infection (OBI). Furthermore, a high prevalence of HDV infection was identified in the study population (29.33%, 22/75) and the circulation of several HBV genotypes and subgenotypes (F1b, F3, F4, and D). Interestingly, this is the first report of the HDV genotype I circulation in this country. These findings demonstrated that HBV and HDV infections are still public health problems in indigenous communities in Colombia.

Circulation of HDV Genotypes in Brazil: Identification of a Putative Novel HDV-8 Subgenotype

Hepatitis D virus (HDV) is classified into 8 genotypes (1 to 8) and several subgenotypes. In Brazil, HDV-3 and HDV-1 predominate; however, most of the diagnosis efforts and molecular studies are directed to the area of endemicity of the Amazon Basin. Here, we determined the molecular epidemiological profile of circulating HDV in Brazilian HBsAg-positive patients between 2013 and 2015 in areas of endemicity and non-areas of endemicity. From 38 anti-HDV-positive individuals, 13 (34.2%) had detectable HDV-RNA and 11 (28.9%) were successfully sequenced. Partial HDAg (~320 nt) sequencing followed by phylogenetic analysis with reference sequences resulted in the identification of HDV-3 (9/11; 81.8%), HDV-5 (1/11; 9.1%), and HDV-8 (1/11; 9.1%). Most HDV-3 samples (8/9; 88.9%) were found in the endemic North region, while one was found in Central-West Brazil, a non-area of endemicity. HDV-5 and 8, genotypes native from African countries, were found in São Paulo, a cosmopolitan city from Southeast Brazil with a high circulation of immigrants. Phylogenetic analysis of HDV-8 strains indicated that the sample determined in our study, along with previously reported sequences from Brazil, formed a highly supported monophyletic clade, likely representing a putative novel HDV-8 subgenotype. IMPORTANCE Considered a neglected pathogen until the last 2 decades, an increase in the availability of genetic data of hepatitis D virus (HDV) strains around the world has been noticed recently, resulting in the proposition of different classifications. Our study aimed to determine the molecular epidemiological profile of HDV isolates circulating in areas of endemicity and non-areas of endemicity in Brazil. Based on the analyzed fragment, HDV-8 sequences clustered out of the clades formed by subgenotypes 8a and 8b might suggest the identification of a novel subgenotype, putatively designated subgenotype 8c. Our findings demonstrate the importance of continuous epidemiological surveillance to map HDV spread pathways and the introduction of imported variants. It also reinforces that as the amount of HDV genomes generated and reported increases, we will have changes in viral classification and, consequently, in our understanding of the dynamics of variability of this viral agent.

Therapeutic Advances in Viral Hepatitis A-E

Viral hepatitis remains a significant global health problem. All forms of viral hepatitis A through E (A-E) can lead to acute symptomatic infection, while hepatitis B and C can lead to chronic infection associated with significant morbidity and mortality related to progression to cirrhosis, end-stage-liver disease, and liver cancer. Viral hepatitis occurs worldwide, though certain regions are disproportionately affected. We now, remarkably, have highly effective curative regimens for hepatitis C, and safe and tolerable medications to suppress hepatitis B activity, and to prevent liver damage and slow disease progression. We have effective vaccines for hepatitis A and B which provide long-lasting immunity, while improved sanitation and awareness can curb outbreaks of hepatitis A and E. However, more effective and available preventive and curative strategies are needed to achieve global eradication of viral hepatitis. This review provides an overview of the epidemiology, transmission, diagnosis, and clinical features of each viral hepatitis with a primary focus on current and future therapeutic and curative options.

Detection and Genetic Characterization of Hepatitis B and D Viruses: A Multi-Site Cross-Sectional Study of People Who Use Illicit Drugs in the Amazon Region

Hepatitis B (HBV) and delta (HDV) viruses are endemic in the Amazon region, but vaccine coverage against HBV is still limited. People who use illicit drugs (PWUDs) represent a high-risk group due to common risk behavior and socioeconomic factors that facilitate the acquisition and transmission of pathogens. The present study assessed the presence of HBV and HBV-HDV co-infection, identified viral sub-genotypes, and verified the occurrence of mutations in coding regions for HBsAg and part of the polymerase in HBV-infected PWUDs in municipalities of the Brazilian states of Amapá and Pará, in the Amazon region. In total, 1074 PWUDs provided blood samples and personal data in 30 municipalities of the Brazilian Amazon. HBV and HDV were detected by enzyme-linked immunosorbent assay and polymerase chain reaction. Viral genotypes were identified by nucleotide sequencing followed by phylogenetic analysis, whereas viral mutations were analyzed by specialized software. High rates of serological (32.2%) and molecular (7.2%) markers for HBV were detected, including cases of occult HBV infection (2.5%). Sub-genotypes A1, A2, D4, and F2a were most frequently found. Escape mutations due to vaccine and antiviral resistance were identified. Among PWUDs with HBV DNA, serological (19.5%) and molecular (11.7%) HDV markers were detected, such as HDV genotypes 1 and 3. These are worrying findings, presenting clear implications for urgent prevention and treatment needs for the carriers of these viruses.

Molecular mechanisms of viral hepatitis induced hepatocellular carcinoma

Chronic infection with viral hepatitis affects half a billion individuals worldwide and can lead to cirrhosis, cancer, and liver failure. Liver cancer is the third leading cause of cancer-associated mortality, of which hepatocellular carcinoma (HCC) represents 90% of all primary liver cancers. Solid tumors like HCC are complex and have heterogeneous tumor genomic profiles contributing to complexity in diagnosis and management. Chronic infection with hepatitis B virus (HBV), hepatitis delta virus (HDV), and hepatitis C virus (HCV) are the greatest etiological risk factors for HCC. Due to the significant role of chronic viral infection in HCC development, it is important to investigate direct (viral associated) and indirect (immune-associated) mechanisms involved in the pathogenesis of HCC. Common mechanisms used by HBV, HCV, and HDV that drive hepatocarcinogenesis include persistent liver inflammation with an impaired antiviral immune response, immune and viral protein-mediated oxidative stress, and deregulation of cellular signaling pathways by viral proteins. DNA integration to promote genome instability is a feature of HBV infection, and metabolic reprogramming leading to steatosis is driven by HCV infection. The current review aims to provide a brief overview of HBV, HCV and HDV molecular biology, and highlight specific viral-associated oncogenic mechanisms and common molecular pathways deregulated in HCC, and current as well as emerging treatments for HCC.

Noninvasive Models for Predicting Liver Fibrosis in Individuals with Hepatitis D Virus/Hepatitis B Virus Coinfection in the Brazilian Amazon Region

Hepatitis D virus (HDV) genotype III is endemic in the western Amazon basin and is considered to cause the most severe form of chronic viral hepatitis. Recently, noninvasive fibrosis scores to determine the stage of liver fibrosis have been evaluated in individuals positive for HDV genotype I, but their utility in HDV genotype III-positive patients is unknown. In this retrospective study conducted in an outpatient viral hepatitis referral clinic in the Brazilian Amazon region, the aspartate aminotransferase (AST) to Aspartate aminotransferase to Platelet Ratio Index (APRI) and Fibrosis Index for Liver Fibrosis (FIB-4) values were calculated and compared with histological fibrosis stages. Among the 50 patients analyzed, the median age at liver biopsy was 35.6 years, 66% were male, and all had compensated liver disease. Histological staging revealed fibrosis stages 0, 1, 2, 3, and 4 in four (8%), eight (16%), 11 (22), 11 (22%), and 16 (32%) patients, respectively. The area under the receiver operating curve (AUROC) of AST-to-alanine aminotransferase (ALT) ratio, APRI, and FIB-4 for detection of significant fibrosis (F ≥ 2) was 0.550 (P = 0.601), 0.853 (P < 0.001), and 0.853 (P < 0.0001), respectively. Lower AUROC values were obtained for cirrhosis: the AST-to-ALT ratio was 0.640 (P = 0.114), APRI was 0.671 (P = 0.053), and FIB-4 was 0.701 (P = 0.023). The optimal cutoff value for significant fibrosis for APRI was 0.708 (sensitivity 84% and specificity 92%) and for FIB-4 was 1.36 (sensitivity 76% and specificity 92%). Aspartate aminotransferase to Platelet Ratio Index and FIB-4 were less useful to predict cirrhosis. In contrast to recent reports from Europe and North America, both APRI and FIB-4 may identify significant fibrosis in HDV-III-infected patients from northwestern Brazil.

Phylodynamic and Phylogeographic Analysis of Hepatitis Delta Virus Genotype 3 Isolated in South America

The hepatitis delta virus (HDV) is a globally distributed agent, and its genetic variability allows for it to be organized into eight genotypes with different geographic distributions. In South America, genotype 3 (HDV-3) is frequently isolated and responsible for the most severe form of infection. The objective of this study was to evaluate the evolutionary and epidemiological dynamics of HDV-3 over the years and to describe its distribution throughout this continent in an evolutionary perspective. While using Bayesian analysis, with strains being deposited in the Nucleotide database, the most recent common ancestor was dated back to 1964 and phylogenetic analysis indicated that the dispersion may have started in Brazil, spreading to Venezuela and then to Colombia, respectively. Exponential growth in the effective number of infections was observed between the 1950s and 1970s, years after the first report of the presence of HDV on the continent, during the Labrea Black Fever outbreak, which showed that the virus continued to spread, increasing the number of cases decades after the first reports. Subsequently, the analysis showed a decrease in the epidemiological levels of HDV, which was probably due to the implantation of the vaccine against its helper virus, hepatitis B virus, and serological screening methods implemented in the blood banks.

HDV infection in immigrant populations

AIMS

Little data have been published so far on the epidemiological aspects of hepatitis D virus (HDV) infection in immigrant populations and even poorer is the information on the virological, phylogenetic, and clinical aspects of this infection in these populations. This review article, aimed primarily at physicians caring for immigrants, summarizes the information available on HDV infection and analyzes data on this topic concerning the immigrant populations.

METHODS AND RESULTS

The prevalence of HDV infection in HBsAg-positive immigrants varies according to the country of origin. For example, in immigrants from sub-Saharan Africa, this prevalence is higher in those born in Equatorial Guinea (24.4%) than those from other African countries (10.3%). The epidemiological impact of HDV infection linked to migratory flows is a function of the different endemicity between countries of origin and countries in which a new existence has been established. This impact is high when immigrants from areas endemic to HDV infection (eg, Equatorial Guinea) settle in areas of low endemicity (eg, Germany or England, with a prevalence of around 4%), while the impact is lesser or nonexistent if the migratory flows are directed toward countries with intermediate endemicity (eg, Italy and Greece, with a prevalence of around 10%).

CONCLUSION

This impact of immigration on HDV epidemiology can be strong when HDV endemicity is high in the country of origin and low in the host country and slight when immigrants move to high or medium endemic countries.

Molecular epidemiology of Hepatitis delta virus infection in Minas Gerais state from Brazil, an area outside the hyperendemic region of the Amazon Basin

BACKGROUND

Hepatitis delta virus (HDV) infections in hepatitis B virus (HBV) carriers are the most severe form of viral hepatitis. HDV prevalence is high in the Brazilian Amazon, but studies in other regions of the country are still scarce and often underestimated its prevalence by including a small numbers of individuals.

OBJECTIVE

This study aimed to determine the serological prevalence of hepatitis D, the genotypes circulating and to evaluate the associated risk factors for acquisition of HDV in Minas Gerais state, Brazil.

METHODS

We screened plasma samples (n = 498) from HBV chronic carriers for anti-HD antibodies using a commercial enzyme-linked immunosorbent assay (ELISA) kit. For those samples that were positive for anti-HD antibodies, we performed a reverse transcriptase (RT) nested-polymerase chain reaction (nested-PCR) in order to detect the viral genome and identify the viral genotypes circulating in the state.

FINDINGS

The prevalence was 6.22% (31/498). Blood transfusion was the only risk factor associated with HDV infection [risk ratio: 3.73; 95% confidence interval (CI): 1.44 to 9.65]. For 26 anti-HD positive patients, HDAg gene sequences were determined and in all patients HDV genotype 1 was found.

CONCLUSIONS

This study confirmed the circulation of HDV in Minas Gerais, an area previously considered non-endemic for hepatitis D in Brazil. The prevalence found in this study is much higher when compared to other studies performed in Brazil, probably because the population in our study was selected with minimal bias. Furthermore, in 26 anti-HD positive plasma samples, we were also able to detect the viral genome, indicating that these patients were experienced an active infection at the time of sample collection. These findings emphasise the importance of anti-HD testing in HBV infected individuals, which may contribute to this disease control in Brazil.

Transmission of Hepatitis B and D Viruses in an African Rural Community

According to the World Health Organization (WHO), an estimated 257 million people worldwide are chronically infected with hepatitis B virus (HBV), with approximately 15 million of them being coinfected with hepatitis D virus (HDV). To investigate the prevalence and transmission of HBV and HDV within the general population of a rural village in Cameroon, we analyzed serum samples from most (401/448) of the villagers. HBV surface antigen (HBsAg) was detected in 54 (13.5%) of the 401 samples, with 15% of them also containing anti-HDV antibodies. Although Cameroon has integrated HBV vaccination into their Expanded Program on Immunization for newborns in 2005, an HBsAg carriage rate of 5% was found in children below the age of 5 years. Of the 54 HBsAg-positive samples, 49 HBV pre-S/S sequences (7 genotype A and 42 genotype E sequences) could be amplified by PCR. In spite of the extreme geographical restriction in the recruitment of study participants, a remarkable genetic diversity within HBV genotypes was observed. Phylogenetic analysis of the sequences obtained from PCR products combined with demographic information revealed that the presence of some genetic variants was restricted to members of one household, indicative of intrafamilial transmission, which appears to take place at least in part perinatally from mother to child. Other genetic variants were more widely distributed, reflecting horizontal interhousehold transmission. Data for two households with more than one HBV-HDV-coinfected individual indicate that the two viruses are not necessarily transmitted together, as family members with identical HBV sequences had different HDV statuses. IMPORTANCE This study revealed that the prevalence of HBV and HDV in a rural area of Cameroon is extremely high, underlining the pressing need for the improvement of control strategies. Systematic serological and phylogenetic analyses of HBV sequences turned out to be useful tools to identify networks of virus transmission within and between households. The high HBsAg carriage rate found among children demonstrates that implementation of the HBV birth dose vaccine and improvement of vaccine coverage will be key elements in preventing both HBV and HDV infections. In addition, the high HBsAg carriage rate in adolescents and adults emphasizes the need for identification of chronically infected individuals and linkage to WHO-recommended treatment to prevent progression to liver cirrhosis and hepatocellular carcinoma.

Evidências científicas sobre a hepatite Delta no Brasil: revisão integrativa da literatura

Resumo Objetivo: Descrever o nível de evidência científica sobre a infecção por vírus da hepatite Delta (VHD) no Brasil. Métodos: Revisão integrativa da literatura, com buscas realizadas nas bases de dados do Medical Literature Analysis and Retrieval System Online, Literatura Latino-americana e do Caribe em Ciências da Saúde, Scientific Eletronic Library Online e Scopus, com análise centrada no nivelamento do rigor metodológico de acordo com o modelo de Melnyk e Fineout-Overholt. Resultados: A busca revelou uma média de duas publicações por ano no intervalo entre 1987 e 2017. Foram selecionados 33 artigos, tendo a maioria (91%) apresentado nível de evidência VI. As publicações ficaram concentradas em periódicos da área de medicina tropical (46%) e virologia (15%). Dos trabalhos, 85% tinha profissional médico com autor e o delineamento mais encontrado foi o descritivo/transversal (69,6%). Conclusão: A produção científica sobre a infecção por VHD no Brasil está centrada em estudos de prevalência, mostrando-se incipiente quanto à produção de estudos com delineamentos mais rígidos como ensaios clínicos.

Hepatitis delta: virological and clinical aspects

There are an estimated 400 million chronic carriers of HBV worldwide; between 15 and 20 million have serological evidence of exposure to HDV. Traditionally, regions with high rates of endemicity are central and northern Africa, the Amazon Basin, eastern Europe and the Mediterranean, the Middle East and parts of Asia. There are two types of HDV/HBV infection which are differentiated by the previous status infection by HBV for the individual. Individuals with acute HBV infection contaminated by HDV is an HDV/HBV co-infection, while individuals with chronic HBV infection contaminated by HDV represent an HDV/HBV super-infection. The appropriate treatment for chronic hepatitis delta is still widely discussed since it does not have an effective drug. Alpha interferon is currently the only licensed therapy for the treatment of chronic hepatitis D. The most widely used drug is pegylated interferon but only approximately 25% of patients maintain a sustained viral response after 1 year of treatment. The best marker of therapeutic success would be the clearance of HBsAg, but this data is rare in clinical practice. Therefore, the best way to predict a sustained virologic response is the maintenance of undetectable HDV RNA levels.

Detection of morbillivirus infection by RT-PCR RFLP analysis in cetaceans and carnivores

Morbillivirus genus comprises several members related to specific hosts, such as canine distemper virus (CDV) and cetacean morbillivirus (CeMV) in which the dolphin morbillivirus (DMV) is included. Both CDV and DMV are able to cause serious outbreak associated with high morbidity and mortality representing an important conservation threat for terrestrial and aquatic mammalian species. This paper describes a new RT-PCR RFLP technique based on a RT-PCR with degenerate primers targeting a 287 bp fragment located on the conserved N terminus of the morbillivirus NP gene, followed by MseI RFLP, in order both to confirm the detection of the virus and to distinguish DMV from CDV. Both carnivores and cetaceans tissues (brain, lung and lymph node) presenting evidence of morbillivirus infection (MI) were analyzed. RT-PCR positive samples were typed by RFLP analysis and then sequenced to confirm the RFLP results. This method was applied during the last morbillivirus cetacean die-off occurred in the Mediterranean basin in 2013, when there was the urgent need of a rapid and economic method to investigate among causes of death on stranded cetaceans. This new technique has proved to be a valuable, reliable, simple and relatively inexpensive diagnostic tool easily applicable also in limited-resource laboratories.

Prevalence and genotype distribution of hepatitis delta virus among chronic hepatitis B carriers in Central Vietnam

Hepatitis D virus (HDV) infection plays an important role in liver diseases. However, the molecular epidemiology and impact of HDV infection in chronic hepatitis B (CHB) remain uncertain in Vietnam. This cross-sectional study aimed to investigate the prevalence and genotype distribution of HDV among HBsAg-positive patients in Central Vietnam. 250 CHB patients were tested for HDV using newly established HDV-specific RT-PCR techniques. HDV genotypes were determined by direct sequencing. Of the 250 patients 25 (10%) had detectable copies of HDV viral RNA. HDV-2 was predominant (20/25; 80%) followed by HDV-1 (5/25; 20%). Proven HDV genotypes share the Asian nomenclature. Chronic hepatitis B patients with concomitant HDV-1 showed higher HBV loads as compared to HDV-2 infected patients [median log10 (HBV-DNA copies/ml): 8.5 vs. 4.4, P = 0.036]. Our findings indicate that HDV infection is highly prevalent and HDV-2 is predominant in Central Vietnam. The data will add new information to the management of HBsAg-positive patients in a highly HBV endemic region to in- or exclude HDV infection in terms of diagnostic and treatment options.

Treatment of hepatitis delta virus genotype 3 infection with peg-interferon and entecavir

OBJECTIVES

Hepatitis delta virus (HDV) is recognized as the most pathogenic and infectious among the hepatotropic viruses. Studies on the treatment of HDV have predominantly included European patients and carriers of genotype 1 (HDV-1) in their clinical protocols. For the Amazon region, data show that infected individuals have mainly Native American ancestry and that >90% of HDV carriers have the genotype 3 (HDV-3). Thus combined therapy clinical protocols do not adequately address the treatment of these patients.

METHODS

A prospective, non-randomized study was conducted in which 22 patients received 180μg of pegylated interferon alpha 2a (PEG-IFN) plus entecavir at a dose of 0.5mg for 48 weeks, with a subsequent 24-week follow-up. Throughout treatment, the patients were monitored for biochemical responses and the kinetics of hepatitis B virus (HBV) and HDV viral loads.

RESULTS

Of the 22 patients treated, 15 presented normal alanine aminotransferase values at the end of treatment (p=0.002). At week 24 of treatment, 86.4% of the patients did not present detectable HDV-RNA; at week 48, the rate of negative patients increased to >95% and remained the same after 6 months. With regard to HBV, only two patients (9%) still presented detectable HBV genetic material at the end of treatment, suggesting the effectiveness of combined therapy in combating the two viruses.

CONCLUSIONS

These findings support the use of this effective therapeutic protocol for HDV-3 in patients of non-European ethnicity and suggest a possible 'easy to treat' variant when compared to HDV-1.