Epidemiological and molecular features of hepatitis B and hepatitis delta virus transmission in a remote rural community in central Africa

Silent HDV epidemics culminates in high levels of liver cirrhosis in endemic region despite 20 years of HBV vaccination

The hepatitis delta virus (HDV) is believed to be a vanishing infection in countries with successful hepatitis B virus (HBV) vaccination programs. We assessed the current status of HDV infection in Tuva, a region of the Russia that has been highly endemic for HBV. The proportion of HDV-infected patients among HBsAg-positive patients in the regional registry in 2020 was 32.7% (786/2401). An analysis of the medical records of 514 HDV patients demonstrated that 37.5% (193/514) had liver cirrhosis at the first doctor's visit, and 7.4% of patients lived in families where another family member had HDV. All HDV patients were infected with genotype HDV-1, 94.5% had HBV genotype D, and 5.5% had genotype A. A serosurvey conducted among 1170 healthy volunteers showed that the average detection rate of HBsAg with anti-HDV was 1.0% (95% CI: 0.57-1.81%). No anti-HDV positive samples were detected in participants aged under 30 years. The HBsAg/anti-HDV positivity rate peaked at 7.4% in patients aged 50-59 years, which was significantly higher than in a similar age cohort surveyed in 2008 (1.6%, p < .0001). A Bayesian analysis showed that HDV circulation in Tuva resulted from two waves of introduction, the first in the 1810s (95% HPD: 1741-1834) from Central Asia, and the second in the 1960s (95% HPD: 1953-1979) from Russia. HBV has a much longer history of circulation in Tuva with the MRCA for the predominant genotype HBV-D dated to 972 (95% HPD: 535-1253) for subtype D1, 1274 (95% HPD: 936-1384) for D2, and 1173 (95% HPD: 1005-1618) for D3. A SkyGrid reconstruction of population dynamics showed an increase in the intensity of HDV spread in recent decades. This situation shows the need for HDV screening and prevention measures among people living with HBV.

The Severity of Hepatitis D in Young Adults of Age 18-25 Years

Background

Current literature on the prevalence and characteristics of hepatitis D virus (HDV) infection in young adults is limited. This study aims to determine the disease characteristics and severity in young adults.

Methods

The case records of HDV RNA positive patients of age 18-25 years were analyzed.

Results

Out of 119 patients, 105 (88%) patients were male. HBV-DNA was detectable in 83 (70%). Hepatitis B e-antigen (HBeAg) was non-reactive in 99 (83%). Cirrhosis was identified in 45 (37.8%) individuals; nine (7.5%) were classified as Child class B or Child class C. Twenty-four (20.2%) had a Model For End-Stage Liver Disease (MELD) score of ≥10, out of these 16 had a score of 15 or more. The risk of decompensation was calculated according to the Baseline-event-anticipation (BEA) score; eight (6.7%) patients were at BEA-A (mild risk), 105 (88.2%) were at BEA-B (moderate risk), and six (5.0%) were at BEA-C (severe risk). Notable findings in patients with cirrhosis included splenomegaly, low total leucocyte counts, low platelets, high bilirubin, elevated aspartate aminotransferase, gamma-glutamyl transferase and international normalization ratio, low albumin, high AST to Platelet Ratio Index (APRI), and high BEA score. The splenic size, platelet count, and albumin levels were independently associated with cirrhosis (p < 0.001, <0.001, and 0.003). A model using a combination of platelet count, albumin, and spleen size was developed to accurately predict cirrhosis in this cohort. It had an area under the receiver operating characteristics (AUROC) of 0.935.

Conclusions

HDV-infected young adults, age 18-25 years, were at moderate to severe risk of disease progression. About one-third of patients had already developed cirrhosis indicating the aggressive nature of the disease.

Underestimation of hepatocellular carcinoma incidence resulting from a competition between modern and traditional medicine: the case of Gabon

Primary liver cancer, particularly hepatocellular carcinoma (HCC), remains a major killer in sub-Saharan Africa. In this dreadful landscape, West and Central Africas are more particularly affected. However, a small country located on the equator, Gabon, is apparently not concerned by this adverse situation. Despite worrying prevalences of many bona fide risk factors of HCC, including high rates of chronic infections with hepatitis viruses and very high alcohol consumption, Gabon presents theoretically an amazingly low incidence of HCC when compared to other countries of the region. Reports from many places in the world have emphasized the widespread underreporting of HCC cases presumably attributable to the difficulties of proper diagnosis or to a lack of local cancer registry. In Gabon, the remarkably vivid tradition of religious initiation called Bwiti includes some therapeutic rituals exerted by healers or Ngangas. Those treatments are particularly popular in case of severe diseases generally associated with a supernatural etiology. In the present paper, we hypothesize that, in Gabon, the remarkably low incidence of HCC is primarily due to the diversion of patients from the modern medical system due to their preference for Ngangas. Promotion of a form of medical syncretism respecting both systems might be an efficient policy to increase the attractiveness of modern medicine and to ultimately promote public health in Gabon.

The epidemiology of hepatitis delta virus infection in Cameroon

OBJECTIVE

To investigate the distribution and risk factors of hepatitis delta virus (HDV) infection in Cameroon.

DESIGN

We tested for hepatitis B virus (HBV) surface antigen (HBsAg) and anti-HDV antibody 14 150 samples collected during a survey whose participants were representative of the Cameroonian adult population. The samples had already been tested for hepatitis C virus and HIV antibodies.

RESULTS

Overall, 1621/14 150 (weighted prevalence=11.9%) participants were HBsAg positive, among whom 224/1621 (10.6%) were anti-HDV positive. In 2011, the estimated numbers of HBsAg positive and HDV seropositives were 1 160 799 and 122 910 in the 15-49 years age group, respectively. There were substantial regional variations in prevalence of chronic HBV infection, but even more so for HDV (from 1% to 54%). In multivariable analysis, HDV seropositivity was independently associated with living with an HDV-seropositive person (OR=8.80; 95% CI: 3.23 to 24.0), being HIV infected (OR=2.82; 95% CI: 1.32 to 6.02) and living in the South (latitude <4°N) while having rural/outdoor work (OR=15.2; 95% CI: 8.35 to 27.6, when compared with living on latitude ≥4°N and not having rural/outdoor work).

CONCLUSION

We found evidence for effective intra-household transmission of HDV in Cameroon. We also identified large differences in prevalence between regions, with cases concentrated in forested areas close to the Equator, as described in other tropical areas. The reasons underlying these geographical variations in HDV prevalence deserve further investigation.

The epidemiological characterization and geographic distribution of hepatitis D virus infection in Libya

Introduction

North Africa is known to be endemic for hepatitis D virus. However, data one the prevalence of this virus in Libya are scanty. This study aimed to determine the prevalence of hepatitis D virus infection in Libya and analyze the demographic factors associated with the infection, and also to assess the variations across the regions and districts.

Methods

A total of 1873 samples collected from all over the country were tested for antibodies against hepatitis B surface antigen and the results were correlated with demographic and geographic variables.

Results

The overall prevalence of hepatitis D virus infection was 1.7%. The prevalence rate was significantly high among those aged over 40 years (P < 0.001) and it was associated with intravenous drug use and coinfection with human immunodeficiency virus and/or hepatitis C virus infection (P < 0.001). The prevalence rates varied with geographic location and differed markedly within the regions the country. The highest rate reported was in the central region of Libya, followed by the western and eastern regions.

Conclusion

Hepatitis D virus infection rate in Libya is considered to be low but is of some concern in some districts. This has been propagated by population displacement and African immigrants, indicating that a continuous epidemiological surveillance program should be implemented.

Ongoing evolution of hepatitis B virus during viremia in patients with febrile in Central Africa

Hepatitis B virus (HBV) infection remains to be a major public health issue worldwide, although there is currently a safe vaccine and effective antiviral treatments. In surveillance of infectious diseases in Gabon, HBV viremia was detected in patients with febrile. Whole-genome sequencing was conducted to characterize the HBV strains currently circulating in Gabon and to investigate HBV genome diversity during viremia. Phylogenetic analysis revealed the existence of former subgenotype A5, which exhibits a particular pattern of distribution from several West and Central African countries to Haiti. Furthermore, sequencing analysis identified two similar HBV strains mixed in one sample, and a very rare 1-base pair insertion in the viral precore region. This insertion caused a frameshift mutation, indicating the production of an aberrant fusion protein of the HBV x and e antigens. Our data showed that the detected HBV strain was possibly in an "evolving" state during viremia, a phase of active replication.

High prevalence and diversity of hepatitis B and hepatitis delta virus in Gabon

Although central Africa is classified as having a high endemicity of hepatitis B virus (HBV) and hepatitis D virus (HDV) infection, there is paucity of prevalence studies. For the first time on a country-wide level in Central Africa, we show in Gabon an overall 7.4% prevalence of Hepatitis B surface antigen (HBsAg) and that more than 25% of the HBsAg-positive population are infected by HDV. Although HBV prevalence did not differ significantly between provinces, there is a north-south split in the distribution of HDV seroprevalence, with the highest rates (>66.0%) correlating with the presence of specific ethnic groups in the northeastern provinces. Genotyping revealed high genetic diversity of the HBV and HDV strains circulating in Gabon, including many restricted to this region of the globe. This work confirmed that high exposure to HBV and HDV infection reported in selected regions of Gabon holds true across the whole country.

High prevalence of hepatitis delta virus in Cameroon

Hepatitis delta virus (HDV), a satellite virus of hepatitis B virus (HBV), infects an estimated 15–20 million people worldwide and confers a greater risk for accelerated progression to liver disease. However, limited HDV surveillance data are available in sub-Saharan Africa where HDV diversity is high. To determine the prevalence and diversity of HDV in Cameroon, serological and molecular characterization was performed on 1928 HBsAg positive specimens selected from retrospective viral surveillance studies conducted in Cameroon from 2010–2016. Samples were screened for HDV antibodies on the Abbott ARCHITECT instrument and for HDV RNA on the Abbott m2000 instrument by research assays. HDV positive specimens with sufficient viral load were selected for genomic sequencing. The seroprevalence of HDV in HBsAg positive samples from Cameroon was 46.73% [95% CI; 44.51–48.96%], with prevalence of active HDV infection being 34.2% [95% CI; 32.09–36.41%]. HDV genotypes 1, 6, 7 and 8 were identified amongst N = 211 sequences, including N = 145 genomes. HDV prevalence is high within the study cohort, indicating that a large portion of HBV infected individuals in Cameroon are at elevated risk for severe hepatitis and death. Collectively, these results emphasize the need for HBV vaccination and HDV testing in HBsAg positive patients in Cameroon.

Clinical and virological heterogeneity of hepatitis delta in different regions world-wide: The Hepatitis Delta International Network (HDIN)

BACKGROUND & AIMS

Chronic hepatitis D (delta) is a major global health burden. Clinical and virological characteristics of patients with hepatitis D virus (HDV) infection and treatment approaches in different regions world-wide are poorly defined.

METHODS

The Hepatitis Delta International Network (HDIN) registry was established in 2011 with centres in Europe, Asia, North- and South America. Here, we report on clinical/ virological characteristics of the first 1576 patients with ongoing or past HDV infection included in the database until October 2016 and performed a retrospective outcome analysis. The primary aim was to investigate if the region of origin was associated with HDV replication and clinical outcome.

RESULTS

The majority of patients was male (n = 979, 62%) and the mean age was 36.7 years (range 1-79, with 9% of patients younger than 20 years). Most patients were HBeAg-negative (77%) and HDV-RNA positive (85%). Cirrhosis was reported in 48.7% of cases which included 13% of patients with previous or ongoing liver decompensation. Hepatocellular carcinoma (HCC) developed in 30 patients (2.5%) and 44 (3.6%) underwent liver transplantation. Regions of origin were independently associated with clinical endpoints and detectability of HDV RNA. Antiviral therapy was administered to 356 patients with different treatment uptakes in different regions. Of these, 264 patients were treated with interferon-a and 92 were treated with HBV-Nucs only.

CONCLUSIONS

The HDIN registry confirms the severity of hepatitis delta but also highlights the heterogeneity of patient characteristics and clinical outcomes in different regions. There is an urgent need for novel treatment options for HDV infection.

Prevalent hepatitis B surface antigen among first-time blood donors in Gabon

Despite chronic Hepatitis B virus (HBV) infection being the main cause of younger-onset complex liver disease including cirrhosis and hepatocellular carcinoma (HCC) in Africa, very little is known regarding the seroprevalence of HBV in the Gabonese general population. This investigation aimed to provide strong epidemiological data and risk factors associated with HBV infection in first-time blood donors representative of the urban adult population. The screening of HBsAg was carried out using 4th generation ELISA kits. The overall seroprevalence of HBsAg was 7.28%. The frequency of HBsAg was differential and marked by annual variations in blood donors from 2009 to 2016. Seroprevalence was 2-fold higher among males versus females (OR = 1.90 (95% CI: 1.75-2.06), P<0.001). HBsAg seroprevalence was significantly higher in donors of the age group 25-35 years old compared to donors of the age group <18 years (OR = 1.64 (95% CI: 1.03-2.60), P = 0.04). The seroprevalence of HBsAg in family/replacement donors (FRD) was significantly higher than that of voluntary non-remunerated donors (VNRD) (OR = 0.88 (95% CI: 0.83-0.94), P <0.001). The simultaneous comparison of HBsAg seroprevalence with blood donation type, gender and age showed that the higher prevalence in FRD was significant only in males between 18 and 45 years and in females between 25 and 34 years of age. This study confirms the high endemicity of HBV in Gabon while identifying the most infected age groups for both men and women.

Prevalence of hepatitis D virus infection in sub-Saharan Africa: a systematic review and meta-analysis

BACKGROUND

Hepatitis D virus (also known as hepatitis delta virus) can establish a persistent infection in people with chronic hepatitis B, leading to accelerated progression of liver disease. In sub-Saharan Africa, where HBsAg prevalence is higher than 8%, hepatitis D virus might represent an important additive cause of chronic liver disease. We aimed to establish the prevalence of hepatitis D virus among HBsAg-positive populations in sub-Saharan Africa.

METHODS

We systematically reviewed studies of hepatitis D virus prevalence among HBsAg-positive populations in sub-Saharan Africa. We searched PubMed, Embase, and Scopus for papers published between Jan 1, 1995, and Aug 30, 2016, in which patient selection criteria and geographical setting were described. Search strings included sub-Saharan Africa, the countries therein, and permutations of hepatitis D virus. Cohort data were also added from HIV-positive populations in Malawi and Ghana. Populations undergoing assessment in liver disease clinics and those sampled from other populations (defined as general populations) were analysed. We did a meta-analysis with a DerSimonian-Laird random-effects model to calculate a pooled estimate of hepatitis D virus seroprevalence.

FINDINGS

Of 374 studies identified by our search, 30 were included in our study, only eight of which included detection of hepatitis D virus RNA among anti-hepatitis D virus seropositive participants. In west Africa, the pooled seroprevalence of hepatitis D virus was 7·33% (95% CI 3·55-12·20) in general populations and 9·57% (2·31-20·43) in liver-disease populations. In central Africa, seroprevalence was 25·64% (12·09-42·00) in general populations and 37·77% (12·13-67·54) in liver-disease populations. In east and southern Africa, seroprevalence was 0·05% (0·00-1·78) in general populations. The odds ratio for anti-hepatitis D virus detection among HBsAg-positive patients with liver fibrosis or hepatocellular carcinoma was 5·24 (95% CI 2·74-10·01; p<0·0001) relative to asymptomatic controls.

INTERPRETATION

Findings suggest localised clusters of hepatitis D virus endemicity across sub-Saharan Africa. Epidemiological data are needed from southern and east Africa, and from patients with established liver disease. Further studies should aim to define the reliability of hepatitis D virus testing methods, identify risk factors for transmission, and characterise the natural history of the infection in the region.

FUNDING

Wellcome Trust, Royal Society.

Hepatitis B infection among HIV infected individuals in Gabon: Occult hepatitis B enhances HBV DNA prevalence

In Gabon, a central African country, human immunodeficiency virus (HIV) and hepatitis B virus (HBV) are endemic. In a recent study, conducted in a semi-urban area (Franceville, Gabon), HBV infection was found to be more prevalent among HIV infected individuals. This study aims to investigate the prevalence and genetic diversity of hepatitis B virus infection among HIV infected individuals, predominantly under antiretroviral therapy, living in fully urbanized area: Libreville, capital of Gabon. Serological and molecular tests were performed to detect HBV infection among patients living with HIV/AIDS (PLHA). We used Monolisa HBsAg ULTRA, Anti-HBc Plus and Anti-HBs Plus EIA kits for serological analyses. HBV DNA viral load (HBV DNA VL) was determined by real time PCR and molecular characterization of HBV strains was performed by sequencing and phylogenetic analysis of partial HBV surface and core genes. At all, 70.2% of patients were under antiretroviral therapy. The prevalence of HBsAg was 8.8% (43/487). Detectable HBV DNA was found in 69.7% (30/43) of HBsAg positive patients and in 17.5% (24/137) HBsAg negative patients. HBV DNA VL was significantly higher among patient with CD4 cell counts less than 200 cells/mm³ than those with CD4 cell counts greater than 500 cells/mm³ (p = 0.008). We confirmed the presence of HBV sub-genotypes QS-A3 (40%), and A4 (20%) and HBV-E genotype (40%). The percentage of resistance to Lamivudine was high (40%) and varied according to the M204V/I motif. Occult hepatitis B infection (OBI) was found in patients with isolated HBcAb and among patients who had completed their HBsAg seroconversion. We detected HBV DNA for one patient without any HBV serological marker. This study provides a new landmark for the comprehension of HBV infection in PLHA in urban areas. OBI enhances HBV DNA prevalence and should be investigated in all HBsAg negative individuals.

Host genes regulate transcription of sperm-introduced hepatitis B virus genes in embryo

Hepatitis B virus (HBV) can invade the male germline, and sperm-introduced HBV genes could be transcribed in embryo. This study was to explore whether viral gene transcription is regulated by host genes. Embryos were produced by in vitro fertilization of hamster oocytes with human sperm containing the HBV genome. Total RNA extracted from test and control embryos were subjected to SMART-PCR, SSH, microarray hybridization, sequencing and BLAST analysis. Twenty-nine sequences showing significant identity to five human gene families were identified, with CSH2, EIF4G2, PCBD2, PSG4 and TTN selected to represent target genes. Using qRT-PCR, when CSH2 and PCBD2 (or EIF4G2, PSG4 and TTN) were silenced by RNAi, transcriptional levels of HBV s and x genes decreased (or increased). This is the first report that host genes participate in regulation of sperm-introduced HBV gene transcription in embryo, which is critical to prevent negative impact of HBV infection on early embryonic development.

Hepatitis Delta Virus: Replication Strategy and Upcoming Therapeutic Options for a Neglected Human Pathogen

The human Hepatitis Delta Virus (HDV) is unique among all viral pathogens. Encoding only one protein (Hepatitis Delta Antigen; HDAg) within its viroid-like self-complementary RNA, HDV constitutes the smallest known virus in the animal kingdom. To disseminate in its host, HDV depends on a helper virus, the human Hepatitis B virus (HBV), which provides the envelope proteins required for HDV assembly. HDV affects an estimated 15-20 million out of the 240 million chronic HBV-carriers and disperses unequally in disparate geographical regions of the world. The disease it causes (chronic Hepatitis D) presents as the most severe form of viral hepatitis, leading to accelerated progression of liver dysfunction including cirrhosis and hepatocellular carcinoma and a high mortality rate. The lack of approved drugs interfering with specific steps of HDV replication poses a high burden for gaining insights into the molecular biology of the virus and, consequently, the development of specific novel medications that resiliently control HDV replication or, in the best case, functionally cure HDV infection or HBV/HDV co-infection. This review summarizes our current knowledge of HBV molecular biology, presents an update on novel cell culture and animal models to study the virus and provides updates on the clinical development of the three developmental drugs Lonafarnib, REP2139-Ca and Myrcludex B.

High Prevalence and Diversity of Hepatitis Viruses in Suspected Cases of Yellow Fever in the Democratic Republic of Congo

The majority of patients with acute febrile jaundice (>95%) identified through a yellow fever surveillance program in the Democratic Republic of Congo (DRC) test negative for antibodies against yellow fever virus. However, no etiological investigation has ever been carried out on these patients. Here, we tested for hepatitis A (HAV), hepatitis B (HBV), hepatitis C (HCV), hepatitis D (HDV), and hepatitis E (HEV) viruses, all of which can cause acute febrile jaundice, in patients included in the yellow fever surveillance program in the DRC. On a total of 498 serum samples collected from suspected cases of yellow fever from January 2003 to January 2012, enzyme-linked immunosorbent assay (ELISA) techniques were used to screen for antibodies against HAV (IgM) and HEV (IgM) and for antigens and antibodies against HBV (HBsAg and anti-hepatitis B core protein [HBc] IgM, respectively), HCV, and HDV. Viral loads and genotypes were determined for HBV and HVD. Viral hepatitis serological markers were diagnosed in 218 (43.7%) patients. The seroprevalences were 16.7% for HAV, 24.6% for HBV, 2.3% for HCV, and 10.4% for HEV, and 26.1% of HBV-positive patients were also infected with HDV. Median viral loads were 4.19 × 10⁵ IU/ml for HBV (range, 769 to 9.82 × 10⁹ IU/ml) and 1.4 × 10⁶ IU/ml for HDV (range, 3.1 × 10² to 2.9 × 10⁸ IU/ml). Genotypes A, E, and D of HBV and genotype 1 of HDV were detected. These high hepatitis prevalence rates highlight the necessity to include screening for hepatitis viruses in the yellow fever surveillance program in the DRC.

Hepatitis delta virus: insights into a peculiar pathogen and novel treatment options

Chronic hepatitis D is the most severe form of viral hepatitis, affecting ∼20 million HBV-infected people worldwide. The causative agent, hepatitis delta virus (HDV), is a unique human pathogen: it is the smallest known virus; it depends on HBV to disseminate its viroid-like RNA; it encodes only one protein (HDAg), which has both structural and regulatory functions; and it replicates using predominantly host proteins. The failure of HBV-specific nucleoside analogues to suppress the HBV helper function, and the limitations of experimental systems to study the HDV life cycle, have impeded the development of HDV-specific drugs. Thus, the only clinical regimen for HDV is IFNα, which shows some efficacy but long-term virological responses are rare. Insights into the receptor-mediated entry of HDV, and the observation that HDV assembly requires farnesyltransferase, have enabled novel therapeutic strategies to be developed. Interference with entry, for example through blockade of the HBV-HDV-specific receptor sodium/taurocholate cotransporting polypeptide NTCP by Myrcludex B, and inhibition of assembly by blockade of farnesyltransferase using lonafarnib or nucleic acid polymers such as REP 2139-Ca, have shown promising results in phase II studies. In this Review, we summarize our knowledge of HDV epidemiology, pathogenesis and molecular biology, with a particular emphasis on possible future developments.

The hepatitis delta genotype 8 in Northeast Brazil: The North Atlantic slave trade as the potential route for infection

Hepatitis Delta virus (HDV) is not well known, even though HDV and Hepatitis B virus (HBV) co-infection leads to severe forms of acute and chronic liver diseases. HDV is endemic in the Western Amazon region. Recently, the HDV genotype 8 was found in chronic patients followed at the center for liver studies in the Northeast Brazil, Maranhão. Previous studies suggested that this genotype was introduced in Maranhão during the slave trade. The presence of HDV in that study, which was done outside the Amazon region, led us to investigate whether the virus is found infecting individuals in other regions of Maranhão as well. Thus, we screened ninety-two HBsAg positive individuals from five Municipalities of Maranhão for anti-HD antibody and eight were found positive (8.7%). These eight positive individuals were submitted to polymerase chain reaction (PCR) to investigate active HDV infection. Half of them were positive for a fragment sequence of the delta antigen; their sequence samples were submitted to genotype characterization by phylogenetic analysis. All sequences clustered in a unique branch of the tree separated from the other branch described in Africa. Our study confirmed the presence of HDV-8 in Maranhão. These infected individuals had no evidence of contact with African people. Furthermore, we found individuals infected with HDV-8 in two more different municipalities. More studies like ours are urgent because the co-infection HBV/HDV is more difficult to treat. Identification of the endemic regions and implementation of healthy policies for preventing this infection are urgent in this region.