Epidemiological and clinical evaluation of hepatitis B, hepatitis C, and delta hepatitis viruses in Tajikistan

The distinct spatiotemporal evolutionary landscape of HBV and HDV largely determines the unique epidemic features of HDV globally

Chronic infection of hepatitis B virus (HBV) and hepatitis D virus (HDV) causes the most severe form of viral hepatitis. Due to the dependence on HBV, HDV was deemed to co-evolve and co-migrate with HBV. However, we previously found that the naturally occurred HDV/HBV combinations do not always reflect the most efficient virological adaptation (Wang et al., 2021). Moreover, regions with heavy HBV burden do not always correlate with high HDV prevalence (e.g., East Asia), and vice versa (e.g., Central Asia). Herein, we systematically elucidated the spatiotemporal evolutionary landscape of HDV to understand the unique epidemic features of HDV. We found that the MRCA of HDV was from South America around the late 13th century, was globally dispersed mainly via Central Asia, and evolved into eight genotypes from the 19th to 20th century. In contrast, the MRCA of HBV was from Europe ∼23.7 thousand years ago (Kya), globally dispersed mainly via Africa and East Asia, and evolved into eight genotypes ∼1100 years ago. When HDV stepped in, all present-day HBV genotypes had already formed and its global genotypic distribution had stayed stable geographically. Nevertheless, regionalized HDV adapted to local HBV genotypes and human lineages, contributing to the global geographical separation of HDV genotypes. Additionally, a sharp increase in HDV infections was observed after the 20th century. In conclusion, HDV exhibited a distinct spatiotemporal distribution path compared with HBV. This unique evolutionary relationship largely fostered the unique epidemic features we observe nowadays. Moreover, HDV infections may continue to ramp up globally, thus more efforts are urgently needed to combat this disease.

What Is the Real Epidemiology of Hepatitis D Virus and Why so Many Mixed Messages?

The disease burden of HDV is poorly understood. Our review identified multiple reasons: (1) HDV infection rates are overestimated in the general population due to limited sample sizes, sampling high-risk populations, and significant regional variations, (2) estimates are based on chronic HBV populations, but HBV burden itself is uncertain, (3) there is a lack of testing in at-risk populations, (4) prevalence testing is based on HDV antibody testing and not HDV RNA, which distinguishes between active infection versus prior exposure, (5) older studies used less reliable testing and (6) HBV vaccination programs have affected HDV prevalence, but is often not accounted for.

Hepatitis delta: Epidemiology to recent advances in therapeutic agents

Hepatitis D virus (HDV) was first described in 1977 and is dependent on the presence of hepatitis B surface antigen (HBsAg) for its entry into cells and on the human host for replication. Due to the envelopment with the hepatitis B virus (HBV) envelope, early phases of HDV entry resemble HBV infection. Unlike HBV, HDV activates innate immune responses. The global prevalence of HDV is estimated to be about 5% of HBsAg positive individuals. However, recent studies have described a wide range of prevalence between 12 to 72 million individuals. Infection can occur as super-infection or co-infection. The diagnosis of active HDV infection involves screening with anti HDV antibodies followed by quantitative PCR testing for HDV RNA in those who are HBsAg positive. The diagnostic studies have evolved over the years improving the validity and reliability of the tests performed. HDV infection is considered the most severe form of viral hepatitis and the HDV genotype may influence the disease course. There are eight major HDV genotypes with prevalence varying by geographic region. HDV treatment has been challenging as HDV strongly depends on the host cell for replication and provides few, if any viral targets. Better understanding of HDV virology has led to the development of several therapeutic agents currently being studied in different phase II and III clinical trials. There is increasing promise of effective therapies that will ameliorate the course of this devastating disease.

A Recent Prevalence of Hepatitis B Virus (HBV) Genotypes and Subtypes in Asia: A Systematic Review and Meta-Analysis

Background and Aim: Despite introducing the hepatitis B virus (HBV) vaccine, the incidence of the Hepatitis B virus globally is still a major health concern. This systematic review and meta-analysis were conducted to provide detailed information on the prevalence of HBV genotypes and subtypes in circulation in Asia. Methods: A systematic search for articles describing the prevalence of HBV genotypes and subtypes in Asia was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) guidelines. Results: Our search returned 207 eligible articles involving 49,279 genotypes and 7457 subtypes representing 28 Asian countries. A meta-analysis was performed on our eligible studies using the Random effect Model. The pooled prevalence of HBV genotypes showed that genotype C (30.9%) (95% CI, 27.5–34.5%; I2 = 97.57%; p < 0.001) was the most common HBV genotype in Asia, followed by genotype B (17.8%) (95% CI, 15.5–20.4%; I2 = 97.26%; p < 0.001) and genotype D (15.4%) (95% CI, 11.8–19.8%). Vietnam had the highest prevalence of genotype B, Lebanon had the highest prevalence of genotypes C, and Jordan had the highest prevalence of genotype D. There was variation in genotypic prevalence with respect to the target genes for HBV genotyping. Reverse dot blot hybridization had the highest estimate of genotypes B and C. HBV subtype C2 (40.0%) (95% CI, 33.3–47.0) is the most prevalent HBV subtype. Conclusion: Evidence from this study reveals that HBV genotypes C and B are the most dominant HBV genotypes in Asia, and HBV subtype C2 is more endemic in Asia.

Magnitude and genotype of hepatitis delta virus among chronic hepatitis B carriers with a spectrum of liver diseases in Ethiopia

INTRODUCTION AND OBJECTIVES

Chronic hepatitis D infection contributes substantially to the progression of chronic liver disease, especially in most low and middle-income countries, where hepatitis B virus-related chronic liver disease is endemic. Therefore, this study aimed to determine the magnitude and genotype of hepatitis delta virus (HDV) among patients with chronic hepatitis B (CHB)-related liver diseases in Ethiopia.

PATIENTS AND METHODS

In this cross-sectional study, 323 known HBsAg positive individuals comprising 220 patients with CHB-related liver diseases [121 advanced liver diseases (hepatocellular carcinoma /HCC/ and non-HCC) and 99 chronic hepatitis (CH)], and 103 symptomless blood donors (BD) were enrolled. An ELISA kit was employed to determine HDV infection, and quantitative real-time PCR was used to detect HDV RNA. In addition, a non-coding genomic RNA region was sequenced for genotyping and phylogenetic analysis.

RESULTS

Irrespective of the stage of liver disease, the overall magnitude of HDV was 7.7% (25/323). The frequency of anti-HDV increases with the severity of liver disease, 1.9%, 4%, 10%, and 21.3% among BD, CH, non-HCC, and HCC patients, respectively. HDV RNA has been detected in 1.54 %(5/323) cases with a mean viral load of 4,010,360 IU/ml. All isolates were found to be HDV genotype 1.

CONCLUSIONS

The magnitude of HDV infection increased with the severity of liver disease, indicating HDV infection is more common among patients with CHB-related liver diseases in Ethiopia.

The global hepatitis delta virus (HDV) epidemic: what gaps to address in order to mount a public health response?

BACKGROUND

Co-infection between hepatitis B virus (HBV) and hepatitis delta virus (HDV) causes the severest chronic hepatitis and is associated with a high risk of cirrhosis and hepatocellular carcinoma (HCC). The Global Health Sector Strategy on Viral Hepatitis called for the elimination of hepatitis (- 65% mortality and - 90% incidence) by 2030. Our aims were to summarize key points of knowledge and to identify the gaps that need to be addressed to mount a public health response to HDV.

METHODS

We performed a current literature review in terms of epidemiology by WHO regions, genotypes distribution and their pathogenicity, factors associated with HDV infection, mortality due to HDV infection, testing strategies and treatment.

RESULTS

Prevalence of infection and genotypes are heterogeneous distributed, with highest prevalence in foci around the Mediterranean, in the Middle East, and in Central, Northern Asia and Eastern Asia. Persons who inject drugs (PWID) and migrants from highly endemic areas are highly affected. While antibody detection tests are available, HDV RNA tests of current infection are not standardized nor widely available. The few therapeutic options, including lofartinib, are not widely available; however several new and promising agents have entered clinical trials.

CONCLUSION

HDV infection is an poorly known cause of chronic liver disease. To mount a public health response, we need a better description of the HDV epidemic, standardized testing strategies and better treatment options.

Frequency of Hepatitis C Virus Genotypes in Patients Who Had Hepatocellular Carcinoma in Gastroenterological Hospitals of Tabriz

BACKGROUND

Generally, hepatitis C has been identified as one of the major health issues that about 3% of the world's population have been threatened and affected by it (about 170 million people), and also, it can be considered a factor in acute and chronic hepatitis.

METHODS

The aim of this study is to determine the prevalence of HCV genotypes in Azerbaijan patients. In this study, sampling was done on the referred patients to the hospitals (Mahallati and Behbud Hospital). RNA was extracted after isolation of plasma, and then, after the synthesizing of cDNA, the sample was carried out to the laboratory for performing the real-time PCR in order to determine the genotypes.

RESULTS

The evaluation of HCV genotypes in positive plasma samples showed that dominant subsets were remarkable and the mean age of the patients was 37/3 ± 11/8 (in the age range of 2-63). Among the 235 patients,139 of them (59%) were male. Statistically, the average number of women was more than men (T test, P < 0/05). 1b genotype was reported 70% in the patients above 40 years old, and also, it was reported as 71/6% in the patients under 40 years old that was not statistically significant. The incidence of serotype 3a was higher among the patients younger than 40 years old (3a was 18.1% vs. 15%), and this serotype was prevalent among men (3a was 18.7% vs. 14.6%), which was statistically significant.

CONCLUSION

The findings indicate that among Azerbaijan's patients with chronic hepatitis C, genotypes 1b (71.1%) and 3a (17%) were dominant.

The changing context of hepatitis D

The global epidemiology of hepatitis D is changing with the widespread implementation of vaccination against hepatitis B. In high-income countries that achieved optimal control of HBV, the epidemiology of hepatitis D is dual, consisting of an ageing cohort of domestic patients with advanced liver fibrosis who represent the end stage of the natural history of HDV, and of a younger generation of immigrants from endemic countries who account for the majority of new infections. As observed in Europe in the 1980s, the distinctive clinical characteristic of chronic hepatitis D in endemic countries is the accelerated progression to cirrhosis and hepatocellular carcinoma. Despite some recent progress, the therapeutic management of HDV remains unsatisfactory, as most patients are not cured of HDV with currently available medicines. This review article describes the current epidemiology and clinical features of chronic hepatitis D, based on the literature published in the last 10 years.

Transmission of HIV and HCV within Former Soviet Union Countries

BACKGROUND

Following the collapse of the Union of Soviet Socialist Republic (USSR) in 1991, trans-border mobility increased within the former Soviet Union (FSU) countries. In addition, drug-trafficking and injection drug use began to rise, leading to the propagation and transmission of blood-borne infections within and across the FSU countries. To examine the transmission of blood-borne infections within this region, we analyzed the phylogenetic relationship of publically available sequences of two blood-borne viruses, hepatitis C virus (HCV) and human immunodeficiency virus (HIV), from FSU countries.

METHODS

We analysed 614 and 295 NS5B sequences from HCV genotypes 1b and 3a, respectively, from 9 FSU countries. From 13 FSU countries, we analysed 347 HIV gag and 1282 HIV env sequences. To examine transmission networks and the origins of infection, respectively, phylogenetic and Bayesian analyses were performed.

RESULTS

Our analysis shows intermixing of HCV and HIV sequences, suggesting transmission of these viruses both within and across FSU countries. We show involvement of three major populations in transmission: injection drug user, heterosexual, and trans-border migrants.

CONCLUSION

This study highlights the need to focus harm reduction efforts toward controlling transmission of blood-borne infections among the abovementioned high-risk populations in the FSU countries.

The epidemiology of hepatitis C virus in Central Asia: Systematic review, meta-analyses, and meta-regression analyses

The objective was to delineate hepatitis C virus (HCV) epidemiology in countries of Central Asia (CA), specifically Kazakhstan, Kyrgyzstan, Tajikistan, Turkmenistan, and Uzbekistan. A systematic review was conducted guided by the Cochrane Collaboration Handbook, and reported using PRISMA guidelines. Meta-analyses were performed using DerSimonian-Laird random-effects models with inverse variance weighting. Random-effects meta-regression analyses were performed on general population studies. The systematic review identified a total of 208 HCV prevalence measures. No incidence or Turkmenistan studies were identified. Meta-analyses estimated HCV prevalence among the general population at 0.7% (95%CI: 0.7-0.8%) in Kazakhstan, 2.0% (95%CI: 1.7-2.4%) in Kyrgyzstan, 2.6% (95%CI: 1.7-3.6%) in Tajikistan, and 9.6 (95%CI: 5.8-14.2%) in Uzbekistan. Across CA, the pooled mean prevalence was 13.5% (95%CI: 10.9-16.4%) among non-specific clinical populations, 31.6% (95%CI: 25.8-37.7%) among populations with liver-related conditions, and 51.3% (95%CI: 46.9-55.6%) among people who inject drugs. Genotypes 1 (52.6%) and 3 (38.0%) were most frequent. Evidence was found for statistically-significant differences in prevalence by country, but not for a temporal decline in prevalence. CA is one of the most affected regions by HCV infection with Uzbekistan enduring one of the highest prevalence levels worldwide. Ongoing HCV transmission seems to be driven by injecting drug use and healthcare exposures.

Hepatitis C virus subtype 3a was introduced in the USSR in the early 1980s

A total of 2120 nucleotide sequences of the NS5b region of HCV subtype 3a were analysed, including 310 strains derived from former republics of the USSR (Azerbaijan, Estonia, Lithuania, Russia, Tajikistan and Uzbekistan). Among the viral isolates collected from former regions of the Soviet Union, 294 strains formed 3 sustained phylogenetic clusters, with each having a common origin. Phylodynamic analysis demonstrated that the most recent common ancestors of the current strains inside the three clusters were introduced into the USSR population in 1981±1, 1984±2 and 1985±2, respectively (the confidence intervals were calculated using Student's t-distribution, P<0.05). The time estimation obtained for HCV subtype 3a correlated well with the historical and epidemiological context of this period, and in particular with the start of widespread injection drug use in the USSR in the first half of the 1980s.

MOLECULAR-BIOLOGICAL MARKERS OF HEPATITIS В IN PATIENTS WITH LIVER FIBROSIS/CIRRHOSIS IN UZBEKISTAN

Aim. Evaluate prevalence of genetic variants of hepatitis В viruses in population of various regions of Uzbekistan with hepatitis of various genesis and different severity levels of liver fibrosis and cirrhosis. Materials and methods. Blood plasma and liver biopsy from 39 patients with different severity levels of liver fibrosis and cirrhosis served as study material. Genotyping based on direct sequencing of Pre-Sl/Pre-S2/S HBV DNA region was applied. Results. Hepatitis В virus was detected in 32 samples ofthe 39 provided, frequency of occurrence - 82%, respectively. Phylogenetic analysis has shown, that only genotype D was detected among the examined patients, hepatitis В virus subtype D1 predominated (84.38%) compared with D2 (3.12%) and D3 (12.5%) subtypes. Conclusion. Large-scale sequencing of HBV in Central Asia will allow to evaluate routes of transmission and time of evolutionary separation of virus isolates. Understanding the epidemiology of the infectious process is important for development of programs for prophylaxis and therapy of the infection.

Substantial decline in hepatitis B virus infections following vaccine introduction in Tajikistan

BACKGROUND

Tajikistan, considered highly endemic area for hepatitis B virus (HBV) in a pre-vaccine era, introduced hepatitis B vaccine in 2002 and reported ≥80% coverage with three doses of hepatitis B vaccine (HepB3) since 2004. However, the impact of vaccine introduction has not been assessed.

METHODS

We tested residual serum specimens from a 2010 national serosurvey for vaccine-preventable diseases in Tajikistan and assessed the prevalence of HBV infection across groups defined based on the birth cohorts' routine infant hepatitis B vaccination program implementation and HepB3 coverage achieved (≥80% versus <80%). Serosurvey participants were selected through stratified multi-stage cluster sampling among residents of all regions of Tajikistan aged 1-24 years. All specimens were tested for antibodies against HBV core antigen (anti-HBc) and those found positive were tested for HBV surface antigen (HBsAg). Seroprevalence and 95% confidence intervals were calculated and compared across subgroups using Satterthwaite-adjusted chi-square tests, accounting for the survey design and sampling weights.

RESULTS

A total of 2188 samples were tested. Prevalence of HBV infection markers was lowest among cohorts with ≥80% HepB3 coverage (ages, 1-6 years): 2.1% (95% confidence interval, 1.1-4.3%) for anti-HBc, 0.4% (0.1-1.3%) for HBsAg, followed by 7.2% (4.1-12.4%) for anti-HBc and 2.1% (0.7-6.1%) for HBsAg among cohorts with <80% HepB3 coverage (ages, 7-8 years), by 12.0% (8.7-16.3%) for anti-HBc and 3.5% (2.2-5.6%) for HBsAg among children's cohorts not targeted for vaccination (ages, 9-14 years), and 28.9% (24.5-33.8%) for anti-HBc and 6.8% (4.5-10.1%) for HBsAg among unvaccinated adult cohorts (ages, 15-24 years). Differences across groups were significant (p<0.001, chi-square) for both markers.

CONCLUSIONS

The present study demonstrates substantial impact of hepatitis B vaccine introduction on reducing HBV infections in Tajikistan. To achieve further progress in hepatitis B control, Tajikistan should maintain high routine coverage with hepatitis B vaccine, including birth dose.

Hepatitis D Virus: Introduction and Epidemiology

Hepatitis D is caused by the hepatitis D virus (HDV), a unique RNA pathogen that requires the hepatitis B surface antigen (HBsAg) to infect. Hepatitis D is transmitted by the parenteral route. The main susceptible group is patients with chronic HBsAg infection who become superinfected with the virus. Hepatitis D occurs throughout the globe, but control of hepatitis B virus (HBV) in the last two decades has consistently diminished the circulation of HDV in industrialized countries. However, hepatitis D remains a medical issue for injecting drug users (IDUs), as well as immigrants from endemic HDV areas, who are reintroducing the infection in Europe.

Genotypes and viral variants in chronic hepatitis B: A review of epidemiology and clinical relevance

The Hepatitis B Virus (HBV) has a worldwide distribution and is endemic in many populations. It is constantly evolving and 10 genotypic strains have been identified with varying prevalences in different geographic regions. Numerous stable mutations in the core gene and in the surface gene of the HBV have also been identified in untreated HBV populations. The genotypes and viral variants have been associated with certain clinical features of HBV related liver disease and Hepatocellular carcinoma. For example Genotype C is associated with later hepatitis B e antigen (HBeAg) seroconversion, and more advanced liver disease. Genotype A is associated with a greater risk of progression to chronicity in adult acquired HBV infections. Genotype D is particularly associated with the precore mutation and HBeAg negative chronic hepatitis B (CHB). The genotypes prevalent in parts of West Africa, Central and South America, E, F and H respectively, are less well studied. Viral variants especially the Basal Core Promotor mutation is associated with increased risk of fibrosis and cancer of the liver. Although not currently part of routine clinical care, evaluation of genotype and viral variants may provide useful adjunctive information in predicting risk about liver related morbidity in patients with CHB.

Prevalence of hepatitis D virus infection among hepatitis B virus-infected individuals in India

BACKGROUND

The prevalence of hepatitis D virus (HDV) infection among persons with hepatitis B virus (HBV) infection shows geographic variation and has declined in recent times in several regions. In India, studies during the 1990s showed highly variable anti-HDV prevalence rates among HBV-infected persons; however, data using molecular testing and recent data are not available. We therefore studied the prevalence of HDV infection in HBV-infected patients using tests for anti-HDV and HDV ribonucleic acid (RNA).

METHODS

Two cohorts of patients with HBV infection were enrolled (cohort A, n = 150, January to December 2012; cohort B, n = 168, October 2013 to April 2014). Sera from cohort A were tested for IgG anti-HDV using three enzyme immunoassays and those from cohort B for IgG anti-HDV using an enzyme immunoassay and for HDV RNA using a real-time amplification assay.

RESULTS

Of the 318 subjects (259 male; mean age 36.9 years), 161 (50.6 %) had chronic hepatitis B, 101 (31.8 %) had cirrhosis, 52 (16.3 %) had acute viral hepatitis, and 4 (1.3 %) had acute liver failure. In cohort A, all specimens tested negative for anti-HDV antibodies using all the three assays. In cohort B, all specimens tested negative for anti-HDV IgG as well as HDV RNA.

CONCLUSION

Our data indicate that HDV infection is uncommon in northern India.

Distribution of hepatitis B virus genotypes in azerbaijani patients with chronic hepatitis B infection

BACKGROUND

Hepatitis B virus (HBV) has been classified into ten genotypes (A-J) based on genome sequence divergence, which is very important for etiological and clinical investigations. HBV genotypes have distinct geographical distributions worldwide.

OBJECTIVES

The aim of this study was to investigate the distribution of HBV genotypes among Azerbaijani patients with chronic hepatitis B, came from the Republic of Azerbaijan country to Iran to receive medical care.

PATIENTS AND METHODS

One hundred and three patients with chronic HBV infection, referred to hospitals related to Iran University of Medical Sciences and Tehran Hepatitis Center from August 2011 to July 2014, were enrolled in this cross sectional study. About 3-milliliter of peripheral blood was taken from each patient. After viral DNA extraction, HBV genotypes were tested using the INNO-LiPA™ HBV kit (Innogenetics, Ghent, Belgium). HBV genotyping was confirmed using sequencing of hepatitis B surface antigen (HBsAg) and polymerase (pol) regions of HBV.

RESULTS

The mean age of patients was 35.9 ± 11.7 years (19-66). Of 103 patients, 72 (69.9%) were male. In the present study, the predominant HBV genotype was D (93.2%) followed by genotype A (5.8%) and concurrent infection with A and D genotypes (0.97%).

CONCLUSIONS

The main and frequent HBV genotype among Azerbaijani patients with chronic hepatitis B virus infection was genotype D followed by genotype A.

Distribution of hepatitis C virus genotypes among azerbaijani patients in capital city of iran-tehran

BACKGROUND

Determination of the Hepatitis C virus (HCV) genotype distributed in a particular area has an important role on public health throughout the world.

OBJECTIVES

The aim of this study was to determine the frequency of HCV genotypes in Azerbaijani patients.

PATIENTS AND METHODS

From March 2010 until March 2012, 235 Azerbaijani patients with established chronic hepatitis C, referred to Hospitals related to Iran University of Medical Sciences and Tehran Hepatitis Center, Clinical department of Baqiyatallah Research Center for Gastroeneterology and Liver Disease, were enrolled in this cross sectional study. About 5 mL of peripheral blood was collected from patients and after separation of plasma, viral RNA extracted. HCV-RNA were amplified by RT-nested PCR using primers from the 5´-UTR and genotyped by RFLP assay, and then HCV genotypes were confirmed using sequencing of cloned PCR products into pJET1.2/blunt cloning vector.

RESULTS

HCV genotyping of positive plasma samples demonstrated that predominant HCV subtype was noted for 1b (71.1%) followed by subtype 3a (17.0%), genotype 2 (6.8%), 1a (1.7%), and mixed infection (3.4%). The mean ± SD age of patients was 37.3 ± 11.8 (range: 2-63) years. Out of 235 patients, 139 (59.1%) were male. The frequency of HCV subtype 3a was higher in patients under 40 years old (3a: 18.1% vs. 15.0%), and subtype 3a was higher in male patients (3a: 18.7% vs. 14.6%).

CONCLUSIONS

The current study shows that the predominant HCV genotype among Azerbaijani patients with established chronic hepatitis C is subtype 1b (71.1%) followed by subtype 3a (17.0%).

Prevalence of hepatitis delta virus (HDV) infection in chronic hepatitis B patients with unusual clinical pictures

BACKGROUND

Probably 5% of the HBV carriers have HDV super infection. The risk of fulminant hepatitis, cirrhosis and hepatocellular carcinoma is higher in superinfection than the settings when HBV is alone.

OBJECTIVES

The aim of this study was to evaluate the prevalence of HDV in Iranian HBV isolates and to compare their clinical and virological pictures as well as their HDV genetic variations with other worldwide isolates.

PATIENTS AND METHODS

81 carriers with positive results for HBsAg with upper limit ranges of ALT and low or undetectable levels of HBV viral load who did not respond to HBV therapy were selected. After RT amplification of HDV Delta antigen, direct sequencing and phylogenetic study were performed to explore the genotype(s) and nucleotide/amino acid variations.

RESULTS

12 (14.8%) patients had positive results for both HDV RNA and anti-HDV. The mean ALT level was higher in HDV positive patients (75.9 U/ML) than HBV-mono-infected individuals; however, the mean HBV viral load was lower in coinfected patients than HBV-mono-infected patients. Phylogenetically, genotype I was the only detected genotype, and the most closely related isolates were of Turkish, Italian and Mongolian origin. Within the delta Ag, there were 326 nucleotide mutations, of which 111 and 215 were silent and missense, respectively. The total number of amino acid substitution was 148; most were located in known functional/epitopic domains. There was no correlation between the numbers of amino acid mutations, with clinical, virological status of the patients.

CONCLUSIONS

HDV should be suspected in HBV carriers with unusual clinical and virological pictures. Relatedness of Iranian HDV isolates to Italian and Turkish sequences proposed a common Caucasian origin for the distribution of HDV genotype I in this ethnic group.

Hepatitis delta: the rediscovery

Hepatitis D is returning to western Europe through immigration. The clinical presentation recapitulates the typical features of a florid hepatitis D. Hepatitis D is also being rediscovered in the developing world and in the United States. Hepatitis D virus (HDV) remains endemic in many countries and efforts are underway to map the infection at local levels and improve the medical alert to hepatitis D. In the United States it is generally thought that HDV has gone and hepatitis D is no longer a problem. Awareness of hepatitis D in the country has recently been revived.

Epidemiology and diagnosis of hepatitis D virus

The distribution of hepatitis D virus (HDV) is worldwide but not uniform. Current estimates suggest that 15–20 million people have exposure to HDV. Traditionally, areas of high prevalence are the Mediterranean basin, the Middle East, central Africa, the Amazonian basin and parts of Asia. As a consequence of vaccination against HBV and other prophylactic measures, the prevalence of HDV declined in Italy, Spain, Turkey and Taiwan. This downward trend stopped in the 1990s; a new location for HDV epidemics arose in western Europe, due to migration from endemic areas. HDV appeared in new geographic regions, posing a serious health threat in underdeveloped countries. Testing for anti-HVD antibodies in serum is the initial step in diagnosing HDV infection, but unravelling HDV RNA is essential to identify active replication.

Spatial and temporal dynamics of hepatitis B virus D genotype in Europe and the Mediterranean Basin

Hepatitis B virus genotype D can be found in many parts of the world and is the most prevalent strain in south-eastern Europe, the Mediterranean Basin, the Middle East, and the Indian sub-continent. The epidemiological history of the D genotype and its subgenotypes is still obscure because of the scarcity of appropriate studies. We retrieved from public databases a total of 312 gene P sequences of HBV genotype D isolated in various countries throughout the world, and reconstructed the spatio-temporal evolutionary dynamics of the HBV-D epidemic using a bayesian framework.The phylogeographical analysis showed that India had the highest posterior probability of being the location of the tree root, whereas central Asia was the most probable location of the common ancestor of subgenotypes D1-D3. HBV-D5 (identified in native Indian populations) diverged from the tree root earlier than D1-D3. The time of the most recent common ancestor (tMRCA) of the tree root was 128 years ago, which suggests that the common ancestor of the currently circulating subgenotypes existed in the second half of the XIX century. The mean tMRCA of subgenotypes D1-D3 was between the 1940s and the 1950-60s. On the basis of our phylogeographic reconstruction, it seems that HBV-D reached the Mediterranean area in the middle of the XX century by means of at least two routes: the first pathway (mainly due to the spread of subgenotype D1) crossing the Middle East and reaching north Africa and the eastern Mediterranean, and the second pathway (closely associated with D2) that crossed the former Soviet Union and reached eastern Europe and the Mediterranean through Albania. We hypothesise that the main route of dispersion of genotype D was the unsafe use of injections and drug addiction.

Virologic and clinical characteristics of HBV genotypes/subgenotypes in 487 Chinese pediatric patients with CHB

Background

The association of hepatitis B virus (HBV) genotypes/subgenotypes with clinical characteristics is increasingly recognized. However, the virologic and clinical features of HBV genotypes/subgenotypes in pediatric patients remain largely unknown.

Methods

Four hundred and eighty-seven pediatric inpatients with CHB were investigated, including 217 nucleos(t)ide analog-experienced patients. HBV genotypes/subgenotypes and reverse transcriptase (RT) mutations were determined by direct sequencing. The stage of fibrosis and degree of inflammatory activity were evaluated by the Metavir score system.

Results

Among 487 enrolled pediatric patients, HBV genotype C2 and B2 were the most two prevalent (73.7% and 21.1%). Comparing with HBV/B2 infected patients, no significant difference was observed in the incidence rate and mutant patterns of lamivudine- or adefovir-resistant mutations in HBV/C2 infected patients (P > 0.05). Importantly, we found that the degree of hepatic inflammation degree, fibrosis stage and ALT level were significantly higher in HBV/C2-infected HBeAg positive patients than it was in HBV/B2-infected ones.

Conclusions

The pediatric patients with HBV/C2 infection might be more susceptible to develop severe liver pathogenesis.

Hepatitis delta virus

Hepatitis delta virus (HDV) is a small, defective RNA virus that can infect only individuals who have hepatitis B virus (HBV); worldwide more than 15 million people are co-infected. There are eight reported genotypes of HDV with unexplained variations in their geographical distribution and pathogenicity. The hepatitis D virion is composed of a coat of HBV envelope proteins surrounding the nucleocapsid, which consists of a single-stranded, circular RNA genome complexed with delta antigen, the viral protein. HDV is clinically important because although it suppresses HBV replication, it causes severe liver disease with rapid progression to cirrhosis and hepatic decompensation. The range of clinical presentation is wide, varying from mild disease to fulminant liver failure. The prevalence of HDV is declining in some endemic areas but increasing in northern and central Europe because of immigration. Treatment of HDV is with pegylated interferon alfa; however, response rates are poor. Increased understanding of the molecular virology of HDV will identify novel therapeutic targets for this most severe form of chronic viral hepatitis.

Seroepidemiology and risk factors of hepatitis B virus in Aden, Yemen

BACKGROUND

There is little published data concerning hepatitis B virus (HBV) infection in Aden and no data concerning risk factors for infection. This study aimed to determine the prevalence of HBV infection and risk factors for infection in Aden, Yemen.

METHODS

A prospective cross sectional survey of individuals attending primary health care facilities was stratified by age and population size. Five hundred and thirty five participants were interviewed and serum was screened for the presence of Immunoglobin G HBV core antibodies (antiHBc). AntiHBc positive participants were tested for antibodies to hepatitis B surface antigen (HBsAg). A case-control analysis of risk factors for HBV was undertaken comparing risk factors between antiHBc positive cases and seronegative controls.

RESULTS

The age-standardized seroprevalence for antiHBc was 16.2% (95% confidence interval (CI) 13.1-19.3) and for HBsAg was 1.5% (95% CI 0.5-2.5). The seroprevalence of antiHBc and HBsAg was estimated to range from 5.5% and 0% in infants to 40% and 4.6% in adults, respectively (p<0.001). Age (AOR=1.03, 95% CI=1.01-1.05), household size (>5-9 members, AOR=2.9, 95% CI=1.1-7.6) and ownership of a landline telephone (AOR=2.8, 95% CI=1.3-5.8) were independent risk factors for HBV infection.

CONCLUSIONS

HBV is still a public health problem in this community, with older individuals having much higher prevalence than younger generations. The results of this study would categorise Aden as a low HBV endemic zone. Perinatal transmission does not seem to be a major route of transmission.

Geographical and genetic diversity of the human hepatitis B virus

Hepatitis B virus (HBV) is one of the most widely distributed viruses that infect humankind. Distinct clinical and virological characteristics of the HBV-infection have been reported in different geographical parts of the world and are increasingly associated with genetic diversity of the infecting virus. HBV is classified into genotypes and subgenotypes that are associated with ethnicity and geography. The genetic diversity of HBV in its various aspects has been the subject of extensive investigations during the last few decades. Since molecular epidemiology research tools have become widely available, the number of new publications in this field has grown exponentially. This review summarises the recent publications on the geographical distribution of genetic variants of HBV, and proposes updated criteria for the identification of new genotypes and subgenotypes of the virus.

A 28-year study of the course of hepatitis Delta infection: a risk factor for cirrhosis and hepatocellular carcinoma

BACKGROUND & AIMS

Chronic infection with hepatitis Delta virus (HDV) is a risk factor for cirrhosis and hepatocellular carcinoma (HCC); predictors of disease outcome are, however, poorly defined. We tracked the course of HDV infection in 299 patients over a mean period of 233 months.

METHODS

We analyzed data from patients who had been HDV positive for at least 6 months (230 males; mean age, 30 years) admitted from 1978 to 2006 to Maggiore Hospital, Milan. HDV infection was defined by the presence of HDV antigen in liver tissue or serum HDV RNA in anti-HDV/hepatitis B surface antigen seropositive patients. At enrollment, 7 patients had acute hepatitis, 101 had mild-moderate chronic hepatitis, 76 had severe chronic hepatitis, and 104 had histologic or clinical cirrhosis. Ninety patients were treated with interferon, 62 with corticosteroids, and 12 with nucleoside analogues; 135 received no therapy.

RESULTS

Over a mean period of 233 months, 82 patients developed cirrhosis. Among the 186 total patients with cirrhosis, 46 developed HCC, 43 ascites, 44 jaundice, and 1 encephalopathy. Female sex, alcohol abuse, and HDV replication were associated with liver decompensation; HBV replication and interferon were associated with HCC development. By the end of the study, 186 patients were still alive, 63 had died, and 29 had received liver transplants. The main cause of death was liver failure (n = 37, 59%); HDV replication was the only independent predictor of mortality.

CONCLUSIONS

Persistent HDV replication leads to cirrhosis and HCC at annual rates of 4% and 2.8%, respectively, and is the only predictor of liver-related mortality.

Hepatitis D: thirty years after

The key to the discovery of the Hepatitis D Virus (HDV) was the description in Turin, Italy in the mid-1970s of the delta antigen and antibody in carriers of the hepatitis B surface antigen. The new antigen was first thought to be a marker of the Hepatitis B Virus (HBV) and in view of its intricate true nature, it would have possibly died away as another odd antigenic subtype of HBV, like many that were described in the 1970s. Fortunately, instead, a collaboration started in 1978 between the Turin group, and the National Institute of Health and Georgetown University in the US. With American facilities and expertise this collaboration led just a year later, in 1979, to the unfolding of an unexpected and amazing chapter in virology. Experiments in chimpanzees demonstrated that the delta antigen was not a component of the HBV but of a separate defective virus requiring HBV for its infection; it was named the hepatitis D virus to conform to the nomenclature of hepatitis viruses and classified within the genus Deltavirus. The animal experiments were also seminal in proposing to future clinical interpretation, the paradigm of a pathogenic infection (hepatitis D), that could develop only in HBV-infected patients, was mainly transmitted by superinfection of HDV on chronic HBV carriers and had the ability to strongly inhibit the helper HBV. The discovery of the HDV has driven three directions of further research: (1) The understanding of the replicative and infectious mechanisms of the HDV. (2) The assessment of its epidemiological and medical impact. (3) The search for a therapy for chronic hepatitis D (CHD). This review summarizes the progress achieved in each field of research in the thirty years that have passed since the discovery of HDV.

Molecular and contextual markers of hepatitis C virus and drug abuse

The spread of hepatitis C virus (HCV) infection involves a complex interplay of social risks, and molecular factors of both virus and host. Injection drug abuse is the most powerful risk factor for HCV infection, followed by sexual transmission and additional non-injection drug abuse factors such as co-infection with other viruses and barriers to treatment. It is clearly important to understand the wider context in which the factors related to HCV infection occur. This understanding is required for a comprehensive approach leading to the successful prevention, diagnosis, and treatment of HCV. An additional consideration is that current treatments and advanced molecular methods are generally unavailable to socially disadvantaged patients. Thus, the recognition of behavioral/social, viral, and host factors as components of an integrated approach to HCV is important to help this vulnerable group. Equally important, this approach is key to the development of personalized patient treatment - a significant goal in global healthcare. In this review, we discuss recent findings concerning the impact of drug abuse, epidemiology, social behavior, virology, immunopathology, and genetics on HCV infection and the course of disease.