Molecular epidemiological study of hepatitis B virus among migrant workers from Cambodia, Laos, and Myanmar to Thailand

Dried blood spot-based host genome analysis technique targeting pathological associations with hepatitis B: Development and clinical application in the Cambodian population

AIM

Reports of patients with hepatitis B have highlighted associations between polymorphisms in the human leukocyte antigen (HLA)-DPB1, CXCL13, and CXCR5 genes and disease pathology. Owing to its potential to contribute to the development of new diagnostic and therapeutic methods, we aimed to establish a reliable host genome analysis technique that can be used in countries with inadequate infrastructure.

METHOD

We compared multiple commercially available kits for dried blood spot (DBS)-based sample collection to develop a basic DBS-based host genome analysis technique. We then collected blood samples from Cambodian patients with hepatitis  B and performed single-nucleotide polymorphism genotyping and HLA allele typing by the DBS system.

RESULT

We were able to perform single-nucleotide polymorphism genotyping and HLA allele typing with host DNA samples obtained using a combination of a HemaSpot™ filter paper-based device and a SMITEST® EX-R&D DNA extraction kit. The accuracy of genotyping using samples obtained by this method was not inferior to one using samples obtained by venipuncture. In the Cambodian population, significant associations of HLA-DPB1*04:01 with protection against chronic hepatitis B virus (HBV) infection, and HLA-DPB1*05:01 and HLA-DPB1*13:01 with susceptibility to chronic HBV infection were identified.

CONCLUSION

Based on the DBS system, we clarified the associations of HLA-DPB1 alleles with chronic HBV infection in the Cambodian population for the first time. Because the DBS is a low-cost, durable, transportable, and easy-to-handle modality, genetic analysis based on the DBS system is a feasible strategy for obtaining a deeper understanding of HBV epidemiology, especially in middle- or low-income countries.

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.

Prevalence and genotype distribution of viral hepatitis B in Cambodia between 1990 and 2020: a systematic review and meta-analysis

Background

Hepatitis B virus (HBV) infection is one of the major public health problems globally as well as in Cambodia. Continuous information on HBV infection burden is required to implement effective disease control strategies. This study aimed to determine the prevalence and genotype distribution of HBV infection in Cambodia through a systematic review with meta-analysis.

Methods

Four databases (PubMed, Web of Science, Scopus, and Google Scholar) were used to search published studies reporting either HBV prevalence or genotype distribution in Cambodia until August 21, 2020. Reviews, modeling studies, and studies conducted among Cambodian permanently living abroad were excluded. The Freeman–Tukey double arcsine transformation was implemented to achieve approximate normality. The DerSimonian and Laird method was used to compute pooled estimates based on the transformed values and their variance. Possible publication bias was assessed by the Egger test and the funnel plot.

Results

A total of 22 studies were included, covering 22,323 people. Ten studies reported HBV prevalence in the general population. The HBV infection prevalence was 4.73% (95%CI: 2.75–7.17%) in the general population and 19.87% (95%CI: 10.95–30.63%) in high-risk/co-infected groups. By sub-group analysis, the prevalence was 6.81% (95% CI: 4.43–9.66) in adults older than 15 years old, 2.37% (95% CI:0.04–7.05) in children 6–15 years old, and 2.47% (95% CI: 0.96–4.59) in children less than five years old. The prevalence of HBV infection decreased over time. Predominant HBV genotypes were genotypes C and B with 82.96% and 16.79%, respectively.

Conclusions

The decrease in HBV infection prevalence in Cambodia demonstrates the effects of national hepatitis B immunization, improved clinical hygiene, and the use of disposable devices. However, the estimated HBV prevalence among the general population indicates an intermediate endemicity level of HBV infection. Therefore, population screening and linkage to care, high vaccination coverage, health promotion, and HBV surveillance are essential to meet the WHO 2030 goal.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13690-022-00880-9.

Hepatitis B e Antigen (HBeAg) Rapid Test and Alanine Aminotransferase Level-Based Algorithm to Identify Pregnant Women at Risk of HBV Mother-to-Child Transmission: The ANRS 12345 TA PROHM Study

Background

The paucity of hepatitis B virus (HBV) DNA measurement in low-/middle-income countries hinders the identification of HBV-infected pregnant women at risk of perinatal transmission. This study evaluates the validity of an algorithm selecting HBeAg-positive women and HBeAg-negative women with alanine aminotransferase (ALT) ≥40 IU/L as a predictor of high HBV DNA level.

Methods

All women with reactive samples for hepatitis B surface antigen (HBsAg) were assessed with an SD BIOLINE HBeAg rapid test and HBV DNA quantification was performed. Validities of HBeAg and of the algorithm to identify HBV DNA >2 thresholds (5.3 and 7.3 log10 IU/mL) were evaluated.

Results

For the 515 HBsAg-positive women, median age was 29 years, 92 (17.9%) were HBeAg positive, 47 (9.1%) were HBeAg negative with ALT ≥40 IU/L, and 144 (28.0%) had an HBV DNA >5.3 log₁₀ IU/mL. Sensitivity and specificity of HBeAg were 61.8% and 99.2% for HBV DNA >5.3 log₁₀ IU/mL and 81.3% and 96.7% for HBV DNA >7.3 log₁₀ IU/mL. For the algorithm, sensitivity and specificity were 79.2% and 93.3% for HBV DNA level >5.3 log₁₀ IU/mL and 92.7% and 88.1% for HBV DNA >7.3 log₁₀ IU/mL. The AUCs for the algorithm (0.92 and 0.94 for HBV DNA >5.3 and 7.3, respectively) were significantly greater (P < .001) than the AUCs for HBeAg (0.81 and 0.89 for HBV DNA >5.3 and 7.3, respectively).

Conclusions

An algorithm using HBeAg and ALT level could be an effective strategy to identify HBV-infected pregnant women at risk of perinatal transmission in countries where HBV DNA quantification is not routinely available.

Distribution of hepatitis B virus genotypes in the general population of Myanmar via nationwide study

Background

Hepatitis B virus (HBV) infections are a severe health concern worldwide. HBV is a DNA virus with a rapid rate of mutation. Based on heterogeneity of the nucleotide sequence, the HBV strains are divided into nine genotypes, each with a characteristic geographical distribution. Identifying and tracking alterations of HBV genotypes is important in epidemiological and transmission studies, and contributes to predicting the risk for development of severe liver disease and response to antiviral treatment. The present study was undertaken to detect HBV genotypes and sub-genotypes in the general population of different states and regions in Myanmar.

Methods

In 2015, a total of 5547 adults of the general population, residing in seven states, seven regions and the Nay Pyi Taw Union Territory, were screened for Hepatitis B Surface antigen (HBsAg) by the immunochromatographic test (ICT). Of the 353 HBsAg positive samples, the HBVDNA was identified using polymerase chain reactions (PCR) targeting the DNA sequences encoding the Pre-S region. A total of 153 PCR positive samples were subsequently subjected to genotyping by partial genome sequencing in both directions. The resulting sequences were then edited, aligned, and compared with reference sequences using the National Centre for Biotechnology Information (NCBI) web-based genotyping tool.

Results

Three HBV genotypes (HBV genotype B, genotype C and genotype D) were detected in Myanmar, of which genotype HBV genotype C (66.7%) was the most prevalent, followed by HBV genotype D (32%) and HBV genotype B (1.3%). Sub-genotyping revealed a total of 7 variants within the B, C and D genotypes: 2 (B4 and B5) in HBV genotype B, 3 (C1, C5 and C7) in HBV genotype C, and 2 (D3 and D6) in HBV genotype D.

Conclusion

HBV genotype C, sub-genotype C1 was predominantly distributed in all states and regions of Myanmar. This study is the first report on the nationwide distribution of HBV genotypes and sub-genotypes in Myanmar. We believe our findings will enable huge support for the hepatitis disease surveillance program, since HBV infection is one of the National Priority Diseases in Myanmar.

Existence of hepatitis B virus surface protein mutations and other variants: demand for hepatitis B infection control in Cambodia

Background

This study aimed to detect Hepatitis B virus (HBV) genome sequences and their variants as of nationwide scale using dried blood spot (DBS) samples and to provide up-to-date reference data for infection control and surveillance in Cambodia.

Method

Among 2518 children age 5–7 years and their 2023 mothers participated in 2017 Cambodia nationwide sero-survey on hepatitis B surface antigen (HBsAg) prevalence using multistage random sampling strategy, 95 mothers and 13 children positive to HBsAg were included in this study. HBV DNA was extracted from DBS, then performed polymerase chain reaction. HBV genotypes and potential variants were examined by partial and full length genomic analysis.

Results

HBsAg positive rate was 4.7% (95/2023) in mothers and 0.52% (13/2518) in their children. Genotype C (80.49%) was abundantly found throughout the whole Cambodia whilst genotype B (19.51%) was exclusively found in regions bordering Vietnam. S gene mutants of HBV were found in 24.29% of mothers and 16.67% of children with HBV DNA positive sera. Full-length genome analysis revealed the homology of 99.62–100% in each mother-child pair. Genotype B was clarified to recombinant genotype B4/C2 and B2/C2. Double (48.39%) and combination mutation (32.26%) were observed in core promoter region of HBV C1 strains.

Conclusions

This study showed the capable of DBS for large-scale molecular epidemiological study of HBV in resource limited countries. Full-genome sequences yield the better understanding of sub-genotypes, their variants and the degree of homology between strains isolated from mother-child pairs calls for effective strategies on prevention, control and surveillance of mother-to-child HBV transmission in Cambodia.

High possibility of hepatocarcinogenesis in HBV genotype C1 infected Cambodians is indicated by 340 HBV C1 full-genomes analysis from GenBank

Approximately 75% of hepatocellular carcinomas (HCC) occur in Asia; core promoter mutations are associated with HCC in HBV genotype C, the dominant genotype in Cambodia. We analyzed these mutations in Cambodian residents and compared them with HBV full genomes registered in GenBank. We investigated the characteristics of 26 full-length HBV genomes among 35 residents positive for hepatitis B surface antigen in Siem Reap province, Cambodia. Genotype C1 was dominant (92.3%, 24/26), with one case of B2 and B4 each. Multiple mutations were confirmed in 24 Cambodian C1 isolates, especially double mutation at A1762T/G1764A in 18 isolates (75.0%), and combination mutation at C1653T and/or T1753V and A1762T/G1764A in 14 isolates (58.3%). In phylogenetic analysis, 16 of 24 isolates were located in the cluster with Laos, Thailand, and Malaysia. In 340 GenBank-registered C1 strains, 113 (33.2%) had combination mutation amongst which 16.5%, 34.2%, and 95.2% were found in ASC, chronic hepatitis, and liver cirrhosis (LC)/HCC respectively (P < 0. 001). Mutations were abundantly found in 24 Cambodian C1 isolates, and 340 C1 strains from GenBank showed mutation in genotype C1 brings high possibility of LC/HCC occurrence. Therefore, we suggest that Cambodian people infected with HBV genotype C1 have high possibility of hepatocarcinogenesis.

Maternal Hepatitis B Infection Burden, Comorbidity and Pregnancy Outcome in a Low-Income Population on the Myanmar-Thailand Border: A Retrospective Cohort Study

Objectives

Hepatitis B virus (HBV) was believed to have minimal impact on pregnancy outcomes apart from the risk of perinatal transmission. In more recent years, there have been reports of adverse associations, most consistently preterm birth (PTB), but this is in the context of high rates of caesarean section. The aim of this study was to explore the association of HBV on pregnancy outcomes in marginalized, low-income populations on the Myanmar-Thailand border.

Methods

HBsAg positive (+) point of care rapid detection tests results were confirmed by immunoassays. Women with a confirmed HBsAg status, HIV- and syphilis-negative at first antenatal care screening, singleton fetus and known pregnancy outcome (Aug-2012 to Dec-2016) were included. Logistic regression analysis was used to evaluate associations between HBV group (controls HBsAg negative, HBsAg+/HBeAg-, or HBsAg+/HBeAg+) and pregnancy outcome and comorbidity.

Results

Most women were tested, 15,046/15,114 (99.6%) for HBV. The inclusion criteria were not met for 4,089/15,046 (27.2%) women due mainly to unavailability of pregnancy outcome and nonconfirmation of HBsAg+. In evaluable women 687/11,025 (6.2%) were HBsAg+, with 476/11,025 (4.3%) HBsAg+/HBeAg- and 211/11,025 (1.9%) were HBsAg+/HBeAg+. The caesarean section rate was low at 522/8,963 (5.8%). No significant associations were observed between pregnancy comorbidities or adverse pregnancy outcomes and HBV status.

Conclusions

The results highlight the disease burden of HBV in women on the Myanmar-Thailand border and support original reports of a lack of significant associations with HBsAg+ irrespective of HBeAg status, for comorbidity, and pregnancy outcomes in deliveries supervised by skilled birth attendants.

Usefulness of a serial algorithm of HBsAg and HBeAg rapid diagnosis tests to detect pregnant women at risk of HBV mother-to-child transmission in Cambodia, the ANRS 12328 pilot study

BACKGROUND

In Cambodia, access to hepatitis B surface antigen (HBsAg) screening is low for pregnant women and Hepatitis B Virus (HBV) DNA quantification is poorly accessible.

OBJECTIVES

To evaluate the performance of a serial algorithm using two HBV rapid diagnostic tests (RDTs), in which samples positive for HBsAg were further tested for HBeAg as a surrogate marker for HBV DNA quantification.

STUDY DESIGN

In 2015, we prospectively collected plasma samples from 250 pregnant women consulting for antenatal care in one hospital in Phnom Penh including 128 with a known positive HBsAg status. All specimens were tested with the SD BIOLINE HBsAg RDT and HBsAg ELISA assay. In ELISA-positive samples, HBeAg status was determined using the SD BIOLINE HBeAg RDT and HBV DNA quantification was assessed.

RESULTS

Sensitivity and specificity of HBsAg RDT were 99.2% (97.7-99.9) and 100% (97.0-100), respectively. Among the 128 ELISA-positive samples, 29 (23%) tested HBeAg positive and 34 (26.5%) had HBV DNA > 5.3 Log₁₀ IU/mL. Sensitivity and specificity of HBeAg RDT in identifying viremic samples were 76.5% (62.2.0-90.7) and 96.8% (93.3-100) for HBV DNA > 5.3 Log₁₀ IU/mL and 89.3% (77.8-100) and 96.0% (92.2-99.8) for HBV DNA > 7.3 Log₁₀IU/mL. Among the 99 negative HBeAg RDT women, 8 had HBV DNA > 5.3 Log10 IU/mL and 7 of them harbored BCP/PC HBV mutants.

CONCLUSIONS

A combination of HBsAg and HBeAg RDTs could be a low-cost strategy to identify HBV-infected pregnant women at risk of perinatal transmission in a country were HBV DNA quantification is not routinely available.

Reactivation of a Vaccine Escape Hepatitis B Virus Mutant in a Cambodian Patient During Anti-Hepatitis C Virus Therapy

A 76-year-old Cambodian man co-infected with hepatitis B virus (HBV) and hepatitis C virus (HCV) 6c-1 presented for care. HBV DNA was intermittently detectable despite anti-HBs levels being above the protective threshold. During treatment for HCV, HBV DNA levels increased. Sequencing revealed multiple mutations including vaccine escape mutation and mutations predicted to enhance fitness. This case represents exacerbation of an HBV vaccine escape mutant during a direct-acting antiviral therapy.

Hepatitis B Virus Genotype C is Predominant in Myanmar

Myanmar is adjacent to India, Bangladesh, Thailand, Laos and China. In Myanmar, the prevalence of hepatitis B virus (HBV) infections is 6.5% and accounts for 60% of hepatocellular carcinoma. HBV has nine genotypes that have been identified by molecular genetic analysis. HBV genotypes are associated with several clinical features. We reviewed the prevalence of HBV genotypes in Myanmar and neighboring countries. We also reviewed HBV genotypes in refugees from Myanmar. HBV subgenotype C1 is predominant in Myanmar. As HBV genotype C is associated with hepatocellular carcinoma (HCC), it is important to screen for cirrhosis and HCC and to prevent their development in HBV-infected individuals of Myanmar.

Hepatitis B among immigrants from Myanmar: Genotypes and their clinical relevance

Hepatitis B virus (HBV) from 76 adult immigrants in Australia from Myanmar was characterized to determine the prevalence of different HBV genotypes and subgenotypes. A mutational analysis was then performed to determine the presence of clinically significant mutations and correlate them to clinical outcomes. Initial genotyping revealed 68 patients with genotype C (89.5%) and eight patients with genotype B (10.5%). Phylogenetic analysis revealed the large majority of the genotype C infections were of subgenotype C1 (67/68). Sequencing of the HBV polymerase gene (and overlapping surface gene) revealed no mutations associated with antiviral resistance. HBV surface gene mutations were detected in 10 patients with subgenotype C1. HBV BCP/PC sequencing was obtained for 71/76 (93%) patients. BCP and/or PC mutations were identified in 57/71 (80%) of PCR positive patients. Treatment had been commenced for 15/76 (18%) patients, a further 26 untreated patients were in a stage of disease where HBV treatment would be considered standard of care. It was identified that genotype C1 is the predominant sub-genotype in this population. Genotype C is known to be associated with increased risk of development of HCC. This highlights the need for screening for HCC given the potential for the development of liver cancer. It was also identified that people with HBV were potentially not receiving optimal therapy in a timely fashion.

Hepatitis B vaccination for international travelers to Asia

There is a wide range in prevalence of hepatitis B virus (HBV) infection and HBV immunization programs between different regions. Hepatitis B is a vaccine preventable disease yet is still endemic in the majority of countries in Asia. Despite the decreasing global prevalence of chronic HBV infection, there is still considerable risk of HBV infection among international travelers to high endemic areas. Numbers of international travelers are expected to increase year by year; thus immunization among this cohort is a crucial preventive measure. Among international travelers to Asia, HBV immunization should be recommended for those without previous HBV vaccination who plan to travel to countries with intermediate to high prevalence of HBV, and especially for those individuals at greater risk of HBV infection; including travelers engaging in casual sex, getting a tattoo or piercing, and those having dental surgery or other medical procedures. Longer duration of travel is also associated with a greater risk of HBV infection. Travelers from low HBV prevalence countries, especially those born before implementation of universal HBV vaccination, might benefit from HBV vaccination during long-term traveling to HBV intermediate to high endemic country.

Viral Hepatitis in Cambodia: Past, Present, and Future

The prevalence of viral hepatitis represents Cambodia as 1 of the highest endemic countries in the world. But the prevalence of viral hepatitis B among 5-year-olds is on a decreasing trend due to the effect of nationwide vaccination against hepatitis B. There are key interventions to address viral hepatitis by the Cambodian Ministry of Health. There are so far no comprehensive national guidelines for the prevention, care, and treatment of viral hepatitis.

In 2014, the coverage of hepatitis B vaccine at birth and HepB3 vaccine was very high, at 87 and 97% respectively. Other interventions include the screening of viral hepatitis B and C among blood donors; the enhancement of infection prevention and control at health facilities; the program for People Who Use Drugs (PWUDs) and People Who Inject Drugs (PWIDs); control and prevention of HIV/AIDS and sexually transmitted diseases (STDs); and improved sanitation, clean water, and food safety.

The diagnosis of viral hepatitis B and C could be made only at the national and provincial referral hospitals and there are no specific antiviral therapies for people who are infected with hepatitis B and C.

A 13-Year Retrospective Study on Primary Liver Cancer in Cambodia: A Strikingly High Hepatitis C Occurrence among Hepatocellular Carcinoma Cases

OBJECTIVES

Hepatocellular carcinoma (HCC) is the main type of primary liver cancer (PLC) worldwide, but cholangiocarcinoma (CCA) may be predominant in some specific regions of Southeast Asia. The aim of the present study was to delineate a pattern of Cambodian PLC patients attending the Calmette Hospital in the Cambodian capital Phnom Penh.

MATERIALS AND METHODS

A total of 553 medical charts diagnosing PLCs from January 2003 to May 2015 were obtained from both the Oncology and Hepato-Gastroenterology Departments of the Calmette Hospital.

RESULTS

HCC was the predominant type of PLC recorded, with 511 cases (92.4%), whereas CCA represented merely 7.6% (42 cases) of the overall series. Hepatitis B virus (HBV; 44.3%) and hepatitis C virus (HCV; 43%) infection rates were similar among the HCC patients, while small subsets of CCA patients were infected with HBV (15.4%) or HCV (11.5%). Most HCC (84%) and CCA (73.8%) patients received palliative treatment only.

CONCLUSION

The present study indicates that HCC is the main form of primary hepatic neoplasm among PLC patients attending a hospital in Cambodia. HBV and HCV infections represented equivalent burdens and major contributing factors to HCC. Therefore, the implementation of prevention programs for these infectious agents should become a priority for health policy makers in the country.

Progress towards hepatitis B prevention through vaccination in the Western Pacific, 1990-2014

Hepatitis B infections are responsible for more than 300 thousand deaths per year in the Western Pacific Region. Because of this high burden, the countries and areas of the Region established a goal of reducing hepatitis B chronic infection prevalence among children to less than 1% by 2017. This study was conducted to measure the progress in hepatitis B prevention and assess the status of achievement of the 2017 Regional hepatitis B control goal. A literature review was conducted to identify studies of hepatitis B prevalence in the countries and areas of the region, both before and after vaccine introduction. A mathematical model was applied to assess infections and deaths prevented by hepatitis B vaccination and hepatitis B prevalence in countries without recent empirical data. The majority of countries and areas (22 out of 36) were estimated to have over 8% prevalence of chronic hepatitis B infection among persons born before vaccine introduction. After introduction of hepatitis B vaccine, most countries and areas (24 out of 36) had chronic infection prevalence of less than 1% among children born after vaccine introduction. It was estimated that in the past 25 years immunization programmes in the Western Pacific Region have averted 7,167,128 deaths that would have occurred in the lifetime of children born between 1990 and 2014 if hepatitis B vaccination programmes had not been established. Regional prevalence among children born in 2012 was estimated to be 0.93%, meaning that the Regional hepatitis B control goal was achieved. While additional efforts are needed to further reduce hepatitis B transmission in the region, this study demonstrates the great success of the hepatitis B vaccination efforts in the Western Pacific Region.

Characteristics of liver cancer at Khmer-soviet Friendship Hospital in Phnom Penh, Cambodia

BACKGROUND

Hepatocellular carcinoma (HCC) is one of the most frequent cancers in South East Asian countries including Cambodia, where prevalence of chronic carriers of hepatitis B and C virus (HBV and HCV) is reported to be very high. We reviewed HCC cases admitted to a cancer hospital in Phnom Penh, which is the only one hospital for cancer treatment and care in Cambodia during the study period.

MATERIALS AND METHODS

Information was collected from medical records of 281 cases (210 males and 71 females) diagnosed as primary HCC from 2006 to 2011.

RESULTS

The subjects were 7-81 years old with a median age of 53 years. Hypochondriac pain was the most common complained symptom (74%). One third of the cases presented with jaundice. Nearly half had ascites at their first visit. One third had liver cirrhosis. Nearly three fourths of the cases presented with tumor sized more than 50 mm in diameter, and in almost all cases (97.4%) the size was more than 20 mm. Among 209 subjects tested, hepatitis virus carriers were 75.6%; 46.4% for HBV only, 21.5% for HCV only, and 7.7% for both viral infections. Median age of patients with HBV was about ten years younger than those with HCV.

CONCLUSIONS

This study revealed the characteristics of HCC cases in Cambodia, although there were several limitations. Most HCC cases were infected with HBV and/or HCV, and diagnosed at late stages with complications. This implicated that public health intervention to prevent HBV and HCV infection is of high priority.

Seroprevalence, genotypic distribution and potential risk factors of hepatitis B and C virus infections among adults in Siem Reap, Cambodia

AIM

We investigated hepatitis B virus (HBV) and hepatitis C virus (HCV) infections among adults in Siem Reap, Cambodia, to consider the prevention strategy in cooperation with the Ministry of Health in Cambodia.

METHODS

Serological tests for determining HBV and HCV infections and questionnaires were performed from 2010 to 2012 among the general population in the province of Siem Reap. Multivariate logistic regression analysis was conducted to clarify the factors related to HBV and HCV infections.

RESULTS

There were 483 participants, comprising 194 men and 289 women (age range, 18-89 years). The prevalence of hepatitis B surface antigen was not very high at 4.6%, while anti-hepatitis B core (anti-HBc) was high at 38.5%. All HBV DNA samples were classified as genotype C. Anti-HBc showed the trend that the older the age, the higher the positive rate (P = 0.0002). The prevalence of HCV RNA and anti-HCV were 2.3% and 5.8%, respectively. HCV RNA was detected in 39.3% of anti-HCV positive samples and most of them were classified as genotype 6 (54.5%) and 1 (27.3%). Remarkably, in multivariate logistic regression analysis, history of operation and blood transfusion were significantly associated with the positivity for HBV infection and HCV RNA, respectively.

CONCLUSION

Our results showed that operation and blood transfusion were potential risk factors for HBV and HCV infection, respectively, and supposed that horizontal HBV transmission may be frequent in adults in Cambodia. Hence, for reducing HBV and HCV infections, it is necessary to improve the safety of blood and medical treatment.

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.

Molecular epidemiology of hepatitis B virus in Asia

Although safe and effective vaccines against hepatitis B virus (HBV) have been available for three decades, HBV infection remains the leading cause of chronic hepatitis, cirrhosis and hepatocellular carcinoma (HCC) worldwide, especially in Asian countries. HBV has been classified into at least 9 genotypes according to the molecular evolutionary analysis of the genomic DNA sequence and shown to have a distinct geographical distribution. Novel HBV genotypes/subgenotypes have been reported, especially from Southeast Asian countries. The clinical characteristics and therapeutic effectiveness of interferon (IFN) and nucleos(t)ide analogues vary among different HBV genotypes. Mutations at T1653C in subgenotype C2 from Japan and South Korea, C/A1753T and C1858T in subgenotype C1 from Vietnam, and C1638T and T1753V in subgenotype B3 from Indonesia were reported to be associated with advanced liver diseases including HCC. Genotype distribution in Japan has been changed by an increasing ratio of subgenotype A2 in chronic hepatitis B. While a large number of epidemiological and clinical studies have been reported from Asian countries, most of the studies were conducted in developed countries such as Taiwan, China, South Korea and Japan. In this review, the most recent publications on the geographical distribution of genetic variants of HBV and related issues such as disease progression and therapy in Asia are updated and summarized.

Distribution of HBV genotypes from two blood transfusion centers in western Saudi Arabia

Aim: To determine the distribution of HBV genotypes among HBsAg-positive blood donors in Makkah and Jeddah. Materials & methods: A total of 158 volunteered HBsAg-positive male blood donors donated blood samples at two transfusion centers in western Saudi Arabia. RFLP digestion was performed on 83 PCR products of the S gene. A subset of 77 positive samples were sequenced and aligned with reference Genbank sequences. Results: RFLP showed the following genotype distribution: 71 (85.6%) D; two (2.4%) E; one (1.2%) A; one (1.2%) B; one (1.2%) C; five (6.0%) untypable; one (1.2%) mixed genotypes D+A; and one (1.2%) mixed genotype D+C. Seventy-seven samples were genotyped by sequencing as follows: 73 (94.8%) D, three (3.9%) E; and one (1.3%) A. The study showed that there is concordance in the results of RFLP and sequencing in 67 samples and discrepancy in ten samples: genotypes B, genotype C, one of genotype E and dual genotypes by RFLP could only been detected as genotype D by sequencing. Sequencing showed the RFLP untypable samples as genotypes D and E. Conclusion: HBV type D is the most prevalent genotype in western Saudi Arabia. RFLP is a reliable tool for predicting genotype D in Saudi population.

Chronic hepatitis B prevalence among children and mothers: results from a nationwide, population-based survey in Lao People's Democratic Republic

BACKGROUND

Hepatitis B is regarded as a serious public health issue in Lao People's Democratic Republic (Lao PDR), a Southeast Asian country. However, disease epidemiology among the general population is not well known, and thus a nationwide cross-sectional survey for hepatitis B surface antigen (HBsAg) prevalence in children and their mothers was conducted.

METHODS AND FINDINGS

We applied three-stage cluster sampling using probability proportionate to size. After randomly selecting child (5 to 9 years old) and mother (15 to 45 years old) pairs from the selected villages, questionnaires and HBsAg rapid tests were conducted. Data from 965 child and mother pairs were analyzed. Multivariate logistic regression analyses were used to investigate the independent association of individual background characteristics for the odds of being HBsAg positive. In total, 17 children and 27 mothers were HBsAg positive. HBsAg prevalence was estimated to be 1.7% (95% confidence interval: 0.8%-2.6%) in children, and 2.9% (95% confidence interval: 1.7%-4.2%) in their mothers after taking sampling design and weight of each sample into account. Mother's infection status was positively associated with HBsAg positivity in children (p<0.001), whereas other potential risk factors, such as ethnicity, proximity to health centers, and history of surgery, were not. There were no significant associations between mother's HBsAg status and history of surgery, and other sociodemographic factors.

CONCLUSIONS

Despite the slow implementation of the hepatitis B vaccination program, HBsAg prevalence among children and their mothers was not high in Lao PDR compared to reports from neighboring countries. The reasons for the differences in prevalence among these countries are unclear. We recommend that prevalence surveys be conducted in populations born before and after the implementation of a hepatitis B vaccination program to better understand the epidemiology of hepatitis B.

Hepatitis B virus genetic variation and TP53 R249S mutation in patients with hepatocellular carcinoma in Thailand

Chronic hepatitis B virus (HBV) infection and dietary exposure to aflatoxin B1 (AFB1) are major risk factors for hepatocellular carcinoma (HCC). The aim of this study was to evaluate the role of HBV genetic variation and the R249S mutation of the p53 gene, a marker of AFB1-induced HCC, in Thai patients chronically infected with HBV. Sixty-five patients with and 89 patients without HCC were included. Viral mutations and R249S mutation were characterized by direct sequencing and restriction fragment length polymorphism (RFLP) in serum samples, respectively. The prevalences of T1753C/A/G and A1762T/G1764A mutations in the basal core promotor (BCP) region were significantly higher in the HCC group compared to the non-HCC group. R249S mutation was detected in 6.2% and 3.4% of the HCC and non-HCC groups, respectively, which was not significantly different. By multiple logistic regression analysis, the presence of A1762T/G1764A mutations was independently associated with the risk of HCC in Thai patients.

Prevalence of hepatitis C and B virus among patients infected with HIV: a cross-sectional analysis of a large HIV care programme in Myanmar

Co-infection with the hepatitis C virus (HCV) and/or hepatitis B virus (HBV) influences the morbidity and mortality of patients with HIV. A cross sectional analysis was of 11,032 HIV-infected patients enrolled in the Integrated HIV Care Program from May 2005 to April 2012 and Epi-info 3.5 was used to determine the serological prevalence of chronic hepatitis B and hepatitis C. The mean ± standard deviation age of patients was 36 ± 8.4 years (adult cohort) and 7 ± 3 years (paediatric cohort). The sero prevalence of hepatitis B surface antigen, hepatitis C (anti HCV antibodies) and triple infection are 8.7%, 5.3% and 0.35%, respectively. Men who have sex with men are at the highest risk of being co-infected with hepatitis B while intravenous drug users are at the highest risk of being co-infected with hepatitis C. It is important to screen for hepatitis B and C in HIV infected people in order to provide quality care for HIV patients with co-infection.

The distribution of hepatitis B virus genotypes in Thailand

Phylogenetic analysis was performed on hepatitis B virus (HBV) strains obtained from 86 hepatitis B surface antigen (HBsAg) positive donors from Thailand originating throughout the country. Based on the S gene, 87.5% of strains were of genotype C while 10.5% were of genotype B, with all genotype B strains obtained from patients originating from the central or the south Thailand. No genotype B strains were found in the north of Thailand. Surprisingly, one patient was infected with a genotype H strain while another patient was infected with a genotype G strain. Complete genome sequencing and recombination analysis identified the latter as being a genotype G and C2 recombinant with the breakpoint around nucleotide position 700. The origin of the genotype G fragment was not identifiable while the genotype C2 fragment most likely came from strains circulating in Laos or Malaysia. The performance of different HBsAg diagnostic kits and HBV nucleic acid amplification technology (NAT) was evaluated. The genotype H and G/C2 recombination did not interfere with HBV detection.

HIV and Hepatitis B coinfection among perinatally HIV-infected Thai adolescents

OBJECTIVES

This study aimed to determine the prevalence of hepatitis B virus (HBV) coinfection and HBV seropositivity in perinatally HIV-infected adolescents. A secondary objective was to describe the clinical characteristics of adolescents with chronic HBV/HIV coinfection.

MATERIALS AND METHODS

Multicenter cross-sectional study of perinatally HIV-infected adolescents aged 12-25 years. HBV surface antigen, surface antibody (anti-HBs) and core antibody (anti-HBc) were measured. Coinfection was defined as having persistently positive HBV surface antigen. Seroprotective antibody from immunization was defined as having anti-HBs ≥10 mIU/mL with negative anti-HBc. HBV DNA quantitation and rtM204V/I mutation analysis (lamivudine resistance-associated mutation) were performed in adolescents with chronic HBV infection.

RESULTS

From November 2010 to March 2011, 521 patients were enrolled. Mean (SD) of CD4 lymphocyte count was 685 (324) cells/μL. The prevalence of HBV/HIV coinfection was 3.3% (95% confidence interval: 1.9-5.2%). Protective antibody against HBV was found in 18% of population, and this was significantly higher among adolescents who received than those who did not receive HBV revaccination after receiving antiretroviral therapy (93% versus 6%, P < 0.01). Among adolescents with chronic HBV infection, 88% have received lamivudine; however, 69% have HBV DNA >10 copies/mL and 75% had the rtM204V/I mutation.

CONCLUSIONS

The prevalence of HBV coinfection in HIV-infected Thai adolescents was 3.3%. Most HIV-infected adolescents had no HBV protective antibody; therefore, revaccination with HBV vaccine is encouraged. The high prevalence of HBV-lamivudine resistance underscores the importance of HBV screening prior to antiretroviral therapy initiation to guide the selection of optimal regimen for coinfected children.

Challenges in Providing Treatment and Care for Viral Hepatitis among Individuals Co-Infected with HIV in Resource-Limited Settings

Hepatitis B and C infections are prevalent among HIV-infected individuals with different epidemiologic profiles, modes of transmission, natural histories, and treatments. Southeast Asian countries are classified as "highly prevalent zones," with a rate of hepatitis B and C coinfection in people living with HIV/AIDS of approximately 3.2-11%. Majority of hepatitis B coinfection is of genotype C. Most of the patients infected with hepatitis C in Thailand have genotype 3 which is significantly related to intravenous drug use whereas, in Vietnam, it is genotype 6. The options for antiretroviral drugs are limited and rely on global funds and research facilities. Only HBV treatment is available for free through the national health scheme. Screening tests for HBV and HCV prior to commencing antiretroviral treatment are low. Insufficient concern on hepatitis-virus-related liver malignancy and long-term hepatic morbidities is noted. Cost-effective HCV treatment can be incorporated into the national health program for those who need it by utilizing data obtained from clinical research studies. For example, patients infected with HCV genotype 2/3 with a certain IL-28B polymorphism can be treated with a shorter course of interferon and ribavirin which can also help reduce costs.

A high variability of mixed infections and recent recombinations of hepatitis B virus in Laos

In Lao PDR, where more than 8% of the population are chronic carriers of HBsAg, multiple genotypes and subgenotypes co-circulate and are prone to generate recombinant viruses. Phylogenetic analyses of multiple clones per donor revealed mixed infections of subgenotypes B1, B2, B4, C1, C5, I1 and I2 in almost 6% of HBsAg positive rejected blood donors. Recombination analyses and distance calculations furthermore showed that about 65% (17/26) of the mixed infected donors showed recombinations in the S-gene alone, involving the predominant genotypes B and C. These results suggest that, at least in Laos, hepatitis B virus (HBV) mixed infections lead to frequent recombinations. In many donors with recombinant strains, the recombinant fragment and a non-recombinant strain of the same genotype co-existed (127/185 analysed recombinant fragments). For a large proportion of these (60/127), the most closely related known virus was found, although not always exclusively, in the same donor. Recombinant virus strains are largely distinct. This is reflected in an unexpected diversity in recombination breakpoints and the relatively rare recombinations with identical recombination patterns of the same genotypes in different donors. Recent recombination events would explain the limited spread of each of the recombinants. Using a published mutation rate of 4.2×10⁻⁵ mutations per site and year, the observed minimum genetic distances of 0–0.60% between parent strain and recombinant fragment would correspond to 0–71 years of evolution from a most recent common ancestor (MRCA). Thus several lines of evidence are suggestive of recent independent recombination events, a proportion of these even occurring within the same donors. In conclusion, our analyses revealed a high variability of mixed infections as a very probable breeding ground of multiple variable recombination events in Laos that so far have not led to new dominant strains.

Low prevalence of hepatitis B virus pre-S deletion mutation in Indonesia

The molecular epidemiological study of hepatitis B virus (HBV) in Indonesia is still limited. This study was aimed to identify the prevalence of HBV pre-S deletion/insertion mutations, and to assess the association of pre-S deletion mutation with liver disease progression in Indonesia. Pre-S mutations were identified by direct sequencing. Of the 265 subjects, 32 samples (12.1%) harbored pre-S deletion/insertion mutations. The prevalence of those pre-S mutations was 2.7% (2/75), 12.9% (8/62), 16.7% (11/66), and 17.7% (11/62) in asymptomatic carrier, chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma groups, respectively. Statistical analysis showed significant difference among them (P = 0.024). In HBV genotype B (HBV/B), pre-S1, pre-S1/S2, and pre-S2 deletion mutations were detected respectively in 3 (17.6%), 4 (23.5%), and 9 (52.9%) of 17 samples. On the other hand, in HBV/C, 12 of 15 samples (80.0%) showed a pre-S2 deletion mutation, and only 2 samples (13.3%) demonstrated a pre-S1/S2 deletion mutation. These results suggest that in HBV/B deletion mutation tends to occur in pre-S1 or pre-S1/S2 region, while in HBV/C the deletion mutation usually occurs in the pre-S2 region. Analysis of complete genome of four viruses confirmed that 3 isolates were classified into HBV/B3, and 1 isolate was HBV/C1. However, SimPlot and BootScan analyses showed that isolate 08.10.002 was an intragenotypic recombinant between HBV/B3 and HBV/B4. As conclusion, the prevalence of HBV pre-S mutations was relatively low in Indonesian patients compared to those from Taiwan, Japan, and other Asian countries. There was a weak association between pre-S deletion mutation and progressive liver disease.

Identification of four novel subgenotypes (C13-C16) and two inter-genotypic recombinants (C12/G and C13/B3) of hepatitis B virus in Papua province, Indonesia

Four novel subgenotypes (C6, C11, C12, and D6) of hepatitis B virus (HBV) were identified in Papua, a multiethnic province of Indonesia. To characterize the HBV strains in Papua, serum samples collected from 515 indigenous inhabitants (mean age: 26.6±9.6 years) in a previously unexamined area, Nabire, located in northern Papua, were used in the present study. Among 46 samples whose 1.6-kilobase (kb) HBV DNA sequence was amplified, 38 (83%) were typeable into known subgenotypes [B3 (n=4), C1 (n=2), C5, (n=1), C6 (n=5), C12 (n=13), and D6 (n=13)]. An analysis of the full-length sequence of the eight remaining HBV/C isolates whose sequence was either unclassifiable or uncertain within the 1.6-kb sequence showed no significant evidence of recombination in six isolates, and inter-genotypic recombination in two isolates (NAB20 and NAB46). By pairwise comparisons and a maximum-likelihood phylogenetic analysis, six non-recombinant isolates were considered significantly remote from known HBV/C isolates of subgenotypes C1-C12, and were classifiable into four novel subgenotypes (tentatively designated C13-C16). NAB20 and NAB46 were hybrids of C13/B3 and C12/G, respectively, displaying recombination breakpoints in the 5'-terminus of the P gene. Notably, the distribution of presumably indigenous subgenotypes C11-C16 was associated with particular language speakers in Papua.

High incidence of hepatitis B infection-associated cirrhosis and hepatocellular carcinoma in the Southeast Asian patients with portal vein thrombosis

Background

Portal vein thrombosis (PVT) is a rare condition associated with serious morbidity and mortality. The objective of this study was to determine the frequency, clinical presentations, and risk factors of PVT from the set of data firstly collected among the Southeast Asian population.

Methods

A retrospective study was undertaken to identify patients diagnosed with thrombosis of the portal system and other abdominal veins. The hospital medical records were retrieved based on the selected ICD-10 codes. Clinical presentations were collected and risk factors determined.

Results

From 2000-2009, 467 hospital charts with designated ICD-10 codes of I81, I82.2, I82.3, I82.8, I82.9, or K55.0 were identified. PVT (I81) was the most common thrombosis (194 cases, 41.54%). The majority of PVT patients were males (65%), older than 40 years (75%), and presented with abdominal distension/ascites (69%), splenomegaly (54.6%), and abdominal pain (50.5%). Overall, the predominant risk factor was hepatocellular carcinoma (HCC) (52.5%), followed by liver cirrhosis without cancer (9.3%), abdominal infection/inflammation (9.3%), cholangiocarcinoma (8.2%), and abdominal intervention (7.7%). In young patients, abdominal interventions including umbilical catheterization (23.1%) and hepatectomy (7.7%) were the most frequent risks whereas in older cases, primary hepatobiliary cancer and cirrhosis (78%) were the major risks. Liver metastases from other organs were infrequently found. Chronic hepatitis B virus (HBV) infection was the main etiology associated with cirrhosis/HCC leading to PVT in this cohort. A third of the older PVT patients (age >40) had HBV and very few carried hepatitis C virus (HCV) whereas none of the young PVT patients (age <20) had HBV or HCV. A variety of abdominal infections/inflammations were also found including liver abscess, splenic abscess, cholangitis, cholecystitis, pancreatitis, omphalitis, and abdominal tuberculosis. Single cases of systemic lymphangiomatosis and Klippel-Trénaunay vascular malformation syndrome were also identified. Other thrombophilic conditions such as myeloproliferative neoplasms, paroxysmal nocturnal hemoglobinuria, protein S deficiency, and anti-phospholipid syndrome were rarely encountered.

Conclusion

HBV is the major risk of PVT in the Southeast Asian population. Several risk factors identified in this population have rarely been described and some are remarkably different from those reported in the West. Host and environmental factors may play a causal role in the initiation and development of PVT in various ethnicities and geographic locations.