New trends of HCV infection in China revealed by genetic analysis of viral sequences determined from first-time volunteer blood donors

Distribution pattern, molecular transmission networks, and phylodynamic of hepatitis C virus in China

In China, few molecular epidemiological data on hepatitis C virus (HCV) are available and all previous studies were limited by small sample sizes or specific population characteristics. Here, we report characterization of the epidemic history and transmission dynamics of HCV strains in China. We included HCV sequences of individuals belonging to three HCV surveillance programs: 1) patients diagnosed with HIV infection at the Beijing HIV laboratory network, most of whom were people who inject drugs and former paid blood donors, 2) men who have sex with men, and 3) the general population. We also used publicly available HCV sequences sampled in China in our study. In total, we obtained 1,603 Ns5b and 865 C/E2 sequences from 1,811 individuals. The most common HCV strains were subtypes 1b (29.1%), 3b (25.5%) and 3a (15.1%). In transmission network analysis, factors independently associated with clustering included the region (OR: 0.37, 95% CI: 0.19-0.71), infection subtype (OR: 0.23, 95% CI: 0.1-0.52), and sampling period (OR: 0.43, 95% CI: 0.27-0.68). The history of the major HCV subtypes was complex, which coincided with some important sociomedical events in China. Of note, five of eight HCV subtype (1a, 1b, 2a, 3a, and 3b), which constituted 81.8% HCV strains genotyped in our study, showed a tendency towards decline in the effective population size during the past decade until present, which is a good omen for the goal of eliminating HCV by 2030 in China.

Prevalence and factors associated with hepatitis C among pregnant women in China: a cross-sectional study

Pregnant women infected with HCV should be given attention due to their special physiological stage and the effect on offspring health. To examine the prevalence of HCV infection among pregnant women in part of China and explore relevant factors during pregnancy, a cross-sectional study was conducted in four maternal and children health care institutions (MCHC) in Guangdong, Hunan and Chongqing. Pregnant women who were delivered, induced or spontaneous abortion were included and relevant information was collected through the Hospital Information System. Results showed that the prevalence of HCV among pregnant women in four MCHCs was 0.11% (95% CI 0.09-0.13%). Age, occupations, regions, syphilis-infection, intrahepatic cholestasis of pregnancy (ICP), and placenta previa were significant factors (all P < 0.05). Age and syphilis-infection were positively correlated with HCV infection (Z = 3.41, P = 0.0006; OR = 18.16, 95% CI 9.34-35.29). HCV and HBV infection were risk factors of ICP (OR = 4.18, 95% CI 2.18-8.04; OR = 2.59, 95% CI 2.31-2.89). Our study indicates that the prevalence of HCV among pregnant women in the three provinces(city) was low compared with the general population in China. Older age and syphilis-infection increased the risk of HCV infection during pregnancy. HCV infection was a risk factor of ICP. Generally, we need keep a watchful eye on HCV infection and relevant factors mentioned above during pregnancy in clinic, especially those also infected with syphilis. HCV testing based on risk factors is recommended in antenatal care and obstetrics.

HCV 6a was expanding and became the predominant subtype among blood donors between 2004 and 2019 in Guangdong, China

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Currently, HCV 6a has replaced 1b as the most prevalent subtype in blood donors in Guangdong.

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HCV 6a was the predominant subtype in males and older donors, while 1b predominated in females and younger donors.

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HCV 6a may expand from Guangdong to other districts of China, and is worthy of attention.

Phylogenetic signature and prevalence of natural resistance-associated substitutions for hepatitis C virus genotypes 3a and 3b in southwestern China

Background

Patients infected with hepatitis C (HCV) genotype (GT) 3, especially GT3b, are still difficult to cure. GT3b is more common than GT3a in southwestern China. Here we aimed to investigate the prevalence of naturally occurring RASs in HCV GT3 in southwestern China and performed phylogenetic analysis.

Methods

Serum samples were collected from patients with HCV GT3 infection. Sanger sequencing was used to validate resistance-associated substitutions (RASs). Phylogenetic analysis was performed using MEGA X and the observed-minus-expected-squared algorithm was used to analyze amino acid covariance.

Results

A total of 136 patients were enrolled, including 41 HCV GT3a and 95 GT3b infected patients. In the NS5A region, the proportion of RASs found in GT3b (99%) was notably higher than in GT3a (9%). In the NS3 region, RASs prevalence in GT3b (5%) was lower than in GT3a (24%). NS5B-specific RASs were rare. Both the NS5A30k and L31 M substitutions occurred in 96% of GT3b sequences. The A30K + L31M combination was found in 94% of GT3b isolates, however, there were no A30K or L31M mutations observed in the GT3a sequence.

Conclusions

Significant differences were observed between HCV GT3a and GT3b in terms of RAS prevalence. The origin of GT3a appears to be more diverse compared with GT3b in southern China. Studies specifically aimed at HCV GT3b infection should be initiated to gain more insight into this subtype.

Distribution and changes in hepatitis C virus genotype in China from 2010 to 2020

BACKGROUND

Hepatitis C virus (HCV) causes a large number of infections worldwide. New infections seem to be increasing according to a report of the World Health Organization in 2015. Although direct-acting antivirals are quite effective for most genotypes of the HCV, some genotypes fail to respond. Therefore, the trend of genotype distribution is vital to better control the development of this infection.

AIM

To analyze the distribution and trends of the HCV genotype before and after the emergence of direct-acting antivirals in China.

METHODS

We searched all literature published in five electronic databases-China National Knowledge Infrastructure, Wan Fang Data, VIP Chinese Journal Database, Chinese Biomedical Literature Service System, and PubMed-from January 1, 2010 to December 31, 2020. The search strategy combined medical subject headings and free-text terms, including “hepatitis C virus” or “HCV” and “genotype” or “subtype” and ”China” or “Chinese”. Additional relevant articles were searched by manual selection. Data were extracted to build a database. All of the data were totaled according to regions, periods, routes of transmission, and sexes. The percentages in various stratifications were calculated.

RESULTS

There were 76110 samples from 30 provinces included in the study. Genotype 1 (G1) accounted for 58.2% of cases nationwide, followed by G2, G6, G3b, G3a, unclassified and mixed infections (17.5%, 7.8%, 6.4%, 4.9%, 1.8%, and 1.2%, respectively). The constitution of genotype varied among different regions, with G6 and G3b being more common in the south and southwest, respectively (28.1%, 15.4%). The past ten years have witnessed a decrease in G1 and G2 and an increase in G3 and G6 in almost all regions. The drug-use population had the most abundant genotypes, with G6 ranking first (33.3%), followed by G1 and G3b (23.4%, 18.5%).

CONCLUSION

G3 and G6 pose a new challenge for HCV infection. This study revealed the distribution of HCV genotypes in China over the past 10 years, providing information for HCV management strategies.

Geographic Distribution of HCV Genotypes and Efficacy of Direct-Acting Antivirals in Chronic HCV-Infected Patients in North and Northeast China: A Real-World Multicenter Study

OBJECTIVE

To assess the geographic distribution of HCV genotypes, effectiveness, and safety of DAA treatment for HCV-infected patients in North and Northeast China.

METHODS

The geographic distribution of HCV genotypes was analyzed in 2162 patients recruited from April 2018 to February 2021. Sustained virologic response rates at 12 (SVR12) or 24 (SVR24) weeks posttreatment and safety were analyzed in 405 patients who completed DAA treatment according to patient baseline characteristics and treatment.

RESULTS

Four genotypes and six subtypes were identified as follows: 1b (1187, 54.90%), 2a (790, 36.54%), 3a/b (134, 6.20%), 6a/n (44, 2.04%), mixed genotypes (2a-6a or 2a-3a) (7, 0.32%). Overall, 99.01% patients achieved SVR12, while 98.43% achieved SVR24. All patients treated with elbasvir/grazoprevir (EBR/GZR), sofosbuvir/velpatasvir ± ribavirin (SOF/VEL ± RBV), and SOF/ledipasvir (LDV) achieved SVR12 or SVR24; 92.86% SVR12 and 95.83% SVR24 were observed in patients using SOF + RBV. SVR12 was higher in noncirrhosis versus compensated cirrhosis patients (100% vs. 97.09%, p=0.022). No severe drug-related adverse event was observed.

CONCLUSIONS

Genotypes 1b and 2a were dominant subtypes in North and Northeast China. The approved drug regimens EBR/GZR and SOF/LDV for subtype 1b and SOF/VEL for nongenotype 1b are the optimal effective and safety profile.

Worldwide prevalence, genotype distribution and management of hepatitis C

Hepatitis C virus (HCV) is one of the leading causes of chronic liver disease, cirrhosis, and hepatocellular carcinoma, resulting in major global public health concerns. The HCV infection is unevenly distributed worldwide, with variations in prevalence across and within countries. The studies on molecular epidemiology conducted in several countries provide an essential supplement for a comprehensive knowledge of HCV epidemiology, genotypes, and subtypes, along with providing information on the impact of current and earlier migratory flows. HCV is phylogenetically classified into 8 major genotypes and 57 subtypes. HCV genotype and subtype distribution differ according to geographic origin and transmission risk category. Unless people with HCV infection are detected and treated appropriately, the number of deaths due to the disease will continue to increase. In 2015, 1.75 million new viral infections were mostly due to unsafe healthcare procedures and drug use injections. In the same year, access to direct-acting antivirals was challenging and varied in developing and developed countries, affecting HCV cure rates based on their availability. The World Health Assembly, in 2016, approved a global strategy to achieve the elimination of the HCV public health threat by 2030 (by reducing new infections by 90% and deaths by 65%). Globally, countries are implementing policies and measures to eliminate HCV risk based on their distribution of genotypes and prevalence.

The distribution of hepatitis C virus infection in Shanghai, China: a time-spatial study

BACKGROUND

Shanghai, as a pilot city of China to achieve the goal of eliminating hepatitis C, its strategy of allocating medical resources is a pressing problem to be solved. This study aims to infer the time-spatial clustering patterns of HCV-infected cases, and grasp the dynamic genotype distribution of HCV, thereby inform elimination strategies of HCV with efficacy and efficiency.

METHODS

Reported HCV cases including their demographic information in Shanghai city from 2005 to 2018 were released from the National Infectious Disease Reporting Information System, population data at community scale, geographical layers of hospitals, communities and districts were gathered from former research. Blood samples of HCV-infected individuals were collected during 2014-2018 from 24 sentinel hospitals, HCV-antibody test, qualitative nucleic acid test and NS5B/5'UTR gene amplification were performed accordingly to determine the genotypes of the specimen. Furthermore, global and local spatial self-correlation analysis of both acute and chronic HCV infections were conducted at community scale year by year, then time-spatial clusters of acute and chronic HCV infections and HCV genotype distribution of specimen collected from sentinel hospitals by districts were mapped by using Arcmap10.1.

RESULTS

A total of 2631 acute HCV cases and 15,063 chronic HCV cases were reported in Shanghai from 2005 to 2018, with a peak in 2010 and 2017, respectively. The mean age of chronic HCV patients was 49.70 ± 14.55 years, 3.34 ± 0.32 years older than the acute (t = 10.55, P-value < 0.01). The spatial distribution of acute HCV infection formed one primary cluster (Relative Risk = 2.71), and the chronic formed one primary cluster and three secondary clusters with Relative Risk ranged from 1.94 to 14.42, meanwhile, an overlap of 34 communities between acute and chronic HCV clusters were found with time period spans varied from 6 to 12 years. Genotype 1 (N = 257, 49.71%) was the most prevalent HCV genotype in Shanghai, genotype 3 infections have increased in recent years. Baoshan district presented cluster of acute HCV and the highest proportion of genotype 2, Pudong new area was the cluster of chronic HCV and occupied the highest proportion of genotype 3.

CONCLUSIONS

Despite the low prevalence of HCV infection, it is still needed to push forward the elimination process in Shanghai, as there is a certain amount of HCV infected people waiting to be treated. The time-spatial clustering patterns and the dynamic of HCV genotype distribution together indicated a changing constitution of different transmission routes of HCV infection, thus, a focused strategy may be needed for high-risk population related to genotype 3 infection like drug users, in addition to an enforcement of the existing measures of preventing the iatrogenic and hematogenic transmission of HCV.

Subclinical Hepatitis C Virus Infection in Patients with Chronic Obstructive Pulmonary Disease: Evidence from a Cross-Sectional Multicenter Observation Study

Background: Patients with hepatitis virus C (HCV) infection have declined levels of forced expiratory volume (FEV), which is a prognostic marker for chronic obstructive pulmonary disease (COPD). Objectives: The current study primarily aimed to investigate the incidence of subclinical HCV infection (clinical signs are absent but positive HCV RNA test performed by polymerase chain reaction) in patients with COPD of Zhejiang province, China, and its secondary aim was to investigate the clinical influence of HCV infection on COPD severity by body mass index, airflow obstruction, dyspnea, and exercise capacity (BODE) scoring index and pulmonary function tests (PFT). Methods: A total of 252 patients with COPD (confirmed by routine lab tests, BODE index, and PFT) were included in a cross-sectional multicenter study. An anti-HCV antibody test was used to diagnose HCV infection. Hepatitis virus C RNA was tested for patients with a HCV antibody-positive test. Results: Twelve patients had a positive anti-HCV antibody test. Of 12 anti-HCV antibody positive test patients, 10 were positive for the HCV RNA. The prevalence of anti-HCV antibody positivity and HCV RNA positivity was 12/ 252 and 10/ 252, respectively. The partial arterial pressure of oxygen was the same for patients with HCV RNA positive test compared to those with a negative anti-HCV antibody test (59.70 ± 5.50 mmHg vs. 63.84 ± 15.63 mmHg, P = 0.791). Patients with a positive HCV RNA test had a higher partial arterial pressure of carbon dioxide compared to those with a negative anti-HCV antibody test (43.70 ± 1.89 mmHg vs. 49.42 ± 7.33 mmHg, P = 0. 007). BODE index was higher for patients with HCV RNA positive test than those with anti-HCV antibody test negative (6 (3 - 7) vs. 4 (2 - 6), P < 0.0001). Among the variables of BODE index scoring, the values of distance walked in 6 min (P < 0.0001) and % predicted forced expiratory volume in 1 s (P < 0.0001) were fewer for patients with HCV RNA positive test than those with a negative anti-HCV antibody test. Conclusion: This study demonstrated that subclinical HCV infection may be observed in COPD patients.

Prevalence and trends of transfusion-transmittable infections among blood donors in Southwest China

BACKGROUND

The high prevalence of transfusion-transmitted infections (TTIs) is causing serious harm to human health worldwide. The aim of this research was to assess the prevalence and influencing factors of TTIs in Southwest China.

METHODS

A retrospective study of blood donor records from January 2008 to December 2015 was conducted. All samples were screened for HBV, HCV, HIV and syphilis. The donor's data was recorded and analyzed statistically using SPSS software.

RESULTS

We revealed that the prevalence of TTIs showed a decreasing trend from 2.39 to 1.98%, and this was slightly lower than that in other regions of China. Syphilis infection was the most serious issue among blood donors in Southwest China, which demonstrated a significantly higher rate than that in other areas of China. The high infection rate of the female and farmer groups in rural regions is worth noting. The logistic regression model showed that age, occupation and donor category was the influential factors for TTIs.

CONCLUSIONS

The overall prevalence of TTIs demonstrated a decreasing trend from 2008 to 2015 in Southwest China, but there is still a sufficient threat to blood safety, and more efforts are needed to further guarantee blood safety in China.

Rapid and Sensitive Detection of Hepatitis C Virus in Clinical Blood Samples Using Reverse Transcriptase Polymerase Spiral Reaction

This study established a new polymerase spiral reaction (PSR) that combines with reverse transcription reactions for HCV detection targeting 5'UTR gene. To avoid cross-contamination of aerosols, an isothermal amplification tube (IAT), as a separate containment control, was used to judge the result. After optimizing the RT-PSR reaction system, its effectiveness and specificity were tested against 15 different virus strains which included 8 that were HCV positive and 7 as non-HCV controls. The results showed that the RT-PSR assay effectively detected all 8 HCV strains, and no false positives were found among the 7 non-HCV strains. The detection limit of our RT-PSR assay is comparable to the real-time RT-PCR, but is more sensitive than the RT-LAMP. The established RT-PSR assay was further evaluated for detection of HCV in clinical blood samples, and the resulting 80.25% detection rate demonstrated better or similar effectiveness compared to the RT-LAMP (79.63%) and real-time RT-PCR (80.25%). Overall, the results showed that the RT-PSR assay offers high specificity and sensitivity for HCV detection with great potential for screening HCV in clinical blood samples.

How would China achieve WHO's target of eliminating HCV by 2030?

Introduction: Hepatitis C virus (HCV) infection is a major global health concern on the rise, prompting unprecedented efforts by the World Health Organization (WHO) to eliminate this epidemic by 2030. Being the country with the largest HCV-infected population in the world, China has been faced with a general lack of awareness for HCV, low treatment uptake and subpar collaborations among healthcare providers and stakeholders. Areas covered: This review discusses the epidemiological situations of HCV infection and the challenges in HCV management in China. This review also explores micro-elimination strategies in China, identifying potential sub-populations for concerted efforts in eliminating HCV. As DAAs are increasingly recognized as a more effective alternative to traditional regimens, the cost-effectiveness and budget impacts of bringing more DAAs into the reimbursement lists are also addressed. Several small-scale targeted literature searches were conducted in PubMed for various topics covered in the article, and hand searching was performed to fill any data gaps. More recent data were used wherever possible. Expert opinion: Considering the unique socioeconomical landscape of China, micro-elimination strategies might be more effective and should be targeted at high-risk populations. Varying regional needs in HCV care across the country necessitate decentralized approaches in research and policy-making.

HCV genotype 6 prevalence, spontaneous clearance and diversity among elderly members of the Li ethnic minority in Baisha County, China

The epidemiology of hepatitis C virus varies widely across geographical regions and ethnic groups. Our previous study showed that 6 strains isolated from Baisha County, Hainan Island, China, were all new genotype 6 (gt6) subtypes which differed significantly from subtypes of other regions. In the current study, we conducted a comprehensive epidemiological survey of HCV in the Li ethnic group, native to Baisha County. Anti-HCV antibodies were detected by 2 independent ELISAs in all participants, and positive results confirmed by the recombinant immunoblot assay (RIBA) and HCV RNA viral loads were measured. Univariate chi-square test and multivariable logistic regression analyses were used to determine the risk factors for HCV infection and spontaneous clearance rates. Indeterminate RIBA results were excluded or included in analyses; consequently, findings were expressed as a range. Direct sequencing of partial regions within NS5B and E1 was employed for genotyping. Among 1682 participants, 117 to 153 were anti-HCV positive (7.0%-9.1%), with 42.7%-52.6% confirmed to have cleared infection. Anti-HCV positivity was associated with older age (≥60 years) (OR = 0.02, 95% CI 0.01-0.05, P < 0.01) and surgery (OR = 2.75, 95% CI 1.36-5.57, P < 0.01), with no significant difference found between the HCV infection group and the HCV spontaneous clearance group. The gt6 subtype distribution characteristics of Baisha County were unique, complex and diverse. The sequences did not cluster with known gt6 subtypes but formed 4 Baisha community-specific groups. HCV infection in members of the Li minority ethnic group is characterized by high prevalence rates in the elderly, high spontaneous clearance rates and broad gt6 diversity.

Subtype-Specific Prevalence of Hepatitis C Virus NS5A Resistance Associated Substitutions in Mainland China

Resistance associated substitutions (RASs) can reduce the efficacy of direct-acting antiviral agents (DAAs) targeting hepatitis C virus (HCV) and lead to treatment failure. Clinical data of HCV NS5A RASs prevalence are limited in China and need to be investigated. A total of 878 unique patient samples with different genotypes (GT) (1b: n = 489, 2a: n = 203, 3a: n = 60, 3b: n = 78, 6a: n = 48) were collected from around mainland China by KingMed Laboratory and analyzed for NS5A RASs distribution by Sanger sequencing. Phylogeographic analyses based on NS5A domain 1 sequences indicated circulation of both locally and nationally epidemic strains. Relatively high frequency of Y93H (14.1%) was only detected in GT1b but not in other subtypes. High frequency of L31M was found in both GT2a (95.6%) and GT3b (98.7%) sequences. Due to the overlapping incidence of A30K, 96% of GT3b isolates had NS5A RASs combination A30K + L31M, which confers high levels of resistance to most NS5A inhibitors. No RASs were detected in GT6a strains. Meanwhile, baseline NS5A RASs fingerprints were also evaluated in 185 DAA treatment-naive GT1b patients with next generation sequencing method. Patients presenting with Y93H had statistically higher entropy of HCV NS5A sequences. Taken together, subtype-specific distribution patterns of NS5A RASs were observed. GT1b patients with higher HCV complexity tend to have a greater chance of Y93H presence, while GT3b patients are naturally resistant to current NS5A inhibitors and their treatment may pose a challenge to real-world DAA application.

Molecular evolution of hepatitis C virus in China: A nationwide study

The evolutionary and epidemic history and the regional differences of hepatitis C virus (HCV) are complex and remain unclear in the vast territory China. Here we recruited 1540 HCV-RNA positive patients sampled in 29 provinces across whole China, which is the largest sample capacity and the most comprehensive geographic coverage of China to our knowledge. 1b, 2a, 3b, 6a and 3a were the major subtypes in China. 1b was the most predominant subtype which presented in every province. The second most predominant subtype, 2a, appeared to concentrate in the north of China. Subtypes 3a and 3b were mainly found in the Southwest region, while 6a was restricted in the South region. We further estimated the origins of the dominating subtypes and discovered for the first time that a Chinese-specific transmission pattern for some strains of subtype 2a which was restricted in north China, and Chinese subtype 3b originated from Thailand.

Hepatitis C virus genotypes and subtypes circulating in Mainland China

The hepatitis C virus (HCV) exhibits global genotypic diversity. HCV genotyping plays an important role in epidemiological studies and clinical management. Herein, we report the results of HCV genotype and subtype detection in a large number of clinical samples, as performed by an independent laboratory in China. In total, four HCV genotypes and 18 subtypes were identified among 32 030 patients from 29 provinces and municipalities in China. Five dominant subtypes were detected from 98.84% of the samples: 1b (n=16 713, 52.18%), 2a (n=9188, 28.69%), 3b (n=2261, 7.06%), 6a (n=2052, 6.41%) and 3a (n=1479, 4.62%). Twelve rare subtypes were detected, of which four (that is, 6b, 6j, 6q and 6r) are reported for the first time in the Chinese population. Genotypes 4, 5 and 7 were not detected. Mixed infections of the dominant subtypes were found in a small portion of samples (n=65, 0.203%), in the following combinations: 1b–2a, 1b–3b, 1b–6a, 3a–3b, 1b–3a and 2a–6a. No mixed infections with rare subtypes were found. Males, compared with females, showed higher HCV subtype diversity, a lower percentage of HCV1b and 2a and a higher percentage of rare subtypes and mixed infections. Our analyses revealed the comprehensive distribution patterns of HCV genotypes in the general population of mainland China. HCV genotypic patterns were differentially distributed on the basis of geography, sex and age.

Naturally Occurring Resistance-Associated Variants to Hepatitis C Virus Direct-Acting Antiviral Agents in Treatment-Naive HCV Genotype 6a-Infected Patients

BACKGROUND AND OBJECTIVE

The direct-acting antiviral agents (DAAs) antiviral therapy has drastically improved the prognosis of hepatitis C virus (HCV) patients. However, the viral drug resistance-associated variants (RAVs) can limit the efficacy of DAAs. For the HCV-6a is not the predominant prevalent genotype; the data on the prevalence of naturally occurring RAVs in it is scarce. Our study aims to assess the prevalence of RAVs in treatment-naive HCV-6a patients.

METHODS

Nested PCR assays were performed on 95 HCV-6a patients to amplify HCV viral regions of NS3, NS5A, and NS5B.

RESULTS

In NS3/4A region, we detected Q80K in 95.5% isolates (84/88) and D168E in 2.3% isolates (2/88). In NS5A region, we detected Q30R in 93.2% isolates (82/88), L31M in 4.6% isolates (4/88), and H58P in 6.8% isolates (6/88). In NS5B region, we detected A15G in 2.3% isolates (2/88), S96T in 1.1% isolates (1/88), and S282T in 20.7% isolates (17/88) and we detected I482L in 100% isolates (4/4), V494A in 50% isolates (2/4), and V499A in 100% isolates (4/4).

CONCLUSIONS

RAVs to DAAs preexist in treatment-naive HCV-6a patients. Further studies should address the issue of the impact of RAVs in response to DAA therapies for HCV-6a patients.

Prevalence of hepatitis C virus infection and its correlates in a rural area of southwestern China: a community-based cross-sectional study

OBJECTIVES

Hepatitis C virus (HCV) infection is a major public health problem in southwestern China. Our aim of the study was to assess the prevalence of HCV infection and its correlates in the Yi population of this region.

METHODS

A community-based survey was conducted to investigate sociodemographic characteristics and other associated factors for HCV infection in a rural area of southwestern China. Blood samples were collected and tested for antibodies to HCV. Anti-HCV positive samples were further assessed for HCV RNA.

RESULTS

A total of 2558 participants aged ≥14 years were included in our analysis. Of them, 2.8% (95% CI 2.2% to 3.5%) were positive for HCV antibody. Multiple logistic regression analysis revealed that sex (male vs female: adjusted OR (aOR)=3.30, 95% CI 1.80 to 6.07), marital status (unmarried vs married: aOR=0.27, 95% CI 0.09 to 0.80), ever using injection drug (aOR=28.65, 95% CI 15.9 to 51.64) and ever having blood transfusion (aOR=7.64, 95% CI 1.94 to 30.16) were significantly associated with HCV infection (indicated by positive HCV antibody). Stratified analysis by HIV infection found that in HIV-negative individuals, sex (male vs female: aOR=3.84, 95% CI 1.88 to 7.85), ever using injection drug (aOR=22.15, 95% CI 8.45 to 58.04), having multiple sexual partners (aOR=2.57, 95% CI 1.26 to 5.23), and ever having blood transfusion (aOR=16.54, 95% CI 4.44 to 61.58) were significantly associated with HCV infection and in HIV-positive individuals, ever using injection drug (aOR=8.96, 95% CI 3.16 to 25.38) was associated with HCV infection.

CONCLUSION

The data suggested a higher risk of HCV infection in this area when compared with the rest of China and some unique associated factors. Rapid scale-up of targeted interventions are needed to prevent further transmission and consequent morbidities.

Population dynamics of hepatitis C virus subtypes in injecting drug users on methadone maintenance treatment in China associated with economic and health reform

The extensive genetic heterogeneity of hepatitis C virus (HCV) requires in-depth understanding of the population dynamics of different viral subtypes for more effective control of epidemic outbreaks. We analysed HCV sequences data from 125 participants in Wuhan, China. These participants were newly infected by subtype 1b (n=13), 3a (n=15), 3b (n=50) and 6a (n=39) while on methadone maintenance treatment (MMT). Bayesian phylogenies and demographic histories were inferred for these subtypes. Participants infected with HCV-1b and 3a were clustered in well-supported monophyletic clades, indicating local subepidemics. Subtypes 3b and 6a strains were intermixed with other Chinese isolates, as well as isolates from other Asian countries, reflecting ongoing across geographic boundary transmissions. Subtypes 1b and 3a declined continuously during the past ten years, consistent with the health and economic reform in China, while subtype 3b showed ongoing exponential growth and 6a was characterized by several epidemic waves, possibly related to the recently growing number of travellers between China and other Asian countries. In conclusion, results of this study suggest that HCV subtype 3b and 6a subepidemics in China are currently not under control, and new epidemic waves may emerge given the rapid increase in international travelling following substantial economic growth.

Phylogeographical Analysis Reveals Distinct Sources of HIV-1 and HCV Transmitted to Former Blood Donors in China

Historically, coinfection of HIV and hepatitis C virus (HCV) was frequent among Chinese former blood donors (FBDs). This is largely due to ignorance/lack of education regarding appropriate sterilizing techniques and/or the availability of single-use needles and equipment. Although HCV shares identical transmission routes with HIV, the source of HCV in the Chinese blood donor population still remains unknown. In this study, we investigated the evolution and transmission of HCV and HIV in the Chinese FBD group. Similar to previous reports, two HCV subtypes (HCV 1b and 2a) and one HIV subtype (Thai-B) were identified in FBDs. The HCV 1b subtype had a similar evolutionary rate of 1.9 × 10^-3 substitutions/site/year to that of HIV (2.06 × 10^-3 substitutions/site/year), while the HCV 2a subtype had a faster evolutionary rate of 3.8 × 10^-3 substitutions/site/year. Phylogeographical analysis indicated that the introduction of HCV 1b into FBDs was estimated to be earlier than that of HCV 2a and HIV (late 1970s vs. late 1980s). Bayesian Skyline Plot (BSP) analysis further confirmed our findings, showing that HCV 1b infections breached a fast exponential growth from 1991 to 1998, while the HCV 2a infections had a fast exponential growth that occurred in around 1996-2001. Overall, this investigation helps to better understand HCV transmission in China and supports improvements of HCV prevalence control.

Hepatitis C Virus in mainland China with an emphasis on genotype and subtype distribution

Due to the low fidelity of the RNA-dependent RNA polymerase, Hepatitis C virus (HCV) mutates quite frequently. There are seven genetically divergent genotypes (GTs) distributed in the world, each of which contains several closely related subtypes. The peer-reviewed literatures reporting the prevalence rate of HCV GTs in Chinese hospitalized patients were identified by systematic searching of three electronic databases, and the prevalence rates were pooled through 137 qualified studies. The significant difference between HCV GT and HCV viral load and severity of hepatitis were analyzed under Chi-squared or Fisher's exact test. Data from epidemiological studies on hospitalized patients demonstrated that HCV GTs 1-6 have been found in China, of which 1b (62.78%(95% CI: 59.54-66.02%)) and 2a (17.39% (95% CI: 15.67-19.11%)) are the two predominant subtypes. HCV GTs and subtypes exhibits significant regional divergence. In North, Northwest, Northeast, East (except Jiangxi province) and Central China (except Hunan province), HCV-1b, 2a remain the two predominant subtypes; South China shows the most abundant genetic diversity that 14 subtypes were found, and HCV-3 in the Southwest China remains higher prevalent subtype than the other regions. In addition, co-infection in Liaoning province of Northeast China is the most diverse with 10 co-infection types, and Tibet has the highest rate of co-infection. The associations between HCV GTs and patients group, severity of illness and antiviral treatment efficacy were also discussed in this review.

Hepatitis B, C, and D virus infection showing distinct patterns between injection drug users and the general population

BACKGROUND AND AIM

Hepatitis B, C, and D virus (HBV, HCV, and HDV) infections are known to be prevalent in injection drug users (IDUs); however, the relationship between the molecular epidemiologic features of hepatitis virus infection in high-risk individuals and the general population has not yet been established.

METHODS

In total, 1049 IDUs and 672 individuals who underwent physical examinations at Chenzhou hospital, Hunan Province, China, were enrolled. HBV, HCV, and HDV infections were screened with serologic tests in both populations. HBsAg-positive, anti-HCV IgG-positive, and anti-HDV IgG-positive samples were further confirmed by polymerase chain reaction, quantitative polymerase chain reaction, and DNA sequencing.

RESULTS

Significantly higher HBV (21.54 vs 16.52%, P = 0.01), HCV (45.95% vs 1.34%, P < 0.001), and HDV (5.62% vs 0.30%, P < 0.001) infections were detected in IDUs compared with the general population. The dual infection of HBV/HCV or HBV/HDV was also significantly higher in IDUs than in the general population. HBV genotype B and HDV genotype II were dominants in both populations. HCV infection showed genotype 6a (49.52%) dominant in IDUs, but genotype 1b accounted for 50% infection, which was followed by genotype 6a (33.33%) in the general population. Higher viral loads were associated with HBV genotype B and HCV genotype 6a compared with non-dominant genotypic infections.

CONCLUSIONS

HBV and HDV infections shared similar patterns by IDUs and the general populations, and HCV infection exhibited distinct features between two populations. Our results suggest different molecular epidemiologic characteristics of HBV, HCV, and HDV infection in two populations.

Assessment of HCV genotypes in Yunnan Province of Southwest China

Recently, we reported that the frequency of hepatitis C virus (HCV) genotypes and subtypes has rapidly changed among intravenous drug users (IDUs) in Yunnan Province over the last 5 years; this is especially true for subtype 6a which has increased in frequency from 5 to 15%. Here, we assessed 120 HCV-positive plasma samples from the general population (GP). HCV NS5B fragments were amplified and sequenced by PCR. We identified four HCV genotypes (1, 2, 3 and 6) and seven HCV subtypes (1b, 2a, 3a, 3b, 6a, 6n, and 6k) in this population. Genotype 3 was predominant, with a distribution frequency of 0.484, followed by genotype 1 (0.283), genotype 6 (0.133) and genotype 2 (0.100). HCV subtypes 3b (frequency 0.292) and 1b (frequency 0.283) were the most common subtypes. A comparison of the current data with previous results reported for IDUs showed that the distribution frequencies of genotypes 1, 2 and 6 were significantly different between patients in the GP and IDUs (P < 0.05). Among the HCV subtypes, the distribution frequencies of 1b, 2a, 6a, and 6n were significantly different between patients in the GP and IDU groups (P < 0.05). Moreover, Phylogenetic analyses showed that HCV subtype 6a strains isolated from IDUs and the GP were intermixed and not separately clustered. HCV subtype 6a was predominant not only among IDUs but also among those in the GP in the Guangdong Province and Vietnam. However, HCV subtype 6a was predominant only among IDUs and not among those in the GP in the Yunnan and Guangxi Provinces. Our results indicate that the HCV subtype 6a could rapidly spread across China.

An outbreak of HCV genotype 6a and 2a infection in South China: Confirmation of iatrogenic transmission by phylogenetic analysis of the NS5B region

An outbreak of hepatitis C virus (HCV) infections, for which the risk factor was unknown, was previously identified in North Guangdong, China. In the present study, a total of 736 local residents were surveyed regarding their lifetime risk factors for HCV infection. Serum anti‑HCV antibodies and HCV RNA were examined to confirm infection. In the HCV‑positive samples, the core and nonstructural protein 5B sequences were amplified, and phylogenetic analysis was performed to determine the association between HCV subtypes and transmission routes. A total of 374 individuals were positive for anti‑HCV antibodies. Blood transfusion, blood product transfusion, people who inject drugs and intravenous injection at a local clinic were identified as independent risk factors for HCV infection. Phylogenetic analysis revealed that the two predominant subtypes of HCV, 2a and 6a, were primarily focused in four homologous clusters. Patients with a history of intravenous injection at a local clinic were more likely to be found in the four clusters, compared with patients exposed to other risk factors. The present emergency retrospective survey showed a specific epidemiological feature of HCV infection in Zijin County and found genetic homology among individuals exposed to intravenous injection at a local clinic. Further evidence is required to confirm the causal association between the outbreak of HCV infection and intravenous injection.

Changing Epidemiology of Hepatitis C Virus Genotype among Patients with Human Immunodeficiency Virus/Hepatitis C Virus Co-Infection in China

BACKGROUND

Co-infection with hepatitis C virus (HCV) has become the most common cause of death in human immunodeficiency virus (HIV) infected patients on antiretroviral therapy. The distribution of HCV genotypes varies with geographical regions and time, and limited studies have focused on the HCV genotype in HIV/HCV co-infection.

METHODS

The distribution of HCV genotypes was evaluated in 414 patients with HIV/HCV co-infection in three regions (South, Central and Northwest) of China from 2008 to 2010. The NS5B region of HCV was characterized using nested reverse transcription polymerase chain reaction. Nucleotide sequences obtained were subjected to phylogenetic analysis, and genotypes were assigned using published reference genotypes.

RESULTS

Genotype 3 was the most prevalent HCV strain (36.2%), followed by genotype 6 (30.0%), genotype 1 (28.5%), genotype 2 (5.1%), and genotype 5 (0.2%). The distribution varied geographically. Genotype 6 (37.6%) was the predominant strain while genotype 1 (20.2%) was less common in the South compared to the Central and Northwest regions (all P < 0.001). The distribution also varied temporally. There was no significant difference in genotype distribution in Guangdong (a province in the South region), between patient cohorts from 2005-2008 and 2009-2010. However, outside Guangdong, genotypes 3 and 6a became significantly more prevalent (22.4% vs.42.2%, P< 0.001; 8.0% vs. 19.8%, P = 0.004), and genotype 1 less prevalent (54.4% vs.26.6%, P< 0.001) over time.

CONCLUSION

The most dramatic shift in genotypic distribution was the movement of HCV genotypes 3 and 6a outside of Guangdong in HIV/HCV co-infected patients. This movement appeared closely associated with transmission via injected drug use.

Hepatitis C Virus Increases Free Fatty Acids Absorption and Promotes its Replication Via Down-Regulating GADD45α Expression

BACKGROUND Hepatitis C virus (HCV) infection, as a major cause of chronic hepatic diseases, is always accompanied with an abnormality of lipid metabolism. The aim of this study was to investigate the pathogenic role of free fatty acids (FFA) in human HCV infection. MATERIAL AND METHODS Peripheral blood lipid indexes among HCV patients with different viral loads (199 samples) and healthy donors (80 samples) were detected by clinical biochemistry tests. HCV replication and the expression of growth arrest and DNA-damage-inducible gene 45-α (GADD45α) in Huh7 cells and clinical samples were quantified by quantitative real-time polymerase chain reaction (qRT-PCR) and Western blotting. Lipid accumulation in Huh7 cells was detected by immunofluorescence. RESULTS In this study, we found that FFA showed a significant positive correlation with viral load in peripheral blood of HCV patients, but not total cholesterol (TC), triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), or low-density lipoprotein cholesterol (LDL-C). GADD45α expression in HCV patients dramatically decreased with the increase of viral load. In Huh7 cells, FFA treatment significantly enhanced HCV replication. HCV infection inhibited GADD45α expression, and this effect was further enhanced with the presence of FFA treatment. Ectopic expression of GADD45α in HCV-infected Huh7 cells markedly inhibited the absorption of FFA and HCV replication. However, FFA significantly elevated GADD45α expression without HCV infection. CONCLUSIONS These results demonstrated that HCV down-regulates GADD45α expression to enhance FFA absorption and thus facilitate its replication. GADD45α is an essential mediator for the pathogenesis of HCV infection. Thus, our study provides potential clues in the search for novel therapeutics and fatty lipid control options for HCV patients.

Distribution of hepatitis C virus genotypes in volunteer blood donors from Chengdu, China

Hepatitis C virus (HCV) is a significant pathogen of global concern. The virus is usually spread through blood contact, such as transfusion, hemodialysis and injection of illegal drugs. HCV genotypes have a geographic distribution in different areas. In this paper, we focus on the distribution of HCV genotypes from volunteer blood donors in Chengdu. The prevalence of genotypes was analyzed using phylogenetic analysis. Phylogenetic trees were constructed based on the HCV core and NS5B regions from 313 sequences. HCV sequences were classified into six subtypes, and HCV genotypes were determined with the following results: 1b in 283, 2a in 14, 3b in seven, 3a in three, 6a in five and 6u in one. Subtype 1b was the most common and accounted for approximately 90.41 % (283/313), and a virus of subtype 6u was isolated for the first time from the Chengdu area. Genotypes 4 and 5 were not detected.

Hepatitis C Virus Subtype and Evolution Characteristic Among Drug Users, Men Who Have Sex With Men, and the General Population in Beijing, China

The aim of this study was to characterize the current molecular epidemiology of hepatitis C virus (HCV) infection and evaluate the evolutionary patterns of HCV subtypes in Beijing, China, among different subpopulations.The whole blood samples and behavioral data were collected from a total of 10,354 subjects, including drug users (DUs), men who have sex with men (MSM), and the general population, in Beijing from 2010 to 2011. Samples were tested for HCV infection using both enzyme-linked immunosorbent assay (ELISA) and real-time PCR. All viremic subjects were then sequenced by nested PCR over core/E1 and NS5B regions. Phylogenetic and phylogeographic analysis was performed by BEAST software.In total, 217 subjects (2.1%) were tested positive for HCV by antibody or vRNA-based testing. HCV prevalence rates for DUs, MSM, and the general population were 26.2%, 0.54%, and 0.37%, respectively. The 156 HCV RNA-positive samples were sequenced. Nine HCV genotypes, including 1a, 1b, 2a, 3a, 3b, 6a, 6n, 6u and 6v, were detected. The most prevalent subtypes were 3b (36.09%), 1b (32.54%), and 3a (16.57%). Bayesian evolutionary analysis estimated that the time of introduction of subtype 1b into Beijing was 2004 (95% CI: 1997.7, 2007.7), with subtypes 3a and 3b being introduced later in 2006. Evolutionary analyses further suggested that subtype 1b from Beijing and Shanghai were closely related, whereas subtype 3a sequences were more similar with sequences from Yunnan, Guangzhou, Hong Kong, and Jiangsu. Subtype 3b sequences were closely related to those from Yunnan, Guangdong, and Hong Kong.Thus, the current HCV epidemic in Beijing is complex, heavily affecting DUs, and involving multiple genotypes that likely spread from different regions in China with its large migrant population.

Multiple Introduction and Naturally Occuring Drug Resistance of HCV among HIV-Infected Intravenous Drug Users in Yunnan: An Origin of China's HIV/HCV Epidemics

Background

The human immunodeficiency virus 1 (HIV-1) epidemic in China historically stemmed from intravenous drug users (IDUs) in Yunnan. Due to a shared transmission route, hepatitis C virus (HCV)/HIV-1 co-infection is common. Here, we investigated HCV genetic characteristics and baseline drug resistance among HIV-infected IDUs in Yunnan.

Methods

Blood samples of 432 HIV-1/HCV co-infected IDUs were collected from January to June 2014 in six prefectures of Yunnan Province. Partial E1E2 and NS5B genes were sequenced. Phylogenetic, evolutionary and genotypic drug resistance analyses were performed.

Results

Among the 293 specimens successfully genotyped, seven subtypes were identified, including subtypes 3b (37.9%, 111/293), 3a (21.8%, 64/293), 6n (14.0%, 41/293), 1b (10.6%, 31/293), 1a (8.2%, 24/293), 6a (5.1%, 15/293) and 6u (2.4%, 7/293). The distribution of HCV subtypes was mostly related to geographic location. Subtypes 3b, 3a, and 6n were detected in all six prefectures, however, the other four subtypes were detected only in parts of the six prefectures. Phylogeographic analyses indicated that 6n, 1a and 6u originated in the western prefecture (Dehong) and spread eastward and showed genetic relatedness with those detected in Burmese. However, 6a originated in the southeast prefectures (Honghe and Wenshan) bordering Vietnam and was transmitted westward. These subtypes exhibited different evolutionary rates (between 4.35×10⁻⁴ and 2.38×10⁻³ substitutions site^-1 year^-1) and times of most recent common ancestor (tMRCA, between 1790.3 and 1994.6), suggesting that HCV was multiply introduced into Yunnan. Naturally occurring resistance-associated mutations (C316N, A421V, C445F, I482L, V494A, and V499A) to NS5B polymerase inhibitors were detected in direct-acting antivirals (DAAs)-naïve IDUs.

Conclusion

This work reveals the temporal-spatial distribution of HCV subtypes and baseline HCV drug resistance among HIV-infected IDUs in Yunnan. The findings enhance our understanding of the characteristics and evolution of HCV in IDUs and are valuable for developing HCV prevention and management strategies for this population.

24 versus 48 Weeks of Peginterferon Plus Ribavirin in Hepatitis C Virus Genotype 6 Chronically Infected Patients with a Rapid Virological Response: A Non-Inferiority Randomized Controlled Trial

Objectives

The optimal treatment of hepatitis C virus (HCV) genotype 6 is unclear owing to its limited geographic distribution. Because of a high predictive value of rapid virological response (RVR) for sustained virological response (SVR), we conducted an open-label randomized controlled trial to compare 24- and 48-week peginterferon/ribavirin combination therapy for patients with HCV genotype 6 in Southern China who achieved an RVR.

Methods and Findings

Treatment-naive, non-cirrhotic patients with chronic hepatitis C genotype 6 were treated with pegylated interferon α-2a (180 μg/week) and ribavirin (800–1,200 mg, according to weight) for 4 weeks. Patients who achieved an RVR, which was defined as HCV RNA negativity at week 4 (<50 IU), were randomized to receive either an additional 20 or 44 weeks of treatment (24- and 48-week treatment groups, respectively). The primary outcome measure was SVR. From January 2011 to June 2014, 152(152/210, 72.4%) patients with HCV genotype 6a and RVR were randomized 1:1 to the 24- or 48-week treatment group. The SVR rates in the 24- and 48-week groups in the intention-to-treat analysis were 90.8% (69/76) and 88.2% (67/76), respectively; those in the per-protocol analysis were 95.7% (67/70) and 97.0% (64/66), respectively. More patients in the 48-week group had anemia (46.1% vs. 28.9%, P = 0.03), but other adverse events were comparable between the groups. The limitation of the present study was that only patients from Southern China were enrolled which may inhibit the extensive application of the findings.

Conclusion

Twenty-four weeks of peginterferon/ribavirin combination therapy was non-inferior to 48 weeks in patients with HCV genotype 6a in Southern China who achieved an RVR.

Trial Registration

ClinicalTrials.gov NCT01263860

Genotypic distribution and hepatic fibrosis among HIV/HCV co-infected individuals in Southern China: a retrospective cross-sectional study

Background

End-stage liver disease and hepatocellular carcinoma due to hepatitis C virus (HCV) co-infection are increasingly common causes of death among HIV-infected individuals. However, there are few clinical investigations of HIV/HCV co-infected individuals from low and middle-income nations. Here, we compare the epidemiology of HCV-infected and HIV/HCV co-infected individuals in Southern China and examine hepatic fibrosis scores in co-infected individuals.

Methods

We conducted a retrospective cross-sectional study of treatment-naïve HIV/HCV co-infected and HCV mono-infected subjects. Bivariate and multivariate models were used to examine the association between demographics and HCV genotype. Among co-infected individuals, we also studied the relationship between fibrosis scores derived from non-invasive studies and HCV genotype.

Results

Data were collected from 175 HCV-infected individuals, including 89 (51 %) HIV/HCV co-infected individuals. HIV/HCV co-infection was correlated with intravenous drug use (AOR 46.25, p < 0.001) and not completing high school (AOR 17.39, p < 0.001) in a multivariate model. HIV/HCV co-infected individuals were more likely to be infected with HCV genotype 6a (p < 0.0001) or 3a (p < 0.023), whereas increased fibrosis (FIB-4 score) was associated with HCV genotype 3a infection (β 2.18, p < 0.001).

Discussion

Our results suggest that intravenous drug use is driving HIV/HCV co-infection in Southern China. While additional studies are needed, HCV genotype 6a is more common and genotype 3a appears to be associated with more severe hepatic fibrosis in co-infected individuals.

Conclusions

Future HIV/HCV co-infection research in China should focus on at risk populations, HCV testing uptake, and genotype-specific treatment.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-015-1135-1) contains supplementary material, which is available to authorized users.

The evolutionary patterns of hepatitis C virus subtype 2a and 6a isolates linked to an outbreak in China in 2012

An HCV outbreak occurred in 2012 in China, affecting hundreds of patients. We characterized HCV subtype 2a and 6a sequences from 60 and 102 patients, respectively, and co-analyzed them with 82 local controls and 103 calibrating references. The close grouping of the patients׳ sequences contrasted sharply with the diversity of local controls. Scaled by the calibrating references, the emergence of patients׳ isolates was estimated at 2-5 years before sampling. In contrast, the controls intermingled with the calibrating references that were much older. For both subtypes, the major and minor clusters could be defined, with the closeness to indicate linked transmission.

CONCLUSION

HCV sequences from the study patients grouped into three subtype 2a and two subtype 6a clusters, in addition to three 6a solitary branches, representing descendants of eight earlier strains that were distinct and otherwise sporadic. Due to iatrogenic transmission through reusing needles, five strains were highly selected and preferentially spread.

Effective epitope identification employing phylogenetic, mutational variability, sequence entropy, and correlated mutation analysis targeting NS5B protein of hepatitis C virus: from bioinformatics to therapeutics

Hepatitis C virus (HCV) is considered as a foremost cause affecting numerous human liver-related disorders. An effective immuno-prophylactic measure (like stable vaccine) is still unavailable for HCV. We perform an in silico analysis of nonstructural protein 5B (NS5B) based CD4 and CD8 epitopes that might be implicated in improvement of treatment strategies for efficient vaccine development programs against HCV. Here, we report on effective utilization of knowledge obtained from multiple sequence alignment and phylogenetic analysis for investigation and evaluation of candidate epitopes that have enormous potential to be used in formulating proficient vaccine, embracing multiple strains prevalent among major geographical locations. Mutational variability data discussed herein focus on discriminating the region under active evolutionary pressure from those having lower mutational potential in existing experimentally verified epitopes, thus, providing a concrete framework for designing an effective peptide-based vaccine against HCV. Additionally, we measured entropy distribution in NS5B residues and pinpoint the positions in epitopes that are more susceptible to mutations and, thus, account for virus strategy to evade the host immune system. Findings from this study are expected to add more details on the sequence and structural aspects of NS5B protein, ultimately facilitating our understanding about the pathophysiology of HCV and assisting advance studies on the function of NS5B antigen on the epitope level. We also report on the mutational crosstalk between functionally important coevolving residues, using correlated mutation analysis, and identify networks of coupled mutations that represent pathways of allosteric communication inside and among NS5B thumb, finger, and palm domains.

HLA-B alleles B*15:01 and B*15:02: opposite association with hepatitis C virus infection in Chinese voluntary blood donors

BACKGROUND

Although human leukocyte antigens (HLA) have been shown in association with the outcomes of hepatitis C virus (HCV) infection among different ethnic groups, such studies remain absent in China, where the HCV prevalence is higher than the global average.

METHODS

In this study, 426 HCV-infected and 709 uninfected blood donors were analyzed, among whom the HLA alleles were sequenced using a high-resolution genotyping method.

RESULTS

At the 2-digit level, none of the alleles showed a statistical difference between the HCV-infected and uninfected groups. However, at the 4-digit level, the HLA-B alleles B*15:01 and B*15:02 showed an opposite association with HCV infection, i.e. B*15:01 was significantly higher in the HCV-infected group (odds ratio, OR = 1.561, p = 0.010), while B*15:02 was significantly higher in the uninfected group (OR = 0.778, p = 0.016). We also identified a higher frequency of B*13:02 in the HCV-infected group (OR = 1.515, p = 0.009) and a higher frequency of B*07:05 in the uninfected group (OR = 0.299, p = 0.001).

CONCLUSIONS

The frequencies of four HLA alleles, B*07:05, B*13:02, B*15:01, and B*15:02, were found to be significantly different between the HCV-infected and uninfected blood donors in China, revealing an inverse relation of B*15:01 and B*15:02 with HCV infection. This finding suggests that the ethnic genetic variations of HLA may greatly affect the host immune responses against HCV.

The global burden of liver disease: the major impact of China

Liver disease is a major cause of illness and death worldwide. In China alone, liver diseases, primarily viral hepatitis (predominantly hepatitis B virus [HBV]), nonalcoholic fatty liver disease, and alcoholic liver disease, affect approximately 300 million people. The establishment of the Expanded Program on Immunization in 1992 has resulted in a substantial decline in the number of newly HBV-infected patients; however, the number of patients with alcoholic and nonalcoholic fatty liver diseases is rising at an alarming rate. Liver cancer, one of the most deadly cancers, is the second-most common cancer in China. Approximately 383,000 people die from liver cancer every year in China, which accounts for 51% of the deaths from liver cancer worldwide. Over the past 10 years, China has made some significant efforts to shed its "leader in liver diseases" title by investing large amounts of money in funding research, vaccines, and drug development for liver diseases and by recruiting many Western-trained hepatologists and scientists. Over the last two decades, hepatologists and scientists in China have made significant improvements in liver disease prevention, diagnosis, management, and therapy. They have been very active in liver disease research, as shown by the dramatic increase in the number of publications in Hepatology. Nevertheless, many challenges remain that must be tackled collaboratively. In this review, we discuss the epidemiology and characteristics of liver diseases and liver-related research in China.

Global epidemiology and genotype distribution of the hepatitis C virus infection

The treatment of chronic hepatitis C virus (HCV) infection has the potential to change significantly over the next few years as therapeutic regimens are rapidly evolving. However, the burden of chronic infection has not been quantified at the global level using the most recent data. Updated estimates of HCV prevalence, viremia and genotypes are critical for developing strategies to manage or eliminate HCV infection. To achieve this, a comprehensive literature search was conducted for anti-HCV prevalence, viraemic prevalence and genotypes for all countries. Studies were included based on how well they could be extrapolated to the general population, sample size and the age of the study. Available country estimates were used to develop regional and global estimates. Eighty-seven countries reported anti-HCV prevalence, while HCV viraemic rates were available for fifty-four countries. Total global viraemic HCV infections were estimated at 80 (64-103) million infections. Genotype distribution was available for ninety-eight countries. Globally, genotype 1 (G1) was the most common (46%), followed by G3 (22%), G2 (13%), and G4 (13%). In conclusion, the total number of HCV infections reported here are lower than previous estimates. The exclusion of data from earlier studies conducted at the peak of the HCV epidemic, along with adjustments for reduced prevalence among children, are likely contributors. The results highlight the need for more robust surveillance studies to quantify the HCV disease burden more accurately.

The genetic diversity and evolutionary history of hepatitis C virus in Vietnam

Vietnam has a unique history in association with foreign countries, which may have resulted in multiple introductions of the alien HCV strains to mix with those indigenous ones. In this study, we characterized the HCV sequences in Core-E1 and NS5B regions from 236 Vietnamese individuals. We identified multiple HCV lineages; 6a, 6 e, 6h, 6k, 6l, 6 o, 6p, and two novel variants may represent the indigenous strains; 1a was probably introduced from the US; 1b and 2a possibly originated in East Asia; while 2i, 2j, and 2m were likely brought by French explorers. We inferred the evolutionary history for four major subtypes: 1a, 1b, 6a, and 6 e. The obtained Bayesian Skyline Plots (BSPs) consistently showed the rapid HCV population growth from 1955 to 1963 until 1984 or after, corresponding to the era of the Vietnam War. We also estimated HCV growth rates and reconstructed phylogeographic trees for comparing subtypes 1a, 1b, and HCV-2.

Current challenges and the management of chronic hepatitis C in mainland China

Despite decreasing prevalence, new cases of hepatitis C in China are increasing recently with growing percentage of patients who are with advanced disease, aging, or not eligible for interferon-based treatments. Hepatitis C infection represents a serious public health burden. This review was based on expert's consensus during a medical forum on hepatitis sponsored by the Beijing Wu Jie-Ping Medical Foundation. The literature searches were conducted in PubMed and critical publications in Chinese journals. Data on hepatitis C prevalence, risk factors, viral or host features, and treatment modalities were extracted and reviewed. Recent large-scale surveys reported reducing prevalence of hepatitis C to approximately 0.4% in China, partly because of regulation changes to safer medical practices and illegalizing commercial blood donations. Patient demographics evolved from being dominated by former paid blood donors to include intravenous drug users and others. Although hepatitis C genotype 1 is the most common, other genotypes are emerging in prevalence. The current standard of care is interferon-based without direct acting antivirals. However, many patients failed therapy because of high treatment costs, substantial needs to manage side effects, difficulties with treatment monitoring in the rural areas, and growing populations of elderly and cirrhotic patients. The lack of high efficacy therapies with good safety profile and low disease awareness in China resulted in increasing public burden of advanced hepatitis C disease. Despite significant reduction of hepatitis C prevalence, iatrogenic, nosocomial, and community transmissions are still significant. In addition to promoting disease awareness, interferon-free regimens are needed to reduce the public health burden.

Increased prevalence of hepatitis C virus subtype 6a in China: a comparison between 2004-2007 and 2008-2011

Different hepatitis C virus (HCV) genotypes exhibit differences in disease pathogenesis and progression, as well as disease outcomes and response to therapy. Tracking the change of HCV genotypes in various epidemiological settings is critical for both disease surveillance and the development of improved antiviral treatment. Here, we tracked the changes in the prevalence of the HCV genotypes in China between 2004-2007 and 2008-2011. HCV-RNA-positive sera were collected from volunteer blood donors during the period 2008-2011. The genotypes were determined by phylogenic analysis using the NS5B and E1 sequences. Geographical and demographic distribution patterns related to the HCV genotypes obtained in 2008-2011 were compared with our previous study, which recorded data in the period 2004-2007. Pearson chi-square test and t-test were used to statistically analyze the results. In 2008-2011, HCV subtypes 1b and 6a were detected in 43.8 % (184/420) and 34.3 % (144/420), respectively. The male/female ratio was found to be higher for HCV genotype 6 than for genotypes 1 and 2. When compared with the period of 2004-2007, although no significant difference was found in gender or age for genotypes 1, 2, 3 and 6, the subtype 6a frequency was significantly increased from 11 % to 26.5 % in the blood donors from outside of Guangdong Province in 2008-2011. A pattern of increase in HCV subtype 6a was found in blood donors outside of Guangdong Province, indicating that HCV subtype 6a has rapidly spread from Guangdong to other regions of China over the past 10 years.

A reliable multiplex genotyping assay for HCV using a suspension bead array

The genotyping of the hepatitis C virus (HCV) plays an important role in the treatment of HCV because genotype determination has recently been incorporated into the treatment guidelines for HCV infections. Most current genotyping methods are unable to detect mixed genotypes from two or more HCV infections. We therefore developed a multiplex genotyping assay to determine HCV genotypes using a bead array. Synthetic plasmids, genotype panels and standards were used to verify the target-specific primer (TSP) design in the assay, and the results indicated that discrimination efforts using 10 TSPs in a single reaction were extremely successful. Thirty-five specimens were then tested to evaluate the assay performance, and the results were highly consistent with those of direct sequencing, supporting the reliability of the assay. Moreover, the results from samples with mixed HCV genotypes revealed that the method is capable of detecting two different genotypes within a sample. Furthermore, the specificity evaluation results suggested that the assay could correctly identify HCV in HCV/human immunodeficiency virus (HIV) co-infected patients. This genotyping platform enables the simultaneous detection and identification of more than one genotype in a same sample and is able to test 96 samples simultaneously. It could therefore provide a rapid, efficient and reliable method of determining HCV genotypes in the future.

Migration patterns of hepatitis C virus in China characterized for five major subtypes based on samples from 411 volunteer blood donors from 17 provinces and municipalities

We investigated the migration patterns of hepatitis C virus (HCV) in China. Partial E1 and/or NS5B sequences from 411 volunteer blood donors sampled in 17 provinces and municipalities located in five large regions, the north-northeast, northwest, southwest, central south, and southeast, were characterized. The sequences were classified into eight subtypes (1a, n = 3; 1b, n = 183; 2a, n = 83; 3a, n = 30; 3b, n = 44; 6a, n = 55; 6n, n = 10; 6v, n = 1) and a new subtype candidate. Bayesian evolutionary analysis by sampling trees of the E1 sequences of the five major subtypes revealed distinct migration patterns. Subtype 1b showed four groups: one is prevalent nationwide with possible origins in the north-northeast; two are locally epidemic in the central south and northwest, respectively, and have spread sporadically to other regions; and the fourth one is likely linked to the long-distance dispersion among intravenous drug users from the northwest. Subtype 2a showed two groups: the larger one was mainly restricted to the northwest and seemed to show a trend toward migration via the Silk Road; the smaller one was geographically mixed and may represent descendants of those that spread widely during the contaminated plasma campaign in the 1990s. Subtype 3a exhibited three well-separated geographic groups that may be epidemically unrelated: one showed origins in the northwest, one showed origins in the southwest, and the other showed origins in the central south. In contrast, subtype 3b had a mixture of geographic origins, suggesting migrations from the southwest to the northwest and sporadically to other regions. Structurally resembling the tree for subtype 3a, the tree for subtype 6a showed four groups that may indicate migrations from the central south to southeast, southwest, and northwest. Strikingly, no subtype 6a strain was identified in the north-northeast.

IMPORTANCE

With a population of greater than 1.3 billion and a territory of >9.6 million square kilometers, China has a total of 34 provinces and municipalities. In such a vast country, the epidemic history and migration trends of HCV are thought to be unique and complex but variable among regions and are unlikely to be represented by those observed in only one or at best a few provinces and municipalities. However, due to the difficulties in recruiting patients, all previous studies for this purpose have been based only on data from limited regions, and therefore, geographical biases were unavoidable. In this study, such biases were greatly reduced because we utilized samples collected from volunteer blood donors in 17 provinces and municipalities. To our knowledge, this is the first study in which the HCV isolates represented such a large portion of the country, and thus, the results should shed light on the current understanding of HCV molecular epidemiology.

Characteristics of HCV co-infection among HIV infected individuals from an area with high risk of blood-borne infections in central China

OBJECTIVE

Hepatitis C virus (HCV) and human immunodeficiency virus (HIV) co-infection has been proved to be a growing public health concern. The prevalence and genotypic pattern vary with geographic locations. Limited information is available to date with regard to HCV genotype and its clinical implications among those former commercial blood donor communities. The aims of this study were to genetically define the HCV genotype and associated clinical characteristics of HIV/HCV co-infected patients from a region with commercial blood donation history in central China.

METHODS

A cross sectional study, including 164 HIV infected subjects, was conducted in Shanxi province central China. Serum samples were collected and HCV antibody testing, AST and ALT testing were performed. Seropositive samples were further subjected to RT-PCR followed by direct sequence coupled with phylogenetic analysis of Core-E1 and NS5B regions performed in comparison with known reference genotypes.

FINDINGS

A total of 139 subjects were HCV antibody positive. Genotype could be determined for 88 isolates. Phylogenetic analysis revealed that the predominant circulating subtype was HCV 1b (65.9%), followed by HCV 2a (34.1%). The HCV viral load in the subjects infected with HIV1b was significantly higher than those infected with HCV 2a (P = 0.006). No significant difference for HCV RNA level was detected between ART status, CD4+ cell count level and HIV RNA level. Serum AST and ALT level were likely to increase with HCV RNA level, although no significance was observed. Those who had conducted commercial donation later than 1991 (OR 3.43, 95% CI: 1.12-10.48) and had a short duration of donation (OR 0.35, 95% CI: 0.13-0.96) were more likely to be infected with HCV 1b.

CONCLUSION

These results suggest that HCV subtype 1b predominates in this population, and the impact of HIV status and ART on HCV disease progression is not significantly correlated.

Distribution and clinical correlates of viral and host genotypes in Chinese patients with chronic hepatitis C virus infection

BACKGROUND AND AIM

Chronic hepatitis C virus (HCV) infection is relatively frequent in China. This study investigated the clinical, demographic, and viral and host genetic characteristics that may influence disease manifestations and clinical management.

METHODS

In this cross-sectional observational study, treatment-naïve Han ethnic adults with recently confirmed chronic HCV infection were enrolled at 28 hospitals across China. HCV genotype and host interleukin 28B (IL28B) genotypes were determined and compared with patient demographic parameters and medical status.

RESULTS

Among the 997 HCV-positive patients analyzed, 56.8% were infected with HCV genotype 1b, followed in prevalence by genotypes 2, 3, and 6, with substantial regional variation. Overall, 84.1% of patients were IL28B genotype CC (rs12979860), with little regional variation. Cirrhosis was reported in 10.1% of patients and was significantly associated with hepatitis B virus coinfection, low HCV viral load, low serum alanine aminotransferase, high serum aspartate aminotransferase, diabetes, and high pickled food consumption. Medical procedures were common transmission risk factors; however, lifestyle-associated risk factors, including intravenous drug abuse and tattoos or piercings, were more common in patients with HCV genotype 3 or 6.

CONCLUSIONS

Most HCV-infected Han Chinese patients were IL28B genotype CC (rs12979860). HCV genotypes varied by geographic region, and disease characteristics differed according to HCV genotype. Relatively frequent detection of advanced liver disease may reflect limitations on access to antiviral therapy, and suggests that greater awareness of factors that influence HCV-associated disease may help avoid clinical complications and improve patient outcomes.

Molecular epidemiologic characterization of a clustering HCV infection caused by inappropriate medical care in Heyuan City of Guangdong, China

Background

From November 2011 to January 2012, a number of clustering cases of HCV infection were reported in Zijin County, Heyuan City, Guangdong, China. Most patients in the clustering cases suspected that they could be infected due to inappropriate medical care in the clinic located at the Xiangshui road. However, the molecular epidemiology of the clustering cases remains unknown.

Methodology

The residents, living at Xiangshui Road, with HCV antibody positive reported from 2011 and 2012 were recruited. A survey of the HCV infected individuals from the clustering cases was conducted. Each participant underwent a questionnaire defining demographic characteristics and health care history. HCV serological test and viral load test were performed to confirm the infection status. Molecular phylogenetic analysis and Bayesian coalescence analysis were conducted to further confirm the HCV subtype distribution and to reconstruct the associated demographic history and time-scaled phylogeny among the clustering cases.

Principal Findings

The molecular phylogenetic analysis revealed that only two HCV subtypes, 2a and 6a, were found among the clustering cases. There was no close HCV subtype evolutionary relation was observed among patients from the same family. The 6a cluster showed higher viral loads than the 2a cluster. In addition, the Bayesian skyline plot analysis showed that both the HCV 2a and 6a subtype infections among the Heyuan cases experienced an “expansion-diminishment-expansion” featured dissemination. The 2a clustering infection occurred in 2004, and the 6a clustering cases originated in 2006.

Conclusions

The molecular epidemiological characters imply that the inappropriate medical practices were possibly associated with the clustering HCV cases in Heyuan City during 2011, 2012. Latent HCV subtypes 2a and 6a infection may cause the prevalence and become a new public health issue in Guangdong, China.

A panel of 16 full-length HCV genomes was characterized in China belonging to genotypes 1-6 including subtype 2f and two novel genotype 6 variants

In this study, we characterized the full-length genomes of 16 HCV isolates obtained from patients in a single hospital in China using overlapping PCR followed by DNA sequencing. The obtained genomes are 9414-9628 nucleotides in length, and each genome contains a single ORF of 9021-9102 nucleotides. Nine genomes represent the common subtypes 1a, 1b, 2a, 2b, 3a, 3b, and 6a, while seven represent the infrequent lineages 1c, 2f, 4d, and 5a, and two novel genotype 6 variants. GZ51969 and GZ52540 are subtype 1b isolates belonging to two unique clusters designated A and B, which account for 29.5% and 59.5% of the 1b infections in China, respectively. ZS542 and GZ98799 represent the first two complete genomes of the provisionally assigned subtype 2f. ZS96 and ZS202 are novel genotype 6 variants that may qualify for two new subtypes. ZS17, ZS537, and ZS631 represent three alien subtypes, namely, 1c, 4d, and 5a, which were detected in China for the first time in this study and may have been recently introduced as a result of globalization. Taken together, these results confirmed a large variety of HCV taxonomic lineages in China through the sequencing of their full-length genomes. These lineages represent six genotypes, 11 subtypes, and two novel variants. They were characterized for achieving a better understanding of the HCV genetic variation patterns and for possible future research applications.

The current hepatitis C virus prevalence in China may have resulted mainly from an officially encouraged plasma campaign in the 1990s: a coalescence inference with genetic sequences

In this study, we investigated hepatitis C virus (HCV) molecular epidemiology and evolutionary dynamics. Both E1 and NS5B sequences were characterized in 379 of 433 patients in southern China and classified into five major subtypes: 1b in 256 patients, 6a in 67 patients, 2a in 29 patients, 3a in 14 patients, and 3b in 13 patients. Using the E1 sequences obtained, along with those from other studies using samples from China, we inferred the HCV epidemic history by means of coalescence strategies. Five Bayesian skyline plots (BSPs) were estimated for the five subtypes. They concurrently highlighted the rapid growth in the HCV-infected population size from 1993 to 2000, followed by an abrupt slowing. Although flanked on both sides by variable population sizes, the plots showed distinct patterns of rapid HCV growth. Coincidently, 1993 to 2000 was a period when contaminated blood transfusions were common in China due to a procedural error in an officially encouraged plasma campaign. The abrupt slowing in 1998 to 2000 corresponded to the central government outlawing paid blood donations in 1998. Using a parametric model, the HCV population growth rates were estimated during 1993 to 2000. It was revealed that the 6a rate was the highest, followed by those of 1b, 2a, 3b, and 3a. Because these rates differed significantly (P < 1e-9) from each other, they may help explain why 6a is increasingly prevalent in southern China and 1b is predominant nationwide. These rates are approximately 10-fold higher than those reported elsewhere. These findings suggested that during the plasma campaign, certain barriers to efficient viral transmission were removed, allowing wide HCV dissemination.

Update on epidemiology of hepatitis B and C in China

A high rate of chronic hepatitis B virus (HBV) infection in China is mainly caused by perinatal or early childhood transmission. Administration of universal HBV vaccination in infants has led to a dramatic decrease in HBV epidemiology, with hepatitis B surface antigen (HBsAg) prevalence declining from 9.75% in 1992 to 7.18% in 2006. The major HBV genotypes are B and C, with B being more prevalent in the southern part and C more prevalent in the northern part of China. A national survey carried out in 1992 showed that the hepatitis C virus (HCV) infection rate was 3.20% in general population in China. After implementation of mandatory HCV screening for blood transfusion and other precautions to prevent blood-borne disease since 1993, the new cases of HCV infection associated with blood or blood product has become very rare. Although the anti-HCV prevalence would be much higher in high-risk groups, a survey carried in 2006 showed that the anti-HCV prevalence rate was only 0.43% in general population. This sharp decline in HCV infection rate was mainly due to stringent administration and monitoring of blood donors and blood products, but may also be related to the remarkably improved specificity of anti-HCV test. The predominant HCV genotype in China is genotype 1b (60-70%), and the host interleukin-28b rs12979860 CC genotype is very frequent in Chinese population (over 80%).

Prevalence of IL-28B and ITPA genotypes in Chinese Han population infected persistently with hepatitis C virus genotype 6 or HCV-1

The geographic distribution, demographics, epidemiology, host factors, and clinical characteristics of persistent HCV-6 infection in China need further characterization. This multicenter study enrolled 63 patients with persistent HCV-6 infection and 63 patients with persistent HCV-1 infection as controls. Blood biochemistry, quantitation of HCV RNA levels, and identification of host IL-28B genotypes (rs12979860, rs8099917, and rs12980275) and ITPA genotype (rs1127354) were performed to estimate potential variability in host factors that may affect response to treatment. The mean HCV-6 RNA level (3.8E6 IU/ml) was significantly higher than that in patients infected with HCV-1 (1.7E6 IU/ml; P < 0.001). Patients persistently infected with HCV-6 had a high prevalence of IL-28B rs12979860 CC genotype (92.1%), rs8099917 TT genotype (93.7%), and rs12980275 AA genotype (90.5%). Their prevalence in patients infected with HCV-1 was only modestly lower (82.5%, 84.1%, and 82.5%, respectively; P > 0.05). The inosine triphosphate pyrophosphatase (ITPA) SNP rs1127354 CC genotype was present in 66.7% of patients infected with HCV-6, comparable to that of patients infected with HCV-1 (65.1%; P > 0.05). There were no differences in the liver function, proportion of hepatic cirrhosis patients or patients with increased serum glucose between these two groups. Persistent HCV-6 infection in Chinese Han is found mainly in the southern China. Chinese Han with chronic HCV-1 or HCV-6 infection have IL-28B genotypes, suggesting responsiveness to interferon-based pharmacotherapy. Most patients (67%) possess the ITPA genotype associated with susceptibility to ribavirin-induced hemolysis. The routes of transmission for HCV-6 genotype were more diversified than HCV-1 genotype. The outbreak of HCV-6 infection through blood transfusion progressed faster than HCV-1.