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

Hepatitis C virus subtype distribution and resistance-associated substitutions in high-risk population groups in Guangdong Province, China

OBJECTIVE

In Guangdong Province, hepatitis C virus (HCV) had been found to confer resistance to direct-acting antivirals (DAAs). There were few studies of HCV subtypes and resistance-associated substitutions (RASs) of HCV in different high-risk populations. In this study, we aimed to determine the subtype distribution and the RASs in high-risk population groups, including drug users (DU), men who have sex with men (MSM), female sex workers (FSW), and male patients with sexually transmitted diseases (STD) in Guangdong Province (a highly developed province with a large population).

METHODS

Using a city-based sampling strategy,1356 samples were obtained from different population groups. Phylogenetic analyses determined subtypes based on Core, NS5B, or NS5A sequences. HCV subtype distribution and RASs in various risk groups and regions were analyzed.

RESULTS

Ten subtypes, of which 6 h and 6 k were novel in Guangdong, were identified. The primary subtype among all risk groups was 6a. RASs in 1b and 3a were different from those observed in other studies. Subtype 3b in western Guangdong was higher than the other three regions. No RASs were found in 6a or any other genotype 6.

CONCLUSIONS

The HCV subtypes are expanding in high-risk populations in Guangdong. Drug use by other risk groups and commercial sex by DU may bridge the dissemination of 6a from DU to other populations. The RAS profiles of 1b and 3a differed from those reported in studies conducted in southwestern China. Further research is required to determine the reason for this discrepancy. Moreover, the combination of RASs was high in subtype 3b. To guide HCV treatment of subtype 3b, pretreatment subtyping of HCV genotype 3 should be considered in western cities in the near future.

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.

The distribution of hepatitis C viral genotypes shifted among chronic hepatitis C patients in Yunnan, China, between 2008-2018

Object

The hepatitis C virus (HCV) is prevalent across China, with a distinctive genotypic distribution that varies by geographical region and mode of transmission. Yunnan is one such geographical region wherein the local population continues to experience a high level of HCV infection, severely straining public health resources. This high prevalence is likely due to the increased incidence of intravenous drug use in that region, as Yunnan is a major point of entry for illegal heroin into China.

Methods

We investigated 510 individuals with chronic HCV infections in Yunnan Province from 2008 through 2018. Using reverse transcription PCR and Sanger sequencing to amplify and sequence samples. Bayesian analyses was performed to estimate the common ancestors and Bayesian skyline plot to estimate the effective viral population size. Molecular network was conducted to explore the characteristics of HCV transmission.

Results

We successfully amplified and sequenced a total of 503 viral samples and genotyped each as either 3b (37.6%), 3a (21.9%), 1b (19.3%), 2a (10.5%), HCV-6 (10.1%), or 1a (0.6%). Over this 11-year period, we observed that the proportion of 3a and 3b subtypes markedly increased and, concomitantly, that the proportion of 1b and 2a subtypes decreased. We also performed Bayesian analyses to estimate the common ancestors of the four major subtypes, 1b, 2a, 3a, and 3b. Finally, we determined that our Bayesian skyline plot and transmission network data correlated well with the changes we observed in the proportions of HCV subtypes over time.

Conclusions

Taken together, our results indicate that the prevalence of HCV 3a and 3b subtypes is rapidly increasing in Yunnan, thus demonstrating a steadily growing public health requirement to implement more stringent preventative and therapeutic measures to curb the spread of the virus.

Molecular epidemiology and genotype distribution of hepatitis C in Pakistan; a multicenter cross-sectional study

Pakistan has second highest burden of hepatitis C virus (HCV) infected patients in the World. Little is known about the molecular epidemiology and risk factors for prevailing HCV genotypes in Pakistan. Considering this a multicenter cross-sectional study was conducted at 23different viral hepatitis control and prevention centers. A total of 175,897 patients were registered and screened for HCV, out of which 73,180 (41.6%) were found positive on Architect screening test. The screened positive patients were sequentially tested on RT-PCR; where 41,241 (56.35%) were detected positive. Molecular characterization results showed genotype 3 (73.9%) as the most prevalent type, followed by genotype 1 (9.7%), and genotype 4 (0.3%) was isolated for the first time in Pakistan. On regression analysis; risk factors associated with genotype 3 and 1 included; age group of 30-50 years, rural residence, exposure to >10 injections, barber shaving, circumcision by barbers, and low literacy rate. Phylogenetic analysis based on genotypes identified in this study and sequences isolated from Pakistan in last 10 years demonstrated that genotype 3 and 1 are endemic locally in Punjab province. The high prevalence rate of HCV is a threat for a generalized epidemic and genetic recombination with such variability of genotypes identified here is an alarming condition. More focused attention and resources should be spent in awareness of the population to prevent the spread of HCV among high risk population.

Hepatitis C virus prevalence and incidence estimates among Chinese blood donors

BACKGROUND

Hepatitis C virus (HCV) is an important transfusion-transmitted virus with global significance. The objective of this study was to evaluate the HCV prevalence and incidence among Chinese blood donors from 2013 to 2016.

STUDY DESIGN AND METHODS

Whole blood and apheresis platelet donations collected from five Chinese blood centers from June 1, 2013, to December 31, 2016, were screened in parallel by two different enzyme-linked immunosorbent assays for anti-HIV 1/2, hepatitis B surface antigen, anti-HCV, and syphilis. Screening-reactive samples were further confirmed by western blot. Confirmatory positive rates among first-time and repeat donors were used to estimate the prevalence and incidence rates. Multivariable logistic regression modeling was used to examine factors associated with HCV infection.

RESULTS

A total of 1,276,544 donations were collected from five Chinese blood centers, of which an estimated 1203 were confirmed HCV positive. The overall HCV prevalence among first-time donors was 166.56 per 100,000 donors (95% confidence interval, 156.04-177.08). The HCV incidence rate was estimated to be 15.21 (95% confidence interval, 11.83-19.56) per 100,000 person-years among repeat donors. Multivariable logistic regression results showed that increased age, lower educational levels, ethnicity, and occupation were all important factors associated with HCV confirmatory status among first-time donors (p < 0.01).

CONCLUSIONS

HCV infection is still an important concern for transfusion safety in China. Our findings indicate that continued strong efforts are needed to monitor and control the risk of transfusion-transmitted HCV infection in China. Moreover, to reduce unnecessary donor loss, HCV donor screening procedures should be improved by incorporating confirmatory testing into routine blood center operations.

Complete genome sequencing and evolutionary analysis of HCV subtype 6xg from IDUs in Yunnan, China

Background

HCV genotype 6 (HCV-6) typically circulates in Southeast Asia and exhibits the highest genetic diversity among the eight HCV genotypes. In our previous work, a group of HCV-6 sequences was not clearly classified. Here, we further characterized this HCV-6 variant and analyzed the evolutionary history of the enlarged HCV-6 family.

Methods

Blood samples from eight HCV seropositive samples collected from intravenous drug users (IDUs) in 2014 in Yunnan Province, China. The full-length HCV genome sequences were amplified by using reverse transcription PCR followed by DNA sequencing and phylogenetic analysis. Bayesian evolutionary analysis was performed with the complete coding region sequences of subtype 6a-6xh.

Results

The eight genomes had the same coding region of 9051 nucleotides. The complete coding region sequences of the eight HCV isolates formed a distinct phylogenetic group from the previously assigned HCV-6 subtypes (6a-6xf), however which clustered with 6xg reference sequences that were found in Kachin State, Myanmar, and recently assigned and released. The p-distances of the eight isolates to subtype 6a-6xf and 6xh ranged from 0.143 to 0.283. Based on the HCV-6 complete coding region sequences, we constructed a timescaled phylogenetic tree to reveal the HCV-6 evolutionary history, in which there were four HCV-6 phylogenetic subsets, whose median tMRCAs were 294.8, 388.5, 348.5 and 197.0 years ago, respectively. Subtype 6xg clustered into Subset I, and had the most recent common ancestor with subtype 6n, which dated back to 101.2 (95% HPD: 78.7, 125.8) years ago. The genetic evolutionary analysis further confirmed that subtype 6xg originated from Myanmar, and transmitted to Dehong through cross-border IDUs.

Conclusion

The HCV-6 variant characterized in this study belonged to newly assigned subtype 6xg. Our finding further confirmed the assignment of 6xg. HCV-6 family was highly divers and had a complicated evolutionary history in Southeast Asia. It is necessary to further characterize HCV-6 genetics in this region.

The nationwide distribution and trends of hepatitis C virus genotypes in mainland China

Comprehensive data on hepatitis C virus (HCV) genotypes distribution is critical for treatment regimen selection, vaccine design, and drug development. This study aimed to understand the dynamic distribution of HCV genotypes in Mainland China. Three hundred sixty-two studies published from January 1993 to December 2017 involving 64 891 samples (5133 injecting drug users, 2748 volunteer blood donors, 1509 former paid plasma donors, 160 sexually encounters, and 1992 human immunodeficiency virus (HIV)/HCV coinfection patients) were eligible for the quantitative synthesis estimation. Pooled proportion of HCV genotypes (and 95% confidence intervals [CIs]) was estimated through the Freeman-Tukey double arcsine transformation by period, region, and risk group. A sharp decline of the subtype 1b was observed in all regions except in northwestern and central regions. The genotypes 3 and 6 showed an obvious increase in southern and southwestern regions and have already spread nationwide. After 2010, subtype 1b was the most dominant variant in all regions and risk groups, accounting for 54.0% (95% CI, 51.9-56.1) of all national infections. Subtype 2a was the second most prevalent strain in all regions except in the south and southwest, with 15.4% (95% CI, 13.1-17.8) national infections. The subtype 6a in southern region and 3b and 3a in southwestern region had a higher proportion of infections than that in other regions. In addition, the genotypes 3 and 6 are already prevalent in almost all risk groups. The distribution of HCV genotypes were sharply shifting in China in the past three decades. The HCV subtype 1b posed a sharp decline, whereas genotypes 3 and 6 played an increasing role in the regional and populational HCV pandemic.

Genotype distribution of hepatitis C virus in 952 cases from 2014 to 2016 in Hunan Province, China

INTRODUCTION

Few large-scale investigations on genotype (GT) distribution of hepatitis C virus (HCV) in Hunan Province, China, are reported.

MATERIAL AND METHODS

We recruited all of the 952 patients in the census register of Hunan Province who were first diagnosed with HCV infection in the Second Xiangya Hospital, Central South University in 2014-2016. HCV genotypes were surveyed. The genotype distribution pattern was compared with those of the neighboring regions in China.

RESULTS

Among the 952 patients, genotype 1 (GT1) (69.9%) was the most common HCV genotype, followed by GT6 (19.0%), GT3 (8.4%), and GT2 (2.6%). GT4 and GT5 were not found. One case had mixed infection of GT3 and GT6. Predominance of GT1 HCV was more evident in the patients aged ≥ 40 years than in those aged < 40 years (79.5% vs. 47.9%, χ2 = 95.993, p < 0.001). HCV genotype distribution had gender difference (χ2 = 44.695, p < 0.001), with GT3 and GT6 more prevalent in males than in females (36.2% vs. 18.2%, χ2 = 39.088, p < 0.001) while GT1 more prevalent in females than in males (80.1% vs. 60.3%, χ2 = 44.276, p < 0.001). Though Hunan Province is located in central China, its HCV genotype priority was similar with the change trend in south and southwest China, while distinguished from those of other regions, in particular from the neighboring central province, Hubei Province.

CONCLUSIONS

HCV GT1 was the most predominant HCV genotype in Hunan Province, and GT6 and GT3 accounted for a significant percentage, especially in young patients. The HCV distribution pattern was more similar to those of the regions in south China.

Analysis of Transmission Routes of Hepatitis C Virus Based on Virus Genotyping in 341 Cases with Different Suspected Initial Infection Time Points in Hunan Province, China

Background

Few investigations have been reported on the changing trends in transmission routes of hepatitis C virus (HCV) and the corresponding HCV genotype (GT) distribution in Hunan province, China.

Material/Methods

HCV GTs, suspected viral transmission routes, and time of initial infections were investigated in 341 HCV-infected patients in 2016.

Results

Genotype 1 (GT1) (72.1%) was the most prevalent HCV GT, followed by GT6 (17.6%), GT3 (7.6%), and GT2 (2.6%). GT4 and GT5 were not found. The predominant HCV transmission routes were blood-related routes (57.5%) and intravenous drug use (IDU) (15.0%); 52.2% of the patients got HCV infection before 1994, 25.6% from 1994 to 1998, and 22.2% after 1998; 93.5% of the infections via blood-related transmission routes were with HCV GT1, 61.5% via IDU or feculent sexual contact were with HCV GT6, and 50.0% via non-healthcare invasive procedures were with HCV GT6. HCV infections via IDU or feculent sexual behavior were more prevalent in young males, while infections via invasive cosmetic procedures occurred more in young females, and both had a shorter time interval from suspected infection to confirmed clinical diagnosis. Multinomial logistic regression confirmed the time points of the initial HCV infections and suspected viral transmission routes were correlated with HCV GT distribution.

Conclusions

HCV GT1 infections via blood-related transmission routes in Hunan province have continually decreased since 1994. However, younger patients infected with HCV, especially with HCV GT6 via IDU, feculent sexual behavior, and non-healthcare invasive procedures, have significantly increased.

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.

Younger trend of cirrhosis incidence in genotype 3 HCV infected patients in Eastern China

The diversity of HCV genotypes is ever-evolving and requires continuous surveillance. The aim of this study was to investigate the dynamics of HCV genotypes, and their associated demographic and clinical patterns in China. By searching computerized hospital information system, a total of 1155 HCV-positive patients eligible for analysis were retrospectively identified from 12 380 consecutive in-patients in the Department of Infectious Diseases, Ruijin Hospital in China between 2009 and 2014. The percentages of HCV genotype 1, 2, 3, or 6 were 61.3%, 12.8%, 18.5%, or 7.4%, respectively. The number of patients hospitalized for HCV infection increased gradually over the study period, particularly those infected by genotype 3 HCV. Patients of genotype 1, 2, 3, or 6 were significantly different. Genotype 1 or two patients were much older, with higher proportion of blood transfusion history. In contrast, genotype 3 or six patients were younger, predominantly male, with more exposure to intravenous drug use. The cirrhosis incidence was higher in genotype 1 or two patients, followed by genotype 3 and six patients. Strikingly, genotype 3 cirrhotic patients were younger, and their estimated infection durations were also shorter, suggestive of a faster disease progression in genotype 3 patients. Multivariate analysis demonstrated that presence of HBcAb was an independent predictor of cirrhosis (OR 2.19, 95%CI 1.27-3.42; P = 0.004). The leading increase and the younger trend of cirrhosis incidence in genotype 3 patients argue for a higher priority to manage the infection in this highly at-risk population.

Partial sequencing analysis of the NS5B region confirmed the predominance of hepatitis C virus genotype 1 infection in Jeddah, Saudi Arabia

Chronic hepatitis C virus (HCV) infection and its progression are major health problems that many countries including Saudi Arabia are facing. Determination of HCV genotypes and subgenotypes is critical for epidemiological and clinical analysis and aids in the determination of the ideal treatment strategy that needs to be followed and the expected therapy response. Although HCV infection has been identified as the second most predominant type of hepatitis in Saudi Arabia, little is known about the molecular epidemiology and genetic variability of HCV circulating in the Jeddah province of Saudi Arabia. The aim of this study was to determine the dominance of various HCV genotypes and subgenotypes circulating in Jeddah using partial sequencing of the NS5B region. To the best of our knowledge, this is the first study of its kind in Saudi Arabia. To characterize HCV genotypes and subgenotypes, serum samples from 56 patients with chronic HCV infection were collected and subjected to partial NS5B gene amplification and sequence analysis. Phylogenetic analysis of the NS5B partial sequences revealed that HCV/1 was the predominant genotype (73%), followed by HCV/4 (24.49%) and HCV/3 (2.04%). Moreover, pairwise analysis also confirmed these results based on the average specific nucleotide distance identity: ±0.112, ±0.112, and ±0.179 for HCV/1, HCV/4, and HCV/3, respectively, without any interference between genotypes. Notably, the phylogenetic tree of the HCV/1 subgenotypes revealed that all the isolates (100%) from the present study belonged to the HCV/1a subgenotype. Our findings also revealed similarities in the nucleotide sequences between HCV circulating in Saudi Arabia and those circulating in countries such as Morocco, Egypt, Canada, India, Pakistan, and France. These results indicated that determination of HCV genotypes and subgenotypes based on partial sequence analysis of the NS5B region is accurate and reliable for HCV subtype determination.

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.

Prevalence and Clinical Impact of Human Pegivirus-1 Infection in HIV-1-Infected Individuals in Yunnan, China

Human Pegivirus-1 (HPgV-1) may have a beneficial impact on disease progression in human immunodeficiency virus-1 (HIV-1) infection. However, analysis of the genotypic diversity of HPgV-1 and its relevance to the progression of HIV-1 disease remains limited. A total of 1062 HIV-1-infected individuals were recruited in all sixteen prefectures of Yunnan province, China. The reverse transcription nested polymerase chain reaction (RT-nPCR), phylogenetic analyses, and clinical data analyses were used to detect HPgV-1 infection, determine genotype, and analyze HPgV-1 genotype impact on HIV-1 disease progression. The overall positive rate of HPgV-1 RNA was 23.4% (248/1062), and the frequency of HPgV-1 infection in injecting drug users (IDUs) (28.5%, 131/460) was significantly higher than in heterosexuals (19.4%, 117/602). Multiple genotypes were identified in 212 subjects with successful sequencing for the E2 gene, including genotype 7 (55.7%), genotype 3 (34.9%), genotype 4 (4.7%), genotype 2 (3.3%), and an unclassified group (1.4%). Moreover, genotype 7 predominated in IDUs, whereas genotype 3 was the most common in heterosexuals. Our results revealed that HPgV-1 genotype 7 groups exhibited significantly lower HIV-1 viral load and higher CD4⁺ cell counts. This finding suggests that HPgV-1 genotype 7 may be associated with a better progression of HIV-1 disease.

Hepatitis C Virus Genotype Analyses in Chronic Hepatitis C Patients and Individuals With Spontaneous Virus Clearance Using a Newly Developed Serotyping Assay

BACKGROUND

We developed a novel HCV serotyping assay and detected the genotypes in chronic hepatitis C (CHC) patients and individuals with spontaneous viral clearance (SVC).

METHODS

Nine hundred and ninety-seven patients were enrolled in a previous study; their samples were genotyped originally using the molecular assays. Among them, 190 patients achieved sustained virological response; the post-treatment samples were also serotyped. Moreover, 326 samples from follow-up cohorts were serotyped, among whom 66 were from SVC individuals, and 260 from CHC patients.

RESULTS

Nine hundred and fifty-eight out of 997 samples were available for serotyping, among which 29 samples generated indeterminate serotyping results. The consistency between the genotyping and serotyping assays was 91.50% (850/929). The specificity and sensitivity were 98.45% and 88.77% for genotype 1, 96.42% and 93.97% for genotype 2, and 94.15% and 80.52% for non-genotype 1 or 2. However, only 41 of 60 genotype-6 samples were correctly serotyped. Little difference was found in the 190 paired serotyping results. No difference existed in the genotype distribution between the SVC and CHC groups (P = 0.08).

CONCLUSIONS

The assay provides an accurate alternative for determining HCV genotypes, whereas it is not recommended for detecting genotype 6. Furthermore, it facilitates identifying the genotypes in SVC individuals. HCV genotype has little impact on SVC.

Molecular epidemiology of hepatitis C infections in Ningxia, China: genotype, phylogeny and mutation analysis

Background

Current prevalence and genotype distribution of hepatitis C virus (HCV) infection remain unknown in Ningxia, northwest China.

Methods

From June to December 2013, 13,022 individuals were screened in Ningxia HIV/AIDS Sentinel Surveillance System, with their demographic features collected and serum samples tested for HCV antibody. Sero-positive drug users were further subjected to sequencing of NS5B and Core regions of HCV.

Results

The anti-HCV prevalence was 0.34 % among individuals without history of drug use, while it was 15.80 % among drug users. Of 79 NS5B sequences amplified from drug users, 64 (81.0 %) were male and 51 (64.0 %) were injection drug users (IDUs). Subtype 3a (40.5 %) and 1b (25.3 %) were the most predominant subtypes, followed in frequency by 3b (10.1 %) and 2a (7.6 %). Subtype distribution has no significant difference between injection and non-injection drug users. Based on phylogeographic analysis, HCV strains in Ningxia IDUs were mainly originated from two sites, Yunnan province (in southwest China bordering Myanmar, also known as Burma) and Xinjiang Autonomous Region (in northwest China on the border of Central Asia), which are the two major drug trafficking originates in China. Previously reported drug-resistance mutations were also scanned in this treatment-naïve population. Amino acid substitutions (C316N) associated with direct anti-viral agents (DAA) resistance were identified in the NS5B region in seven samples.

Conclusion

This study is the first to reveal the existence of multiple genotypes of HCV in Ningxia, an inland province in northwest China, suggesting the rapid spreading of the virus.

Electronic supplementary material

The online version of this article (doi:10.1186/s12985-016-0635-y) contains supplementary material, which is available to authorized users.

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.

Evolving Diversity of Hepatitis C Viruses in Yunnan Honghe, China

The Chinese Honghe Autonomous Prefecture (Honghe) in Yunnan Province is a unique ethnic area because it is inhabited by more than ten different minority ethnic groups. Geographically, Honghe directly shares a border with Vietnam. The objective of this study was to investigate genetic diversity and distribution of the Hepatitis C virus (HCV) in Honghe. Ninety nine subjects who were infected with HCV or HCV/HIV (Human Immunodeficiency Virus Type 1) were recruited into this study. HCV genotypes and subtypes were determined based on the sequences of the core/envelope 1 (C/E1) and the nonstructural protein 5B (NS5B) genomic regions. The viral diversity and origins of dissemination were examined by phylogenetic analyses. Three HCV genotypes (1, 3 and 6) with six subtypes (1b, 3b, 3a, 6a, 6n and 6v) were identified. The most predominant form was genotype 3 (54.6%) followed by 6 (34.3%), and 1 (9.1%). The HCV subtype 3b appeared to be the most frequent form (38.4%) followed by 6n (20.2%) and 3a (16.2%). Statistical analyses suggested a possible rise of the genotype 6a in Honghe among intravenous drug users with HCV/HIV co-infections. Further phylogenetic analyses suggested that similar HCV-6a viruses might have been circulating in the Honghe area for more than a decade, which likely originated from Vietnam or vice versa. Two HCV samples with single HCV infection (SC34 and SC45) were isolated that could represent new recombinant variants. Although the genetic prevalence of HCV in Honghe is in general agreement with that of Southwest China and Yunnan Province, the diversity of HCV genotypes and subtypes in Honghe is somewhat unique and evolving. Information presented here should provide useful information for future health surveillance and prevention of HCV infection in this area.

Response to Pegylated Interferon Plus Ribavirin in Patients with Hepatitis C Virus Genotype 6a Infection from Guangdong and Guangxi Province of China

Aim. Our aim is to survey the treatment effect of PEG-IFN plus ribavirin in patients infected with HCV genotype 6a in Guangdong and Guangxi province of China and investigate best course of antiviral treatment for patients with HCV-6a infection. Methods. 515 eligible patients received subcutaneous 180 μg PEG-IFNα-2a or 1.5 μg/kg PEG-IFNα-2b once weekly plus oral ribavirin. Primary outcome was SVR by intention-to-treat analysis. Secondary outcome was RVR, cEVR, ETR, and relapse rate. Results. SVR in patients with HCV-6a infection treated for 48 weeks was comparable to that in patients with HCV-2/3 infection (80.9% versus 82.5%, p = 0.812) and higher than that in patients with HCV-1b infection (80.9% versus 67.2%, p = 0.014). ETR (98.9% versus 90.6%, p = 0.016), virological response at month 3 of end-of- treatment (88.8% versus 76.6%, p = 0.044), SVR (80.9% versus 65.6%, p = 0.032), and virological response at month 12 of end-of-treatment (76.4% versus 60.9%, p = 0.04) in patients with HCV-6a infection treated for 48 weeks were higher than those in patients with HCV-6a infection treated for 24 weeks. Conclusion. SVR in patients with HCV-6a treated for 48 weeks was comparable to that in patients with HCV-2/3 infection and higher than that in patients with HCV-1b infection; patients with HCV-6a infection treated for 48 weeks had a superior treatment response than patients treated for 24 weeks.

Analysis of HCV-6 isolates among Asian-born immigrants in North America reveals their high genetic diversity and a new subtype

We characterized full-length genomes for 15 HCV-6 isolates, all from Asian immigrants living in North America. Among these isolates, nine were novel variants showing >15% nucleotide differences from their nearest relatives, representing lineages distinct from known subtypes. The other six were classified into subtypes 6c, 6h, 6q, 6r, and 6s. The partial sequences were also determined for five additional HCV-6 isolates, three from the US and two from Canada. The latter two were assigned to new subtype 6xf as they were found to classify with two other isolates for which we recently reported their full-length genomes. We further analyzed partial Core-E1 sequences of 100 HCV-6 isolates sampled in North America, seven from the US and 93 from Canada and all from Asian immigrants except for four from Caucasians. These 100 isolates belonged to 20 assigned subtypes and 16 unclassified lineages showing great genetic diversity and enhanced significance to public health.

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.

Hepatitis C Virus RNA Real-Time Quantitative RT-PCR Method Based on a New Primer Design Strategy

Viral nucleic acids are unstable when improperly collected, handled, and stored, resulting in decreased sensitivity of currently available commercial quantitative nucleic acid testing kits. Using known unstable hepatitis C virus RNA, we developed a quantitative RT-PCR method based on a new primer design strategy to reduce the impact of nucleic acid instability on nucleic acid testing. The performance of the method was evaluated for linearity, limit of detection, precision, specificity, and agreement with commercial hepatitis C virus assays. Its clinical application was compared to that of two commercial kits--Cobas AmpliPrep/Cobas TaqMan (CAP/CTM) and Kehua. The quantitative RT-PCR method delivered a good performance, with a linearity of R(2) = 0.99, a total limit of detection (genotypes 1 to 6) of 42.6 IU/mL (95% CI, 32.84 to 67.76 IU/mL), a CV of 1.06% to 3.34%, a specificity of 100%, and a high concordance with the CAP/CTM assay (R(2) = 0.97), with a means ± SD value of -0.06 ± 1.96 log IU/mL (range, -0.38 to 0.25 log IU/mL). The method was superior to commercial assays in detecting unstable hepatitis C virus RNA (P < 0.05). This quantitative RT-PCR method can effectively eliminate the influence of RNA instability on nucleic acid testing. The principle of primer design strategy may be applied to the detection of other RNA or DNA viruses.

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.

Genotype Distribution and Molecular Epidemiology of Hepatitis C Virus in Hubei, Central China

Background

Little is known about the molecular epidemiology of hepatitis C virus (HCV) infection in Central China.

Methodology/Principal Findings

A total of 570 patients from Hubei Province in central China were enrolled. These patients were tested positive for HCV antibody prior to blood transfusion. Among them, 177 were characterized by partial NS5B and/or Core-E1 sequences and classified into five subtypes: 1b, 83.0% (147/177); 2a, 13.0% (23/177); 3b, 2.3% (4/177); 6a, 1.1% (2/177); 3a, 0.6% (1/177). Analysis of genotype-associated risk factors revealed that paid blood donation and transfusion before 1997 were strongly associated with subtypes 1b and 2a, while some subtype 2a cases were also found in individuals with high risk sexual behaviors; subtypes 3b, 6a, and 3a were detected only in intravenous drug users. Phylogeographic analyses based on the coalescent datasets demonstrated that 1b, 2a, 3b, and 6a were locally epidemic in Hubei Province. Among them, subtype 1b Hubei strains may have served as the origins of this subtype in China, and 2a and 3b Hubei strains may have descended from the northwest and southwest of China, respectively, while 6a Hubei strains may have been imported from the central south and southwest.

Conclusion/Significance

The results suggest that the migration patterns of HCV in Hubei are complex and variable among different subtypes. Implementation of mandatory HCV screening before donation has significantly decreased the incidence of transfusion-associated HCV infection since 1997. More attention should be paid to intravenous drug use and unsafe sexual contact, which may have become new risk factors for HCV infection in Hubei Province.

An expanded taxonomy of hepatitis C virus genotype 6: Characterization of 22 new full-length viral genomes

We characterized the full-length genomes of 22 hepatitis C virus genotype 6 (HCV-6) isolates: 10 from Vietnam (classified into subtypes 6e, 6h, 6p, 6r, 6s, and 6u), one from China (confirmed as a new subtype 6xd), and 11 from the Lao PDR (representing a new subtype 6xe plus eight novel variants). With these 22 new genomes, HCV-6 now has a diverse and extended taxonomic structure, comprised of 28 assigned subtypes (denoted 6a-6xe) and 27 unassigned lineages, all of which have been represented by full-length genomes. Our phylogenetic analyses also included many partially-sequenced novel variants of HCV-6 from Lao PDR. This revealed that Lao HCV isolates are genetically very diverse and are phylogenetically distributed in multiple lineages within genotype 6. Our results suggest that HCV-6 has been maintained in Laos, a landlocked country, since the common ancestor of genotype 6 and indicates historical dispersal of HCV-6 across Southeast Asia.

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We characterized 22 full-length genomes of HCV-6.

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They confirmed two new subtypes 6xd and 6xe plus eight novel variants.

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We also reanalyzed many partially-sequenced novel HCV-6 variants from Lao PDR.

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They are phylogenetically distributed across the whole of genotype 6.

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They indicate historical dispersal of HCV-6 across Southeast Asia.

Performance comparison of the versant HCV genotype 2.0 assay (LiPA) and the abbott realtime HCV genotype II assay for detecting hepatitis C virus genotype 6

The Versant HCV genotype 2.0 assay (line probe assay [LiPA] 2.0), based on reverse hybridization, and the Abbott Realtime HCV genotype II assay (Realtime II), based on genotype-specific real-time PCR, have been widely used to analyze hepatitis C virus (HCV) genotypes. However, their performances for detecting HCV genotype 6 infections have not been well studied. Here, we analyzed genotype 6 in 63 samples from the China HCV Genotyping Study that were originally identified as genotype 6 using the LiPA 2.0. The genotyping results were confirmed by nonstructural 5B (NS5B) or core sequence phylogenetic analysis. A total of 57 samples were confirmed to be genotype 6 (51 genotype 6a, 5 genotype 6n, and 1 genotype 6e). Four samples identified as a mixture of genotypes 6 and 4 by the LiPA 2.0 were confirmed to be genotype 3b. The remaining two samples classified as genotype 6 by the LiPA 2.0 were confirmed to be genotype 1b, which were intergenotypic recombinants and excluded from further comparison. In 57 genotype 6 samples detected using the Realtime II version 2.00 assay, 47 genotype 6a samples were identified as genotype 6, one 6e sample was misclassified as genotype 1, and four 6a and five 6n samples yielded indeterminate results. Nine nucleotide profiles in the 5' untranslated region affected the performances of both assays. Therefore, our analysis shows that both assays have limitations in identifying HCV genotype 6. The LiPA 2.0 cannot distinguish some 3b samples from genotype 6 samples. The Realtime II assay fails to identify some 6a and all non-6a subtypes, and it misclassifies genotype 6e as genotype 1.