Genetic variation of hepatitis C virus in a cohort of injection heroin users in Wuhan, China

The Transmission Route and Selection Pressure in HCV Subtype 3a and 3b Chinese Infections: Evolutionary Kinetics and Selective Force Analysis

Hepatitis C virus (HCV) genotype 3 (GT-3) represents 22–30% of all infections and is the second most common genotype among all HCV genotypes. It has two main subtypes, GT-3a and GT-3b, that present epidemiological differences in transmission groups. This report generated 56 GT-3a and 64 GT-3b whole-genome sequences to conduct an evolutionary kinetics and selective force analysis with reference sequences from various countries. Evolutionary analysis showed that HCV GT-3a worldwide might have been transmitted from the Indian subcontinent to South Asia, Europe, North America and then become endemic in China. In China, GT-3a may have been transmitted by intravenous drug users (IDUs) and become endemic in the general population, while GT-3b may have originated from IDUs and then underwent mutual transmission between blood donors (BDs) and IDUs, ultimately becoming independently endemic in IDUs. Furthermore, the spread of GT-3a and GT-3b sequences from BD and IDU populations exhibit different selective pressures: the proportion of positively selected sites (PPSs) in E1 and E2 from IDUs was higher than in BDs. The number of positive selection sites was higher in GT-3b and IDUs. These results indicate that different selective constraints act along with the GT-3a and GT-3b genomes from IDUs and BDs. In addition, GT-3a and GT-3b have different transmission routes in China, which allows us to formulate specific HCV prevention and control strategies in China.

The distinct epidemic characteristics of HCV co-infection among HIV-1-infected population caused by drug injection and sexual transmission in Yunnan, China

Hepatitis C virus (HCV) infection was frequent in human immunodeficiency virus (HIV) patients in Yunnan province. We studied the epidemic characteristics of HCV in HIV/HCV co-infected patients. Serum from 894 HIV-1 patients was collected, together with basic information and biochemical features. All samples were infected with HIV through injecting drug users (IDUs) and sexual transmission (ST). The NS5B gene was amplified and sequenced to affirm HCV genotype. In total, 202 HIV patients were co-infected with HCV, and most (81.19%) of co-infected patients were IDUs. Genotype 3b was predominant (37.62%) in these samples, and its frequency was similar in patients with IDU and ST. The frequencies of genotypes 1a, 1b, 3a, 6a, 6n, 2a and 6u were 3.96%, 16.34%, 23.76%, 6.93%, 10.40%, 0.50% and 0.50%, respectively. However, genotype 3a showed significantly different frequency in HCV patients with IDU and ST (P = 0.019). When HCV patients were divided into subgroups, the haemoglobin (HGB) level was significantly higher in patients with genotype 3a than in patients with 3b (P = 0.033), 6a (P = 0.006) and 6n (P = 0.007), respectively. Although no difference existed among HCV subgroups, HIV-viral load was identified to be positively correlated with the HGB level and CD4⁺ cells when dividing HCV/HIV co-infected persons into male and female groups. In conclusion, genotype 3b was the predominant HCV genotype in Yunnan HIV/HCV co-infected persons. The HGB level was higher in patients with genotype 3a than others. HIV-viral load was positively correlated with the HGB level and CD4⁺ cells in the male or female HCV-infected group.

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.

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.

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.

Global genotype distribution of hepatitis C viral infection among people who inject drugs

BACKGROUND & AIMS

Hepatitis C viral infection (HCV) after injection drug use is very prevalent. The kind of genotype determines the response to treatment. However, no systematic review update on the global genotype distribution of HCV in people who inject drugs (PWID) is currently available.

METHODS

A systematic review was performed by using the keywords: Genotype, Hepatitis C, Injection drug user/Intravenous drug user/Substance user/ PWID, Name of countries in Pubmed, Embase and PsycINFO. The results were compared with the review of Gower et al. in 2014, concerning the distribution of HCV genotypes in the general HCV population.

RESULTS

Using these keywords, 132 studies in 48 countries (from 1995 to 2015) were collected. After grading these results, the data of 48 studies were used to determine the distribution of genotypes in PWID. Genotype 1 is the most prevalent genotype all over the world in PWID. In Europe, genotypes 1, 3 and 4 are highly prevalent. In North and South America and in Australia genotype 1 and 3 are most prevalent. In Asia genotype 2 and 6, and Africa genotype 1a and 4 are mostly observed. Overall, the most important differences comparing with the general population are a lower prevalence of genotype 1b in the PWID population and higher prevalence of genotype 1a and 3.

CONCLUSIONS

There is a different prevalence of genotype distribution in PWID than in the general population. Genotype 3 is especially highly prevalent in the Western countries.

LAY SUMMARY

Hepatitis C viral infection after injection drug use is very prevalent. The most important genotype causing HCV infection in PWID globally is genotype 1, as is the case in the general population, but also genotype 3 is highly prevalent in PWID. Genotype 4 is most prevalent in Africa, spreading into Europe, whereas genotype 2 and 6 are more located in Asia. The most important difference comparing to the general population are generally lower prevalence of genotype 1b, and higher prevalence of genotype 1a and 3 in PWID. As the genotype nowadays still determines the treatment, and as there is a different genotype distribution than in the general population, it is important to identify the genotype also in PWID.

Exploratory social network analysis and gene sequencing in people who inject drugs infected with hepatitis C virus

Social networks facilitate the transmission of hepatitis C virus (HCV) in people who inject drugs (PWID). The aim of this study was to assess how certain network structural characteristics are related to HCV infections in PWID and to determine the most susceptible individuals for HCV transmission in a network of PWID. PWID (N = 80) from central China were recruited from a previous follow-up case-control study. Demographic and behavioural information was obtained from a computerized database for each group. HCV RNA was extracted from blood specimens. Sequences were used to construct a phylogenetic tree and to determine genetic distances. Socio-metric social links were established between participants. Network measures were calculated using UCINET. Three HCV genotypes were identified, covering five subtypes. The density of the social networks for the whole sample (N = 80), case group (n = 31) and control group (n = 49) was 0.038, 0.054 and 0.008, respectively. PWID infected with HCV were in frequent contact with others within their group. There were four pairs of nodes with genotypic distances of 0.000 that were identified and clustered in subtypes 6a and 1b; each subject pair was linked and found in one clique. Three of the five most active nodes were infected with HCV. These three nodes served as a bridge, contributing to the connection of other nodes. These findings identify susceptible individuals for HCV transmission in PWID based on their frequent contact with others in the network. These results provide data that could be used for modelling HCV transmission patterns and in public health policies.

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.

Subtype distribution of hepatitis C virus in Jiangsu, China

Hepatitis C virus (HCV) genotype distribution varied by regions and transmission modes. In this study, we investigated HCV genotype distribution in five cities of Jiangsu, China, all of which are located in the Yangtze River Delta Region. A total of 363 samples were collected during 2011-2012. C/E2 and NS5B fragments of HCV were amplified using a multiple RT-nested PCR strategy and subjected to sequencing. Phylogenetic analysis was performed for HCV genotyping. Among 106 PCR positive cases, HCV subtypes 1a (0.9%), 1b (61.3%), 2a (15.1%), 3a (4.7%), 3b (9.4%), 6a (6.6%), and 6n (1.9%) were detected. Together with our previous data, we found that HCV subtypes were more among injection drug users (IDUs) (nine) than among general population (GP) (six), and the most common subtype among GP was 1b (73.9%), followed by 2a (14.5%), while the top four common subtypes among IDUs were 3a, 1b, 3b, and 6a, with similar prevalence rates (24.4%, 22.7%, 20.9%, and 17.4%, respectively). There were nine HCV subtypes prevalent among IDUs in Jiangsu, more than those in Xinjiang, Hubei, Yunnan, Guangxi, Guangdong, and Hong Kong. The top four common subtypes among IDUs in Jiangsu covered all the two most common HCV subtypes (except 6n subtype) observed in six targeted provinces/region. These results suggested that Jiangsu may be an important gathering place for various HCV subtypes and the gathering may be involved in the large scale of population migration from other regions of China to Eastern China.

Current status and emerging challenges in the treatment of hepatitis C virus genotypes 4 to 6

Hepatitis C virus (HCV) genotypes 4, 5 and 6 are mainly present in Africa, the Middle East and Asia and they have been less extensively studied with respect to epidemiology, natural disease history and therapeutic endpoints. Response rates to a 48-wk combined peginterferon/ribavirin treatment range to 40%-69% for HCV 4, 55%-60% for HCV 5 and 60%-90% for HCV 6. Response-guided schedules are recommended to optimize the outcomes of peginterferon/ribavirin treatment in HCV 4 and, in form of preliminary data, for HCV 6, but no data are yet available to support such an individualization of therapy for HCV 5. Recently, the direct-acting antivirals (DAAs) with pan-genotypic activities simeprevir, sofosbuvir and daclatasvir have been recommended in triple regimens with peginterferon/ribavirin for the treatment of HCV genotypes 4 to 6 infections. In the future, DAA-based interferon-free therapies are awaited to drastically improve treatment outcomes in HCV. However, efforts to improve treatment outcomes with peginterferon/ribavirin should continue, as the HCV 4-6 infected population is mainly based in resource-limited settings with restricted access to the costly DAAs.

Advances in genetic studies of substance abuse in China

Summary

The importance of genetic factors in substance addiction has long been established. The rationale for this work is that understanding of the function of addiction genes and delineation of the key molecular pathways of these genes would enhance the development of novel therapeutic targets and biomarkers that could be used in the prevention and management of substance abuse. Over the past few years, there has been a substantial increase in the number of genetic studies conducted on addiction in China; these studies have primarily focused on heroin, alcohol, and nicotine dependence. Most studies of candidate genes have concentrated on the dopamine, opioid, and serotonin systems. A number of genes associated with substance abuse in Caucasians are also risk factors in Chinese, but several novel genes and genetic risk factors associated with substance abuse in Chinese subjects have also been identified. This paper reviews the genetic studies of substance abuse performed by Chinese researchers. Genotypes and alleles related to addictive behavior in Chinese individuals are discussed and the contributions of Chinese researchers to the international corpus of knowledge about the genetic understanding of substance abuse are described.

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.

Epidemiology of hepatitis C virus infection and risk factor analysis in the Hebei Province, China

Background

In 1985, a hepatitis C virus (HCV) outbreak caused by plasmapheresis donation was reported in the Hebei Province, China. However, studies assessing the epidemic features and risk factors of HCV in the general population of Hebei have been limited until now.

Methods

The multicenter cluster sampling method was used to collect samples. The participants were interviewed. Relevant information was obtained from the general population using a standardized questionnaire, and association and logistic regression analyses were conducted. Serum samples were taken to test anti-HCV by enzyme immunoassays.

Results

A total of 4562 participants from 11 cities of the Hebei Province were enrolled. The average anti-HCV positive rate was 0.62% (29/4562), which was 1.07% in the rural population, compared with 0.22% in the urban population. The anti-HCV positive rate in the 40–59-year age group was higher than in those aged <40 years. History of blood transfusion and transmission in families were the main risk factors for HCV infection in this area.

Conclusion

The anti-HCV positive rate in Hebei has decreased significantly from that two decades ago. Safety of blood products and health education about HCV still need to be improved.

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.

Epidemiological distribution and genotype characterization of hepatitis C virus and HIV co-infection in Wuhan, China, where the prevalence of HIV is low

Little is known about the epidemiological characteristics of HIV/hepatitis C virus (HCV) co-infection in cities in China with low HIV prevalence. This study evaluated the level of exposure to different risk factors associated with HCV transmission and characterized the distribution of HCV genotypes in 356 HIV-1-positive patients in Wuhan, central China. HIV transmission routes were distributed as follows: heterosexual contact, male-to-male sexual contact, intravenous drug use, blood transfusion, and unknown route. HCV antibodies were detected by a third-generation enzyme-linked immunosorbent assay. HCV-positive plasmas were subjected to RNA extraction, RT-PCR amplification, and sequencing. Phylogenetic analysis characterized HCV subtypes and the evolutionary origin of circulating HCV strains. Ninety-two of 356 (25.8%) patients infected with HIV were anti-HCV-positive. Among co-infected patients, the predominant risk for HCV transmission was intravenous drug use (87.3%). Six HCV subtypes (1a, 1b, 2a, 3a, 3b, and 6a) were detected. HCV genotype 6a was most prevalent, occurring in 39.3% of all patients, followed by genotypes 1b (24.7%), 3b (18.0%), and 3a (9.8%). The least frequent genotypes were 1a (4.9%) and 2a (3.3%). Intravenous drug use was strongly associated with genotype 6a, and infection by blood or blood product transfusion was strongly associated with genotype 1b. Genotype 2a was detected only among those infected by male-to-male sexual contact. The distribution of HCV subtypes suggests that the city plays a crucial role as a hub of HCV transmission in China. Exposure to multiple risk factors associated with HCV transmission was common among patients co-infected with HIV and HCV.

Complex patterns of HCV epidemic in Suzhou: evidence for dual infection and HCV recombination in East China

BACKGROUND

HCV transmission is closely associated with injection drug use (IDU), and co-circulation of multiple subtypes has been found among injection drug users (IDUs) in China.

OBJECTIVES

To investigate HCV subtype characterizations among IDUs and general population (GP) in Suzhou, a city at the important "Hu-ning" transportation line.

STUDY DESIGN

During January 2010 to May 2011, 123 HCV positive plasma from IDUs and 131 stored HCV positive sera from general individuals were collected in Suzhou. HCV C/E2 and NS5B fragments were amplified using a new multiple RT-nested PCR strategy and subsequent sequenced. Genotypes were characterized by phylogenetic analyses.

RESULTS

Eight HCV subtypes (1a, 1b, 2a, 3a, 3b, 6a, 6n, and 6u) were detected among Suzhou IDUs, and six subtypes (1b, 2a, 3a, 3b, 6a and 6n) among GP. HCV subtype distribution is distinct between IDUs and GP. Interestingly, we detected discrepancy of genotyping results between C/E2 and NS5B regions in one general individual, indicating the presence of HCV intersubtype recombinant in China. The recombinant belongs to a 3a/1b recombinant. We also detected dual infections in one general individual and two IDUs. They include dual infections between 1b and 3a, 3a and 6a, and two distinct lineages of 3b.

CONCLUSIONS

Complex patterns of HCV epidemic among IDUs, as well as GP, in Suzhou, might imply a spread of HCV from IDUs to GP. The finding of one HCV 3a/1b intersubtype recombinant might represent the first report of HCV recombination in China.

Changing pattern of clinical epidemiology on hepatitis C virus infection in southwest china

BACKGROUND

The changing pattern of hepatitis C virus (HCV) infection could have a significant impact on future medical prevention practices and therapies.

OBJECTIVES

The purpose of this study was to describe the changing pattern of HCV infection in southwest China using clinical epidemiology, and to assess the association between the genotypes distribution and certain potential risk factors.

PATIENTS AND METHODS

A retrospective analysis which included 1208 subjects with chronic HCV registered at the Southwest Hospital (Chongqing, Southwest China) was performed. The information was reviewed and the data collected from clinical records and short telephone interviews when necessary. HCV genotypes were determined by nucleotide sequencing of the CE1 regions followed by phylogenic analysis with the published HCV genotype. HCV genotype distribution was analyzed according to the patients' age, gender, risk exposure, and the initial risk exposure.

RESULTS

Among the 1 208 patients, the HCV subtype 1b was the most prevalent (32.9%), followed by subtype 3b (18.9%), 6a (18.0%), 3a (12.8%) and 2a (10.4%), while subtypes 1a and 6k accounted for cases of HCV infection in only 9 and 3 cases respectively. Individuals older than 40 years were mainly infected with subtypes 1b and 2a, whereas younger patients were predominantly infected with genotypes 3 and 6. Subtypes 1b and 2a were observed more frequently among 44.4% and 16.0% patients respectively, with a history of invasive operations. Subtypes 3b and 6a constituted the majority of HCV infections among intravenous drug users (IDUs) (28.7% and 34.9%, respectively). A significant difference (P < 0.001) was observed between the HCV genotype distributions, according to the potential route of infection.

CONCLUSION

In southwest China, the most common remaining subtype is the 1b genotype, but this has declined significantly among young patients. This is followed by subtype 3b and 6a which has increased significantly, especially among young patients. The distribution of such genotypes was also variable according to gender and age. The changing pattern of HCV infection was associated with changes in the modes of HCV acquisition, which raises an alarm signal concerning the major steps that need to be taken in order to reduce such infections in southwest China.

HCV 6a prevalence in Guangdong province had the origin from Vietnam and recent dissemination to other regions of China: phylogeographic analyses

BACKGROUND

Recently in China, HCV 6a infection has shown a fast increase among patients and blood donors, possibly due to IDU linked transmission.

METHODOLOGY/FINDINGS

We recruited 210 drug users in Shanwei city, Guangdong province. Among them, HCV RNA was detected in 150 (71.4%), both E1 and NS5B genes were sequenced in 136, and 6a genotyped in 70. Of the 6a sequences, most were grouped into three clusters while 23% represent emerging strains. For coalescent analysis, additional 6a sequences were determined among 21 blood donors from Vietnam, 22 donors from 12 provinces of China, and 36 IDUs from Liuzhou City in Guangxi Province. Phylogeographic analyses indicated that Vietnam could be the origin of 6a in China. The Guangxi Province, which borders Vietnam, could be the first region to accept 6a for circulation. Migration from Yunnan, which also borders Vietnam, might be equally important, but it was only detected among IDUs in limited regions. From Guangxi, 6a could have further spread to Guangdong, Yunnan, Hainan, and Hubei provinces. However, evidence showed that only in Guangdong has 6a become a local epidemic, making Guangdong the second source region to disseminate 6a to the other 12 provinces. With a rate of 2.737×10⁻³ (95% CI: 1.792×10⁻³ to 3.745×10⁻³), a Bayesian Skyline Plot was portrayed. It revealed an exponential 6a growth during 1994-1998, while before and after 1994-1998 slow 6a growths were maintained. Concurrently, 1994-1998 corresponded to a period when contaminated blood transfusion was common, which caused many people being infected with HIV and HCV, until the Chinese government outlawed the use of paid blood donations in 1998.

CONCLUSIONS/SIGNIFICANCE

With an origin from Vietnam, 6a has become a local epidemic in Guangdong Province, where an increasing prevalence has subsequently led to 6a spread to many other regions of China.

The effects of widespread methadone treatment on the molecular epidemiology of hepatitis C virus infection among injection drug users in Hong Kong

The distribution of HCV genotypes among injection drug users in Hong Kong was assessed in context of methadone treatment availability. Three time periods were defined by the year of initiating injection-on or before 1980, 1981-1994, and 1995-2006-with methadone becoming widely available since the second period. Of the 273 HCV RNA-positive cases, the most prevalent subtype was HCV 6a (52.4%), followed by HCV 1b (38.5%). The new variants of HCV subtypes 6e and 6h were detected. Both subtypes 1b and 6a were prevalent among older injectors, while subtype 3a was more common in young injectors and those initiating injection recently during the third time period. Age (P < 0.05) and recent injection frequency (P < 0.01) were independently associated with HCV 6a infection. Subtype 1b was predominant in the first period, whereas 6a was more common in the second and third. Subtype 1b sequences appeared to have originated at two positions on the phylogenetic tree, while 6a showed a more disperse distribution suggestive of multiple introductions. Phylogenetic analysis on the NS5B region did not reveal specific clustering of any subtype/genotype. Overall, there was no suggestion of outbreaks of HCV. The extensive use of methadone may have protected Hong Kong from the emergence of HCV clusters among injection drug users.

HCV subtype characterization among injection drug users: implication for a crucial role of Zhenjiang in HCV transmission in China

Background

HCV transmission is closely associated with drug-trafficking routes in China. However, the transmission route of HCV in Eastern China remains unclear. Here, we investigate the role of Zhenjiang city of Jiangsu province, an important transportation hub linking Shanghai with other regions of China, in HCV transmission.

Methodology/Principal Findings

A total of 141 whole blood samples were collected from injection drug users (IDUs) in Zhenjiang and then tested for HCV infection. Of them, 115 HCV positive plasmas were subjected to RNA extraction, RT-PCR amplification, and sequencing. The subtype characterization and the evolutionary origin of HCV strains circulating in Zhenjiang were determined using polygenetic or phylogeographic analyses. Seven HCV subtypes 1b, 2a, 3a, 3b, 6a, 6e and 6n were detected among Zhenjiang IDUs, showing a complex HCV epidemic. The most predominant subtypes were 3a (38%) and 1b (26.8%). Among these subtypes, subtypes 3b, 6n and 6e originated from Southwestern China (i.e., Yunnan and/or Guangxi), subtypes 2a and 6a from Southern China (i.e., Guangdong), subtype 1b from Central (i.e., Henan) and Northwestern (i.e., Xinjiang) China, and subtype 3a from Southwestern (i.e., Yunnan) and Northwestern (i.e., Xinjiang) China. From Zhenjiang, subtypes 1b and 2a were further spread to Eastern (i.e., Shanghai) and Northern (i.e., Beijing) China, respectively.

Conclusions/Significance

The mixing of seven HCV subtypes in Zhenjiang from all quarters of China indicates that as an important middle station, Zhenjiang plays a crucial role in HCV transmission, just as it is important in population migration between other regions of China and Eastern China.

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

Recently, we studied hepatitis C virus (HCV) sera-prevalence among 559 890 first-time volunteer blood donors in China. From randomly selected 450 anti-HCV positive donors, we detected HCV RNA in 270 donors. In this study, we amplified HCV E1 and/or NS5B sequences from 236 of these donors followed by DNA sequencing and phylogenetic analysis. The results indicate new trends of HCV infection in China. The HCV genotype distribution differed according to the donors' region of origin. Among donors from Guangdong province, we detected subtypes 6a, 1b, 3a, 3b, 2a, and 1a at frequencies of 49.7%, 31.0%, 7.6%, 5.5%, 4.1%, and 2.1%, respectively. Among donors from outside Guangdong, we detected 1b, 2a, 6a, 3b, 3a, 6e, and 6n at frequencies 57.1%, 13.2%, 11.0%, 9.9%, 4.4%, 2.2%, and 2.2%, respectively. Although we found no significant differences among regions in age or gender, subtype 6a was more common (P < 0.001) in donors from Guangdong than those from elsewhere, whilst subtypes 1b (P < 0.02) and 2a (P < 0.001) were more frequent outside Guangdong. Disregarding origins, the male/female ratio was higher for subtype 6a-infected donors (P < 0.05) than for subtype 1b donors, whilst the mean age of subtype 2a donors was 8-10 years older (P < 0.05) than that for all other subtypes. Detailed phylogenetic analysis of our sequence data provides further insight into the transmission of HCV within China, and between China and other countries. The predominance of HCV 6a among blood donors in Guangdong is striking and mandates studies into risk factors for its acquisition.

Review of HIV and HCV infection among drug users in China

PURPOSE OF REVIEW

Drug abuse has resulted in a huge public health and economic burden in China, especially the rapid spread of HIV/AIDS and hepatitis C virus (HCV) infection. Multiple HIV and HCV subtypes were detected among drug users in China, this study reviews the molecular distribution of HIV and HCV among injection drug users (IDUs) and explores new epidemiologic trends of HIV and HCV among drug users in China.

RECENT FINDINGS

The 2009 National Narcotic Control Commission report showed that the percentage of users of 'new-type drugs', including amphetamine-type stimulants (ATS: methamphetamine and MDMA/ecstasy) and ketamine, was about 27% of total drug users. The pooled data from published papers showed that CRF07BC was the predominant HIV-1 subtype, which accounted for 38.8%, and it was followed by AE, which accounted for 22.7% among HIV-positive IDUs. Following these, the CRF08BC, B' and C subtypes accounted for about 10.8%, 9.9% and 9.2%, respectively. Subtype 6a was the predominant HCV subtype, accounting for 36.7%, and subtypes 3b, 1a, 3a and 1b were the next most predominant subtypes.

SUMMARY

With the increase of 'new-type drugs' use and AE HIV-1 subtype infection among IDUs, the situation regarding HIV/AIDS and HCV infection has become complicated. More comprehensive prevention and intervention strategies should be instigated for the extensive high-risk populations in China.

Hepatitis C infection among intravenous drug users attending therapy programs in Cyprus

The most high-risk population for HCV transmission worldwide today are intravenous drug users. HCV genotypes in the general population in Cyprus demonstrate a polyphyletic infection and include subtypes associated with intravenous drug users. The prevalence of HCV, HBV, and HIV infection, HCV genotypes and risk factors among intravenous drug users in Cyprus were investigated here for the first time. Blood samples and interviews were obtained from 40 consenting users in treatment centers, and were tested for HCV, HBV, and HIV antibodies. On the HCV-positive samples, viral RNA extraction, RT-PCR and sequencing were performed. Phylogenetic analysis determined subtype and any relationships with database sequences and statistical analysis determined any correlation of risk factors with HCV infection. The prevalence of HCV infection was 50%, but no HBV or HIV infections were found. Of the PCR-positive samples, eight (57%) were genotype 3a, and six (43%) were 1b. No other subtypes, recombinant strains or mixed infections were observed. The phylogenetic analysis of the injecting drug users' strains against database sequences observed no clustering, which does not allow determination of transmission route, possibly due to a limitation of sequences in the database. However, three clusters were discovered among the drug users' sequences, revealing small groups who possibly share injecting equipment. Statistical analysis showed the risk factor associated with HCV infection is drug use duration. Overall, the polyphyletic nature of HCV infection in Cyprus is confirmed, but the transmission route remains unknown. These findings highlight the need for harm-reduction strategies to reduce HCV transmission.

The neglected hepatitis C virus genotypes 4, 5 and 6: an international consensus report

Abstract Hepatitis C virus (HCV) genotypes 4, 5 and 6 represent >20% of all HCV cases worldwide. HCV-4 is mainly seen in Egypt, where it represents 90% of all HCV cases. Antischistosomal therapy was the main cause of contamination there, followed by procedures performed by informal providers and traditional healers such as dental care, wound treatment, circumcision, deliveries, excision and scarification. It is also highly prevalent in sub-Saharan Africa and in the Middle East. In Europe, its prevalence has recently increased particularly among intravenous drug users and in immigrants. HCV-5 is mainly found in South Africa, where it represents 40% of all HCV genotypes, but four pockets of HCV-5 were found in France, Spain, Syria and Belgium and sporadic cases were found elsewhere. The mode of transmission is mainly iatrogenic and transfusion. HCV-6 is found in Hong Kong, Vietnam, Thailand and Myanmar and also in American and Australian from Asian origin. The response to treatment in HCV-4 is intermediate between HCV-1 and HCV-2 and HCV-3. A sustained viral response is achieved in 43-70% with pegylated interferon and ribavirin. It is higher in Egyptians than Europeans and Africans and is negatively related to insulin resistance and to the severity of fibrosis. It increases to >80% with 24 weeks of therapy only if a rapid virological response is achieved. In HCV-5, a sustained virological response is achieved in >60% with 48 weeks of therapy. HCV-6 is also considered an easy-to-treat genotype, leading to a response in 60-85% of cases.

Clinical evaluation of a colorimetric oligonucleotide chip for genotyping hepatitis C virus

INTRODUCTION

Hepatitis C virus (HCV) is a major cause of chronic liver disease worldwide. It is associated with the development of end-stage liver disease and hepatocellular carcinoma. Studies have shown that determination of hepatitis C virus (HCV) genotypes is clinically important for prediction of the clinical course and the outcome of antiviral therapy. The aim of this study was to evaluate a colorimetric oligonucleotide chip, which can be used for the rapid and economical detection of the genotypes/subtypes of hepatitis C virus.

DESIGN AND METHODS

A total of 860 serum specimens were tested by an oligonucleotide chip genotyping test. Partial genotype results were compared with those obtained by sequencing method and INNOLiPA HCV II assay. The relative sensitivities of the methods were assessed by using the 5'NCR amplicon from the HCV RNA fluorescent amplicor HCV tests and Light Cycler.

RESULTS

Of 860 serum specimens tested for their genotypes/subtypes by the oligonucleotide array, 607 HCV positive serum samples could be typed by the sequencing method and 60 of 607 HCV positive serum specimens were typed by INNOLiPA HCV II method. Identification of genotype/subtypes by nucleotide sequencing and INNOLiPA HCV II assay showed respective coincidence rates of 99.8% and 96.7% with the HCV oligonucleotide chip results. And the colorimetric method exhibited 99.8% of relative sensitivity compared with the fluorescent amplicor HCV tests.

CONCLUSION

To our knowledge this oligonucleotide chip genotyping method offers a fast and convenient way to determine the genotype in large-scale settings. The tests can be easily adapted by a clinical diagnostic laboratory.

Changes in modes of hepatitis C infection acquisition and genotypes in southwest China

BACKGROUND

The shift in the distribution of HCV genotypes could have a significant impact on practical medical issues.

OBJECTIVES

To describe the recent distribution and evolution of HCV genotypes in southwest China.

STUDY DESIGN

HCV genotypes were determined by nucleotide sequencing of the CE1 regions followed by phylogenic analysis with the published HCV genotype. HCV genotype distribution was analyzed according to patients' age, risk exposure, and the first time of risk exposure.

RESULTS

Among the 371 cases, subtypes 1a (0.8%), 1b (42.0%), 2a (9.7%), 3a (12.1%), 3b (21.0%), 4a (0.3%), and 6a (14.0%) were found. Genotypes 3 and 6 were significantly more frequent (85.4%) among IDUs than among other subjects (32.5%, P<0.001), they were also more frequent among subjects aged 40 years or under (63.6%) than older patients (21.6%, P<0.001), among patients infected after 1997 (54.4%) than those infected before 1997 (27.3%, P=0.001). Age 40 years or under (P<0.001) and infection via IDU (P<0.001) were independently associated with genotypes 3 and 6 in the multivariate stepwise logistic regression analysis. IDU was detected as a cause of infection in 27.8% of HCV cases; it was more frequent among younger patients (40.4%) than older ones (7.1%, P<0.001), among patients infected after 1997 (40.3%) than those infected before 1997 (16.2%, P<0.001).

CONCLUSION

In southwest China, the relative prevalence of genotypes 3 and 6 has increased significantly, and that of genotypes 1b and 2a has declined significantly among young patients. This shift in distribution was associated with changes in the modes of HCV acquisition.

Molecular and contextual markers of hepatitis C virus and drug abuse

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