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

Review on the molecular epidemiology of sexually acquired hepatitis C virus infection in the Asia-Pacific region

INTRODUCTION

Sexual acquisition has emerged as a transmission route for hepatitis C virus (HCV) of growing importance among human immunodeficiency virus (HIV)-positive populations. In Western countries, HCV epidemics have been increasingly detected among men who have sex with men (MSM). This review describes the molecular epidemiology of sexually acquired HCV infection in the Asia-Pacific region.

METHODS

A systematic search was performed on PubMed in March 2019. Either abstract or full-text of each publication in the search results was screened for eligibility. Studies from different countries/cities involving eligible cases, who acquired HCV sexually with identified subtype, were synthesized for the evaluation of molecular epidemiology in the Asia-Pacific region. Two large-scale systematic reviews on the genotype distribution of HCV at a population level and among PWID were used as references for comparison.

RESULTS AND DISCUSSION

Overall, 13 full-text articles with 549 subjects originating from nine countries/cities were reviewed. A total of five genotypes and 14 subtypes were identified, dominated by subtypes 1b (23.0%), 2a (19.1%) and 3a (29.5%). A majority of the infected cases occurred in HIV-positive MSM. In some places, notably Hong Kong, India and Indonesia, the predominant subtype in sexually acquired HCV infection in MSM was different from that circulating in the general population. Shared transmission networks between people who inject drugs (PWID) and MSM were shown in Australia and New Zealand, whereas overlapping risk elicited from a small number of subjects existed in Tokyo, Taipei and Guangxi. MSM-specific clusters were identified in Hong Kong, Taipei and Hubei.

CONCLUSIONS

The distribution of sexually acquired HCV was sparsely scattered across countries/cities in the Asia-Pacific region. The threat of overlapping risk differed by locations, whereas transnational outbreaks remained uncommon. The paucity of information has hindered progress with comprehensive assessment in the Asia-Pacific region, where seroprevalence of HCV among HIV-positive MSM was relatively high.

Molecular epidemiology of acute HCV infection in HIV-positive patients from Hong Kong, Taipei, Tokyo

BACKGROUND

Acute hepatitis C virus (HCV) infections have been increasingly reported among human immunodeficiency virus (HIV)-positive men who have sex with men (MSM) in the Asia-Pacific region. It remains unknown whether international network of HCV transmission has occurred in this region.

METHODS

HIV-positive patients with acute HCV infection, defined as HCV seroconversion within a year or documented acute hepatitis with seroconversion, diagnosed in Hong Kong, Taipei and Tokyo during 2010-2016 were included in this molecular epidemiology study. The NS5B region of the HCV genome (365 bp) was amplified using nested polymerase chain reaction and sequenced.

RESULTS

Of 234 HIV-positive patients with acute HCV infection, all were male with 94% being MSM. At the diagnosis of acute HCV infection, 73.5% had concurrent sexually transmitted diseases and 88.0% were receiving combination antiretroviral therapy. The most prevalent HCV genotype was 3a, 2a and 1b in Hong Kong, Taipei and Tokyo respectively. Nine independent clusters belonging to five genotypes (1b, 2a, 2c, 3a and 6a) were identified, each of which occurred in one city without overlapping except for one 3a sequence from Taipei that was closely related genetically to the Hong Kong cluster.

CONCLUSIONS

No international network of HCV transmission was identified among HIV-positive patients in the three Asia-Pacific cities. The transmission dynamics of sexually acquired HCV differed by city, but the risk of intercity clustering should not be ignored.

Hepatitis C virus genotype diversity and distribution among methadone maintenance treatment patients in Jiangsu, China

BACKGROUND

Heroin users are vulnerable and represent a highly-infected reservoir for hepatitis C virus (HCV) infection. This study investigated HCV prevalence and genotypes distribution among heroin users who received methadone maintenance treatment (MMT) in Jiangsu.

METHODS

From June to December in 2016, a total of 534 patients among nine MMT clinics in six regions of Jiangsu were enrolled, with their demographic characteristics collected and serum samples tested for HCV antibody. 395 samples were seropositive and furthered to RNA extraction. HCV NS5B region fragments were amplified and subsequently sequenced.

RESULTS

Among HCV seropositive samples, 240 were characterized by NS5B partial sequences and classified into four genotypes (GPs) and eight subtypes. HCV GP3 predominated and accounted for 66.3%, followed by GP1 (27.5%), GP6 (4.2%) and GP2 (2.1%). HCV subtypes 3b (41.7%) and 3a (24.6%) were the most common subtypes. None of the demographic characteristics showed a significant difference when comparing with HCV genotypes. The geographic feature shown GPs in six regions were the same, but the frequency of subtypes exhibited regional divergence. Phylogenetic analyses demonstrated that 3b had become a local endemic in Jiangsu.

CONCLUSION

The distribution of HCV subtypes among heroin users in Jiangsu province was complex. The data could provide more precise estimates for HCV prevalence and genotype distribution as well as heroin users of Jiangsu province.

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.

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.

Age and gender distribution of Hepatitis C virus prevalence and genotypes of individuals of physical examination in WuHan, Central China

Approximately 170 million people in the world are infected with Hepatitis C virus (HCV). There are no published population based studies about the prevalence of HCV genotypes and the associations of genotype and Infection frequency with gender and age in WuHan. We aimed to investigate the distribution of HCV prevalence and genotypes among different gender and age patients with chronic HCV infection in WuHan from 2011 to 2015. A total of 2685 anti-HCV positive serum samples from individuals of physical examinationwere recruited from the Renmin Hospital of WuHan University, Hubei Province in China from January 2011 to December 2015. From these 2685 anti-HCV positive serum samples, 496 samples were with a positive PCR for HCV RNA. The number of HCV infection showed an increase with year, but the annual infection rate has remained similar (χ² = 2.94, P = 0.568). 2685 cases were infected with HCV from 2011 to 2015 in WuHan city of China. Blood transfusion (18.14 %) was the main routs of transmission, followed by Surgery (8.94 %). The highest prevalence of HCV infection was at the age group 50–59 (25.85 % of 2685) and the lowest prevalence was 0–9 (0.93 % of 2685). HCV genotype 1 was the most prevalent (73.39 %), followed by genotypes 2 (17.14 %), 3 (5.25 %) and 6 (3.22 %). Genotype 4 and 5 was not detected in these patients. The most prevalent subtype was subtype 1b (71.98 %), followed by genotypes 2a (17.14 %). Five patients had mixed infection across the HCV subtypes. Among all genotypes, genotype 1 was highest in both male (73.27 %) and female (73.47 %) patients, followed by genotype 2. Genotype 1 (male: 29.84 % of 496, vs female: 43.55 % of 496, χ² = 20.07, P < 0.0001), genotype 2 (male: 6.25 % of 496, vs female: 10.89 % of 496, χ² = 6.81, P = 0.009), and 6 (male: 1.41 % of 496, vs female: 1.81 % of 496, χ² = 0.626, P = 0.401) were more common in female patients than males, while no significant gender differences were observed for genotype 6. Among age group 50–59 years Genotype 1 was most common in male patients (29.05 % of 148) followed in 20–29 years (23.65 % of 148), genotype 2 in the age group 60–69 (12 cases of 31) and genotype 3 in the age group 50–59 (4 cases of 13) and genotype 6 was most frequent in the age group 30–39 (4 cases of 7). The frequency of HCV prevalence was significantly higher in female patients compared to males before ages 60, while the opposite result was observed after 60 years. The most common HCV genotype in WuHan was subtype 1b followed by 2a and more common among women than males patients. Further studies are needed to collect a large number of samples to estimate the different epidemiology of the HCV genotypes, because the sample size of non-genotype 1b and 2a is not large enough and other factors like disease history/monthly income/etc. are not included in our study.

SEQUENCE SIMILARITY BETWEEN THYROID SELF-PROTEIN AND HEPATITIS C VIRUS POLYPROTEIN: possible triggering mechanism of autoimmune thyroiditis

ABSTRACT Background - Exposure to viral antigens that share amino acid sequence similar with self- antigens might trigger autoimmune diseases in genetically predisposed individuals, and the molecular mimicry theory suggests that epitope mimicry between the virus and human proteins can activate autoimmune disease. Objective - The purpose of this study is to explore the possible sequence similarity between the amino acid sequences of thyroid self-protein and hepatitis C virus proteins, using databanks of proteins and immunogenic peptides, to explain autoimmune thyroid disease. Methods - Were performed the comparisons between the amino acid sequence of the hepatitis C virus polyprotein and thyroid self-protein human, available in the database of National Center for Biotechnology Information on Basic Local Alignment Search Tool. Results - The sequence similarity was related each hepatitis C virus genotype to each thyroid antigen. The similarities between the thyroid and the viral peptides ranged from 21.0 % (31 identical residues out of 147 amino acid in the sequence) to 71.0% (5 identical residues out of 7 amino acid in the sequence). Conclusion - Bioinformatics data, suggest a possible pathogenic link between hepatitis C virus and autoimmune thyroid disease. Through of molecular mimicry is observed that sequences similarities between viral polyproteins and self-proteins thyroid could be a mechanism of induction of crossover immune response to self-antigens, with a breakdown of self-tolerance, resulting in autoimmune thyroid disease.

Participation dynamics of a cohort of drug users in a low-threshold methadone treatment programme

BACKGROUND

The low-threshold methadone maintenance treatment (MMT) programme in Hong Kong has been in place for about 40 years. Assessment of the participation pattern of methadone users may inform future programme development to achieve effective harm reduction.

METHODS

Longitudinal clinical data of methadone users who first registered for MMT in the year 2008 in Hong Kong were retrieved after ethical and institutional approval. Participation pattern of this cohort was evaluated by examining users' frequency of attendance and then the overall retention rate. A subgroup of consistent users who remained on treatment in 2012 and/or 2013 was analysed. Comparison was made between high- and low-frequency users, and among high/moderate and low consistency users, to test their correlations with socio-demographics and social connectivity.

RESULTS

The cohort of methadone users registering in the year 2008 was composed of 351 persons, 77 % of whom were ethnic Chinese, with a median age of 34 and the duration of heroin dependency of 6 years. The participation pattern of methadone users was highly variable, with a 6-year retention rate of 38 %. Discontinuations or 'breaks' of >28 days had occurred in 212 (60 %) methadone users. About one third (n = 117) were high-frequency users who had attended more than twice a week for at least 90 % of their treatment periods. The dosages received by high-frequency users were generally higher. Of those continuing on treatment in the fifth and/or sixth year (n = 185), 30 (16 %), 29 (16 %) and 126 (68 %) gave a high, moderate and low level of consistency as defined by the lengths of breaks. High/moderate consistency users had a longer history of heroin use and a higher degree of connectivity with other users by social network analysis.

CONCLUSIONS

Despite the variability of frequency and consistency of attendance of drug users enrolling in the low-threshold MMT programme in Hong Kong, a consistent pattern could be seen in the proportional distribution of dosage and participation efforts. Whereas an adequate dosage was a potential predictor of optimal frequency of attendance, demographics and connectivity had varied between continued users with different levels of consistency.

Diverse origins of hepatitis C virus in HIV co-infected men who have sex with men in Hong Kong

Background

Worldwide, Hepatitis C (HCV) infection has been increasingly recognized in HIV-positive men who have sex with men (MSM). The objective of this study was to characterize the transmission dynamics of acute HCV infection in HIV-positive MSM in Hong Kong using a molecular approach.

Findings

We retrospectively examined 24 HIV-positive MSM with acute HCV infection diagnosed between 2009 and 2014 in Hong Kong. Detection and molecular characterization of HCV was successfully performed in 22 (91.7 %) patients. Genotype 3a was the most prevalent as identified in 14 (63.6 %) MSM, followed by 1a in 4 (18.2 %), 6a in 2 (9.1 %), and 1each (4.5 %) for 1b and 2a. The high prevalence of genotype 3a in MSM was in stark contrast to its rarity among HCV infected injection drug users (IDU) in Hong Kong. Phylogenetic analyses revealed a monophyletic HCV-3a cluster composing of MSM without injection history, and a homologous pair with HCV-6a genotype. There was otherwise no temporal or genetic clustering of the corresponding HIV sequences.

Conclusions

The origin of sexually acquired acute HCV infections in HIV-positive MSM was diverse and not directly linked with local IDU. The transmission dynamics of HIV and HCV infections in MSM in Hong Kong were evidently unrelated.

Hepatitis C virus genotype 6: virology, epidemiology, genetic variation and clinical implication

Hepatitis C virus (HCV) is a serious public health problem affecting 170 million carriers worldwide. It is a leading cause of chronic hepatitis, cirrhosis, and liver cancer and is the primary cause for liver transplantation worldwide. HCV genotype 6 (HCV-6) is restricted to South China, South-East Asia, and it is also occasionally found in migrant patients from endemic countries. HCV-6 has considerable genetic diversity with 23 subtypes (a to w). Although direct sequencing followed by phylogenetic analysis is the gold standard for HCV-6 genotyping and subtyping, there are also now rapid genotyping tests available such as the reverse hybridization line probe assay (INNO-LiPA II; Innogenetics, Zwijnaarde, Belgium). HCV-6 patients present with similar clinical manifestations as patients infected with other genotypes. Based on current evidence, the optimal treatment duration of HCV-6 with pegylated interferon/ribavirin should be 48 wk, although a shortened treatment duration of 24 wk could be sufficient in patients with low pretreatment viral load who achieve rapid virological response. In addition, the development of direct-acting antiviral agents is ongoing, and they give high response rate when combined with standard therapy. Herein, we review the epidemiology, classification, diagnosis and treatment as it pertain to HCV-6.

Hepatitis C genotype distribution and homology among geographically disparate injecting drug users in Afghanistan

Hepatitis C virus (HCV) prevalence is high among injecting drug users in Afghanistan, but transmission dynamics are poorly understood. Samples from HCV-infected injecting drug users were sequenced to determine circulating genotypes and potential transmission linkages. Serum samples were obtained from injecting drug user participants in Hirat, Jalalabad, and Mazar-i-Sharif between 2006 and 2008 with reactive anti-HCV rapid tests. Specimens with detected HCV viremia were amplified and underwent sequence analysis. Of 113 samples evaluated, 25 samples (35.2%) were only typeable in NS5B, nine samples (12.7%) were only typeable in CE1, and 37 samples (52.1%) were genotyped in both regions. Of those with typeable HCV, all were Afghan males with a mean age of 31.1 (standard deviation [SD] ± 8.0) years and mean duration of injecting of 3.9 (SD ± 4.3) years. Most reported residence outside Afghanistan in the last decade (90.1%) and prior incarceration (76.8%). HCV genotypes detected were: 1a, (35.2%, n = 25), 3a (62.0%, n = 44), and 1b (2.8%, n = 2). Cluster formation was detected in NS5B and CE1 and were generally from within the same city. All participants within clusters reported being a refugee in Iran compared to 93.5% of those outside clusters. Only 22.2% (4/11) of those within clusters had been refugees in Pakistan and these four individuals had also been refugees in Iran. Predominance of genotype 3a and the association between HCV viremia and having been a refugee in Iran potentially reflects migration between Afghanistan and Iran among IDUs from Mazar-i-Sharif and Hirat and carry implications for harm reduction programs for this migratory population.

Systematic review: Asian patients with chronic hepatitis C infection

BACKGROUND

Chronic hepatitis C (CHC) infection is a risk factor for both the development of end-stage liver disease and hepatocellular carcinoma (HCC). Globally, approximately 170 million people are chronically infected with the hepatitis C virus (HCV), and the majority of these individuals come from the western Pacific and Southeast Asia regions (94.6 million persons combined). CHC is an understudied and underappreciated health problem in many Asian countries and in the US, where Asians represent one of the fastest growing groups of new Americans.

AIM

To perform a systematic review of the current literature on the epidemiology, diagnosis and screening, clinical characteristics and response to anti-viral therapy of Asians with CHC.

METHODS

Using a PubMed search of 'hepatitis C' and 'Asia,' 341 original manuscripts published in peer-reviewed journals were identified, and 99 were selected based on their relevance.

RESULTS

Many Asian CHC patients do not have easily identifiable risk factors and may be underdiagnosed. Rates of HCV infection in Asians on community screening in the US are unexpectedly high, and there is a high prevalence of HCV genotype 6 in Southeast Asia and Southern China. HCV-infected Asians tend to present at older age and may have higher risk of HCC; however, they respond better to anti-viral therapy than non-Asians across all HCV genotypes.

CONCLUSIONS

Given the high HCV endemicity in Asia, lack of identifiable risk factors and favourable treatment response rates in Asians, we advocate the screening for HCV infection of all Asians who come from areas where HCV prevalence is ≥2%.