Emerging HIV infections with distinct subtypes of HIV-1 infection among injection drug users from geographically separate locations in Guangxi Province, China

Rapidly Spreading Human Immunodeficiency Virus Epidemic Among Older Males and Associated Factors: A Large-scale Prospective Cohort Study in Rural Southwest China

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Human immunodeficiency virus incidence was associated with males, older age, less than secondary schooling and not currently being married.

Background

Increasing risk of human immunodeficiency virus (HIV) heterosexual transmission can raise the potential for a more diffuse and generalized epidemic. In response to the paucity of data on HIV incidence among heterosexuals in China, we conducted a large-scale, population-based cohort study located in rural southwest China.

Methods

Baseline enrollment for the study was conducted from 2013 to 2014 and follow-up at 12 months was from 2014 to 2015 among adults 20 years or older in 3 rural counties of Southwest China. Study participants were informed of the study by brochures and leaflets distributed in outreach activities. Interviews and blood collection were conducted in private rooms. Blood samples were tested for HIV infection.

Results

The HIV prevalence of the sample was 0.29% (95% confidence interval [CI], 0.27–0.30) (2063 of 722,795) among the total adult population of 1,090,296 potential participants 20 years or older at baseline. Of the 720,732 individuals who tested HIV-negative at baseline, 493,990 (69%) completed the follow-up. Overall HIV incidence was 2.73 (95% CI, 2.38–3.08) per 10,000 person-years (PY) (235 of 860,627 PY). Human immunodeficiency virus incidence was associated with males, older age, less than secondary schooling and not currently being married. Human immunodeficiency virus incidence was 71.28 (95% CI, 35.21–107.35) per 10,000 PY among males aged 50 to 69 years who had less than secondary schooling and were divorced or widowed. Heterosexual sex was the dominant transmission mode for HIV seroconversions (99.0%).

Conclusions

Older heterosexual males were at disproportionate risk of HIV infection. Health authorities in China need to develop and implement innovative interventions suitable for the broader population of older heterosexuals.

HIV Epidemiology and Prevention in Southwestern China: Trends from 1996-2017

The aim of this review is to describe long-term HIV epidemiology and prevention trends in Guangxi, a provincial-level region located along a major drug trafficking corridor in southwestern China. Between 1996 and 2006, HIV transmission in Guangxi was primarily fueled by Injection Drug Use (IDU). Since 2006, heterosexual sex has become the dominant mode of HIV transmission, followed by drug injection. Moreover, older, heterosexual adults appear to be at increased risk for HIV. The vast majority of new HIV cases are attributed to local HIV subtypes already circulating within Guangxi (93%), though imported subtypes are associated with younger age groups. Since 2011, HIV incidence in Guangxi has stabilized, due in part to HIV prevention efforts that include expanded HIV testing, antiretroviral treatment, and other intervention measures. Between 1996 and 2017, Guangxi, China experienced dramatic changes in the primary HIV transmission mode and at-risk age group. Due in part to local and National AIDS control and prevention campaigns, HIV incidence trends in Guangxi no longer appear to be increasing.

HIV-1 Transmissions Among Recently Infected Individuals in Southwest China are Predominantly Derived from Circulating Local Strains

Although the Guangxi region accounts for 10% of all HIV-1 cases new reported in 2011 in China, the sources of the transmitted HIV-1 strains are virtually unknown. To determine the extent to which recent HIV infections were derived from already circulating local strains as opposed to recently introduced strains, we performed a cross-sectional molecular epidemiological investigation of recent infections across Guangxi during 2012-2013. HIV-1 nucleotide sequences were amplified and sequenced. Phylogenetic analyses of pol gene regions were used to determine HIV-1 transmission source strains. Based on 229 sequences generated, the subtype/CRF distribution was as follows: CRF01_AE (61.1%), CRF07_BC (18.8%), CRF08_BC (16.6%), CRF55_01B (3.1%), and subtype B' (0.4%). In total, 213 of 229 (93.0%) sequenced transmission strains were derived from already-circulating local strains. Multivariate logistic regression analysis showed that only an age of 18-25 years was significantly associated with transmission from outside Guangxi (compared to >25 years, AOR: 5.15, 95% CI: 1.18-22.48, p < 0.01). This is the first study to use a Bayesian discrete phylogeographic approach to analyze transmission source strains in China. Our results provide useful data for designing evidence-based prevention strategies and methods for combating the rapid spread of sexually transmitted HIV in Guangxi.

Characterization of a New HIV-1 CRF01_AE/CRF07_BC Recombinant Virus in Tianjin, China

HIV is notorious for its rapid evolution since its transmissions from monkey to human. Currently, HIV contains multiple subtypes, circulating recombinant forms (CRFs) and unique recombinant forms (URFs). Here, from an HIV-positive mother and her child in Tianjin, China, we identified a novel HIV-1 second-generation recombinant virus (TJ20170316 and TJ20170317) between CRF01_AE and CRF07_BC. Near full-length genomes (NFLGs) were obtained from both samples, and they shared very close sequences, except some point mutations. Phylogenetic analyses of the NFLGs showed that they consist of CRF01_AE backbone and part CRF07_BC sequences. Recombinant Identification Program and Simplot software identified four breakpoints in gag, pol, vif, and tat genes in TJ20170316, totally different from other reported CRFs and URFs. The emergence of such URFs in Tianjin, China, highlights the complexity of HIV-1 epidemic and more measures should be taken to prevent HIV transmissions.

Methadone maintenance-lessons from two systems in China

In Hong Kong, methadone maintenance treatment (MMT) was launched in the 1970s, almost 30 years before the counterpart programme’s inauguration in Mainland China. Both were established in response to perceived public crises—addiction-related crime and HIV outbreak, respectively—and both are now regular services under two systems in the same country. Effectiveness of MMT in achieving the stated goals was evident in each case and provides useful lessons on strategies for dealing with the varied concerns related to illicit drug use. Today, with changing patterns of drug addiction, increasing competition for resources, and changing attitudes towards addiction and its treatment, the two MMT systems are confronted with similar challenges to achieve sustainability.

Effects of high CD4 cell counts on death and attrition among HIV patients receiving antiretroviral treatment: an observational cohort study

Current WHO guidelines recommend initiating ART regardless of CD4+ cell count. In response, we conducted an observational cohort study to assess the effects of pre-ART CD4+ cell count levels on death, attrition, and death or attrition in HIV treated patients. This large HIV treatment cohort study (n = 49,155) from 2010 to 2015 was conducted in Guangxi, China. We used a Cox regression model to analyze associations between pre-ART CD4+ cell counts and death, attrition, and death or attrition. The average mortality and ART attrition rates among all treated patients were 2.63 deaths and 5.32 attritions per 100 person-years, respectively. Compared to HIV patients with <350 CD4+ cells/mm³ at ART initiation, HIV patients with >500 CD4+ cells/mm³ at ART initiation had a significantly lower mortality rate (Adjusted hazard ratio: 0.56, 95% CI: 0.40–0.79), but significantly higher ART attrition rate (AHR: 1.17, 95% CI: 1.03–1.33). Results from this study suggest that HIV patients with high CD4+ cell counts at the time of ART initiation may be at greater risk of treatment attrition. To further reduce ART attrition, it is imperative that patient education and healthcare provider training on ART adherence be enhanced and account for CD4 levels at ART initiation.

Overview of HIV molecular epidemiology among people who inject drugs in Europe and Asia

HIV strains continuously evolve, tend to recombine, and new circulating variants are being discovered. Novel strains complicate efforts to develop a vaccine against HIV and may exhibit higher transmission efficiency and virulence, and elevated resistance to antiretroviral agents. The United Nations Joint Programme on HIV/AIDS (UNAIDS) set an ambitious goal to end HIV as a public health threat by 2030 through comprehensive strategies that include epidemiological input as the first step of the process. In this context, molecular epidemiology becomes invaluable as it captures trends in HIV evolution rates that shape epidemiological pictures across several geographical areas. This review briefly summarizes the molecular epidemiology of HIV among people who inject drugs (PWID) in Europe and Asia. Following high transmission rates of subtype G and CRF14_BG among PWID in Portugal and Spain, two European countries, Greece and Romania, experienced recent HIV outbreaks in PWID that consisted of multiple transmission clusters including subtypes B, A, F1, and recombinants CRF14_BG and CRF35_AD. The latter was first identified in Afghanistan. Russia, Ukraine, and other Former Soviet Union (FSU) states are still facing the devastating effects of epidemics in PWID produced by A_FSU (also known as IDU-A), B_FSU (known as IDU-B), and CRF03_AB. In Asia, CRF01_AE and subtype B (Western B and Thai B) travelled from PWID in Thailand to neighboring countries. Recombination hotspots in South China, Northern Myanmar, and Malaysia have been generating several intersubtype and inter-CRF recombinants (e.g. CRF07_BC, CRF08_BC, CRF33_01B etc.), increasing the complexity of HIV molecular patterns.

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

Background

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

Methods

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

Results

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

Conclusion

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

Analysis of HIV Correlated Factors in Chinese and Vietnamese Female Sex Workers in Hekou, Yunnan Province, a Chinese Border Region

Objectives

To assess the prevalence and correlated factors of HIV-1 among Chinese and Vietnamese female sex workers (FSW) in the border county of Hekou, Yunnan province, China.

Methods

A cross-sectional survey was conducted collecting information on demographics, sexual behavior, medical history, and drug use. Blood samples were obtained to test for HIV/STIs. Multivariate logistic regression model was used to examine associations between factors and HIV-1 infection.

Results

Of 345 FSWs who participated in this study, 112 (32.5%) were Chinese and 233 (67.5) were Vietnamese. Vietnamese FSWs were significantly more likely to be HIV-1 positive (7.7%) compared with Chinese FSWs (0.9%) (p = 0.009). In multivariate analysis, sexual debut at age≤16 (OR 3.8: 95% CI: 1.4, 10.6), last client’s payment <150 RMB ($22 USD) (OR: 5.2, 95% CI; 1.7, 16.6), and HSV-2 (OR: 12.3; 95% CI: 1.6, 94.8) were significant for HIV-1 infection.

Conclusions

Differences in HIV prevalence in Vietnamese and Chinese FSWs may be indicative of differential risk. It is important to characterize the nature of trans-border transmission in order to gain a better understanding of the potential impact on the international HIV epidemic. Understanding the correlated factors for HIV in Vietnamese and Chinese FSWs is important for designing interventions for this vulnerable population.

HIV-1 Treatment-as-Prevention: A Cohort Study Analysis of Serodiscordant Couples in Rural Southwest China

The Chinese national observational cohort study suggests that the treatment-as-prevention (TasP) approach can be an effective public health HIV-1 prevention strategy. However, results from that study may have been biased because the follow-up time of index patients prior to their initiation of antiretroviral therapy (ART) was excluded. In this study, we correct for such bias by using an extended time-dependent Cox regression model to conduct a cohort study analysis of serodiscordant couples in Guangxi of China, inclusive of all follow-up time. During the follow-up of this observational cohort study of HIV-1 sero-discordant couples, the positive index partners may have never be treated with ART, or enter untreated but subsequently began treatment, or may have been treated immediately upon entry into the public health system. The treatment effectiveness of ART in HIV-1 acquisition among HIV-negative partners is assessed by the extended Cox regression model with treatment status as a time-varying covariate. A total of 6548 sero-discordant couples were included in the cohort study analysis. Among them, 348 negative partners sero-converted. HIV seroincidence was significantly higher among the nontreated (4.3 per 100 person-years, 3.7-4.9) compared with those receiving ART (1.8 per 100 person-years, 1.5-2.0). An overall 35% reduction in risk of HIV transmission was associated with receiving ART (adjusted hazard ratio [AHR] 0.65, 95% confidence interval [CI] 0.51-0.83), and the yearly risk reduction was also significant in the first 3 consecutive years of follow-up. Moreover, ART was found to be significantly inversely associated with multiple baseline characteristics of index partners. TasP may be feasible on a national or regional scale. In addition to other proven preventive strategies such as the use of condoms, ART adherence to maintain viral suppression would then be the key challenge for successful TasP implementation.

Development of an HIV-1 Subtype Panel in China: Isolation and Characterization of 30 HIV-1 Primary Strains Circulating in China

Background

The complex epidemic and significant diversity of HIV-1 strains in China pose serious challenges for surveillance and diagnostic assays, vaccine development and clinical management. There is a lack of HIV-1 isolates in current canonical HIV-1 subtype panels that can represent HIV-1 diversity in China; an HIV-1 subtype panel for China is urgently needed.

Methods

Blood samples were collected from HIV-1 infected patients participating in the drug-resistance surveillance program in China. The samples were isolated, cultured and stored as neat culture supernatant. The HIV-1 isolates were fully characterized. The panel was used to compare 2 viral load assays and 2 p24 assays as the examples of how this panel could be used.

Results

An HIV-1 subtype panel for China composed of 30 HIV-1 primary strains of four subtypes (B [including Thai-B], CRF01_AE, CRF07_BC and G) was established. The samples were isolated and cultured to a high-titer (10⁶-10⁹ copies/ml)/high-volume (40ml). The HIV-1 isolates were fully characterized by the final viral load, p24 concentration, gag-pol and envC2V3 sequencing, co-receptor prediction, determination of the four amino acids at the tip of the env V3-loop, glycosylation sites in the V3 loop and the drug-resistance mutations. The comparison of two p24 assays and two viral load assays on the isolates illustrated how this panel may be used for the evaluation of diagnostic assay performance. The Pearson value between p24 assays were 0.938. The viral load results showed excellent concordance and agreement for samples of Thai-B, but lower correlations for samples of CRF01_AE.

Conclusion

The current panel of 30 HIV-1 isolates served as a basis for the development of a comprehensive panel of fully characterized viral isolates, which could reflect the current dynamic and complex HIV-1 epidemic in China. This panel will be available to support HIV-1 research, assay evaluation, vaccine and drug development.

Genetic Characteristics of CRF01_AE Among Newly Diagnosed HIV-1-Infected 16- to 25-Year Olds in 3 Geographic Regions of Guangxi, China

The aim of this study was to analyze the distribution of clusters and drug resistance of CRF01_AE among newly diagnosed, treatment-naïve HIV-infected teenagers and young adults in 3 major HIV-affected geographic regions of Guangxi Province, including the cities of Hezhou, Liuzhou, and Nanning. Samples were sequentially collected from newly diagnosed HIV-infected 16- to 25-year olds in these 3 regions from 2009 to 2013. The viral genome was extracted, and the partial pol gene was amplified and sequenced. Phylogenetic analyses were used to determine HIV-1 subtypes and CRF01_AE clusters. Transmitted drug resistance (TDR) mutations were identified using the 2009 WHO list of TDR mutations. A total of 216 sequences were obtained from CRF01_AE strains, which accounted for 83.1% of the 260 genotyped samples, of which 36 were from Hezhou, 147 from Liuzhou, and 33 in Nanning. Most (83.3%, 180/216) were from heterosexuals, followed by injection drug users (5.6%), homosexuals (4.2%), and unknown risk group (6.9%). Based on phylogenetic analyses by the maximum likelihood method, 5 distinct clusters (cluster 1-5) were identified with 213 (98.6%) sequences, whereas 3 (1.4%) sequences were ungrouped. In Hezhou, 88.9% (32/36) of CRF01_AE infections were caused by cluster 2, and 11.1% (4/36) were caused by cluster 1. In Liuzhou, 83.0% (122/147) of the CRF01_AE strains were found in cluster 1, 11.6% (17/147) from cluster 2, 1.4% (2/147) from cluster 3, 2.7% (4/147) from cluster 4, and 0.7% (1/147) from cluster 5. The distribution of CRF01_AE clusters was more even in Nanning than it was in the other 2 regions, with 18.2% (6/33) from cluster 1, 36.3% (12/33) from cluster 2, 9.1% (3/33) from cluster 3, 18.2% (6/33) from cluster 4, and 12.1% (4/33) from cluster 5. The most frequent TDR mutations were M46I (2) in the protease region and Y181C (2) from the reverse transcriptase fragment. Clusters 1 and 2 of CRF01_AE strains were prevalent in Liuzhou and Hezhou, respectively. However, multiple CRF01_AE clusters existed in Nanning. This can be partially explained by the high mobility of laborers in Nanning, the capital city of Guangxi. The prevalence of TDR was low.

Bridging the epidemic: a comprehensive analysis of prevalence and correlates of HIV, hepatitis C, and syphilis, and infection among female sex workers in Guangxi Province, China

INTRODUCTION

Female sex workers (FSWs) are at highest risk for contracting HIV and facilitating the current heterosexual HIV epidemic in Guangxi, China, yet little is known of the impact of recent harm reduction campaigns in the province. We analyzed sentinel surveillance data collected between 2010 and 2012 in Guangxi to explore correlations between the prevalence of HIV, hepatitis C (HCV), and syphilis and risk behaviors of different categories of FSWs in Guangxi.

METHODS

The sentinel surveillance data for 5,1790 FSWs in all 14 prefectures and 64 city/county regions of Guangxi, China from 2010 to 2012 were collected. Differences between three categories of FSWs (grouped by venue) and disease trends (HIV, HCV, and syphilis) by year were analyzed using bivariate and multivariate logistic regression analyses as to evaluate risk factors correlated with HIV, HCV, or syphilis infection.

RESULTS

HIV and HCV prevalence remained constant across the three FSW categories; however, syphilis prevalence showed a significant increase from 5.7% to 7.3% for low-tier FSWs. Most cases with HIV, HCV, syphilis and intravenous drug use were seen in low-tier FSWs. Testing positive for HIV and syphilis were most correlated with being HCV positive (AOR 4.12 and AOR 4.36), only completing elementary school (AOR 3.71 and AOR 2.35), low tier venues (AOR 2.02 and AOR 2.00), and prior STI (AOR 1.40 and AOR 3.56), respectively. HCV infection was correlated with ever injecting drugs (AOR 60.65) and testing positive for syphilis (AOR 4.16) or HIV (AOR 3.74).

CONCLUSIONS

This study highlights that low tier FSWs with lower formal education levels are the most vulnerable population at risk for acquiring and transmitting HIV, HCV, and syphilis in Guangxi, China. Condom distribution with evolution to safer sex practices are the reasons to explain the non-increasing prevalence of HIV, HCV in Guangxi for 2010-2012.

HIV-1 diversity, drug-resistant mutations, and viral evolution among high-risk individuals in phase II HIV vaccine trial sites in southern China

HIV-1 prevalence in Guangxi, China, has been growing since 1996, when the first case was reported. Over half of HIV-1 positive patients in Guangxi Province were injecting drug users (IDUs), possibly because of the province’s location near drug-trafficking routes. Since a phase II HIV vaccine trial is ongoing there, a current characterization of the subtypes of HIV-1 among IDUs in Guangxi would provide critical information for future HIV vaccine trials, as well as further control and prevention of HIV-1 transmission. Thus, we conducted a molecular epidemiological investigation of HIV-1 samples from 2008–2010 among IDUs in multiple cities in Guangxi Province. Our results, based on the gag/pol fragment, indicated a very high proportion (78.47%) of HIV-1 CRF08_BC recombinants, some CRF01_AE (15.38%) recombinants, and a low proportion of CRF07_BC (6.15%) recombinants among the IDUs. The high proportion of CRF08 HIV-1 strains among recent IDUs matches the vaccine candidate constructs. However, future vaccine development should also incorporate CRF01-targeted vaccine candidates. Distinct Env sequence evolution patterns were observed for CRF08_BC and CRF01_AE, indicating that different local selection pressures have been exerted on these two HIV-1 subtypes. Unique drug-resistant mutations were also detected, and our data indicate that HIV treatment programs should consider pre-existing drug-resistant mutations.

Subtype CRF01_AE dominate the sexually transmitted human immunodeficiency virus type 1 epidemic in Guangxi, China

Human immunodeficiency virus type 1 (HIV-1) infection by sexual transmission in Guangxi, China had increased dramatically. However, limited information is available on the genetic characterization of the HIV-1 epidemic. In this study, HIV-1 seropositive drug-naïve patients infected by heterosexual transmission were enrolled. The full length gag and pol genes were sequenced followed by phylogenetic analysis, recombinant analysis and drug resistant analysis. Multiple subtypes were identified, including CRF01_AE (80.1%), CRF07_BC (6.4%), CRF08_BC (10.2%), subtype B (1.7%), and URFs (1.7%). In the phylogenetic tree, two large CRF01_AE clusters were identified. One cluster is originating from Vietnam strains as being reported previously in intravenous drug users. One novel cluster was identified and showed close relationship to strains from Fujian province. Inter-subtype recombination among CRF01_AE, subtype B and C was identified. Low level drug-resistance in drug-naïve heterosexually transmitted infections was found. The results suggested that multiple originating CRF01_AE strains dominated the HIV-1 epidemic in heterosexual transmission in Guangxi province.

Emerging variability in HIV-1 genetics among recently infected individuals in Yunnan, China

Background

Yunnan has the longest endured Human Immunodeficiency Virus-1 (HIV-1) epidemic in China, and the genetic diversity of HIV-1 constitutes an essential characteristic of molecular epidemiology in this region. To obtain a more comprehensive picture of the dynamic changes in Yunnan’s HIV-1 epidemic, a cross-sectional molecular epidemiological investigation was carried out among recently infected individuals.

Methodology/Principal Findings

We sequenced partial gag (HXB2∶781–1861) and env (HXB2∶7002–7541) genes from 308 plasma samples of recently infected patients. With phylogenetic analysis, 130 specimens generated interpretable genotyping data. We found that the circulating genotypes included: CRF08_BC (40.8%), unique recombinant forms (URFs, 27.7%), CRF01_AE (18.5%), CRF07_BC (9.2%), subtype B (2.3%) and C (1.5%). CRF08_BC was the most common genotype, and was predominant in both intravenous drug users (IDUs) and heterosexually transmitted populations. CRF08_BC and CRF07_BC still predominated in eastern Yunnan, but CRF08_BC showed increasing prevalence in western Yunnan. Strikingly, the URFs raised dramatically in most regions of Yunnan. Seven different types of URFs were detected from 12 prefectures, suggesting that complicated and frequent recombination is a salient feature of Yunnan’s HIV-1 epidemic. Among URFs, two BC clusters with distinctive recombination patterns might be potential new CRF_BCs. CRF01_AE was no longer confined to the prefectures bordering Myanmar, and had spread to the eastern part of Yunnan, especially the capital city of Kunming, with a large number of infections in the transient population. The ratios of the main genotypes showed no statistical differences between infected IDUs and heterosexually transmitted infections.

Conclusions/Significance

The changing patterns of the dominant HIV-1 genotypes in Yunnan indicate the complex evolving dynamic nature of the epidemic. Understanding new trends in molecular epidemiology of HIV-1 infection is critical for adjusting current prevention strategies and vaccine development in Yunnan.

DNA prime-protein boost using subtype consensus Env was effective in eliciting neutralizing antibody responses against subtype BC HIV-1 viruses circulating in China

Previously, we have shown that DNA prime-protein boost is effective in eliciting neutralizing antibodies (NAb) against randomly selected HIV-1 isolates. Given the genetic diversity of HIV-1 viruses and the unique predominant subtypes in different geographic regions, it is critical to test the DNA prime-protein boost approach against circulating viral isolates in key HIV endemic areas. In the current study, the same DNA prime-protein boost vaccine was used as in previous studies to investigate the induction of NAb responses against HIV-1 clade BC, a major subtype circulating in China. A codon optimized gp120-BC DNA vaccine, based on the consensus envelope (Env) antigen sequence of clade BC, was constructed and a stable CHO cell line expressing the same consensus BC gp120 protein was produced. The immunogenicity of this consensus gp120-BC was examined in New Zealand White rabbits by either DNA prime-protein boost or protein alone vaccination approaches. High levels of Env-specific antibody responses were elicited by both approaches. However, DNA prime-protein boost but not the protein alone immune sera contained significant levels of NAb against pseudotyped viruses expressing HIV-1 BC Env antigens. Furthermore, high frequencies of CD4 binding site-targeted antibodies were found in the DNA prime- protein boost rabbit sera indicating that the positive NAb may be the result of antibodies against conformationally sensitive epitopes on HIV-1 Env. The findings support that DNA prime-protein boost was effective in eliciting NAb against a key HIV-1 virus subtype in China. This result may lead to the development of regional HIV vaccines through this approach.

A comprehensive mapping of HIV-1 genotypes in various risk groups and regions across China based on a nationwide molecular epidemiologic survey

Background

China is experiencing a dynamic HIV/AIDS epidemic. While serology based surveillance systems have reported the spread of HIV/AIDS, detailed tracking of its transmission in populations and regions is not possible without mapping it at the molecular level. We therefore conducted a nationwide molecular epidemiology survey across the country.

Methods

HIV-1 genotypes were determined from 1,408 HIV-positive persons newly diagnosed in 2006. The prevalence of each genotype was estimated by weighting the genotype’s prevalence from each province- and risk-specific subpopulation with the number of reported cases in the corresponding subgroups in that year.

Results

CRF07_BC (35.5%), CRF01_AE (27.6%), CRF08_BC (20.1%), and subtype B' (9.6%) were the four main HIV-1 strains in China. CRF07_BC and CRF08_BC were the primary drivers of infection among injecting drug users in northeastern and southeastern China, respectively, and subtype B' remained dominant among former plasma donors in central China. In contrast, all four strains occurred in significant proportions among heterosexuals nationwide, pointing to an expansion of the HIV-1 epidemic from high-risk populations into the general population. CRF01_AE also replaced subtype B as the principal driver of infection among men-who-have-sex-with-men.

Conclusions

Our study provides the first comprehensive baseline data on the diversity and characteristics of HIV/AIDS epidemic in China, reflecting unique region- and risk group-specific transmission dynamics. The results provide information critical for designing effective prevention measures against HIV transmission.

Short communication: phylogenetic characterization of HIV type 1 CRF01_AE V3 envelope sequences in pregnant women in Northern Vietnam

Characterization of HIV-1 strains is important for surveillance of the HIV-1 epidemic. In Vietnam HIV-1-infected pregnant women often fail to receive the care they are entitled to. Here, we analyzed phylogenetically HIV-1 env sequences from 37 HIV-1-infected pregnant women from Ha Noi (n=22) and Hai Phong (n=15), where they delivered in 2005-2007. All carried CRF01_AE in the gp120 V3 region. In 21 women CRF01_AE was also found in the reverse transcriptase gene. We compared their env gp120 V3 sequences phylogenetically in a maximum likelihood tree to those of 198 other CRF01_AE sequences in Vietnam and 229 from neighboring countries, predominantly Thailand, from the HIV-1 database. Altogether 464 sequences were analyzed. All but one of the maternal sequences colocalized with sequences from northern Vietnam. The maternal sequences had evolved the least when compared to sequences collected in Ha Noi in 2002, as shown by analysis of synonymous and nonsynonymous changes, than to other Vietnamese sequences collected earlier and/or elsewhere. Since the HIV-1 epidemic in women in Vietnam may still be underestimated, characterization of HIV-1 in pregnant women is important to observe how HIV-1 has evolved and follow its molecular epidemiology.

Parental LTRs are important in a construct of a stable and efficient replication-competent infectious molecular clone of HIV-1 CRF08_BC

Circulating recombinant forms (CRFs) of HIV-1 have been identified in southern China in recent years. CRF08_BC is one of the most predominant subtypes circulating in China. In order to study HIV subtype biology and to provide a tool for biotechnological applications, the first full-length replication-competent infectious molecular clone harboring CRF08_BC is reported. The construction of this clone pBRGX indicates that a moderate-copy number vector is required for its amplification in E. coli. In addition, it is shown that the parental CRF08_BC LTRs are important for generating this efficient replication-competent infectious clone. These observations may aid in the construction of infectious clones from other subtypes. Both the pBRGX-derived virus and its parental isolate contain CCR5 tropism. Their full-length genomes were also sequenced, analyzed, compared and deposited in GenBank (JF719819 and JF719818, respectively). The availability of pBRGX as the first replication-competent molecular clone of CRF08_BC provides a useful tool for a wide range of studies of this newly emergent HIV subtype, including the development of HIV vaccine candidates, antiviral drug screening and drug resistance analysis.

Crossing over: drug network characteristics and injection risk along the China-Myanmar border

Border areas are important locations for understanding HIV transmission. This study examines individual and network correlates of border crossing and equipment sharing among methadone maintenance clients in Ruili City, a Chinese city on the Myanmar border. Data are from 298 clients enrolled in the Ruili Methadone Treatment Center. Clients were interviewed about drug use, HIV/AIDS knowledge, treatment motivation, and their social networks. Multinomial and logistic regression analysis were performed. Thirty percent of clients reported injecting in Myanmar. Compared to drug networks that usually inject in China, networks that inject equally in both places (border crossing) are more likely to share equipment. The association between HIV positive status and border-crossing was marginally significant and robust. Results indicate some added degree of risk among clients and drug networks who border-cross to use drugs. More research is needed to understand this phenomenon.

Needle sharing and sex-related risk behaviours among drug users in Shenzhen, a city in Guangdong, southern China

Intravenous drug users (IDUs) are at high risk of contracting HIV, but there is a geographic bias in such research efforts in China. The aim was to study the pattern of needle sharing and sex-related risk behaviours among drug users in southern China. About 260 drug users in a detoxification centre completed an anonymous questionnaire (response rate=87.3%). The results show that needle sharing among IDUs was prevalent (60.6% and 45.3% for male and female IDUs, respectively); the sharers were often friends, spouses, and acquaintances. Few IDUs sterilized the used needles properly. Commercial sex behaviours (males: 44%; females: 60%) as well as multiple partnership (males: 60%; females: 53%) were also prevalent among all male and female drug users studied. Inconsistent condom use with commercial sex partners, spouses, and regular sex partners was also very common. Yet, few of all drug users studied perceived the susceptibility of contracting HIV (11%) or sexually transmitted diseases (24%) in the future. A better HIV-related knowledge level was associated with lower levels of risk behaviours. It is concluded that harm reduction programmes are urgently warranted in China.

Genetic characterization of 13 subtype CRF01_AE near full-length genomes in Guangxi, China

Guangxi is an important transit area for HIV transmission in South China. Characterization of the full-length genome of HIV-1 prevalent in the area is important for phylogenetic analysis and vaccine development. CRF01_AE is one of the most rapidly spreading subtypes in Guangxi. In this study, we reported thirteen near full-length CRF01_AE genomes from Guangxi, China. The nearly full-length genome was reverse transcripted and amplified in two halves with the 1-kb overlap regions. The PCR products were sequenced directly. The sequence analysis showed that all of 13 strains were CRF01_AE recombinant subtypes. Two clusters were set up with all of the sequences that grouped separately with sequences from Vietnam and Fujian, China, which strongly suggested multiple introductions of CRF01_AE strains into Guangxi province. The results will improve our understanding on the phylogenetic relationship of CRF01_AE strains in South China and also help in the development of a successful HIV vaccine.

High prevalence and genetic diversity of HCV among HIV-1 infected people from various high-risk groups in China

BACKGROUND

Co-infection with HIV-1 and HCV is a significant global public health problem and a major consideration for anti-HIV-1 treatment. HCV infection among HIV-1 positive people who are eligible for the newly launched nationwide anti-HIV-1 treatment program in China has not been well characterized.

METHODOLOGY

A nationwide survey of HIV-1 positive injection drug uses (IDU), former paid blood donors (FBD), and sexually transmitted cases from multiple provinces including the four most affected provinces in China was conducted. HCV prevalence and genetic diversity were determined. We found that IDU and FBD have extremely high rates of HCV infection (97% and 93%, respectively). Surprisingly, people who acquired HIV-1 through sexual contact also had a higher rate of HCV infection (20%) than the general population. HIV-1 subtype and HCV genotypes were amazingly similar among FBD from multiple provinces stretching from Central to Northeast China. However, although patterns of overland trafficking of heroin and distinct HIV-1 subtypes could be detected among IDU, HCV genotypes of IDU were more diverse and exhibited significant regional differences.

CONCLUSION

Emerging HIV-1 and HCV co-infection and possible sexual transmission of HCV in China require urgent prevention measures and should be taken into consideration in the nationwide antiretroviral treatment program.

Phylodynamic analysis of the dissemination of HIV-1 CRF01_AE in Vietnam

To estimate the epidemic history of HIV-1 CRF01_AE in Vietnam and adjacent Guangxi, China, we determined near full-length nucleotide sequences of CRF01_AE from a total of 33 specimens collected in 1997-1998 from different geographic regions and risk populations in Vietnam. Phylogenetic and Bayesian molecular clock analyses were performed to estimate the date of origin of CRF01_AE lineages. Our study reconstructs the timescale of CRF01_AE expansion in Vietnam and neighboring regions and suggests that the series of CRF01_AE epidemics in Vietnam arose by the sequential introduction of founder strains into new locations and risk groups. CRF01_AE appears to have been present among heterosexuals in South-Vietnam for more than a decade prior to its epidemic spread in the early 1990s. In the late 1980s, the virus spread to IDUs in Southern Vietnam and subsequently in the mid-1990s to IDUs further north. Our results indicate the northward dissemination of CRF01_AE during this time.

Predictors of HIV infection and prevalence for syphilis infection among injection drug users in China: community-based surveys along major drug trafficking routes

Objective

To assess the predictors and prevalence of HIV infection among injection drug users in highly endemic regions along major drug trafficking routes in three Chinese provinces.

Methods

We enrolled participants using community outreach and peer referrals. uestionnaire-based interviews provided demographic, drug use, and sexual behavior information. HIV was tested via ELISA and syphilis by RPR.

Results

Of the 689 participants, 51.8% were HIV-infected, with persons living in Guangxi having significantly lower prevalence (16.4%) than those from Xinjiang and Yunnan (66.8% and 67.1%, respectively). Syphilis seropositivity was noted in 5.4%. Longer duration of IDU, greater awareness of HIV transmission routes, and living in Xinjiang or Yunnan were associated with HIV seropositivity on multivariable analysis. Independent risk factors differed between sites. In Guangxi, being male and having a longer duration of IDU were independent risk factors for HIV infection; in Xinjiang, older age and sharing needles and/or syringes were independent factors; in Yunnan, more frequent drug injection, greater awareness of HIV transmission routes, and higher income were independent predictors of HIV seropositivity.

Conclusion

Prevalence rates of HIV among IDUs in China are more than two out of three in some venues. Risk factors include longer duration of IDU and needle sharing. Also associated with HIV were factors that may indicate some success in education in higher risk persons, such as higher knowledge. A systemic community-level intervention with respect to evidenced-based, population-level interventions to stem the spread of HIV from IDU in China should include needle exchange, opiate agonist-based drug treatment, condom distribution along with promotion, and advocacy for community-based VCT with bridges to HIV preventive services and care.

Dynamic analysis of genetic diversity of gag and env regions of HIV-1 CRF07_BC recombinant in intravenous drug users in Xinjiang Uvghur Autonomous Region, China

The aim of this study was to investigate the genetic variation of HIV-1 CRF07_BC, the most prevalent circulating strain in intravenous drug users (IDUs) in China. We studied the diversity in the C2-V5 region of the HIV-1 env gene and in the p17-p24 region of the HIV-1 gag gene from the same samples in 12 IDUs who were divided into two groups according to the length of infection time. Two IDUs were longitudinally monitored from the time of seroconversion for 2-2.5 years. The viral divergence from the founder strain and the viral population diversity between sequential time points were analyzed in two men. The data show that the divergence of the env gene is higher than that of gag in general, while the diversity of the gag gene is sometimes higher than that of env during the course of HIV evolution. In addition, env and gag gene diversity increased over time. The observed patterns and associations may enhance our understanding of HIV-1 evolution.

Factors influencing a low rate of hepatitis C viral RNA clearance in heroin users from Southern China

AIM: To study the virological and host factors influencing hepatitis C infection outcomes in heroin users in southern China.

METHODS: HCV RNA and associated factors were analyzed among 347 heroin users from Guangxi Zhuang Autonomous Region, southern China who were hepatitis C virus (HCV) EIA positive for two or more consecutive visits.

RESULTS: Using the COBAS AMPLICOR HCV TEST, a remarkably low HCV RNA negative rate of 8.6% was detected. After multivariate logistic regression analysis, HCV RNA clearance was significantly associated with the presence of HBsAg (OR = 8.436, P < 0.0001), the lack of HIV-1 infection (OR = 0.256, P = 0.038) and age younger than 25 (OR = 0.400, P = 0.029).

CONCLUSION: Our study suggests HCV infection among Chinese heroin users results in high levels of viral persistence even amidst factors previously found to enhance viral clearance. Prospective studies of a possible genetic component within the Chinese population and the pathogenicity of non-genotype 1 HCV infections are needed.

Migration and transmission of blood-borne infections among injection drug users: understanding the epidemiologic bridge

Migration is one of many social factors contributing to the spread of HIV and other blood-borne or sexually transmitted infections (STI). Bringing together large numbers of people from diverse settings, the process of migration moves infected individuals to diverse geographic locations. Injection drug users (IDU) are a relatively mobile group, often moving between cities, smaller communities, and across international borders for reasons of work, security, or access to narcotics. This mobility indicates the potential for IDU who engage in risky behavior outside their home areas to transmit HIV infection to other IDU, their sex partners, and others in the population. The objectives of this review are to examine: (1) the influence of drug trafficking and the spread of drug use on the diffusion of HIV, (2) the influence of migration on drug use and HIV-related risk behaviors among migrants, and (3) the mobility patterns of IDU and its role in the spread of HIV. We also discuss the potential policy implications of addressing prevention and care issues in mobile drug using populations.

A nascent HIV type 1 epidemic among injecting drug users in Kabul, Afghanistan is dominated by complex AD recombinant strain, CRF35_AD

Injecting drug use (IDU), common in global centers of heroin production, confers significant risk for HIV-1 infection. Once introduced into IDU networks, an explosive rise in HIV-1 infection typically occurs, fueled principally by needle sharing. New HIV-1 epidemics in IDUs have occurred in Russia, China, Thailand, Spain, Iran, and in other countries, and some have spread into other risk groups in their respective countries. In Afghanistan, the introduction of HIV-1 into IDU networks has begun, but a recent report of 3% HIV-1 prevalence suggests that the epidemic is still at an early stage. Here we establish, by complete genome sequencing and phylogenetic analysis of four viral strains from Afghan IDUs, that all are the same complex recombinant strain, combining HIV-1 subtypes A and D and herein termed CRF35_AD. Published partial HIV-1 sequences from an HIV-1 epidemic among IDUs in Iran, already at 23.2% HIV-1 prevalence, are either CRF35_AD or a related recombinant. Voluntary HIV-1 screening and harm reduction programs in Afghanistan, applied now, could limit the spread of HIV-1, both in IDUs and in other social networks.

Limitations to contact tracing and phylogenetic analysis in establishing HIV type 1 transmission networks in Cuba

Sequence analysis can be used to evaluate transmission networks. We have used retrospective samples to examine two HIV-1 transmission networks established by contact tracing. Regions of the HIV-1 region representing segments of gag and env were amplified by RT-PCR from frozen plasma samples and the sequence of each PCR product was determined. Within one of the networks (composed of 38 subjects) we found only a subset of the tested sequence clusters was consistent with the reported epidemiological linkage. Of 15 presumed transmission events where sequence data were available, 9 could be rejected either by subtype mismatch or by phylogenetic tests. In the other network (composed of 89 subjects) we were able to assess sequences for 26 presumed transmission events, 18 of which were rejected based on subtype discordance. Long lags in time between the time of transmission and the time of sequence sampling (ranging from 2 to 18 years) may limit the sensitivity for the detection of sequence linkage. Also, superinfection and incomplete epidemiological information are other factors that will limit the concordance of phylogenetic reconstruction and reported epidemiological linkage.

Molecular epidemiology of HIV type 1 subtypes in Taiwan: outbreak of HIV type 1 CRF07_BC infection in intravenous drug users

In Taiwan, sexual transmission is responsible for most HIV-1 infections with two dominant subtypes, subtype B and CRF01_AE, distributing among homosexual and heterosexual groups, respectively. Recently, intravenous drug use has become an emerging route of HIV-1 transmission and contributed to a significant increase of HIV-1 infection. To characterize the HIV isolates responsible for the outbreak among intravenous drug users (IDUs), phylogenetic analysis was performed to analyze the protease/RT sequences amplified from HIV-1-infected IDUs at National Taiwan University Hospital and Taipei City STD Control Center. CRF07_BC, which is circulating in northern China, was demonstrated to account for the majority of HIV-1 infection in IDUs in the past 2 years. Although these Taiwanese CRF07_BC sequences shared the same breakpoint positions as those described in the CRF07_BC reference sequences, they formed a unique cluster in the phylogenetic tree, suggesting they originated from a founder virus. This finding was further supported by the relative low genetic diversity and unique sequence features. Our results demonstrated the emergence of CRF07_BC and its association with the HIV-1 outbreak among IDUs between 2004 and 2005 in Taiwan. This finding not only helps us to have a better understanding of the HIV evolution in Asia, but also has important implications for vaccine design in the future.

Patterns of HIV prevalence and HIV risk behaviors among injection drug users prior to and 24 months following implementation of cross-border HIV prevention interventions in northern Vietnam and southern China

In 2002, we implemented a 4-year HIV prevention intervention for injection drug users (IDUs) in Lang Son Province, Vietnam, and Ning Ming County, Guangxi Province, China, a cross-border region seriously affected by inter-twined epidemics of heroin injection and HIV infection. The interventions involve peer education on HIV risk reduction and provision of new needles/syringes through direct distribution and pharmacy vouchers. We consider this to be a structural intervention in which risk reduction information and sterile injection equipment are diffused through the IDU populations and not limited to those who actually interact with peer educators. The evaluation of structural interventions poses complex methodological challenges. The evaluation of our interventions relies primarily on cross-sectional surveys (interviews and HIV testing) of samples of IDUs selected using a combination of targeted cluster and snowball methods. We consider this to be an appropriate, albeit imperfect, design given the study context. This paper presents analyses of data from the IDU surveys conducted just prior to implementation of the interventions and 24 months thereafter. The cross-border interventions have reached large proportions of the IDUs in the project sites, drug-related HIV risk behaviors have declined in frequency, and HIV prevalence among IDUs has been stable in China and declined in Vietnam over the 24 months since the interventions were implemented. Attribution of these positive trends to the interventions must be qualified in light of possible sampling biases and the absence of control groups. However, we believe that the structural interventions implemented by the cross-border project have played a role in stabilizing HIV prevalence among IDUs two years after they were initiated. Evidence of further diffusion of the interventions among IDUs and continued stability or decline of HIV prevalence would strengthen this case.

High risk populations and HIV-1 infection in China

China is currently experiencing one of the most rapidly expanding HIV epidemics in the world. Although the overall prevalence rate is still low, with a population of 1.3 billion, high-risk factors which have contributed to the HIV/AIDS epidemics worldwide continue to prevail in China, including a high rate of injecting drug use and needle sharing, commercial sex with low rates of condom use, and concurrent sex with both commercial sex workers and non-commercial casual or steady sex partners. In addition, there are increasing "double risk" populations overlapping drug users and sex workers, as well as increasing rates of STDs and HIV among high-risk populations. Sexual transmission, therefore, may serve as a bridge connecting high-risk populations with general populations. There is an urgent need to prevent the spread of HIV from these high-risk populations into the general population of China.

Prevalence and correlates of HIV risk behaviors among drug users in China

This study examined the prevalence and correlates of HIV risk behaviors among 1,153 current drug users in China. Chi-squared tests of differences were used to test if drug users differed from non-users; logistic regression was used to identify behavior-specific risk factors. Results indicate that 60% of drug users injected drugs and more than one third shared needles. Compared to non-users, drug users had higher rates of risky sexual behavior and HIV/STDs. Among drug users, ethnic minorities and migrants were most vulnerable to unprotected casual sex and needle sharing. Drug users who experienced social isolation were associated with lower odds of risk behaviors; those who had experiences of anti-social behaviors and commercial sex, poor HIV knowledge, and perceived greater vulnerability were more prone to unprotected casual sex and needle sharing. Additional correlates of unprotected casual sex included being single, depression, and taking drugs/alcohol during sex. Additional risk factors of needle sharing included education and initiated drug use at younger ages. It is imperative that HIV interventions in China target drug users and address behavior-specific risk factors.

Prevalence, health outcomes, and patterns of psychotropic substance use in a Chinese population in Hong Kong: a population-based study

Two anonymous population-based surveys were conducted between August 2001 and April 2002 using computer-assisted telephone interviews of 3793 male and 3244 female randomly selected residents of Hong Kong in order to estimate the prevalence of psychotropic substance use and identify risk factors and associations with health outcomes among users in Hong Kong. The study cohort was comprised of ethnically Chinese adults between the ages of 18 and 60 years of age. In the last 12 months, 5% of males and 1.8% of females had used psychotropic substances such as cannaboids, methylamphetamines, ketamines, cocaine, opiates, barbiturates, and benzodiazepines. Of the male drug users, almost one-third had done so outside of Hong Kong. "Risk factors" for substance use included: younger age, unemployment, being an early school leaver, being unmarried, "heavy alcohol consumption," and smoking. Psychotropic substance use in the past year was strongly associated with increased prevalence of long-lasting (> or =3 months) sexual health problems during the past year and with a higher prevalence of HIV/STD risk behaviors. The prevalence of substance use in Hong Kong has been under-reported. Although significant correlations were noted between substance use and various respondent attributes, the directionality of the associations needs to be determined with longitudinal studies. It may be prudent to integrate substance use and HIV/STD prevention efforts.

Molecular characterization of human immunodeficiency virus type 1 and hepatitis C virus in paid blood donors and injection drug users in china

China is facing a rapid upsurge in cases of human immunodeficiency virus type 1 (HIV-1) and hepatitis C virus (HCV) infection due to large numbers of paid blood donors (PBD), injection drug users (IDU), and sexual partners of infected individuals. In this report, a total of 236 HIV-1-positive blood samples were collected from PBD, IDU, and their sexual partners in the most severely affected provinces, such as Henan, Yunnan, Guangxi, and Xinjiang. PCR was used to amplify the p17 region of gag and the C2-V3 region of env of HIV-1 and the 5' noncoding region and a region of E1/E2 of HCV. Genetic characterization of viral sequences indicated that there are two major epidemics of HIV-1 and multiple HCV epidemics in China. The PBD and transfusion recipients in Henan harbored HIV-1 subtype B', which is similar to the virus found in Thailand, and HCV genotypes 1b and 2a, whereas the IDU in Yunnan, Guangxi, and Xinjiang carried HIV-1 circulating recombinant forms 07 and 08, which resemble those in India, and HCV genotypes 1b, 3a, and 3b. Our findings show that the epidemics of HIV-1 and HCV infection in China are the consequences of multiple introductions. The distinct distribution patterns of both the HIV-1 and HCV genotypes in the different high-risk groups are tightly linked to the mode of transmission rather than geographic proximity. These findings provide information relevant to antiviral therapy and vaccine development in China and should assist public health workers in implementing measures to reduce the further dissemination of these viruses in the world's most populous nation.

HIV-1 CRF01_AE in intravenous drug users in Hanoi, Vietnam

To investigate the molecular epidemiology of HIV-1 among intravenous drug users (IDUs) in Hanoi we collected 17 samples from individuals living in 12 locations in and around Hanoi. The HIV-1 env V3 and gag p17 regions were directly sequenced from the proviral PBMC population. The majority of the IDUs were infected with HIV-1 CRF01_AE and one individual carried a p17/V3 CRF01/subtype C recombinant. The CRF01 viruses found among these individuals did not seem to be directly epidemiologically linked to each other. The sequences were, however, related to previously reported CRF01 sequences from Vietnam and China. Thus, IDUs in Hanoi seem to have derived their infections in Vietnam, but not from the same source. The discovery of the CRF01/C recombinant shows that new viral forms easily can be generated in IDU transmission chains.

Identification and characterization of a new class of human immunodeficiency virus type 1 recombinants comprised of two circulating recombinant forms, CRF07_BC and CRF08_BC, in China

We identified a new class of human immunodeficiency virus type 1 (HIV-1) recombinants (00CN-HH069 and 00CN-HH086) in which further recombination occurred between two established circulating recombinant forms (CRFs). These two isolates were found among 57 HIV-1 samples from a cohort of injecting drug users in eastern Yunnan Province of China. Informative-site analysis in conjunction with bootscanning plots and exploratory tree analysis revealed that these two strains were closely related mosaics comprised of CRF07_BC and CRF08_BC, which are found in China. The genotype screening based on gag-reverse transcriptase sequences of 57 samples from eastern Yunnan identified 47 CRF08_BC specimens (82.5%), 5 CRF07_BC specimens (8.8%), and 3 additional specimens with the novel recombinant structure. These new "second-generation" recombinants thus constitute a substantial proportion (5 of 57; 8.8%) of HIV-1 strains in this population and may belong to a new but yet-undefined class of CRF. This might be the first example of CRFs recombining with each other, leading to the evolution of second-generation inter-CRF recombinants.

Comparative analysis of HIV-1 viral load assays on subtype quantification: Bayer Versant HIV-1 RNA 3.0 versus Roche Amplicor HIV-1 Monitor version 1.5

Quantification of HIV-1 subtypes is essential for appropriate clinical management. Whereas viral load assays were initially developed to accurately quantify subtype B, the recent worldwide spread of non-B subtypes and the introduction of treatment programs in regions with non-B subtypes have prompted adaptations of these assays. The Bayer Versant HIV-1 RNA 3.0 Assay (branched DNA [bDNA] 3.0) and the Roche Amplicor HIV-1 Monitor version 1.5 (Amplicor 1.5) assays are reported to quantify all subtypes in group M; however, evaluation of performance characteristics remains limited. In this study, we evaluated the accuracy and reliability of bDNA 3.0 and Amplicor 1.5 on multiple serially diluted viral isolates from HIV-1 group M, subtypes A through F. Testing was conducted on both assay systems in two independent laboratories. Comparative pansubtype quantification from regression analysis showed that quantification by bDNA 3.0 was approximately 0.3 log-fold lower than that by Amplicor 1.5. Comparative pansubtype accuracy analysis showed data points more closely distributed about their respective regression lines and thus showing greater reliability by bDNA 3.0 than by Amplicor 1.5.

High prevalence of HIV-1 and hepatitis C virus coinfection among injection drug users in the southeastern region of Yunnan, China

The southeastern region of Yunnan province is a key site for drug trafficking and HIV-1 infection spread from the west of Yunnan and Laos to southeastern China. To investigate the prevalence of HIV-1 infection and hepatitis C virus (HCV) coinfection among injection drug users (IDUs) in southeastern Yunnan, three cohorts of 285 addicts, including 242 IDUs and 43 oral drug users, living in the cities of Gejiu and Kaiyuan and the county of Yanshan were studied. HIV-1 and HCV infections were detected by enzyme-linked immunosorbent assay and/or polymerase chain reaction. Data on the age, sex, risk behavior, drug use history, employment, ethnic background, and marriage status were obtained by interview. The overall prevalence of HIV-1 infection was 71.9%. The rate of HCV coinfection among 138 HIV-1-infected IDUs was 99.3%. Most HIV-infected IDUs were 20 to 35 years old (86.7%) and were ethnic Han (75.9%), suggesting that the epidemic in Yunnan is no longer confined to non-Han ethnic minorities. HIV prevalence in female IDUs (81.2%) was significantly higher than in male IDUs (68.2%) ( p <.05). The prevalence of HIV infection reached 68.4% after 1 year of injection drug use. Needle/syringe sharing is the major high risk factor for the spread of HIV-1 and HCV infections. Large-scale educational campaigns are urgently needed to reduce the spread of HIV and HCV infection in these regions.

Importation of multiple HIV type 1 strains into West Papua, Indonesia (Irian Jaya)

HIV-1 from 16 sexually transmitted disease clinic patients in Timika, West Papua, Indonesia was amplified by RT-PCR and subtyped by a combination of envelope and gag region heteroduplex mobility analysis (HMA) and direct PCR DNA sequencing. HMA showed the presence of 14 subtype E (CRF01_AE) and 2 subtype B HIV-1. Phylogenetic analysis of a 540-bp V3-V4 region of gp120 showed that 9 of 10 CRF01_AE variants clustered tightly with a median distance of 1.3% (range, 0.5 to 2.2%) whereas 1 CRF01_AE variant diverged significantly from the others (median distance, 10.7%; range, 10.1 to 11.8%). One subtype B virus envelope was typical of United States/European strains whereas the other appeared to be related to Thai subtype B' variants. These results reflect the independent introduction of multiple HIV-1 strains into West Papua, with the rapid spread in the majority of infected patients tested of a single strain of HIV-1E (CRF01_AE).

Changes in HIV-1 incidence in heroin users in Guangxi Province, China

Guangxi Province, China recently experienced an outbreak of HIV-1 infection among heroin users. We studied HIV-1 incidence rates and associated risk factors for HIV-1 infection among heroin users residing in Pingxiang City. A total of 318 heroin users were followed from February 1998 through January 1999 (median follow-up: 8.1 months). Of these, 130 were prospectively followed from January through September 1999 (median follow-up: 8.3 months). HIV-1 and hepatitis C virus (HCV) incidence rates for each period were calculated. A generalized estimating equation approach was implemented to identify independent risk factors associated with HIV-1 infection across both periods. Among 318 study participants, 97.2% were men. The median age was 22 years. Approximately 60% reported sharing needles. HIV-1 prevalence at baseline was 15.4%. During the first follow-up period, HIV-1 incidence was 2.38 per 100 person years (py), and HCV incidence was 26.8 per 100 py. During the second follow-up period, HIV-1 incidence was 6.86 per 100 py, and HCV incidence was 28.9 per 100 py. After controlling for age and other factors, HCV seropositivity, history of sexually transmitted diseases, and sharing needles were independently associated with HIV-1 infection. These data suggest that HIV-1 incidence was rising over time in Pingxiang City, Guangxi Province. The high incidence of HCV heightens the importance of enhanced prevention programs to reduce injection and needle sharing among heroin users.

A recent outbreak of human immunodeficiency virus type 1 infection in southern China was initiated by two highly homogeneous, geographically separated strains, circulating recombinant form AE and a novel BC recombinant

New outbreaks of human immunodeficiency virus type 1 (HIV-1) among injecting drug users (IDUs) are spreading in China along heroin trafficking routes. Recently, two separate HIV-1 epidemics among IDUs were reported in Guangxi, Southern China, where partial sequencing of the env gene showed subtype C and circulating recombinant form (CRF) AE. We evaluated five virtually full-length HIV-1 genome sequences from IDUs in Guangxi to determine the genetic diversity and the presence of intersubtype recombinants. Sequence analysis showed two geographically separated, highly homogeneous HIV-1 strains. B/C intersubtype recombinants were found in three IDUs from Baise City, in a mountainous region near the Yunnan-Guangxi border. These were mostly subtype C, with portions of the capsid and reverse transcriptase (RT) genes from subtype B. The subtype B portion of the capsid was located in the N-terminal domain, which has been shown to influence virus core maturation, virus infectivity, and binding to cyclophilin A, whereas the subtype B portion of RT was located in the palm subdomain, which is the active site of the enzyme. These BC recombinants differed from a BC recombinant found in Xinjiang Province in northwestern China. CRF AE strains were found in IDUs from Nanning, the capital of Guangxi, and in IDUs from Pingxiang City near the China-Vietnam border. The AE and BC recombinants were both remarkable for their low interpatient diversity, less than 1% for the full genome. Rapid spread of HIV-1 among IDUs may foster the emergence of highly homogeneous strains, including novel recombinants in regions with multiple subtypes.