Characterization of HIV type 1 heterosexual transmission in Yunnan, China

Evolving molecular epidemiological profile of human immunodeficiency virus 1 in the southwest border of China

Background

We have previously reported in Xishuangbanna (Banna) Dai Autonomous Prefecture, a well-developed tourist destination in the southwest border of China, that HIV-1 transmitted dominantly through heterosexual contact with less divergent genotypes and few drug resistant mutations [1]. Due to the rapid increase of newly diagnosed HIV-1 cases per year in Banna in recent years, it’s important to evaluate the evolution of HIV-1 molecular epidemiology for the better understanding of ongoing HIV-1 outbreak in this region.

Methodology/Principal Findings

By sequencing of HIV-1 pol genes and phylogenetic analysis, we conducted a molecular epidemiologic study in 352 HIV-1-seropositive highly active antiretroviral treatment (HAART)-naïve individuals newly diagnosed at the Banna Center for Disease Control and Prevention between 2009 and 2011. Of 283 samples (84.1% taken from heterosexually acquired adults, 10.6% from needle-sharing drug users, 2.8% from men who have sex with men, 0.4% from children born from HIV-1-infected mothers, and 2.1% remained unknown) with successful sequencing for pol gene, we identified 108 (38.2%) HIV-1 subtype CRF08_BC, 101 (35.7%) CRF01_AE, 49 (17.3%) CRF07_BC, 5 (1.8%) C/CRF57_BC, 3 (1.1%) B’, 1 (0.4%) B/CRF51_01B, and 16 (5.7%) unique recombinants forms. Among these infected individuals, 104 (36.7%) cases showed drug resistant or resistance-relevant mutations, and 4 of them conferring high-level resistance to 3TC/FTC, EFV/NVP or NFV. Phylogenetic analysis revealed 21 clusters (2–7 sequences) with only 21.2% (60/283) sequences involved.

Conclusion/Significance

In contrast to our previous findings, CRF08_BC, replaced CRF01_AE, became the dominant genotype of HIV-1 in Banna prefecture. The viral strains with drug resistance mutations were detected frequently in newly diagnosed HIV-1-infected individuals in this region.

Risk behaviors, prevalence of HIV and hepatitis C virus infection and population size of current injection drug users in a China-Myanmar border city: results from a Respondent-Driven Sampling Survey in 2012

Background

Injection drug use has been the major cause of HIV/AIDS in China in the past two decades. We measured the prevalences of HIV and hepatitis C virus (HCV) prevalence and their associated risk factors among current injection drug users (IDUs) in Ruili city, a border region connecting China with Myanmar that has been undergoing serious drug use and HIV spread problems. An estimate of the number of current IDUs is also presented.

Methods

In 2012, Chinese IDUs who had injected within the past six months and aged ≥18 years were recruited using a respondent-driven sampling (RDS) technique. Participants underwent interviews and serological testing for HIV, HBV, HCV and syphilis. Logistic regression indentified factors associated with HIV and HCV infections. Multiplier method was used to obtain an estimate of the size of the current IDU population via combining available service data and findings from our survey.

Results

Among 370 IDUs recruited, the prevalence of HIV and HCV was 18.3% and 41.5%, respectively. 27.1% of participants had shared a needle/syringe in their lifetime. Consistent condom use rates were low among both regular (6.8%) and non-regular (30.4%) partners. Factors independently associated with being HIV positive included HCV infection, having a longer history of injection drug use and experience of needle/syringe sharing. Participants with HCV infection were more likely to be HIV positive, have injected more types of drugs, have shared other injection equipments and have unprotected sex with regular sex partners. The estimated number of current IDUs in Ruili city was 2,714 (95% CI: 1,617–5,846).

Conclusions

IDUs may continue to be a critical subpopulation for transmission of HIV and other infections in this region because of the increasing population and persistent high risk of injection and sexual behaviours. Developing innovative strategies that can improve accessibility of current harm reduction services and incorporate more comprehensive contents is urgently needed.

HIV-1 genetic characteristics and transmitted drug resistance among men who have sex with men in Kunming, China

BACKGROUND

Yunnan has been severely affected by HIV/AIDS in China. Recently, the reported prevalence of HIV-1 among men who have sex with men (MSM) in Yunnan was high in China. To monitor dynamic HIV-1 epidemic among Yunnan MSM, HIV-1 genetic characteristics and transmitted drug resistance (TDR) were investigated.

METHODS

Blood samples from 131 newly HIV-1 diagnosed MSM were continuously collected at fixed sites from January 2010 to December 2012 in Kunming City, Yunnan Province. Partial gag, pol and env genes were sequenced. Phylogenetic, evolutionary and genotypic drug resistance analyses were performed.

RESULTS

Multiple genotypes were identified among MSM in Kunming, including CRF01_AE (64.9%), CRF07_BC (25.2%), unique recombinant forms (URFs, 5.3%), subtype B (3.1%) and CRF08_BC (1.5%). CRF01_AE and CRF07_BC were the predominant strains. The mean of genetic distance within CRF01_AE were larger than that within CRF07_BC. The estimated introducing time of CRF01_AE in Yunnan MSM (1996.9) is earlier than that of CRF07_BC (2002.8). In this study, subtype B was first identified in Yunnan MSM. CRF08_BC seems to be the distinctive strain in Yunnan MSM, which was seldom found among MSM outside Yunnan. The proportion of URFs increased, which further contributed to genetic diversity among MSM. Strikingly, genetic relatedness was found among these strains with MSM isolates from multiple provinces, which suggested that a nationwide transmission network may exist. TDR-associated mutations were identified in 4.6% individuals. The multivariate analysis revealed that non-native MSM and divorced/widowed MSM were independently associated with a higher TDR rate.

CONCLUSION

This work revealed diverse HIV-1 genetics, national transmission networks and a baseline level of TDR in MSM. These findings enhance our understanding of the distribution and evolution of HIV-1 in MSM, and are valuable for developing HIV prevention strategies for MSM.

Multiple independent introductions of HIV-1 CRF01_AE identified in China: what are the implications for prevention?

Background

HIV-1 CRF01_AE accounts for an important fraction of HIV infections in Asia including China, but little is known about the phylogenetic and evolutionary history of this CRF (circulating recombinant form). In the current study, we collected a large number of 1,957 CRF01_AE gag p17 sequences with known sampling year (1990-2010) from 5 global regions representing 15 countries to better understand the phylogenetic relationships and epidemic history of CRF01_AE strains in China.

Methodology/Principal Findings

CRF01_AE gag p17 sequences were retrieved from public databases to explore phylogenetic relationships and phylogeographic dynamics of CRF01_AE in Asia by using maximum-likelihood phylogenetics and Bayesian coalescent-based analyses. We found close phylogenetic relationships between sequences from Thailand, Vietnam and China. Moreover, at least 5 independent introductions and 5 independent autochthonous clades of CRF01_AE, which descended from Thailand or Vietnam were identified in China from 1991 through 2003.

Conclusion/Significance

The current study not only defines the migration of CRF01_AE clades to/in Asia, but also demonstrates the criticalness of identifying the circulating strains in the population for the development of vaccine and microbicides.

Prevalence and correlates of sexual risk behaviors among drug users in western China: implications for HIV transmission

The prevalence and correlates of sexual risk behaviors among drug users in western China and the implications for HIV transmission in this population are described. A cross-sectional survey of male drug users was conducted in methadone maintenance therapy clinics and detoxification centers in three western provinces of China between September 2009 and December 2010. Participants in the study completed a questionnaire about demographics, HIV/AIDS knowledge, drug use history, sexual risk behaviors, and other psychosocial variables. Factors associated with HIV sexual risk behaviors were identified by multiple logistic regression analysis. Of 1,304 drug users surveyed, nearly 54% never used condoms during sexual intercourse with a spouse or cohabitant, and this behavior was associated with coming from Chongqing (OR=1.86, p<0.05), being aged 36 and older (OR=5.03, p<0.05), being married or cohabiting (OR=1.68, p<0.05), having first taken drugs at age 30 and above (OR=1.80, p<0.05), and having received AIDS advice or detection from authorities in the past year (OR=1.95, p<0.05). Twenty-six percent had had sex with casual sexual partners in the past year, and this behavior was associated with being married or cohabiting (OR=0.30, p<0.05), first taking drugs at age 31 and above (OR=0.42, p<0.05), and receiving AIDS advice or HIV detection from authorities in the past year (OR=0.70, p<0.05). About 34% never used a condom when having sex with casual sexual partners, and this behavior was associated with coming from Guangxi (OR=2.81, p<0.05) or Chongqing (OR=2.73, p<0.05). Almost 14% had had commercial sex in the past year, and this behavior was associated with coming from Guangxi (OR=6.26, p<0.05) or Chongqing (OR=5.44, p<0.05) and having exchanged needles or received clean needles from the Needle Exchange Centers in the past year (OR=2.76, p<0.05). Nearly 23% had never used condoms when having commercial sex, and this behavior was associated with having received free condoms from authorities in the past year (OR=0.26, p<0.05). Sexual risk behaviors among drug users in Guangxi, Chongqing, and Xinjiang are common. Additional intervention strategies are needed to control the spread of HIV in this population.

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.

Update on diversity and distribution of HIV-1 subtypes in Yunnan province

The aim of this study was to characterize updated HIV subtypes in Yunnan to determine their origins and distribution within the population. RT-PCR of both the gag and env genes were sequenced from Yunnan province inhabitants newly diagnosed with HIV-1. Sequence data from 290 samples were used for statistical analysis of subtype distribution and phylogenetic tree construction. Distribution data were adjusted to account for different geographical distributions of HIV-1 subtypes in the population. Phylogenetic analysis revealed six HIV-1 subtypes in Yunnan, including eight types of unique recombination forms (URFs). The most prevalent subtypes in this province, CRF07_BC (18·9%), CRF08_BC (39·1%), CRF01_AE (22·4%), and URFs (subtype C, 5·9% and subtype B, 4·5%), were all recombinants. We found significant differences in the distribution of these HIV-1 subtypes not only geographically, but also between various ethnic groups and with respect to transmission routes. Our findings indicate a complex population of HIV-1 subtypes, URFs, and recombinant subtypes in Yunnan province. This diversity could make the prevention and control of HIV infection in Yunnan more difficult due to the possibility of virus recombination or infection by multiple subtypes.

Prospective cohort study of HIV incidence and molecular characteristics of HIV among men who have sex with men(MSM) in Yunnan Province, China

Background

Yunnan has the largest number of reported HIV/AIDS cases among all Chinese provinces, the reported prevalence of HIV among Yunnan men who have sex with men (MSM) passed 10%, while HIV incidence epidemic and molecular characteristics of new infected Yunnan MSM were not evaluated before.

Methods

An 18 months prospective followed up with a frequency of 3 month per visit were conducted among HIV seronegative MSM in Kunming cityduring 2009–2011. Interviewer-administrated questionnaires were carried out. Blood specimens were obtained to test for syphilis and HIV, in which HIV were evaluated by standard HIV enzyme immunoassay (EIA) and HIV nucleic acid amplification testing (NAAT). Near full-length regions of the HIV-1 were evaluated for subtyping, primary drug resistance mutations.

Results

During the follow-up 70.1% of the recruited 378 MSM retained in the cohort. Eleven MSM seroconverted to HIV and fifteen MSM seroconverted to syphilis. The HIV incidence and syphilis incidence was 3.5 (95% CI 1.8-6.2) cases /100 person year(PY) and 5.3 (95% CI 3.0-8.7) cases/100 PY, respectively. Multivariate analysis showed that baseline syphilis infection (aHR, 17.7), occupation (students vs. others [aHR, 5.7], retirees vs. others [aHR, 4.1]), bleeding experience after receptive anal intercourse (aHR,7.6), and minority ethnic(vs. Han) [aHR, 5.7] were independent risk factors for HIV seroconversion(each P<0.05). Among the 7/11 successfully amplified near full-length sequences, 71.4% (5/7) were CRF01_AE, and 28.6% (2/7) were CRF07_BC. Two HIV transmission pairs were detected among seroconverted minority ethnic MSM.

Conclusions

HIV incidence was moderately high among Yunnan MSM. Yunnan province need to strengthen both HIV and syphilis screening among MSM population. Some subpopulations of MSM, such as students, retirees and minority ethnic groups require more HIV epidemic surveillance and strengthened behavior interventions. HIV subtypes and primary drug resistance should be continually monitored to track cross-group transmission of HIV strains.

A novel genotype of GB virus C: its identification and predominance among injecting drug users in Yunnan, China

GB virus C (GBV-C) is prevalent globally and particularly among individuals at risk of parental exposures. Based on genetic diversity, this virus is now classified into six genotypes and many subtypes with distinct geographical distribution. In this study, 120 Injecting Drug Users (IDUs) were recruited from Yunnan province, China. Among them, 43 (35.8%) were positive for GBV-C RNA, 70 (58.3%) and 103 (85.8%) sero-positive for HIV-1 and HCV respectively. This revealed 18.3% of IDUs having GBV-C/HIV/HCV triple infection, which is significantly higher than 7.5% of GBV-C/HIV-1 and 10% of GBV-C/HCV dual infection rates (P<0.05). Based on 5′UTR sequences, the identified 43 viral isolates can be classified into three phylogenetic groups: one (2.3%) and two (4.7%) belonged to genotype 3 and 4, respectively, and the remaining 40 (93%) formed a new group with 97% of bootstrap support. This new GBV-C group was further confirmed by characterizing the E2 region and full-length genome sequences. Analysis of 187 nt 5′UTR sequence showed three previous reported isolates from Southeast Asia were re-classified into this new group. It implies they have the same origin with strains from Yunnan. Although we provisionally assigned this new group as GBV-C genotype 7, a simpler five groups of GBV-C nomenclature is recommended. Genotype 4, 6 and the newly designated genotype 7 could be reclassified as one group, which may represent a single GBV-C genotype. The classification of the other four groups was corresponding to that of previous reported genotype 1, 2, 3 and 5. Furthermore, the diversity of amino acid sequence in the E2 region was analyzed. The inhibitory effect of GBV-C genotype 7 on HIV-1 cell entry could be deduced. Since GBV-C may have a beneficial effect on AIDS disease progression and interact with HCV during co-infection, this finding may raise interests in future studies on this virus that was previously thought to be a “non-pathogenic virus”.

Prevalence of psychological problems and relationships with condom use and HIV prevention behaviors among Chinese female sex workers in Hong Kong

The present study investigated the prevalence of psychological problems and their relationships with relevant HIV prevention behaviors among female sex workers (FSWs). An anonymous cross-sectional survey was conducted. With a mapping exercise, 293 Chinese FSWs were recruited from a red-light district in Hong Kong. Results showed high prevalence of psychological problems among FSWs: substance use (40.4%), probable depression (53.9%), self-harm tendencies (34-38%), poor self-esteem (48-52%), and pessimistic future outlook (46-47%). Inconsistent condom use was common (51% with clients, 23% with one-night-stand sex partner, and 73% with boyfriends). Over 70% had not used HIV-related prevention services in the last 6 months. Multivariate analyses indicated that psychological problems were significantly associated with inconsistent condom use and non-use of prevention services. The poor psychological well-beings of FSWs have important public health implications. Relevant professional services should be provided and integrated with HIV prevention efforts.

High systemic levels of interleukin-10, interleukin-22 and C-reactive protein in Indian patients are associated with low in vitro replication of HIV-1 subtype C viruses

BACKGROUND

HIV-1 subtype C (HIV-1C) accounts for almost 50% of all HIV-1 infections worldwide and predominates in countries with the highest case-loads globally. Functional studies suggest that HIV-1C is unique in its biological properties, and there are contradicting reports about its replicative characteristics. The present study was conducted to evaluate whether the host cytokine environment modulates the in vitro replication capacity of HIV-1C viruses.

METHODS

A small subset of HIV-1C isolates showing efficient replication in peripheral blood mononuclear cells (PBMC) is described, and the association of in vitro replication capacity with disease progression markers and the host cytokine response was evaluated. Viruses were isolated from patient samples, and the corresponding in vitro growth kinetics were determined by monitoring for p24 production. Genotype, phenotype and co-receptor usage were determined for all isolates, while clinical category, CD4 cell counts and viral loads were recorded for all patients. Plasmatic concentrations of cytokines and, acute-phase response, and microbial translocation markers were determined; and the effect of cytokine treatment on in vitro replication rates was also measured.

RESULTS

We identified a small number of viral isolates showing high in vitro replication capacity in healthy-donor PBMC. HIV-1C usage of CXCR4 co-receptor was rare; therefore, it did not account for the differences in replication potential observed. There was also no correlation between the in vitro replication capacity of HIV-1C isolates and patients' disease status. Efficient virus growth was significantly associated with low interleukin-10 (IL-10), interleukin-22 (IL-22), and C-reactive protein (CRP) levels in plasma (p < .0001). In vitro, pretreatment of virus cultures with IL-10 and CRP resulted in a significant reduction of virus production, whereas IL-22, which lacks action on immune cells appears to mediate its anti-HIV effect through interaction with both IL-10 and CRP, and its own protective effect on mucosal membranes.

CONCLUSIONS

These results indicate that high systemic levels of IL-10, CRP and IL-22 in HIV-1C-infected Indian patients are associated with low viral replication in vitro, and that the former two have direct inhibitory effects whereas the latter acts through downstream mechanisms that remain uncertain.

HIV prevalence and risk behaviors among male clients of female sex workers in Yunnan, China

OBJECTIVES

To assess the prevalence and risk factors of HIV among male clients of female sex workers (FSWs) in China.

METHODS

Convenience sampling methods were used to recruit 315 clients using FSW-client and client-client networks. Subjects provided information on sociodemographic characteristics and sexual and drug behavior patterns. Blood samples were collected for HIV testing and urine samples for opiate testing.

RESULTS

Overall HIV prevalence was 6.0%; among drug users, it was 30.8%. 33.7% of respondents reported that they always use condoms in commercial sex and 63.5% that they used a condom in the last commercial sex episode. Drug use (OR: 6.1; 95% CI: 1.7 to 21.4) and lack of a regular sexual partner (OR: 6.3; 95% CI: 1.8 to 21.9) were significantly associated with HIV infection.

CONCLUSIONS

Clients of FSWs serve as potential bridges for HIV transmission from the high-risk FSWs to the low-risk general population, making them a key target for intervention. High HIV prevalence rates among clients in Kaiyuan is particularly alarming given their risk behavior patterns including high rates of partner exchange, low condom use rates, and drug-using behaviors. Innovative interventions are needed to reduce the risk of HIV among clients and reduce the bridge of transmission to the general population.

Functional characteristics of HIV-1 subtype C compatible with increased heterosexual transmissibility

BACKGROUND

Despite the existence of over 50 subtypes and circulating recombinant forms of HIV-1, subtype C dominates the heterosexual pandemic causing approximately 56% of all infections.

OBJECTIVE

To evaluate whether viral genetic factors may contribute to the observed subtype-C predominance.

METHODS

Chimeric viruses were generated using V1-V3 envelope fragments from a subtype-A/C dually infected woman with preferential genital replication of subtype C. Viral adaptation, spread and cell fusion ability were evaluated in vitro using peripheral blood mononuclear cells and HeLa-CD4-CCR5 cell lines, sequencing and cloning. Structural modeling was performed using a crystal structure of gp120-CD4-X5. Phylogenetic analysis was done using subtype-A, subtype-B and subtype-C sequences from blood and cervix of 37 infected women and database sequences.

RESULTS

We identified two envelope motifs, compact V1-V2 loops and V3-316T, which are found at high frequency throughout subtype-C evolution and affect gp120 interactions with CD4 and CCR5, respectively. When a V1-Delta5 deletion or V3-A316T was incorporated into subtype A, each increased viral fusion and spread several fold in peripheral blood mononuclear cell and cell lines with low CCR5 expression. Structural modeling suggested the formation of an additional hydrogen bond between V3 and CCR5. Moreover, we found preferential selection of HIV with 316T and/or extremely short V1-V2 loops in cervices of three women infected with subtypes A/C, B or C.

CONCLUSION

As CD4-CCR5-T cells are key targets for genital HIV infection and cervical selection can favor compact V1-V2 loops and 316T, which increase viral infectivity, we propose that these conserved subtype-C motifs may contribute to transmission and spread of this subtype.

Molecular epidemiological tracing of HIV-1 outbreaks in Hainan island of southern China

OBJECTIVES

To determine the prevalence of HIV in Hainan island and the molecular epidemiological linkages related to risk factors of viral transmission.

METHODS

A governmental HIV/AIDS surveillance program, HIV serological study was conducted in volunteers from several high-risk groups between 1991 and 2006 in Hainan province. By phylogenetic reconstruction, we performed a molecular epidemiological tracing in a representative subset of the HIV-1-seropositive individuals diagnosed during this survey.

RESULTS

Of 499 752 volunteers, 523 (0.1%) accumulated cases of HIV-1 infection (69.2% needle-sharing drug users, 19.3% heterosexually acquired adults, 3.3% receivers of blood transfusion, 0.8% children born from HIV-1-infected mothers, and 7.7% remained unknown) were diagnosed. Among 83 patient samples examined (70 were infected with HIV-1 subtypes CRF01_AE and eight, two, one, one, and one were B', C, CRF08_BC, B, and a new CRF01_AE/B' recombinant, respectively), 66 (79.5%) were segregated into one large cluster (59 sequences) (founder effect) and one small cluster (three sequences) of CRF01_AE, one small cluster (two sequences) of B', and one small cluster (two sequences) of C. Phylogenetic and epidemiological linkages confirmed four heterosexual transmission events and rejected two potential heterosexual transmission suggested by contact tracing. Only two cases of CRF01_AE showed mutations conferring resistance to nucleoside and nonnucleoside reverse transcriptase inhibitors.

CONCLUSION

The reconstruction of current HIV-1 outbreaks by molecular epidemiological tracing is helpful for identifying epidemic sources and for defining prevention strategies.

Sexual behavior and risks for HIV infection and transmission among male injecting drug users in Yunnan, China

OBJECTIVES

To analyze the risk factors, particularly sexual behaviors, associated with HIV infection, and to describe the risks for HIV transmission among male injecting drug users (IDUs) in China.

METHODS

A cross-sectional study of 314 IDUs in Yunnan Province was conducted. Information on demographics, HIV serostatus, and sexual and drug-using behaviors was collected.

RESULTS

HIV prevalence among the study subjects was 59.9%. HIV infection was associated with older age (> or = 27 years), early drug initiation (at < or = 20 years of age), and frequent injection (> or = once a day). Thirty-seven percent reported multiple sexual partners. Consistent condom use rates were lowest with regular partners (23.8%), followed by 42.5% with casual partners, and 57.3% with female sex workers. Ninety-eight percent of subjects received high 'HIV knowledge' scores. Few of the subjects who needed medical care sought it out.

CONCLUSIONS

Despite awareness of HIV, needle sharing and unprotected sex persist in the population, and the HIV prevalence is high. Further interventions should not only seek to educate but also to reduce high-risk behaviors.

Molecular tracing of sexual HIV Type 1 transmission in the southwest border of China

Since the first outbreak of HIV-1 was reported in heroin users in China in 1989, HIV-1 has spread steadily among injection drug users, leading to an exponential growth of nationwide outbreaks from 1998 to 2004. However, the impact of sexual transmission on outbreaks of HIV in China's general population is still unclear. Through a governmental HIV/AIDS surveillance program, an HIV serological study was conducted in volunteers between 1996 and 2005 in Xishuangbanna Dai Autonomous Prefecture of Yunnan province. We performed the transmission reconstruction by molecular epidemiological tracing in a subset of the HIV-1-seropositive individuals diagnosed during this survey. Neighbor joining and maximum likelihood trees based on the HIV-1 pol and env genes were implemented to provide information on putative epidemiological links, which were then confirmed by contact tracing. Of 25,390 volunteers, 501 (2%) accumulated cases of HIV-1 infection (21.1% in needle-sharing drug users, 77.3% in heterosexual adults, 0.4% in homosexual adults, and 1.2% in children born from infected mothers) were diagnosed. Among 44 heterosexually infected and antiretroviral-naive local-traceable individuals (27 infected with HIV-1 subtype CRF01_AE, 15 with CRF08_BC, 1 with G, and 1 with a new B/C recombinant), 18 (40.9%) were coclustered into 8 transmission chains with an average size of 2.25 infections per chain. Phylogenetic and epidemiological linkages confirmed eight heterosexual transmission events. This is the first report providing molecular epidemiological evidence of heterosexual transmission of HIV-1 in China's general population. The reconstruction of transmission of current HIV-1 outbreaks by molecular epidemiological tracing is instrumental in identifying sources of the epidemic and in defining prevention strategies.

The influence of social and sexual networks in the spread of HIV and syphilis among men who have sex with men in Shanghai, China

OBJECTIVES

To analyze characteristics of social and sexual networks and their role as risk factors for HIV and syphilis among men who have sex with men (MSM) in Shanghai, China.

DESIGN

: A cross-sectional study.

METHODS

We recruited 477 participants using a snowball sampling method. We administered a face-to-face questionnaire and provided testing and counseling for HIV and syphilis.

RESULTS

The prevalences of HIV and markers for syphilis were 1.47% (95% confidence interval [CI]: 0.59 to 3.01) and 13.47% (95% CI: 10.53 to 16.88), respectively. The independent factors associated with lower risk for syphilis infection were having a contact network, overlap of social and sexual networks, meeting other MSM at the gym or through the Internet, having 3 to 5 lifetime male anal sex partners, and having a female steady sex partner. A larger male sexual network size, having been married, being more knowledgeable about HIV, having 6 or more lifetime male anal sex partners, and having steady male or female sex partners were independently associated with having unprotected anal or vaginal intercourse.

CONCLUSIONS

Significant associations were found between network characteristics and syphilis infection and unprotected sex. Network-based interventions should be developed to reduce this HIV risk among MSM in China.

Dominance of HIV-1 subtype CRF01_AE in sexually acquired cases leads to a new epidemic in Yunnan province of China

BACKGROUND

Dating back to the first epidemic among injection drug users in 1989, the Yunnan province has had the highest number of human immunodeficiency virus type 1 (HIV-1) infections in China. However, the molecular epidemiology of HIV-1 in Yunnan has not been fully characterized.

METHODS AND FINDINGS

Using immunoassays, we identified 103,015 accumulated cases of HIV-1 infections in Yunnan between 1989 and 2004. We studied 321 patients representing Yunnan's 16 prefectures from four risk groups, 11 ethnic populations, and ten occupations. We identified three major circulating subtypes: C/CRF07_BC/CRF08_BC (53%), CRF01_AE (40.5%), and B (6.5%) by analyzing the sequence of p17, which is part of the gag gene. For patients with known risk factors, 90.9% of injection drug users had C/CRF07_BC/CRF08_BC viruses, whereas 85.4% of CRF01_AE infections were acquired through sexual transmission. No distinct segregation of CRF01_AE viruses was found among the Dai ethnic group. Geographically, C/CRF07_BC/CRF08_BC was found throughout the province, while CRF01_AE was largely confined to the prefectures bordering Myanmar. Furthermore, C/CRF07_BC/CRF08_BC viruses were found to consist of a group of viruses, including C, CRF08_BC, CRF07_BC, and new BC recombinants, based on the characterization of their reverse transcriptase genes.

CONCLUSIONS

This is the first report of a province-wide HIV-1 molecular epidemiological study in Yunnan. While C/CRF07_BC/CRF08_BC and CRF01_AE are codominant, the discovery of many sexually transmitted CRF01_AE cases is new and suggests that this subtype may lead to a new epidemic in the general Chinese population. We discuss implications of our results for understanding the evolution of the HIV-1 pandemic and for vaccine development.

Molecular epidemiology of HIV Type 1 in preparation for a Phase III prime-boost vaccine trial in Thailand and a new approach to HIV Type 1 genotyping

To characterize HIV-1 genotypes in candidate populations for a prime-boost phase III vaccine trial in Thailand, specimens from prevalent and incident HIV-1 infections from a family planning clinic population in Rayong Province and a community cohort in Chon Buri Province, collected from 1998 to 2001, were genotyped. A new multiregion hybridization assay, MHAbce, capable of distinguishing HIV-1 CRF01_AE, subtype B, and subtype C and their recombinants, was developed and applied to prevalent infections. Most incident and selected prevalent infections were studied by complete genome sequencing. By MHAbce, 168 of 194 prevalent infections were genotyped. Of these, 90.5% were CRF01_AE, 2.4% were subtype B, and 7.2% showed discordant or dual probe reactivity, indicative of recombination or dual infection, respectively. Among 23 incident infections, 20 were sequenced. Eighteen CRF01_AE, one subtype B, and one CRF01/B recombinant strains were seen. Two CRF01/B and one CRF01/C recombinant were identified among selected prevalent infections. These results indicate that incident and prevalent HIV-1 infections in Rayong and Chon Buri during 1998-2001 were 90% CRF01_AE, 3% subtype B, and 7% either recombinant or dual. This study frames the genetic diversity of HIV-1 in these cohorts in their preparatory phase for the ongoing ALVACHIV (vCP1521) prime, AIDSVAX B/E boost, phase III vaccine trial and will provide a benchmark for interpretation and analysis.

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.

Molecular epidemiology of the heterosexual HIV-1 transmission in Kunming, Yunnan Province of China suggests origin from the local IDU epidemic

Molecular epidemiological investigation was conducted among injecting drug users (IDUs) (n = 11) and heterosexuals (n = 15) in Kunming, Yunnan Province of China. HIV-1 genotypes were determined based on the nucleotide sequences of 2.6-kb gag-RT region. The distribution of genotypes among IDUs was as follows: CRF07_BC (5/11) and CRF08_BC (5/11); subtype B' (1/11). Similarly, a majority of Kunming heterosexuals (14/15) were infected with CRF07_BC (4/15), CRF08_BC (6 /15), or subtype B' (4/15), known to predominate among IDUs in China. This contrasts with trends in the coastal regions of China and surrounding southeastern Asian countries, where CRF01_AE predominates among heterosexuals. The heterosexual HIV-1 epidemic in Kunming thus appears to derive from the local IDU epidemic. Of note, subtype B' was the most prevalent strain among heterosexuals before 1997, while CRF07_BC and CRF08_BC became predominant in 2002, indicating a transition of HIV-1 genotype distribution between the early and the more recent samples from Kunming heterosexuals.

Heterosexual Transmission of HIV in China: A Systematic Review of Behavioral Studies in the Past Two Decades

OBJECTIVE

The objective of this study was to address the role of heterosexual transmission of HIV in China.

GOAL

The goal of this study was to explore the prevalence of unsafe sex and the likelihood of HIV spread heterosexually from core populations to others.

STUDY

The authors conducted a review of behavioral studies.

RESULTS

Drug users were more likely to be involved in higher-risk sexual behaviors than were those who abstained from using drugs. Most female drug users (52-98%) reported having engaged in commercial sex. Most female sex workers (FSWs) and individuals with sexually transmitted diseases (STDs) had concurrent sexual partners. Many continued to have unprotected sex after noticing STD symptoms in themselves or their sexual partners. From 5% to 26% of rural-to-urban migrants had multiple sexual partners and 10% of males patronized FSWs during migration.

CONCLUSIONS

Factors such as high rates of FSW patronage, low rates of condom use during commercial sex, having sex with both commercial and noncommercial sexual partners, and high rates of STD infection may promote a heterosexual epidemic in China.

HIV/AIDS in Asia

HIV (ie, HIV-1) epidemics in Asia show great diversity, both in severity and timing. But epidemics in Asia are far from over and several countries including China, Indonesia, and Vietnam have growing epidemics. Several factors affect the rate and magnitude of growth of HIV prevalence, but two of the most important are the size of the sex worker population and the frequency with which commercial sex occurs. In view of the present state of knowledge, even countries with low prevalence of infection might still have epidemics affecting a small percentage of the population. Once HIV infection has become established, growing needs for care and treatment are unavoidable and even the so-called prevention-successful countries of Thailand and Cambodia are seeing burgeoning care needs. The manifestations of HIV disease in the region are discussed with the aim of identifying key issues in medical management and care of HIV/AIDS. In particular, issues relevant to developing appropriate highly active antiretroviral treatment programmes in the region are discussed. Although access to antiretroviral therapy is increasing globally, making it work effectively while simultaneously expanding prevention programmes to stem the flow of new infections remains a real challenge in Asia. Genuine political interest and commitment are essential foundations for success, demanding advocacy at all levels to drive policy, mobilise sufficient resources, and take effective action.