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

Analysis of temporal changes in HIV-1 CRF01_AE gag genetic variability and CD8 T-cell epitope evolution

Currently, little is known about the time-dependent evolution of human immunodeficiency virus-1 (HIV-1) circulating recombinant forms (CRF) 01_AE, a dominant recombinant form associated with HIV-1 epidemics worldwide. Since gag is a highly immunodominant HIV-1 protein, we performed a comparative analysis of the CRF01_AE gag protein’s time-dependent changes and evolution. A total of 3105 HIV-1 CRF01_AE gag sequences representing 17 countries from the timeline 1990–2017 were obtained. The sequences’ phylogenetic relationship and epidemic dynamics were analyzed through a Maximum Likelihood tree and Bayesian Skyline plot, respectively. Genomic variability was measured through Shannon entropy and time-dependent immunoevolution was analyzed using changes in proteasomal degradation pattern, cytotoxic T lymphocytes (CTL) epitopes, and Human leukocyte antigens (HLA) restriction profile. The most recent common ancestor of the HIV CRF01_AE epidemic was estimated to be 1974±1. A period of exponential growth in effective population size began in 1982, fluctuated, and then stabilized in 1999. Genetic variability (entropy) consistently increased, however, epitope variability remained comparable; the highest number of novel CTL epitopes were present in 1995–1999, which were lost over time. The spread of the HIV-1 CRF01_AE epidemic is predominant in countries within Asia. Population immunogenetic pressures in the region may have contributed to the initial changes and following adaptation/stabilization of epitope diversity within gag sequences.

Discovering disease-causing pathogens in resource-scarce Southeast Asia using a global metagenomic pathogen monitoring system

SignificanceMetagenomic pathogen sequencing offers an unbiased approach to characterizing febrile illness. In resource-scarce settings with high biodiversity, it is critical to identify disease-causing pathogens in order to understand burden and to prioritize efforts for control. Here, metagenomic next-generation sequencing (mNGS) characterization of the pathogen landscape in Cambodia revealed diverse vector-borne and zoonotic pathogens irrespective of age and gender as risk factors. Identification of key pathogens led to changes in national program surveillance. This study is a "real world" example of the use of mNGS surveillance of febrile individuals, executed in-country, to identify outbreaks of vector-borne, zoonotic, and other emerging pathogens in a resource-scarce setting.

Identification of Two Similar Novel HIV-1 Recombinant Forms (CRF01_AE/CRF07_BC) among Intravenous Drug Users in Guangxi, China

New kinds of HIV-1 circulating recombinant forms (CRFs) and unique recombinant forms (URFs) earn a great prevalence in China nowadays. In this study, we identified 2 similar URFs (2016GXNNIDU037 and 2019QZLSIDU253) both isolated from intravenous drug users (IDUs) in Guangxi, China. Phylogenetic analysis of the near full-length genome (NFLG) revealed 2 URFs both clustered with CRF01_AE but setting up a monophyletic branch, supporting a high bootstrap value. Bootscan analysis and subregional recombinant analysis found that the NFLG of 2016GXNNIDU037 and 2019QZLSIDU253 were both composed of CRF01_AE and CRF07_BC, with 3 CRF07_BC mosaic segments inserted into CRF01_AE backbones. The CRF01_AE segments of the 2 URFs clustered with a previously reported cluster 2 lineage of CRF01_AE. The 5 recombinant breakpoints of the 2 URFs were quite similar. Distinct from CRF01_AE/CRF07_BC URFs reported before, 2016GXNNIDU037 and 2019QZLSIDU253 are new evidence of a high genetic variety of HIV-1 in Guangxi, which may pose new challenges to HIV-1 prevention and molecular epidemiological surveillance in China.

Complicated genotypes circulating among treatment naïve HIV-1 patients in Guangzhou, China

Guangzhou city is the political, economic, and cultural center of the Guangdong Province, China. The molecular epidemiological characteristics of HIV-1 in Guangzhou are not widely known. The aim of this study was to explore the characteristics of HIV-1 genotypes among treatment naïve HIV/AIDS patients living in Guangzhou. HIV-1 RNA was extracted from serum specimens. The partial pol gene of the HIV-1 genome was amplified and sequenced. The genotypes were screened using the subtyping tool COMET and further confirmed by phylogenetic analysis, with the exception of the URFs that were analyzed by jpHMM and RIP. The distributions of HIV genotypes in different risk populations were analyzed. Subsequently, pol sequences were used to construct transmission networks and analyze drug resistance. Twelve HIV-1 genotypes including 3 subtypes and 9 CRFs, with several URFs were identified from 1388 HIV-1 sequences, which were derived from 1490 patients. The main genotypes circulating in Guangzhou were CRF07_BC (38.3%), CRF01_AE (32.3%), and CRF55_01B (10.7%). CRF01_AE was the secondary dominant strain and multiple lineages of CRF01_AE had been identified in Guangzhou. The 01B recombinant forms, including CRF55_01B, CRF59_01B and CRF68_01B, have circulated widely in Guangzhou. 42.22% (586/1388) of the study sequences fell into 143 transmission networks, and the three main clusters revealed that sequences from MSM and HET populations were intermixed. 5.40% (75/1388) of patients had pre-treatment drug resistance. The HIV-1 strains that were present in Guangzhou have demonstrated complex genotypes. Particular attention should be given on these genotypes for the further strategy of prevention and intervention of HIV transmission.

Beijing as the hub of CRF07_BC transmission from the intravenous drug users to men who have sex with men in China

AIDS Research and Human Retroviruses officially retracts the Instant Online/Just Accepted version of the article entitled, "Beijing as the hub of CRF07_BC transmission from the intravenous drug users to men who have sex with men in China" (epub 7 Dec 2020; doi.org/10.1089/aid.2020.0147). A technical issue caused the unedited, accepted version to post online before all plagiarism checks were finalized. Those checks determined that there was too much duplication from previously published sources which prevented the continuance to final publication. The technical issue that caused the premature posting has since been corrected. AIDS Research and Human Retroviruses and its Publisher are committed to upholding the standards of scientific publishing and the community it serves.

BACKGROUND

The HIV-1 CRF07_BC strain has been increasing in frequency in China, is now the major recombination subtype in the men who have sex with men (MSM) population. However, to date, the evolutionary history of CRF07_BC in MSM in China has not been explored in greater detail.

METHODS

All available partial gag, pol and env segments of CRF07_BC were obtained from the Los Alamos HIV database. We performed phylogenetic analysis for these fragments by using the Bayesian Markov Chain Monte Carlo method, as implemented in BEAST. We estimated the history of viral migration between different areas over time using the discrete Bayesian phylogeographical method.

RESULTS

Spatial reconstruction showed that Yunnan had the highest root state posterior probability (0.89 in pol, 0.60 in gag, 0.87 in env). The virus migrated from Yunnan to Beijing in 1990s through intravenous drug users (IDU). The highest root state posterior probability of MSM cluster is Beijing (0.93 in pol, 0.90 in gag and 0.37 in env). In the beginning of 2000s, Beijing became the primary epicenter as CRF07_BC had expanded their geographical distribution to many provinces in China in MSM population. Guangdong and Shanghai were secondary epicenters, with a large extent of viruses.

CONCLUSIONS

This study highlighted the spatial and temporal spread of CRF07_BC in MSM population in China. It revealed that Beijing was the hub of CRF07_BC transmission from IDU to MSM in China.

Characterization of envelope sequence of HIV virus in children infected with HIV in Vietnam

Background:

HIV is characterized by high levels of genetic variability, including increased numbers of heterogeneous sequences of the envelope region. Therefore, studying genetic variability of HIV in relation to viral replication might facilitate prognosis of disease progression.

Methods:

The study was designed as cross-sectional; data and samples of participants collected and analyzed env genes were obtained from 23 children enrolled by Vietnam National Children’s Hospital.

Results:

Substantial mutations in the C2 region were found in patients with high levels of viral replication while changes in the C3 region were mostly found in patients with low viral load. In the V1 region, we found profound amino acid modifications in patients with low HIV viral loads in contrast to the V2 sequence, where we identified single point mutations in patients with increased HIV viral load. The V3 region was relatively homogeneous, while profound deletions in the V4 region were detected in patients with increased viral replication.

Conclusion:

Our results suggest that genetic variations in different regions of the HIV envelope sequence, including both conserved C2 and C3 and variable V1/V2 and V4 regions, might be involved in increased viral infectivity and replication capacity. Such knowledge might help improve prediction of HIV progress and treatment in patients.

New Genomes from the Congo Basin Expand History of CRF01_AE Origin and Dissemination

Although the first HIV circulating recombinant form (CRF01_AE) is the predominant strain in many Asian countries, it is uncommonly found in the Congo Basin from where it first originated. To fill the gap in the evolutionary history of this important strain, we sequenced near complete genomes from HIV samples with subgenomic CRF01_AE regions collected in Cameroon and the Democratic Republic of the Congo from 2001 to 2006. HIV genomes were generated from N = 13 plasma specimens by next-generation sequencing of metagenomic libraries prepared with spiked primers targeting HIV, followed by Sanger gap-filling. Genome sequences were aligned to reference strains, including Asian and African CRF01_AE sequences, and evaluated by phylogenetic and recombinant analysis to identify four CRF01_AE strains from Cameroon. We also identified two CRF02, one CRF27, and six unique recombinant form genomes (01|A1|G, 01|02|F|U, F|G|01, A1|D|01, F|G|01, and A1|G|01). Phylogenetic analysis, including the four new African CRF01_AE genomes, placed these samples as a bridge between basal Central African Republic CRF01_AE strains and all Asian, European, and American CRF01_AE strains. Molecular dating confirmed previous estimates indicating that the most recent common CRF01_AE ancestor emerged in the early 1970s (1968–1970) and spread beyond Africa around 1980 to Asia. The new sequences and analysis presented in this study expand the molecular history of the CRF01_AE clade, and are illustrated in an interactive Next Strain phylogenetic tree, map, and timeline at (https://nextstrain.org/community/EduanWilkinson/hiv-1_crf01).

Laos is Affected by HIV CRF01_AE and the Newly Identified CRF97_01B

Laos is the only landlocked country in Southeast Asia and borders Thailand, Myanmar and Cambodia, the three countries in this region that have been hardest hit by human immunodeficiency virus (HIV). Laos has been regarded as a low-HIV-prevalence country for decades. To understand the status of HIV in Laos in recent years, a retrospective study was performed among 2851 patients visiting a hospital in Vientiane, the capital of Laos, from November 2011 to May 2012. Whole blood samples were obtained from the patients, and DNA was extracted. HIV status was determined by HIV gag fragment-specific PCR assay. Sixty-nine samples were detected as HIV proviral DNA positive with a positive rate of 2.4% (69/2851). Sixty-one near full-length genomic sequences were obtained from the positive samples. The results of phylogenetic analysis showed that the vast majority (91.8%) of the HIV strains belonged to CRF01_AE, and the other five (8.2%) strains were identified as a new HIV circulating recombinant form CRF97_01B, which had a CRF01_AE backbone with an insertion of subtype B in the gag-pol region. Phylogeographic analysis revealed that HIV CRF01_AE circulating in Laos were multiply introduced from Thailand. These results indicated that Laos might be suffering a considerably more serious impact of HIV than previously believed. To keep this country from undergoing the same increase in HIV prevalence observed in its neighbors, immediate intervention measures and sufficient epidemiological research are urgently needed.

Characterization of a Novel HIV-1 Recombinant Form (CRF01_AE/CRF07_BC/CRF08_BC) Identified from Guangxi, China

Recently, more and more kinds of circulating recombinant forms (CRFs) and unique recombinant forms (URFs) were identified in the population in China. A novel HIV-1 recombinant virus (2016GXNNIDU016) was identified in this study, which was isolated from an HIV-1 infected intravenous drug user in Nanning, the capital of Guangxi, China. Phylogenetic analysis of the near full-length genome (NFLG) indicated that the sequence (2016GXNNIDU016) was a monophyletic branch that did not cluster with any previously identified genotype. Recombinant analysis showed that the NFLG of 2016GXNNIDU016 is composed of CRF07_BC, CRF01_AE, and CRF08_BC, including nine mosaic segments. Differing from previously documented CRF01_AE and CRF07/08_BC recombinant forms, 2016GXNNIDU016 increases the genetic complexity of HIV-1 in Guangxi. The constant emergence of novel recombinant forms should draw our attention to make more efforts in supervising and preventing the spread of HIV infection.

Genomic Characterization of a Novel HIV Type 1 Strain Originating from CRF07_BC and CRF01_AE by Heterosexual Transmission in the Lingshan Prefecture of Guangxi Province, China

Recently, an increasing number of circulating recombinant forms (CRFs) and unique recombinant forms of HIV-1 have been identified in China, contributing substantially to the genetic variability of this virus. This study reports a novel second-generation recombinant form of HIV-1 (GX2015QZLS204), composed of segments from the CRF07_BC and CRF01_AE strains, which was isolated from an HIV-positive male individual infected through heterosexual contact, while residing in the Guangxi province of southwest China. Analysis of the near full-length genome sequence showed that one segment of the CRF01_AE virus subtype was inserted into the CRF07_BC subtype backbone. Recombination analysis demonstrated that the genome of GX2015QZLS204 was separated into seven segments with six breakpoints. Subregion trees constructed by the neighbor-joining method confirmed that the CRF01_AE segment was from the previously identified CRF01_AE cluster 2, and the CRF07_BC segment correlated with the CRF07_BC strain originating from the Jiangxi and Xinjiang provinces of China. The emergence of GX2015QZLS204 highlights the frequent generation of novel recombinant forms and the increasing complications of the HIV-1 epidemic among heterosexual transmission (HET) groups in China. This highlights the importance of monitoring HIV-1 molecular epidemiological characteristics and the urgent need for reduction of the HIV-1 epidemic among HET groups in China.

Cross-Continental Dispersal of Major HIV-1 CRF01_AE Clusters in China

Since the 1990s, several distinct clusters of human immunodeficiency virus-type 1 (HIV-1) CRF01_AE related to a large epidemic in China have been identified, but it is yet poorly understood whether its transmission has dispersed globally. We aimed to characterize and quantify the genetic relationship of HIV-1 CRF01_AEs circulating in China and other countries. Using representative sequences of Chinese clusters as queries, all relevant CRF01_AE pol sequences in two large databases (the Los Alamos HIV sequence database and the UK HIV Drug Resistance Database) were selected with the online basic local alignment search (BLAST) tool. Phylogenetic and phylogeographic analyses were then carried out to characterize possible linkage of CRF01_AE strains between China and the rest of the world. We identified that 269 strains isolated in other parts of the world were associated with five major Chinese CRF01_AE clusters. 80.7% were located within CN.01AE.HST/IDU-2, most of which were born in Southeast Asia. 17.8% were clustered with CN.01AE.MSM-4 and -5. Two distinct sub-clusters associated with Chinese men who have sex with men (MSM) emerged in HK-United Kingdom and Japan after 2000. Our analysis suggests that HIV-1 CRF01_AE strains related to viral transmission in China were initially brought to the United Kingdom or other countries during the 1990s by Asian immigrants or returning international tourists from Southeast Asia, and then after having circulated among MSM in China for several years, these Chinese strains dispersed outside again, possibly through MSM network. This study provided evidence of regional and global dispersal of Chinese CRF01_AE strains. It would also help understand the global landscape of HIV epidemic associated with CRF01_AE transmission and highlight the need for further international collaborative study in this field.

Molecular characteristic of HIV-1 CRF01_AE in Nanjing from 2015 to 2017

OBJECTIVE

To investigate the evolutionary dynamics and characteristic of the molecular transmission networks of HIV-1 CRF01_AE in Nanjing.

METHODS

Viral samples were collected from 580 newly diagnosed HIV-1-infected patients. HIV-1 pol sequences were obtained and used for for molecular evolutionary analyses. The ML trees were constructed by MEGA 6.0 using under GTR+ G + I model with 1000 bootstrap replicates. The emergence and estimation of tMRCA and the evolutionary rate of the different CRF01_AE clusters were inferred using Bayesian phylogenetic analysis approaches implemented in the BEAST package. Pairwise genetic distances were calculated under the Tamura-Nei 93 model, a genetic distance threshold of ≤1.2% was used to identify potential transmission clusters. Network diagrams were plotted using Cytoscape 3.3.0.

RESULTS

Of these HIV-1-infected patients, 551 (91.5%) were males. The largest number of infections were attributed to homosexual (462, 79.7%). A total of 518 full-length pol genes were successfully amplified, based on the phylogenetic analysis CRF01_AE was the most predominantly circulating strain (45.0%, 233/518). As shown in the ML tree, three distinct clusters were observed. The 'Nanjing lineage' 1, 2, 3 has an estimated tMRCA around1996.61, 1993.61, 1984.61 respectively. Of 233 Nanjing sequences, 123 (55.2%) distributed in 30 molecular clusters, average Links/node was 7.8 with range (1-33), most of Nanjing strains shared links with local strains.

CONCLUSION

HIV-1 CRF01_AE was the most predominantly circulating strain, the epidemic of CRF01_AE in Nanjing was driven by multiple clusters of HIV-1 strains, and most CRF01_AE stains in our study were estimated to have originated in China in the 1990s.

Another Near Full-Length Sequence of an HIV-1 CRF01_AE/CRF07_BC Recombinant Virus from a Man Who Has Sex with Men in Tianjin, China

Surprisingly, more new unique recombinant forms (URFs) of CRF01_AE/CRF07_BC recombinant viruses were found in Tianjin, China, recently. Here we identified another novel HIV-1 recombinant virus (TJ20170315) isolated from an HIV-1 positive man who has sex with men in Tianjin, China. Phylogenetic analysis of the near full-length genome of TJ20170315 showed that it formed a monophyletic branch within the cluster of CRF01_AE reference sequences. Recombinant analysis showed that the virus kept the CRF01_AE parental backbone, and one CRF07_BC segment was inserted into gag, pol genes of the CRF01_AE backbone. Nowadays, multiple kinds of circulating recombinant forms (CRFs) and URFs were identified among men who has sex with men in China. The emergency of URFs highlights the complexity of HIV-1 infection in Tianjin, China, and implies that the next new CRF and HIV-1 epidemic are coming on the road.

Characterization of a Novel HIV-1 CRF01_AE/CRF07_BC Recombinant Virus Among Men Who Have Sex with Men in Tianjin, China

We report here a novel human immunodeficiency virus type 1 (HIV-1) second-generation recombinant form comprising CRF01_AE and CRF07_BC isolated from an HIV-positive male subject infected among men who have sex with men (MSM) in Tianjin in north China. The phylogenetic analysis of the near full-length genome of TJIH0345 reveals that three regions of CRF01_AE were inserted into the CRF07_BC backbone with five recombinant breakpoints observed in the pol, vif, vpu, and env gene regions whose genome structure is distinctly different from other circulating recombinant forms and unique recombinant forms previously reported. The continued emergence of the novel recombinant strain in Tianjin, China, highlights the increasing complexity of the HIV-1 epidemic among the MSM population, and further molecular epidemiological investigation should be done to track the genetic evolution of HIV-1 strains to prevent HIV transmission.

Increased predominance of HIV-1 CRF01_AE and its recombinants in the Philippines

The growth rate of new HIV infections in the Philippines was the fastest of any countries in the Asia-Pacific region between 2010 and 2016. To date, HIV-1 subtyping results in the Philippines have been determined by characterizing only partial viral genome sequences. It is not known whether recombination occurs in the majority of unsequenced genome regions. Near-full-length genome (NFLG) sequences were obtained by amplifying two overlapping half genomes from plasma samples collected between 2015 and 2017 from 23 newly diagnosed infected individuals in the Philippines. Phylogenetic analysis showed that the newly characterized sequences were CRF01_AE (14), subtype B (3), CRF01/B recombinants (5) and a CRF01/CRF07/B recombinant (1). All 14 CRF01_AE formed a tight cluster, suggesting that they were derived from a single introduction. The time to the most recent common ancestor (tMRCA) for CRF01_AE in the Philippines was 1995 (1992-1998), about 10-15 years later than that of CRF01_AE in China and Thailand. All five CRF01/B recombinants showed distinct recombination patterns, suggesting ongoing recombination between the two predominant circulating viruses. The identification of partial CRF07_BC sequences in one CRF01/CRF07/B recombinant, not reported previously in the Philippines, indicated that CRF07_BC may have been recently introduced into that country from China, where CRF07_BC is prevalent. Our results show that the major epidemic strains may have shifted to an increased predominance of CRF01_AE and its recombinants, and that other genotypes such as CRF07_BC may have been introduced into the Philippines.

Identification of a novel broadly HIV-1-neutralizing antibody from a CRF01_AE-infected Chinese donor

The isolation and characterization of monoclonal broadly neutralizing antibodies (nAbs) from natural HIV-1-infected individuals play very important roles in understanding nAb responses to HIV-1 infection and designing vaccines and therapeutics. Many broadly nAbs have been isolated from individuals infected with HIV-1 clade A, B, C, etc., but, as an important recombinant virus, the identification of broadly nAbs in CRF01_AE-infected individuals remains elusive. In this study, we used antigen-specific single B-cell sorting and monoclonal antibody expression to isolate monoclonal antibodies from a CRF01_AE-infected Chinese donor (GX2016EU04), a broad neutralizer based on neutralizing activity against a cross-clade virus panel. We identified a series of HIV-1 monoclonal cross-reactive nAbs, termed F2, H6, BF8, F4, F8, BE7, and F6. F6 could neutralize 21 of 37 tested HIV-1 Env-pseudotyped viruses (57%) with a geometric mean value of 12.15 μg/ml. Heavy and light chains of F6 were derived from IGHV4-34 and IGKV 2-28 germlines, complementarity determining region (CDR) 3 loops were composed of 18 and 9 amino acids, and somatic hypermutations (SHMs) were 16.14% and 11.83% divergent from their respective germline genes. F6 was a GP120-specific nAb and recognized the linear epitope. We identified for the first time a novel broadly HIV-1-neutralizing antibody, termed F6, from a CRF01_AE-infected donor, which could enrich the research of HIV-1 nAbs and provide useful insights for designing vaccine immunogens and antibody-based therapeutics.

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.

Geographically-stratified HIV-1 group M pol subtype and circulating recombinant form sequences

Accurate classification of HIV-1 group M lineages, henceforth referred to as subtyping, is essential for understanding global HIV-1 molecular epidemiology. Because most HIV-1 sequencing is done for genotypic resistance testing pol gene, we sought to develop a set of geographically-stratified pol sequences that represent HIV-1 group M sequence diversity. Representative pol sequences differ from representative complete genome sequences because not all CRFs have pol recombination points and because complete genome sequences may not faithfully reflect HIV-1 pol diversity. We developed a software pipeline that compiled 6,034 one-per-person complete HIV-1 pol sequences annotated by country and year belonging to 11 pure subtypes and 70 CRFs and selected a set of sequences whose average distance to the remaining sequences is minimized for each subtype/CRF and country to generate a Geographically-Stratified set of 716 Pol Subtype/CRF (GSPS) reference sequences. We provide extensive data on pol diversity within each subtype/CRF and country combination. The GSPS reference set will also be useful for HIV-1 pol subtyping.

Characterization of HIV diversity, phylodynamics and drug resistance in Washington, DC

BACKGROUND

Washington DC has a high burden of HIV with a 2.0% HIV prevalence. The city is a national and international hub potentially containing a broad diversity of HIV variants; yet few sequences from DC are available on GenBank to assess the evolutionary history of HIV in the US capital. Towards this general goal, here we analyze extensive sequence data and investigate HIV diversity, phylodynamics, and drug resistant mutations (DRM) in DC.

METHODS

Molecular HIV-1 sequences were collected from participants infected through 2015 as part of the DC Cohort, a longitudinal observational study of HIV+ patients receiving care at 13 DC clinics. Sequences were paired with Cohort demographic, risk, and clinical data and analyzed using maximum likelihood, Bayesian and coalescent approaches of phylogenetic, network and population genetic inference. We analyzed 601 sequences from 223 participants for int (~864 bp) and 2,810 sequences from 1,659 participants for PR/RT (~1497 bp).

RESULTS

Ninety-nine and 94% of the int and PR/RT sequences, respectively, were identified as subtype B, with 14 non-B subtypes also detected. Phylodynamic analyses of US born infected individuals showed that HIV population size varied little over time with no significant decline in diversity. Phylogenetic analyses grouped 13.5% of the int sequences into 14 clusters of 2 or 3 sequences, and 39.0% of the PR/RT sequences into 203 clusters of 2-32 sequences. Network analyses grouped 3.6% of the int sequences into 4 clusters of 2 sequences, and 10.6% of the PR/RT sequences into 76 clusters of 2-7 sequences. All network clusters were detected in our phylogenetic analyses. Higher proportions of clustered sequences were found in zip codes where HIV prevalence is highest (r = 0.607; P<0.00001). We detected a high prevalence of DRM for both int (17.1%) and PR/RT (39.1%), but only 8 int and 12 PR/RT amino acids were identified as under adaptive selection. We observed a significant (P<0.0001) association between main risk factors (men who have sex with men and heterosexuals) and genotypes in the five well-supported clusters with sufficient sample size for testing.

DISCUSSION

Pairing molecular data with clinical and demographic data provided novel insights into HIV population dynamics in Washington, DC. Identification of populations and geographic locations where clustering occurs can inform and complement active surveillance efforts to interrupt HIV transmission.

Tracing the epidemic history of HIV-1 CRF01_AE clusters using near-complete genome sequences

Human immunodeficiency virus (HIV) has a number of circulating recombinant forms that are the product of recombination between different HIV subtypes. The first circulating recombinant form of HIV-1 to be identified was CRF01_AE, which originated in Central Africa and is now most prevalent in Southeast and East Asia. In this study, we investigated the timescale, evolutionary history, and population genetics of the HIV-1 CRF01_AE strains primarily responsible for the epidemic in Asia. A further aim of our study was to define and standardize the nomenclature and provide well-characterized reference sequences for the phylogenetic transmission clusters of CRF01_AE. We analysed a data set of 334 near-complete genome sequences from various risk groups, sampled between 1990 and 2011 from nine countries. Phylogenetic analyses of these sequences were performed using maximum likelihood and Bayesian methods. Our study confirms that the diversity of HIV-1 CRF01_AE originated in Central Africa in the mid-1970s, was introduced into Thailand between 1979 and 1982, and began expanding there shortly afterwards (1982-1984). Subsequently, multiple clusters significantly contributed to China's HIV epidemic. A Bayesian skyline plot revealed the rapid expansion of CRF01_AE in China around 1999-2000. We identified at least eight different clusters of HIV-1 CRF01_AE formed by rapid expansion into different risk groups and geographic regions in China since the late 1980s.

Fast Dissemination of New HIV-1 CRF02/A1 Recombinants in Pakistan

A number of HIV-1 subtypes are identified in Pakistan by characterization of partial viral gene sequences. Little is known whether new recombinants are generated and how they disseminate since whole genome sequences for these viruses have not been characterized. Near full-length genome (NFLG) sequences were obtained by amplifying two overlapping half genomes or next generation sequencing from 34 HIV-1-infected individuals in Pakistan. Phylogenetic tree analysis showed that the newly characterized sequences were 16 subtype As, one subtype C, and 17 A/G recombinants. Further analysis showed that all 16 subtype A1 sequences (47%), together with the vast majority of sequences from Pakistan from other studies, formed a tight subcluster (A1a) within the subtype A1 clade, suggesting that they were derived from a single introduction. More in-depth analysis of 17 A/G NFLG sequences showed that five shared similar recombination breakpoints as in CRF02 (15%) but were phylogenetically distinct from the prototype CRF02 by forming a tight subcluster (CRF02a) while 12 (38%) were new recombinants between CRF02a and A1a or a divergent A1b viruses. Unique recombination patterns among the majority of the newly characterized recombinants indicated ongoing recombination. Interestingly, recombination breakpoints in these CRF02/A1 recombinants were similar to those in prototype CRF02 viruses, indicating that recombination at these sites more likely generate variable recombinant viruses. The dominance and fast dissemination of new CRF02a/A1 recombinants over prototype CRF02 suggest that these recombinant have more adapted and may become major epidemic strains in Pakistan.

Factors associated with needle sharing among people who inject drugs in Yunnan, China: a combined network and regression analysis

Background

Network analyses have been widely utilized to evaluate large datasets, but have not yet been used to explore factors associated with risk behaviours. In combination with traditional regression analysis, network analyses may provide useful information and highlight key factors for reducing needle sharing behaviours among people who inject drugs (PWID).

Methods

Sociodemographic data, and information on injection behaviour and sexual practices were collected from a cross-sectional survey that was conducted with PWID in five prefectures of Yunnan province, China. A combination of logistic regression and correlation network analyses were used to explore key factors for reducing needle-sharing behaviours among PWID.

Results

In a total of 1 049 PWID, 37.5 % had a history of needle or syringe sharing. The logistic analysis showed that Zhaotong, Qujing, Dehong, or Lincang residents, diazepam use, longer injection duration, needle reuse, and infection with HIV, viral hepatitis, tuberculosis and/or malaria were independently associated with needle sharing. The correlation network analyses showed that, compared to PWID who had never shared needles, PWID who did share needles would achieve harm reduction goals faster and more permanently. HIV serostatus and marital status were found to be closely associated with other risk factors. By combining regression analyses with network analyses, it was shown that PWID who are HIV seropositive will be an ideal target group for harm reduction programs.

Conclusion

Needle-sharing behaviours are common among PWID in Yunnan, and harm reduction programs may help PWID who are HIV seropositive reduce risk behaviours and prevent blood borne diseases.

Electronic supplementary material

The online version of this article (doi:10.1186/s40249-016-0169-y) contains supplementary material, which is available to authorized users.

The application of HIV molecular epidemiology to public health

HIV is responsible for one of the largest viral pandemics in human history. Despite a concerted global response for prevention and treatment, the virus persists. Thus, urgent public health action, utilizing novel interventions, is needed to prevent future transmission events, critical to eliminating HIV. For public health planning to prove effective and successful, we need to understand the dynamics of regional epidemics and to intervene appropriately. HIV molecular epidemiology tools as implemented in phylogenetic, phylodynamic and phylogeographic analyses have proven to be powerful tools in public health planning across many studies. Numerous applications with HIV suggest that molecular methods alone or in combination with mathematical modelling can provide inferences about the transmission dynamics, critical epidemiological parameters (prevalence, incidence, effective number of infections, Re, generation times, time between infection and diagnosis), or the spatiotemporal characteristics of epidemics. Molecular tools have been used to assess the impact of an intervention and outbreak investigation which are of great public health relevance. In some settings, molecular sequence data may be more readily available than HIV surveillance data, and can therefore allow for molecular analyses to be conducted more easily. Nonetheless, classic methods have an integral role in monitoring and evaluation of public health programmes, and should supplement emerging techniques from the field of molecular epidemiology. Importantly, molecular epidemiology remains a promising approach in responding to viral diseases.

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.

Characterization of the Near Full-Length Genome of a Novel HIV-1 CRF01_AE/CRF07_BC Recombinant in an Injection Drug User from Southern Taiwan

HIV-1 CRF07_BC became prevalent in Taiwan after the epidemic among injection drug users (IDUs). We describe a unique recombinant form (URF) consisting of CRF01_AE and CRF07_BC (named URF_0107-H8) genes detected from an IDU. The 8.8 kb near full-length genome of URF_0107-H8 had a CRF01_AE backbone with two CRF07_BC fragments in the reverse transcriptase and integrase region [RT-Int; HXB2 nucleotide (nt) positions 2942-4709] and within the envelop (nt 8467-8722) gene. Phylogenetic analyses revealed that its 1.8 kb RT-Int sequence clustered with those of CRF07_BC strains from Taiwan, while sequences of CRF01_AE portions were more similar to those of Central African origin than contemporaneous CRF01_AE isolates in Taiwan or prevalent in East or Southeast Asia. Recombination breakpoints and phylogenetic relationships of URF_0107-H8 were different from those of CRF01_AE/CRF07_BC URFs previously reported from China. This highlighted the importance of continual monitoring of genetic evolution of HIV strains and the emergence of new recombinants.

Origin and spread of HIV-1 in persons who inject drugs in Bulgaria

Increased HIV transmission in persons who inject drugs (PWIDs) has led to subepidemics and outbreaks in several countries in Europe, including Bulgaria. In this study in Bulgaria, we investigate the origin and spatiotemporal evolutionary history of HIV-1 infections in PWIDs and the distribution of antiretroviral resistance mutations and hepatitis co-infections in these populations. We analyzed HIV-1 polymerase sequences available from 117 of 359 PWIDs diagnosed with HIV/AIDS from 1999 to 2011. Of these, 50 (42.7%) were classified as CRF02_AG, 41 (35.0%) CRF01_AE, 12 (10.3%) URFs, ten (8.5%) subtype B, two (1.7%) subtype F1 and two (1.7%) CRF14_BG. Most recent common ancestor dating suggests that CRF01_AE was likely first introduced from Southeast Asia into persons reporting heterosexual infection in Bulgaria in 1992 and spread subsequently to PWIDs in the capital city of Sofia around 2003. Conversely, CRF02_AG in Bulgaria was likely first introduced into PWID from Germany in 2000 and later entered heterosexual populations around 2009. The overall prevalence of resistance mutations was 6.8% (8/117), of which 5.1% (5/117) was observed in patients on antiretroviral therapy and 1.7% (2/117) was from transmitted drug resistance mutations in drug-naïve individuals. 189/204 (92.6%) PWIDs were also co-infected with hepatitis C (HCV) and 31/183 (16.9%) were co-infected with hepatitis B (HBV). Our study provides valuable molecular epidemiological information on the introduction and distribution of the main HIV-1 subtypes, resistance mutations and hepatitis co-infections among PWIDs with HIV-1 in Bulgaria which can be used to target prevention efforts.

Worldwide Genetic Features of HIV-1 Env α4β7 Binding Motif: The Local Dissemination Impact of the LDI Tripeptide

BACKGROUND

HIV-1 gp120 binds to integrin α4β7, a homing receptor of lymphocytes to gut-associated lymphoid tissues. This interaction is mediated by the LDI/V tripeptide encoded in the V2-loop. This tripeptide mimics similar motifs in mucosal addressin cellular adhesion molecule (MAdCAM) and vascular CAM (VCAM), the natural ligands of α4β7. In this study, we explored the association of V2-loop LDI/V mimotopes with transmission routes and patterns of disease progression in HIV-infected adult and pediatric patients. HIV-1 env sequences available in the Los Alamos HIV Sequence database were included in the analyses.

METHODS

HIV-1 V2-loop sequences generated from infected adults and infants from South and Southeast Brazil, and also retrieved from the Los Alamos database, were assessed for α4β7 binding tripeptide composition. Chi-Square/Fisher Exact test and Mann Whitney U test were used for tripeptide comparisons. Shannon entropy was assessed for conservancy of the α4β7 tripeptide mimotope.

RESULTS

We observed no association between the tripeptide composition or conservation and virus transmission route or disease progression. However, LDI was linked to successful epidemic dissemination of HIV-1 subtype C in South America, and further to other expanding non-B subtypes in Europe and Asia. In Africa, subtypes showing increased LDV prevalence evidenced an ongoing process of selection toward LDI expansion, an observation also extended to subtype B in the Americas and Western Europe.

CONCLUSIONS

The V2-loop LDI mimotope was conserved in HIV-1C from South America and other expanding subtypes across the globe, which suggests that LDI may promote successful dissemination of HIV at local geographic levels by means of increased transmission fitness.

A considerable proportion of CRF01_AE strains in China originated from circulating intrasubtype recombinant forms (CIRF)

BACKGROUND

In this study, the prevalence of HIV-1 CRF01_AE intrasubtype recombinants in China is estimated and their contributions to the epidemic are explored.

METHODS

Available HIV-1 complete genomes of CRF01_AE were retrieved from the HIV database. The two alignments were evaluated with RDP3. Recombinants were defined as cases in which the recombination signal was supported by at least 3 methods with P-values of ≤0.05 after Bonferroni correction for multiple comparisons implemented in RDP3. Phylogenetic analysis was performed to further investigate the role of intrasubtype recombinants in epidemics.

RESULTS

Here, 124 out of the 339 sequences from around the world (36.6 %) showed significant evidence of recombination. Here, 84 of these recombinants were from China, accounting for 54.9 % of local total sequences (84 out of 153). The results indicated non-negligible levels of intrasubtype recombination. Subsequent phylogenetic analysis indicated that a considerable proportion of CRF01_AE strains in China originated from circulating intrasubtype recombinant forms. Three large, well-supported intrasubtype recombinants clusters were identified here. Through a survey of risk factors and sampling cities and provinces, cluster I and cluster II were found to be prevalent primarily among men who have sex with men in major northern cities. Cluster III was prevalent among heterosexuals and intravenous drug users in southern and southwestern provinces.

CONCLUSIONS

The current work highlighted the remarkable prevalence of intrasubtype recombination within the CRF01_AE epidemic and emphasized the value of intrasubtype recombinants, which came to circulate in the same manner as intersubtype recombinants.

Co-infections and transmission networks of HCV, HIV-1 and HPgV among people who inject drugs

Co-infections with human immunodeficiency virus type 1 (HIV-1) and human pegivirus (HPgV) are common in hepatitis C virus (HCV)-infected individuals. However, analysis on the evolutionary dynamics and transmission network profiles of these viruses among individuals with multiple infections remains limited. A total of 228 injecting drug users (IDUs), either HCV- and/or HIV-1-infected, were recruited in Kuala Lumpur, Malaysia. HCV, HIV-1 and HPgV genes were sequenced, with epidemic growth rates assessed by the Bayesian coalescent method. Based on the sequence data, mono-, dual- and triple-infection were detected in 38.8%, 40.6% and 20.6% of the subjects, respectively. Fifteen transmission networks involving HCV (subtype 1a, 1b, 3a and 3b), HIV-1 (CRF33_01B) and HPgV (genotype 2) were identified and characterized. Genealogical estimates indicated that the predominant HCV, HIV-1 and HPgV genotypes were introduced into the IDUs population through multiple sub-epidemics that emerged as early as 1950s (HCV), 1980s (HIV-1) and 1990s (HPgV). By determining the difference in divergence times between viral lineages (ΔtMRCA), we also showed that the frequency of viral co-transmission is low among these IDUs. Despite increased access to therapy and other harm reduction interventions, the continuous emergence and coexistence of new transmission networks suggest persistent multiple viral transmissions among IDUs.

The predominant cluster of CRF01_AE circulating among newly diagnosed HIV-1-positive people in Anhui Province, China

CRF01_AE, which has led a new epidemic in many provinces in China and has displayed complex characteristics, has now evolved into multiple clusters in China. Some clusters often circulate in specific regions or among specific risk populations in China. To better determine the characteristics of CRF01_AE circulating in Anhui Province, we analyzed CRF01_AE based on gag and pol sequences. Our results showed that CRF01_AE circulating in Anhui Province was clearly divided into three clusters. Cluster 1 covered 90% of the sequences in all CRF01_AE. Among Cluster 1, the sequences from men who have sex with men (MSM) and heterosexuals were interwoven. It is suggested that MSM may play a bridge role in transmitting HIV-1 among the different risk groups.

Novel HIV-1 Recombinant Identified in a Foreign Heterosexual Resident in Japan: Relatedness to Recently Reported CRF69_01B, Detected Primarily among Japanese Men Who Have Sex with Men

We report here an HIV-1 recombinant composed of CRF01_AE and subtype B, with a total of eight recombination breakpoints in the gag-pol and vpr-tat regions. This recombinant was identified from a Myanmarese heterosexual male in Japan and showed the chimera structure identical to recently reported CRF69_01B, detected primarily among men who have sex with men in Japan.

High proportion of HIV serodiscordance among HIV-affected married couples in northern Vietnam

INTRODUCTION

Little is known about the state of HIV transmission among married couples in Vietnam. This study aims to clarify HIV serostatus in this group and elucidate risk factors for intra-marital HIV transmission.

METHODS

In 2012, we enrolled a group of HIV-positive married men registered at the HIV outpatient clinic of a referral hospital in northern Vietnam, along with their wives. Sociodemographic, behavioural and clinical data were collected from men and wives. HIV serodiscordant couples were followed until March 2014 to determine seroconversion rate. A phylogenetic analysis was performed based on env V3 sequence to detail cluster formation among men.

RESULTS

Of the 163 HIV-positive men enrolled in the study, 101 (62.0%) had wives testing HIV-negative. Half of men reported injecting drug use (IDU) as a likely transmission route. Couples reported a high incidence of unprotected sexual intercourse prior to diagnosis; the median (inter quartile range) was 4 (4-8) times per month. Only 17 couples (10.4%) reported using condoms during at least half these instances. Multivariable analysis revealed IDU history among men was independently associated with HIV-negative wives (adjusted OR 0.31; 95% CI 0.10-0.95, p=0.041). Phylogenetic analysis of 80 samples indicated CRF01_AE. Of these, 69 (86.3%) clustered with IDU-associated viruses from Vietnam. No HIV seroconversion was identified during a follow-up of 61 serodiscordant couples, with 126.5 person-years of observation during which HIV-infected men were on antiretroviral drug therapy (ART).

CONCLUSION

High HIV serodiscordance was observed among HIV-affected married couples in northern Vietnam. A large number of at-risk wives therefore remain HIV-negative and can be protected with measures including proper use of ART if couples are made aware of the serodiscordance through screening.

HIV-1 prevalence and subtype/recombinant distribution among travelers entering China from Vietnam at the HeKou port in the Yunnan province, China, between 2003 and 2012

The aim of this study was to assess HIV-1 prevalence and the distribution of HIV-1 subtypes among travelers crossing the border at the HeKou land port. Between 2003 and 2012, 22,799 persons were randomly recruited from people entering China from Vietnam. In this crossing border population, a total of 161 (0.71%) travelers were determined as HIV-1-positive. From them, 140 HIV-1-positive serum samples were collected for RNA extraction and subsequent RT-nested PCR amplification of the group-specific antigen (gag)-RT with a length of 2.6 kb. The DNA sequences were analyzed to determine the HIV-1 subtypes/recombinants. We found that the circulating recombinant form 01_AE (CRF01_AE) was the most common HIV-1 subtype, accounting for 49.4% (41/83) of the subtyped 83 samples, followed by CRF08_BC (26.5%, 22/83) and CRF07_BC (7.2%, 6/83). Only 1 sample was classified as subtype C. Thirteen cases could not be clustered into any known subtypes or CRFs and presented as unique recombinant forms (URFs). Of them, 6 recombination patterns were identified. They had distinct structures consisting of fragments of subtypes B, C, CRF01_AE, CRF07_BC and CRF08_BC. Between 2003 and 2012, CRF01_AE and CRE08_BC were shown to be the most prevalent recombinant forms identified each year. But yearly change of each subtype is uncertain regular among in these travelers during the past decade. Understanding the distribution of HIV-1 subtypes/recombinants and how it changes across time among individuals entering China from Vietnam through this land port is crucial to establish strategies for the prevention of HIV cross-border transmission.

Bridging epidemiology with population genetics in a low incidence MSM-driven HIV-1 subtype B epidemic in Central Europe

Background

The HIV-1 epidemic in Slovenia, a small Central European country, has some characteristics that make it an ideal model to study HIV-1 transmission. The epidemic is predominantly affecting men who have sex with men infected with subtype B (89% of all patients), has a low prevalence (less than 1/1000) and is growing slowly. The aim of the present study was to analyze in detail the evolutionary history and the determinants of transmission.

Methods

A total of 223 partial pol gene sequences from therapy naïve individuals were included, representing 52% of all patients newly diagnosed in 13 years (2000–2012) and analyzed together with genetically similar worldwide sequences, selected in a BLAST search.

Results

Combined analysis (maximum likelihood and Bayesian) of HIV-1 transmission chains revealed 8 major clusters (n ≥ 10 patients), 1 group of 4 patients, 2 trios and 12 transmission pairs, thus leaving only 43 (19.3%) Slovenian patients infected with subtype B without a local epidemiological link, indicating a predominance of local transmission of HIV-1 infection. Bayesian analysis performed on a full set of sequences estimated several introductions of HIV-1 into Slovenia, with the most recent common ancestor (tMRCA) of the earliest Slovenian cluster dated to the late 1980s, although tMRCAs obtained from separate independent analysis of each cluster showed considerably more recent estimates. These findings indicate inconsistencies in molecular clock estimation, which we further explored.

We hypothesize that these inconsistent dating estimates across the tree could be caused by an evolutionary rate acceleration of HIV-1 after entering the Slovenia epidemic that is not taken into account by the molecular clock model. It could be caused by a lower transmission rate in this setting, as demonstrated by the low epidemic growth rate estimated by Bayesian skyline plot analysis.

Conclusions

HIV-1 subtype B was introduced into Slovenia at several time points from the late 80s onward. The majority of patients had a local transmission link, indicating a closed HIV community. The observed slower epidemic rate suggests that individuals with a long-lasting infection are the driving force of the epidemic in this region.

Global Dispersal Pattern of HIV Type 1 Subtype CRF01_AE: A Genetic Trace of Human Mobility Related to Heterosexual Sexual Activities Centralized in Southeast Asia

BACKGROUND

Human immunodeficiency virus type 1 (HIV-1) subtype CRF01_AE originated in Africa and then passed to Thailand, where it established a major epidemic. Despite the global presence of CRF01_AE, little is known about its subsequent dispersal pattern.

METHODS

We assembled a global data set of 2736 CRF01_AE sequences by pooling sequences from public databases and patient-cohort studies. We estimated viral dispersal patterns, using statistical phylogeographic analysis run over bootstrap trees estimated by the maximum likelihood method.

RESULTS

We show that Thailand has been the source of viral dispersal to most areas worldwide, including 17 of 20 sampled countries in Europe. Japan, Singapore, Vietnam, and other Asian countries have played a secondary role in the viral dissemination. In contrast, China and Taiwan have mainly imported strains from neighboring Asian countries, North America, and Africa without any significant viral exportation.

DISCUSSION

The central role of Thailand in the global spread of CRF01_AE can be probably explained by the popularity of Thailand as a vacation destination characterized by sex tourism and by Thai emigration to the Western world. Our study highlights the unique case of CRF01_AE, the only globally distributed non-B clade whose global dispersal did not originate in Africa.

Trends of subtype variation of human immunodeficiency virus type 1 in Zhejiang Province, China

The epidemic characteristics of human immunodeficiency virus type 1 (HIV-1) in Zhejiang Province have not been systematically identified. This study presented a dynamic analysis of HIV-1 subtype variation in Zhejiang from 2004 to 2008, based on the surveillance of molecular epidemiology or drug resistance. CRF01_AE was the major strain (43.5 %) spreading across the province, second by B/B' (17.9 %), CRF07_BC (17.1 %), and CRF08_BC (13.7 %). The strains were mainly transmitted by heterosexual contact. Novel recombinant strains and vertical transmission were occasionally reported. Floating population from other provinces accounted for a significant number of HIV-1 cases in Zhejiang. These data may provide us rational intervention strategy for further control of HIV dissemination.

Cross-border sexual transmission of the newly emerging HIV-1 clade CRF51_01B

A novel HIV-1 recombinant clade (CRF51_01B) was recently identified among men who have sex with men (MSM) in Singapore. As cases of sexually transmitted HIV-1 infection increase concurrently in two socioeconomically intimate countries such as Malaysia and Singapore, cross transmission of HIV-1 between said countries is highly probable. In order to investigate the timeline for the emergence of HIV-1 CRF51_01B in Singapore and its possible introduction into Malaysia, 595 HIV-positive subjects recruited in Kuala Lumpur from 2008 to 2012 were screened. Phylogenetic relationship of 485 amplified polymerase gene sequences was determined through neighbour-joining method. Next, near-full length sequences were amplified for genomic sequences inferred to be CRF51_01B and subjected to further analysis implemented through Bayesian Markov chain Monte Carlo (MCMC) sampling and maximum likelihood methods. Based on the near full length genomes, two isolates formed a phylogenetic cluster with CRF51_01B sequences of Singapore origin, sharing identical recombination structure. Spatial and temporal information from Bayesian MCMC coalescent and maximum likelihood analysis of the protease, gp120 and gp41 genes suggest that Singapore is probably the country of origin of CRF51_01B (as early as in the mid-1990s) and featured a Malaysian who acquired the infection through heterosexual contact as host for its ancestral lineages. CRF51_01B then spread rapidly among the MSM in Singapore and Malaysia. Although the importation of CRF51_01B from Singapore to Malaysia is supported by coalescence analysis, the narrow timeframe of the transmission event indicates a closely linked epidemic. Discrepancies in the estimated divergence times suggest that CRF51_01B may have arisen through multiple recombination events from more than one parental lineage. We report the cross transmission of a novel CRF51_01B lineage between countries that involved different sexual risk groups. Understanding the cross-border transmission of HIV-1 involving sexual networks is crucial for effective intervention strategies in the region.

Identification of a novel HIV-1 second-generation recombinant form (CRF01_AE/CRF07_BC) in Jilin, China

We report here a novel HIV-1 second-generation recombinant form (CRF01_AE/CRF07_BC) isolated from an HIV-positive male subject infected through heterosexual contact in Jilin province in northeastern China. Phylogenic analysis shows that this novel second-generation recombinant (JL.RF09) was composed of two well-established circulating recombinant forms (CRF01_AE and CRF07_BC), with two recombinant breakpoints observed in the vpu/env and env gene regions, respectively. The CRF01_AE region of the recombinant was clustered together with a previously described subcluster 4a lineage of CRF01_AE, which is exclusively circulating among men who have sex with men (MSM) in northern China, indicating that the parental origin of the CRF01_AE region in JL.RF09 was from MSM in north China. The CRF07_BC regions of the recombinant are clustered within the CRF07_BC cluster but are distinct from other CRF07_BC references. The detailed origin of CRF07_BC in this recombinant is still not clear. The emergence of the novel HIV-1 recombinant indicates the ongoing generation of recombinants involving CRF01_AE and CRF07_BC, and may provide vital insights into our understanding of the dynamics and complexity of the HIV-1 epidemic in China.

Phylodynamic analysis reveals CRF01_AE dissemination between Japan and neighboring Asian countries and the role of intravenous drug use in transmission

Background

One major circulating HIV-1 subtype in Southeast Asian countries is CRF01_AE, but little is known about its epidemiology in Japan. We conducted a molecular phylodynamic study of patients newly diagnosed with CRF01_AE from 2003 to 2010.

Methods

Plasma samples from patients registered in Japanese Drug Resistance HIV-1 Surveillance Network were analyzed for protease-reverse transcriptase sequences; all sequences undergo subtyping and phylogenetic analysis using distance-matrix-based, maximum likelihood and Bayesian coalescent Markov Chain Monte Carlo (MCMC) phylogenetic inferences. Transmission clusters were identified using interior branch test and depth-first searches for sub-tree partitions. Times of most recent common ancestor (tMRCAs) of significant clusters were estimated using Bayesian MCMC analysis.

Results

Among 3618 patient registered in our network, 243 were infected with CRF01_AE. The majority of individuals with CRF01_AE were Japanese, predominantly male, and reported heterosexual contact as their risk factor. We found 5 large clusters with ≥5 members and 25 small clusters consisting of pairs of individuals with highly related CRF01_AE strains. The earliest cluster showed a tMRCA of 1996, and consisted of individuals with their known risk as heterosexual contacts. The other four large clusters showed later tMRCAs between 2000 and 2002 with members including intravenous drug users (IVDU) and non-Japanese, but not men who have sex with men (MSM). In contrast, small clusters included a high frequency of individuals reporting MSM risk factors. Phylogenetic analysis also showed that some individuals infected with HIV strains spread in East and South-eastern Asian countries.

Conclusions

Introduction of CRF01_AE viruses into Japan is estimated to have occurred in the 1990s. CFR01_AE spread via heterosexual behavior, then among persons connected with non-Japanese, IVDU, and MSM. Phylogenetic analysis demonstrated that some viral variants are largely restricted to Japan, while others have a broad geographic distribution.

Intercontinental dispersal of HIV-1 subtype B associated with transmission among men who have sex with men in Japan

Transmission clusters of HIV-1 subtype B uniquely associated with the epidemic among men who have sex with men (MSM) in East Asia have recently been identified. Using the Los Alamos HIV sequence database and the UK HIV drug resistance database, we explored possible links between HIV MSM epidemics in East Asia and the rest of the world by using phylogenetic and molecular clock analyses. We found that JP.MSM.B-1, a subtype B MSM variant that accounts for approximately one-third of the infections among Japanese MSM, was detected worldwide, in the United Kingdom (n=13), mainland China (n=3), the United States, Germany, Canada, and Taiwan (n=1 each). Interestingly, 10 United Kingdom samples plus two from Germany and the United States formed a distinct monophyletic subgroup within JP.MSM.B-1. The estimated divergence times of JP.MSM.B-1 and the latter subgroup were ∼1989 and ∼1999, respectively. These dates suggest that JP.MSM.B-1 was circulating for many years in Japan among MSM before disseminating to other countries, most likely through global MSM networks. A significant number of other Asian MSM HIV lineages were also detected in the UK HIV drug resistance database. Our study provides insight into the regional and global dispersal of Asian MSM HIV lineages. Further study of these strains is warranted to elucidate viral migration and the interrelationship of HIV epidemics on a global scale.

IMPORTANCE

We previously identified several transmission clusters of HIV-1 subtype B uniquely associated with the epidemic among men who have sex with men (MSM) in East Asia. Using the Los Alamos HIV sequence database and the UK HIV drug resistance database, we explored the possible interplay of HIV MSM epidemics in the different geographic regions and found previously unrecognized interrelationships among the HIV-1 epidemics in East Asia, the United Kingdom, and the rest of the world. Our study provides insight into the regional and global dispersal of Asian MSM HIV lineages and highlights the importance of strengthening HIV monitoring efforts and the need for implementing effective control measures to reduce HIV transmission on a global scale.

Inference of global HIV-1 sequence patterns and preliminary feature analysis

The epidemiology of HIV-1 varies in different areas of the world, and it is possible that this complexity may leave unique footprints in the viral genome. Thus, we attempted to find significant patterns in global HIV-1 genome sequences. By applying the rule inference algorithm RIPPER (Repeated Incremental Pruning to Produce Error Reduction) to multiple sequence alignments of Env sequences from four classes of compiled datasets, we generated four sets of signature patterns. We found that these patterns were able to distinguish southeastern Asian from nonsoutheastern Asian sequences with 97.5% accuracy, Chinese from non-Chinese sequences with 98.3% accuracy, African from non-African sequences with 88.4% accuracy, and southern African from non-southern African sequences with 91.2% accuracy. These patterns showed different associations with subtypes and with amino acid positions. In addition, some signature patterns were characteristic of the geographic area from which the sample was taken. Amino acid features corresponding to the phylogenetic clustering of HIV-1 sequences were consistent with some of the deduced patterns. Using a combination of patterns inferred from subtypes B, C, and all subtypes chimeric with CRF01_AE worldwide, we found that signature patterns of subtype C were extremely common in some sampled countries (for example, Zambia in southern Africa), which may hint at the origin of this HIV-1 subtype and the need to pay special attention to this area of Africa. Signature patterns of subtype B sequences were associated with different countries. Even more, there are distinct patterns at single position 21 with glycine, leucine and isoleucine corresponding to subtype C, B and all possible recombination forms chimeric with CRF01_AE, which also indicate distinct geographic features. Our method widens the scope of inference of signature from geographic, genetic, and genomic viewpoints. These findings may provide a valuable reference for epidemiological research or vaccine design.

The rapidly expanding CRF01_AE epidemic in China is driven by multiple lineages of HIV-1 viruses introduced in the 1990s

Objectives:

We sought to comprehensively analyze the origin, transmission patterns and sub-epidemic clusters of the HIV-1 CRF01_AE strains in China.

Methods:

Available HIV-1 CRF01_AE samples indentified in national molecular epidemiologic surveys were used to generate near full-length genome (NFLG) sequences. The new and globally available CRF01_AE NFLG sequences were subjected to phylogenetic and Bayesian molecular clock analyses, and combined with epidemiologic data to elucidate the history of CRF01_AE transmission in China.

Results:

We generated 75 new CRF01_AE NFLG sequences from various risk populations covering all major CRF01_AE epidemic regions in China. Seven distinct phylogenetic clusters of CRF01_AE were identified. Clusters 1, 2 and 3 were prevalent among heterosexuals and IDUs in southern and southwestern provinces. Clusters 4 and 5 were found primarily among MSM in major northern cities. Clusters 6 and 7 were only detected among heterosexuals in two southeast and southwest provinces. Molecular clock analysis indicated that all CRF01_AE clusters were introduced from Southeast Asia in the 1990s, coinciding with the peak of Thailand's HIV epidemic and the initiation of China's free overseas travel policy for their citizens, which started with Thailand as the first destination country.

Conclusion:

China's HIV-1 epidemic of sexual transmissions, was initiated by multilineages of CRF01_AE strains, in contrast to the mono-lineage epidemic of B′ strain in former plasma donors and IDUs. Our study underscores the difficulty in controlling HIV-1 sexual transmission compared with parenteral transmission.

How the dynamics and structure of sexual contact networks shape pathogen phylogenies

The characteristics of the host contact network over which a pathogen is transmitted affect both epidemic spread and the projected effectiveness of control strategies. Given the importance of understanding these contact networks, it is unfortunate that they are very difficult to measure directly. This challenge has led to an interest in methods to infer information about host contact networks from pathogen phylogenies, because in shaping a pathogen's opportunities for reproduction, contact networks also shape pathogen evolution. Host networks influence pathogen phylogenies both directly, through governing opportunities for evolution, and indirectly by changing the prevalence and incidence. Here, we aim to separate these two effects by comparing pathogen evolution on different host networks that share similar epidemic trajectories. This approach allows use to examine the direct effects of network structure on pathogen phylogenies, largely controlling for confounding differences arising from population dynamics. We find that networks with more heterogeneous degree distributions yield pathogen phylogenies with more variable cluster numbers, smaller mean cluster sizes, shorter mean branch lengths, and somewhat higher tree imbalance than networks with relatively homogeneous degree distributions. However, in particular for dynamic networks, we find that these direct effects are relatively modest. These findings suggest that the role of the epidemic trajectory, the dynamics of the network and the inherent variability of metrics such as cluster size must each be taken into account when trying to use pathogen phylogenies to understand characteristics about the underlying host contact network.

Molecular evolution of the HIV-1 Thai epidemic between the time of RV144 immunogen selection to the execution of the vaccine efficacy trial

The RV144 HIV-1 vaccine trial (Thailand, 2003 to 2009), using immunogens genetically matched to the regional epidemic, demonstrated the first evidence of efficacy for an HIV-1 vaccine. Here we studied the molecular evolution of the HIV-1 epidemic from the time of immunogen selection to the execution of the efficacy trial. We studied HIV-1 genetic diversity among 390 volunteers who were deferred from enrollment in RV144 due to preexisting HIV-1 infection using a multiregion hybridization assay, full-genome sequencing, and phylogenetic analyses. The subtype distribution was 91.7% CRF01_AE, 3.5% subtype B, 4.3% B/CRF01_AE recombinants, and 0.5% dual infections. CRF01_AE strains were 31% more diverse than the ones from the 1990s Thai epidemic. Sixty-nine percent of subtype B strains clustered with the cosmopolitan Western B strains. Ninety-three percent of B/CRF01_AE recombinants were unique; recombination breakpoint analysis showed that these strains were highly embedded within the larger network that integrates recombinants from East/Southeast Asia. Compared to Thai sequences from the early 1990s, the distance to the RV144 immunogens increased 52% to 68% for CRF01_AE Env immunogens and 12% to 29% for subtype B immunogens. Forty-three percent to 48% of CRF01_AE sequences differed from the sequence of the vaccine insert in Env variable region 2 positions 169 and 181, which were implicated in vaccine sieve effects in RV144. In conclusion, compared to the molecular picture at the early stages of vaccine development, our results show an overall increase in the genetic complexity of viruses in the Thai epidemic and in the distance to vaccine immunogens, which should be considered at the time of the analysis of the trial results.

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.

Emergence in Japan of an HIV-1 variant associated with transmission among men who have sex with men (MSM) in China: first indication of the International Dissemination of the Chinese MSM lineage

A survey of HIV-1 strains circulating in the Tokyo-Kanagawa metropolitan area of Japan during 2004 to 2011 (n = 477) identified six Japanese males (patients 1 to 6), who harbored viruses with genome segments derived from a distinct CRF01_AE variant uniquely found among men who have sex with men (MSM) in China (designated CN.MSM.01-1). These six HIV infections were diagnosed in 2010 and 2011 among MSM (3 of 75) and men with unknown risk factors (3 of 63) and differed from the vast majority of HIV infections among MSM in Japan, which are overwhelmingly characterized by subtype B (239 of 246 [97.2%]). Approximately one-third (91 of 239 [38.1%]) of subtype B strains from MSM in Japan belong to a large monophyletic cluster (designated JP.MSM.B-1). In addition, we identified a smaller subtype B cluster (n = 8) (designated JP.MSM.B-2) that also contains strains from two Chinese MSM living in Japan. Interestingly, patients 5 and 6 were found to be coinfected with CRF01_AE (CN.MSM.01-1) and subtype B (JP.MSM.B-2 or JP.MSM.B-1) variants that are unique to the HIV-1 epidemics among MSM in China and Japan, respectively. Our study demonstrates for the first time the effect of the expanding HIV epidemic among MSM in China on transmission in neighboring countries and shows the ongoing mixing of CRF01_AE and subtype B lineages unique to HIV-1 that cocirculate in MSM populations in East Asia. This finding highlights the importance of strengthening epidemiological surveillance in the region and the need for effective measures to limit transmission among MSM in East Asia.

Phylogenetic and temporal dynamics of human immunodeficiency virus type 1 CRF01_AE in China

To explore the epidemic history of HIV-1 CRF01_AE in China, 408 fragments of gag gene sequences of CRF01_AE sampled in 2002-2010 were determined from different geographical regions and risk populations in China. Phylogenetic analysis indicates that the CRF01_AE sequences can be grouped into four clusters, suggesting that at least four genetically independent CRF01_AE descendants are circulating in China, of which two were closely related to the isolates from Thailand and Vietnam. Cluster 1 has the most extensive distribution in China. In North China, cluster 1 and cluster 4 were mainly transmitted through homosexuality.The real substance of the recent HIV-1 epidemic in men who have sex with men(MSM) of North China is a rapid spread of CRF01_AE, or rather two distinctive natives CRF01_AE.The time of the most recent common ancestor (tMRCA) of four CRF01_AE clusters ranged from the years 1990.9 to 2003.8 in different regions of China. This is the first phylogenetic and temporal dynamics study of HIV-1 CRF01_AE in China.

No increase of drug-resistant HIV type 1 prevalence among drug-naive individuals in Northern Vietnam

We reported previously that the prevalence of drug-resistant HIV-1 among antiretroviral therapy (ART)-naive individuals in Northern Vietnam was 2.9% in 2007 and 6.2% in 2008. To investigate the continuing trend of prevalence, we collected plasma samples from 958 individuals in Hai Phong and Hanoi in 2009, extracted viral RNA from HIV-1 antibody-positive samples, and analyzed them genetically. HIV-1 antibody prevalence was 26.8% in injecting drug users (n=302), 13.4% in female sex workers (n=284), 0.5% in blood donors (n=206), and 0.6% in pregnant women (n=166). All HIV-1 strains were CRF01_AE. Nonnucleoside reverse-transcriptase inhibitor resistance mutations were found in two (2.0%) of the 102 successfully analyzed cases (one case with the Y181C and one with the K101E). No nucleoside reverse-transcriptase inhibitor resistance or protease inhibitor resistance mutations were detected. The prevalence of circulating ART-resistant HIV-1 in Northern Vietnam did not increase from 2007 to 2009, although the rate of ART coverage did increase.

Reconstituting the epidemic history of HIV strain CRF01_AE among men who have sex with men (MSM) in Liaoning, northeastern China: implications for the expanding epidemic among MSM in China

HIV CRF01_AE accounted for 84% of the recent infections among men who have sex with men (MSM) in Liaoning Province of northeastern China. CRF01_AE strains were grouped into two distinct clusters (designated clusters 1 and 2) that were also detected in other regions in China. Phylodynamics study revealed that these two CRF01_AE strains were independently introduced into the population of MSM in China in the early and mid-1990s. Our study elucidated unique features of dynamics and interrelationships of MSM epidemics in China.