High prevalence of HIV-1 intersubtype B'/C recombinants among injecting drug users in Dehong, China

Identification of two novel HIV-1 circulating recombinant forms of CRF111_01C and CRF116_0108 in southwestern Yunnan, China

Yunnan, the region hardest hit by HIV/AIDS in China, is also an area with the most abundant HIV-1 genetic diversity. A large number of novel HIV-1 circulating recombinant forms (CRFs) and unique recombinants were identified among injection drug users in Yunnan; however, few were found among sexual contacts. Here, we obtained 15 near full-length genome sequences (NFLGs) from HIV-1 seropositive heterosexual contacts in Yunnan who received antiretroviral therapy during the period from 2014 to 2016. Phylogenetic analysis showed that six NFLGs belonged to CRF01_AE (n = 3) and CRF106_cpx (n = 3), and the other nine sequences were novel inter-subtype recombinants. Of the recombinants, two novel CRFs (CRF111_01 C (n = 4) and CRF116_0108 (n = 4)) and one CRF106_cpx variant (n = 1) were identified. CRF111_01 C had a CRF01_AE backbone with seven subtype C fragments inserted into the gag, pol, vif, env, nef and 3'LTR regions. CRF116_0108 had a CRF08_BC backbone with a CRF01_AE fragment inserted into the pol, tat, rev, vif, vpr, vpu and env regions. Phylogeographic analyses estimated that CRF111_01 C and CRF116_0108 originated approximately 1995.7-1998.6 and 1991.7-1993.7, respectively. These identifications of two novel HIV-1 CRFs highlighted the importance of continuous surveillance in heterosexual contacts and other high-risk groups in this region and the surrounding regions.

An HFman probe-based reverse transcription loop-mediated isothermal amplification (RT-LAMP) assay for HIV-1 detection

Loop-mediated isothermal amplification (LAMP) is suitable for the development of a rapid and cost-effective nucleic acid technique for point of care (POC) applications. However, LAMP methods often generate non-specific amplification, therefore inevitably resulting in false positive results especially when sequence-independent dyes are used to indirectly reflect the results. In this study, we established and optimized a reverse transcription LAMP (RT-LAMP) assay with a high-fidelity DNA polymerase-mediated fluorescent probe (HFman probe) for human immunodeficiency virus-1 (HIV-1) detection. The assay showed high sensitivity and specificity. Using 101 plasma samples with different HIV-1 viral load, we demonstrated that our assay can detect the major HIV-1 subtypes circulating in China, including CRF01_AE, CRF07_BC, CRF08_BC, CRF55_01B, and unique recombinant forms (URFs). We also compared our assay with an approved commercial real-time quantitative polymerase chain reaction (RT-qPCR) kit and found the sensitivity, specificity and consistency was 88.8%, 100% and 89.1%, respectively. The HFman probe-based RT-LAMP assay is a high specific detection method that is rapid, variant-tolerant and simple to operate, and thus is of great significance for timely disclosure of HIV status and rapid POC diagnosis.

First complete-genome documentation of HIV-1 intersubtype superinfection with transmissions of diverse recombinants over time to five recipients

Human immunodeficiency virus type 1 (HIV-1) recombinants in the world are believed to be generated through recombination between distinct HIV-1 strains among coinfection or superinfection cases. However, direct evidence to support transmission of HIV-1 recombinants from a coinfected/superinfected donor to putative recipient is lacking. Here, we report on the origin and evolutionary relationship between a set of recombinants from a CRF01_AE/CRF07_BC superinfected putative donor and diverse CRF01_AE/CRF07_BC recombinants from five putative recipients. Interviews on sociodemographic characteristics and sexual behaviors for these six HIV-1-infected men who have sex with men showed that they had similar ways of partner seeking: online dating sites and social circles. Phylogenetic and recombination analyses demonstrated that the near-full-length genome sequences from six patients formed a monophyletic cluster different from known HIV-1 genotypes in maximum likelihood phylogenetic trees, were all composed of CRF01_AE and CRF07_BC fragments with two common breakpoints on env, and shared 4-7 breakpoints with each other. Moreover, 3' half-genomes of recombinant strains from five recipients had identical/similar recombinant structures with strains at longitudinal samples from the superinfected donor. Recombinants from the donor were paraphyletic, whereas five recipients were monophyletic or polyphyletic in the maximum clade credibility tree. Bayesian analyses confirmed that the estimated time to the most recent common ancestor (tMRCA) of CRF01_AE and CRF07_BC strains of the donor was 2009.2 and 2010.7, respectively, and all were earlier than the emergence of recombinants from five recipients. Our results demonstrated that the closely related unique recombinant forms of HIV-1 might be the descendent of a series of recombinants generated gradually in a superinfected patient. This finding highlights the importance of early initiation of antiretroviral therapy as well as tracing and testing of partners in patients with multiple HIV-1 infection.

Validation of Variant Assembly Using HAPHPIPE with Next-Generation Sequence Data from Viruses

Next-generation sequencing (NGS) offers a powerful opportunity to identify low-abundance, intra-host viral sequence variants, yet the focus of many bioinformatic tools on consensus sequence construction has precluded a thorough analysis of intra-host diversity. To take full advantage of the resolution of NGS data, we developed HAplotype PHylodynamics PIPEline (HAPHPIPE), an open-source tool for the de novo and reference-based assembly of viral NGS data, with both consensus sequence assembly and a focus on the quantification of intra-host variation through haplotype reconstruction. We validate and compare the consensus sequence assembly methods of HAPHPIPE to those of two alternative software packages, HyDRA and Geneious, using simulated HIV and empirical HIV, HCV, and SARS-CoV-2 datasets. Our validation methods included read mapping, genetic distance, and genetic diversity metrics. In simulated NGS data, HAPHPIPE generated pol consensus sequences significantly closer to the true consensus sequence than those produced by HyDRA and Geneious and performed comparably to Geneious for HIV gp120 sequences. Furthermore, using empirical data from multiple viruses, we demonstrate that HAPHPIPE can analyze larger sequence datasets due to its greater computational speed. Therefore, we contend that HAPHPIPE provides a more user-friendly platform for users with and without bioinformatics experience to implement current best practices for viral NGS assembly than other currently available options.

Prevalence of HIV-1 Drug-Resistance Genotypes Among Unique Recombinant Forms from Yunnan Province, China in 2016-2017

To investigate the prevalence and characteristics of drug-resistance genotypes among unique recombinant forms (URFs) in HIV-1 infected people under long-term antiretroviral treatment failure from Yunnan Province. The plasma samples were collected from antiretroviral therapy (ART)-failure experienced individuals from 2016 to 2017 in Yunnan Province, China. The genotyping drug resistance of HIV-1 pol gene fragments was implemented using in-house assay. According to the analysis of RIP and MEGA 7.0, the HIV-1 strains related to URFs were screened for recombinant identification and drug resistance analysis. A total of 130 pol sequences of HIV-1 URF strains were obtained from 1,121 samples. The proportion of HIV-1 URF strains was 11.6% among the ART-failure individuals from 2016 to 2017 in Yunnan. The overall drug-resistance rate of HIV-1 URF strains was 56.9%. Meanwhile, the percentage of protease inhibitors, nucleoside reverse transcriptase inhibitors (NRTIs), and non-nucleoside reverse transcriptase inhibitors (NNRTIs) resistance was 3.8% (5/130), 36.2% (47/130), and 53.8% (70/130), respectively. Mutations such as M184V/I (35.4%) in NRTIs and K103N/R/S/T (25.4%), V179D/E/T/Y (18.9%), G190A/E/R/S (13.8%), and Y181C (9.2%) in NNRTIs were common among the HIV-1 URF strains relative to other mutations. Factors such as male, sexual transmission pathway, and source of the year 2017 were significantly correlated with the development of HIV-1 URF drug resistance. The emergence of the multiple recombinant forms identified in Yunnan indicates active transmission networks of HIV-1 of different HIV-1 subtype/circulating recombinant forms cross-infection in this region. Therefore, it is necessary to further monitor the molecular epidemiology and drug resistance of HIV-1 in Yunnan.

Identification of Three HIV-1 Unique (B/C) Recombinant Forms in Shaanxi, China

HIV-1 intersubtype B/C recombinants were more commonplace reported in high-risk populations in Yunnan province, China. In this study, three unique (B/C) recombinant isolates (2015YL02, 2018YL07, and SN18015) were identified from patients infected with HIV-1 through sexual transmission in Shaanxi province. Phylogenetic and bootscan analyses showed that three recombinants comprised HIV-1 subtype B and subtype C. The recombinant structures revealed that the near full-length sequence of 2015YL02 shared an identical mosaic structure with XC2014EU20, which was isolated from Sichuan province. And two similar breakpoints were observed between 2018YL07 and CRF08_BC in pol gene. The arising B/C recombinant forms enrich evidence of the HIV-1 genetic diversity among sexually transmitted populations and suggest that continuously monitoring HIV-1 molecular epidemiology is needed in Shaanxi province.

Rapid CD4+ T-cell decline is associated with coreceptor switch among MSM primarily infected with HIV-1 CRF01_AE in Northeast China

OBJECTIVE

CRF01_AE is the most prevalent HIV-1 subtype among MSM in China. However, the characteristics and underlying mechanism of the accelerated CD4 T-cell decline in CRF01_AE-infected MSM remain incompletely understood.

DESIGN

A long-term prospective follow-up study was conducted with 1388 MSM at risk of HIV-1 infection in Northeast China. MSM with primary HIV-1 CRF01_AE infection were identified and followed for 3-6 years to explore the determinants of rapid CD4 T-cell decline.

METHODS

Tropism was determined in primary infection by both single genome amplification-based genotypic prediction using four different algorithms and phenotypic determination using clinical isolates. Serial isolates were used to determine phenotype of coreceptor switch. Human leukocyte antigen genotypes and T-cell activation markers were determined.

RESULTS

Fifty-nine MSM primarily infected with HIV-1 CRF01_AE were discovered and recruited for the follow-up study. CCR5-utilizing (R5) viruses accounted for up to 98% of HIV-1 CRF01_AE infections in Northeast China. Survival analysis indicated 39.5% of the patients underwent coreceptor switch within 3 years after infection. After adjustment for other potential risk factors, linear mixed-effect models demonstrated patients experienced R5 to CXCR4-utilizing/dual-tropic (X4/DM) coreceptor switch within 3 years after infection underwent a faster CD4 T-cell decline compared to those without coreceptor switch.

CONCLUSIONS

Primary HIV-1 CRF01_AE infection among MSM in Northeast China is characterized by R5 viral infection and early R5 to X4/DM coreceptor switch, which is associated with rapid CD4 T-cell decline. The findings highlight the importance of immediate treatment among the CRF01_AE-infected MSM.

Burmese injecting drug users in Yunnan play a pivotal role in the cross-border transmission of HIV-1 in the China-Myanmar border region

Injecting drug users (IDUs) are the major risk group for HIV-1 infection in the China-Myanmar border area. There are a large number of Burmese IDUs living in Yunnan (Yunnan-mIDUs) who might be associated with the cross-border transmission of HIV-1. From 2010 to 2013, 617 Yunnan-mIDUs were recruited from three counties of Yunnan, 19.0% of whom were detected to be HIV-1 positive by serological testing. Partial HIV-1 p17, pol, vif-env, and env genes were amplified from the positive samples and were sequenced. Phylogenetic and HIV-1 subtyping analyses revealed that HIV-1 recombinant forms (RFs), including RF_BC (36.4%), RF_01BC (26.1%), RF_01C (9.1%) and RF_01B (1.1%), were predominant among this cohort. Of the identified HIV-1 strains, 14.8%, 9.1% and 3.4% belonged to subtype C, CRF01_AE and subtype B, respectively. Transmission cluster analysis showed that sequences from the Yunnan-mIDUs formed transmission clusters not only with those from Burmese IDUs but also with those from Chinese IDUs, indicating that Yunnan-mIDUs might acquire HIV-1 infection from or spread HIV-1 to both Burmese and Chinese IDUs. Phylogeographic analyses revealed three cross-border transmission patterns associated with Yunnan-mIDUs, in which Yunnan-mIDUs served as the crucial nodes linking the Burmese and Chinese IDUs. These results suggest that Yunnan-mIDUs are a potential viral reservoir for the diffusion of HIV-1 in Yunnan and play a pivotal role in the bidirectional cross-border transmission of HIV-1 in the China-Myanmar border region. More intervention efforts that focus on Yunnan-mIDUs are recommended in Yunnan’s campaign against HIV/AIDS.

Identification of Two New HIV-1 Circulating Recombinant Forms (CRF87_cpx and CRF88_BC) from Reported Unique Recombinant Forms in Asia

The on-going generation of HIV-1 intersubtype recombination has led to new circulating recombinant forms (CRFs) and unique recombinant forms (URFs) in Asia. In this study, we evaluated whether previously reported URFs were actually CRFs. All available complete or near full-length HIV-1 URF sequences from Asia were retrieved from the HIV Los Alamos National Laboratory Sequence database, and phylogenetic, transmission cluster, and bootscan analyses were performed using MEGA 6.0, Cluster Picker 1.2.1, and SimPlot3.5.1. According to the criterion of new CRFs, two new HIV-1 CRFs (CRF87_cpx and CRF88_BC) were identified from these available URFs. CRF87_cpx comprised HIV-1 subtypes B, C, and CRF01_AE, and CRF88_BC comprised subtypes B and C. HIV Blast and bootscan analysis revealed that besides the three representative strains, there were two additional CRF87_cpx strains. Furthermore, we defined seven dominant URFs (dURF01-dURF07), each of which contained two strains sharing same recombination map and can be used as sequence references to facilitate the finding of new potential CRFs in future. These results will benefit the molecular epidemiological investigation of HIV-1 in Asia.

Phylogenetic characteristics of HIV-1 among travelers entering China from Myanmar: A retrospective study

Due to the open policy of the Chinese government, a large number of Burmese individuals enter China at land ports in Yunnan province for travel or business. However, the situation of HIV-1 infection and its phylogenetic characteristics among these travelers remains unclear, which is a potential threat to public health. From January 2003 to December 2012, a total of 1,961 travelers were detected to be positive for HIV-1 infection at land ports between Myanmar and Yunnan province, China. From 1153 (58.8%) Burmese of them, we randomly collected 489 serum samples for HIV-1 subtype/recombinant analysis. Based on successfully obtained 223 gag-RT sequences, 187 of them were genotyped as 2 subtypes and 3 CRFs. CRF01_AE was showed to be the most prevalent genotype (54.3%), followed by subtypes C (13.5%) and B (10.8%). Notably, CRF07_BC (1.3%) and CRF08_BC (4.0%) were mainly distributed in travelers from Shan state and Kachin (91.7%, 11/12), but was not found in travelers from the capital city of Yangon (0/16). Additionally, there were 36 samples (16.1%) were preliminary determined as unique recombinant forms (URFs). The higher HIV-1 infection among entering travelers from Myanmar and its diverse and complex genotypes distribution suggest this bridge population may facilitate the transmission of HIV-1. It is necessary to have the strict monitoring on this population for prevention of HIV-1 cross-border transmission.

Identification of a Novel HIV Type 1 Circulating Recombinant Form (CRF86_BC) Among Heterosexuals in Yunnan, China

In recent years, multiple circulating recombinant forms (CRFs) and unique recombinant forms of human immunodeficiency virus type 1 (HIV-1) have been described in Yunnan, China. Here, we identified a novel HIV-1 CRF (CRF86_BC) isolated from three heterosexuals with no obvious epidemiologic linkage in western Yunnan (Baoshan prefecture) in China. CRF86_BC had a subtype C backbone with four subtype B fragments inserted into the pol, vpr, vpu, env, and nef gene regions, respectively. Furthermore, subregion tree analysis revealed that subtype C backbone originated from an Indian C lineage and subtype B segment inserted was from a Thai B lineage. They are different from previously documented B/C forms in its distinct backbone, inserted fragment size, and break points. This highlighted the importance of continual monitoring of genetic diversity and complexity of HIV-1 strains in this region.

First Appearance of HIV-1 CRF07_BC and CRF08_BC Outside China

Neither full length genomic sequence of CRF07_BC nor that of CRF08_BC was found in any other countries since they originated in Yunnan, China, in early 1990s. Here, we first report that CRF07_BC and CRF08_BC appeared among intravenous drug users in Shan state of Myanmar bordering Yunnan, and confirmed that they spread from China to Myanmar. The introduction of CRF07_BC and CRF08_BC in northern Myanmar may forebode a changing subtype epidemic in Southeast Asia.

Molecular epidemiology of HIV-1 among the HIV infected people of Manipur, Northeastern India: Emergence of unique recombinant forms

According to the Joint National Programme on HIV/AIDS (UNAIDS), the northeastern region of India has the highest HIV prevalence in the country. This study was conducted to determine the current HIV-1 molecular epidemiology of Manipur, a state in northeast India. Blood samples from HIV-1 seropositive subjects were collected between June 2011 and February 2014. The partial regions of HIV-1 genes; pol and tat-vpu-env were independently amplified, sequenced, analyzed, and genotyped. Based on all sequences generated from 110 samples using pol and/or tat-vpu-env gene, the overall HIV-1 genotypes distribution of Manipur was as follows: 65.45% (72/110) subtype C, 32.73% (36/110) unique recombinant forms (URFs), and 1.82% (2/110) subtype B. The distribution of HIV-1 genotypes among the risk groups was: heterosexual: 58.33% (35/60) subtype C, 38.33% (23/60) URFs, and 3.34% (2/60) subtype B; intravenous drug users (IDUs): 85.36% (35/41) subtype C, 9.76% (4/41) URFs, and 4.88% (2/41) subtype B; mother to child (MTC): 50% (3/6) URFs and 50% (3/6) subtype C and blood transfusion: 100% (3/3) subtype C. The findings for the first time revealed the emergence of URFs of HIV-1 in Manipur which is predominant among the sexual and MTC risk groups as compared to IDUs. Taking together, this study illustrated that Manipur is the "recombinant hotspot of HIV" of India. The results will provide the clinical importance for continuous monitoring of HIV-infections in order to design appropriate prevention measures to limit the spread of new HIV infections.

HCV Diversity among Chinese and Burmese IDUs in Dehong, Yunnan, China

HCV transmission is closely associated with drug-trafficking routes in China. Dehong, a prefecture of Yunnan, is the important trade transfer station linking Southeast Asia and China, as well as the drug-trafficking channel linking “Golden triangle” and other regions of China and surrounding countries. In this study, we investigated the HCV genotype diversity among IDUs in Dehong based on 259 HCV positive samples from 118 Chinese and 141 Burmese IDUs. HCV genotypes were determined based on the phylogenies of C/E2 and NS5B genomic sequences. Six HCV subtypes, including 1a, 1b, 3a, 3b, 6n and 6u, were detected. Interestingly, 4 HCV sequences from Burmese IDUs did not cluster with any known HCV subtypes, but formed a well-supported independent clade in the phylogenetic trees of both C/E2 and NS5B, suggesting a potential new HCV subtype circulating in Dehong. Subtype 3b was the predominant subtype, followed by subtypes 6n and 6u. Comparison showed that Dehong had a unique pattern of HCV subtype distribution, obviously different from other regions of China. In particular, HCV subtypes 6u and the potential new HCV subtype had a relatively high prevalence in Dehong, but were rarely detected in other regions of China. There was no significant difference in HCV subtype distribution between Burmese and Chinese IDUs. Few HCV sequences from Burmese and Chinese IDUs clustered together to form transmission clusters. Furthermore, about half of HCV sequences from Burmese IDUs formed small transmission clusters, significantly higher than that from Chinese IDUs (p<0.01). These suggest that the Chinese and Burmese IDUs were relatively isolated from each other in injection drug use behavior and the Burmese IDUs might prefer to inject drugs themselves together. The unique genotype distribution and complex diversity of genotype 6 among IDUs may be associated with the special geographical position of Dehong.

Extensive Genetic Diversity of HIV-1 in Incident and Prevalent Infections among Malaysian Blood Donors: Multiple Introductions of HIV-1 Genotypes from Highly Prevalent Countries

Transfusion-transmissible infections including HIV-1 continue to pose major risks for unsafe blood transfusions due to both window phase infections and divergent viruses that may not be detected by donor screening assays. Given the recent emergence of several HIV-1 circulating recombinant forms (CRFs) in high-risk populations in the Southeast Asia region, we investigated the genetic diversity of HIV-1 among the blood donors in Kuala Lumpur, Malaysia. A total of 211 HIV-positive plasma samples detected among 730,188 donations to the National Blood Centre between 2013 and 2014 were provided (90.5% male, median age: 27.0 years old). Recent or long-term infection status at the time of donation was determined using a limiting antigen avidity enzyme immunoassay (LAg-Avidity EIA). HIV-1 gag-pol genes were amplified and sequenced from residual plasma for 149 cases followed by genotype determination using phylogenetic and recombination analyses. Transmitted antiretroviral resistance mutations were not observed among the blood donors, among which 22.7% were classified as recent or incident infections. Major circulating HIV-1 genotypes determined by neighbour-joining phylogenetic inference included CRF01_AE at 40.9% (61/149), CRF33_01B at 21.5% (32/149), and subtype B at 10.1% (15/149). Newly-described CRFs including CRF54_01B circulated at 4.0%, CRF74_01B at 2.0%, and CRF53_01B and CRF48_01B at 0.7% each. Interestingly, unique HIV-1 genotypes including African subtype G (8.7%), CRF45_cpx (1.3%), CRF02_AG (0.7%) and CRF07_BC (0.7%) from China were detected for the first time in the country. A cluster of subtype G sequences formed a distinct founder sub-lineage within the African strains. In addition, 8.7% (13/149) of HIV-infected donors had unique recombinant forms (URFs) including CRF01_AE/B' (4.7%), B'/C (2.7%) and B'/G (1.3%) recombinants. Detailed analysis identified similar recombinant structures with shared parental strains among the B'/C and B'/G URFs, some of which were sequenced from recently infected individuals, indicating the possible emergence and on-going spread of foreign clades of CRF candidates among the local population. The findings demonstrate extensive molecular complexity of HIV-1 among the infected blood donors in Malaysia, driven in part by the increased spread of recently described CRFs and multiple introductions of previously unreported genotypes from highly prevalent countries.

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.

Genomic Characterization of a Novel HIV-1 Second-Generation Recombinant Form Originated from CRF01_AE and CRF08_BC in Dali Prefecture of Yunnan Province, China

Yunnan seems to be a "hot spot" region of HIV-1 recombination. CRF01_AE and subtype CRF08_BC are two main HIV-1 clades circulating in Yunnan. We report here a novel HIV-1 second-generation recombinant form originated from CRF01_AE and CRF08_BC. The strain (12YN10551) was isolated from a HIV-positive male infected through heterosexual contact in Dali prefecture of Yunnan province, China. This is the first report of HIV-1 near full-length genomic sequence in Dali. Recombinant analysis shows that 12YN10551 was composed of two well-established circulating recombinant forms (CRF01_AE and CRF08_BC). Two CRF01_AE recombinant fragments were inserted into the CRF08_BC backbone genome in the pol/vif/vpr/tat/rev and nef gene regions, respectively. The discovery and characterization of this new recombinant indicate that intersubtype recombination is continuously generating new forms of HIV-1. More work is needed to better monitor the genetic diversity of HIV-1 in this region.

HIV-1 subtype B: Traces of a pandemic

Human migration is a major process that shaped the origin and dissemination of HIV. Within HIV-1, subtype B (HIV-1B) is the most disseminated variant and it is assumed to be the causative agent in approximately 11% of all cases of HIV worldwide. Phylogenetic studies have revealed that HIV-1B emerged in Kinshasa (Africa) and was introduced into the Caribbean region via Haiti in or around 1966 by human migration. After localized dispersion, the virus was brought to the United States of America via homosexual/bisexual contact around 1969. Inside USA, the incidence of HIV-1B infection increased exponentially and it became established in the population, affecting not only homosexual individuals but also heterosexual individuals and injecting drug users. Soon after, the virus was disseminated and became established in other regions, including Europe, Asia, Latin America, and Australia. Recent studies suggest that, in addition to this pandemic clade, several lineages have emerged from Haiti and reached other Caribbean and Latin American countries via short-distance dissemination. Different subtype B genetic variants have also been detected in these epidemics. Four genetic variants have been described to date: subtype B', which mainly circulates in Thailand and other Asian countries; a specific variant mainly found in Trinidad and Tobago; the GPGS variant, which is primarily detected in Korea; and the GWGR variant, which is mainly detected in Brazil. This paper reviews the evolution of HIV-1B and its impact on the human population.

The Genomic Signature of Population Reconnection Following Isolation: From Theory to HIV

Ease of worldwide travel provides increased opportunities for organisms not only to colonize new environments but also to encounter related but diverged populations. Such events of reconnection and secondary contact of previously isolated populations are widely observed at different time scales. For example, during the quaternary glaciation, sea water level fluctuations caused temporal isolation of populations, often to be followed by secondary contact. At shorter time scales, population isolation and reconnection of viruses are commonly observed, and such events are often associated with epidemics and pandemics. Here, using coalescent theory and simulations, we describe the temporal impact of population reconnection after isolation on nucleotide differences and the site frequency spectrum, as well as common summary statistics of DNA variation. We identify robust genomic signatures of population reconnection after isolation. We utilize our development to infer the recent evolutionary history of human immunodeficiency virus 1 (HIV-1) in Asia and South America, successfully retrieving the successive HIV subtype colonization events in these regions. Our analysis reveals that divergent HIV-1 subtype populations are currently admixing in these regions, suggesting that HIV-1 may be undergoing a process of homogenization, contrary to popular belief.

Near Full-Length Identification of a Novel HIV-1 CRF01_AE/B/C Recombinant in Northern Myanmar

The Myanmar-China border appears to be the "hot spot" region for the occurrence of HIV-1 recombination. The majority of the previous analyses of HIV-1 recombination were based on partial genomic sequences, which obviously cannot reflect the reality of the genetic diversity of HIV-1 in this area well. Here, we present a near full-length characterization of a novel HIV-1 CRF01_AE/B/C recombinant isolated from a long-distance truck driver in Northern Myanmar. It is the first description of a near full-length genomic sequence in Myanmar since 2003, and might be one of the most complicated HIV-1 chimeras ever detected in Myanmar, containing four CRF01_AE, six B segments, and five C segments separated by 14 breakpoints throughout its genome. The discovery and characterization of this new CRF01_AE/B/C recombinant indicate that intersubtype recombination is ongoing in Myanmar, continuously generating new forms of HIV-1. More work based on near full-length sequence analyses is urgently needed to better understand the genetic diversity of HIV-1 in these regions.

Genetic Diversity and Drug Resistance Among Antiretroviral Treatment-Failed Individuals from 2010 to 2012 in Honghe, China

The most common antiretroviral treatment (ART) received by individuals infected with HIV-1 in China is the combination therapy, comprised of nucleoside reverse transcriptase inhibitors (NRTIs) and nonnucleoside reverse transcriptase inhibitors (NNRTIs). To assess the prevalence of HIV-1 drug resistance and subtypes in Honghe of Yunnan, China, patient plasmas from ART-failed individuals were collected from January 2010 to December 2012. Genotyping was conducted using an in-house assay on patient plasmas. A total of 254 pol sequences were obtained. The prevalence of drug resistance was 47.2% in ART-failed individuals. Of these drug-resistant individuals, 51.7% harbored HIV strains dually resistant to NRTIs and NNRTIs or protease inhibitors (PIs) (34.2% for NNRTIs and 14.2% for NRTIs). Mutations such as M184V, A62V, T69Ins, K103N, Y181C, and G190A were common among the ART-failed individuals. The frequencies of M184V, A62V, and K103N were 20.5%, 11.0%, and 23.6%, respectively. The most common subtypes in Honghe were CRF08_BC (68.50%) and CRF07_BC (12.20%). The subtypes were almost consistent in different time points for one individual. When receiving ART for 6-12 months, the frequency of HIV-1 drug-resistant variants ranked first. This study shows that the high prevalence of HIV drug resistance observed among the ART-failed individuals should be of increasing concern (monitoring of resistance mutations) in ART regions and facilitate developing novel strategies for prevention and control of HIV infection in China.

The sexually driven epidemic in youths in China's southwestern border region was caused by dynamic emerging multiple recombinant HIV-1 strains

Dehong prefecture, Yunnan province on China’s southwestern border was the gateway of the country’s AIDS epidemic. Studies on HIV-1 molecular epidemiology will provide key information on virus transmission dynamics and help to inform HIV prevention strategies. HIV-1 infected youths (age 16–25 years) diagnosed in the continuous 3 months in 2009 to 2012 were enrolled. By means of phylogenetic and statistical analyses, It was showed that two thirds (133/205) of youths in Dehong, of which 74.1% were infected sexually, were infected by uncharacterized recombinant HIV-1 strains. Among them about 59.4% (79/131) were unique recombinant forms (URFs) and 40.6% (54/131) formed 11 transmission clusters, termed potential circulating recombinant forms (pCRFs). The emergence of recombinants was statistically significant related with people of low education, residents outside the capital city of Dehong and being Myanmar residents. It was the first report with ongoing HIV-1 recombinant strains in a sexually driven epidemic area in China. Great efforts should be put on reducing multiple risk exposures behavior in local young people, containing the spread of pCRFs to other regions, and preventing the URFs from evolving into future CRFs. Collaborative prevention across border is needed to better control the local AIDS epidemic.

Diverse forms of HIV-1 among Burmese long-distance truck drivers imply their contribution to HIV-1 cross-border transmission

BACKGROUND

The China-Myanmar border is a particularly interesting region that has very high prevalence of and considerable diversity of HIV-1 recombinants. Due to the transient nature of their work, long-distance truck drivers (LDTDs) have a comparatively high potential to become infected with HIV-1 and further spread virus to other individuals in the area they travel within. In this study, we hypothesized that Burmese LDTDs crossing the China-Myanmar border frequently may potentially be involved in the cross-border transmission of HIV, and contribute to the extremely high prevalence of HIV-1 inter-subtype recombinants in this border region.

METHODS

A molecular epidemiology study was conducted among 105 Burmese LDTDs between 2008 and 2010. HIV-1 genetic fragments including p17, pol, vif-vpr, vpr-env, and C2V3 were amplified and sequenced. The subtype characterization and HIV-1 transmission were determined by both phylogenetic and phylogeographic analyses.

RESULTS

Diverse forms of HIV-1, including subtypes CRF01_AE (41.9%), C (8.6%), B (4.8%), CRF02_AG (1.0%), and inter-subtype recombinants (33.3%), as well as dual infection (10.5%), were detected among the tested LDTDs. Phylogeographic analyses based on pure subtype revealed that 77.8% Burmese LDTDs acquired HIV-1 infection in Yunnan, and the others in Myanmar. Both the C-related and CRF01_AE-related recombinants from these LDTDs appeared to have close genetic relationship with those from IDUs in Myanmar and Dehong.

CONCLUSIONS

Burmese LDTDs may contribute to HIV-1 transmission along the China-Myanmar border. The results may provide some new perspective for understanding the on-going generation and prevalence of HIV-1 recombinants in the border region.

Near full-length genome identification of a novel HIV-1 recombinant form (CRF01_AE/B'/C) among heterosexuals in Jilin, China

Recombinant forms contribute significantly to the genetic diversity of HIV-1. Here we report a novel HIV-1 recombinant form (CRF01_AE/B'/C) detected from a comprehensive HIV-1 molecular epidemiologic study among heterosexuals in Jilin province of northeastern China. Recombinant analyses of the near full-length genome (NFLG) of the novel HIV-1 recombinant isolate (JL.RF01) showed that the backbone of the genome was CRF01_AE, and three insertions of subtype B' (242, 370, and 233 bp) and C (1142, 230, and 271 bp), respectively, were inserted along the genome. Phylogenetic analyses revealed that the novel HIV-1 recombinant form (CRF01_AE/B'/C) more likely originated from Thailand subtype B' and CRF01_AE and India subtype C. We report a unique mosaic structure that is distinct to HIV-1 CRF01_AE/B'/C recombinant viruses reported to date. The emergence of this novel recombinant form (CRF01_AE/B'/C) suggests the increasing significance of heterosexual transmission contributing to the complexity of the HIV-1 epidemic in northeastern China.