Recombinant Forms Of HIV-1 Research Articles

Human Immunodeficiency Virus Type-1 Genetic Diversity and Drugs Resistance Mutations among People Living with HIV in Karachi, Pakistan.

The human immunodeficiency virus type-1 epidemic in Pakistan has significantly increased over the last two decades. In Karachi, Pakistan, there is a lack of updated information on the complexity of HIV-1 genetic diversity and the burden of drug resistance mutations (DRMs) that can contribute to ART failure and poor treatment outcomes. This study aimed to determine HIV-1 genetic diversity and identify drug-resistance mutations among people living with HIV in Karachi. A total of 364 HIV-positive individuals, with a median age of 36 years, were enrolled in the study. The HIV-1 partial pol gene was successfully sequenced from 268 individuals. The sequences were used to generate phylogenetic trees to determine clade diversity and also to assess the burden of DRMs. Based on the partial pol sequences, 13 distinct HIV-1 subtypes and recombinant forms were identified. Subtype A1 was the most common clade (40%), followed by CRF02_AG (33.2%). Acquired DRMs were found in 30.6% of the ART-experienced patients, of whom 70.7%, 20.7%, and 8.5% were associated with resistance to NNRTIs, NRTIs, and PIs, respectively. Transmitted DRMs were found in 5.6% of the ART-naïve patients, of whom 93% were associated with resistance against NNRTIs and 7% to PIs. The high prevalence of DRMs in ART-experienced patients poses significant challenges to the long-term benefits and sustainability of the ART program. This study emphasizes the importance of continuous HIV molecular epidemiology and drug resistance surveillance to support evidence-based HIV prevention, precise ART, and targeted AIDS care.

Three Novel CRF01_AE/CRF07_BC Recombinant Forms of HIV-1 Identified in Shijiazhuang City, China.

Hebei, a province with a low Human Immunodeficiency Virus (HIV) prevalence, is also a region with the most abundant HIV-1 genetic diversity. HIV-1 recombinant forms have been the key factor influencing the effectiveness of HIV-1 control and therapy. We aimed to study inter-subtype recombinant structures of new HIV-1-second generation recombinant forms. Monitoring the HIV-1 subtype by phylogenetic and recombinant breakpoint analyses are the two most frequent methods among men who have sex with men (MSM). Here, three near full-length genomes (NFLGs) were obtained from HIV-1 seropositive MSM in Shijiazhuang City, China, who have never received antiretroviral therapy in 2021. Phylogenetic analysis indicated that three NFLGs were novel inter-subtype recombinant forms between CRF07_BC and CRF01_AE. For the NFLG 21S009, four CRF07_BC gene fragments were inserted into the pol, vif-vpr, vpu-env, and nef-3` LTR gene regions within a CRF01_ AE backbone, respectively. For the NFLG 21S095, four breakpoints were identified in HIV-1 pol and vpu regions. The NFLG 21S370 contained four gene recombinant breakpoints within HIV-1 pol and vpu-env gene regions. Of these three NFLGs, the NFLG 21S009 contained the most breakpoints, distributed in the pol, vif, vpr, vpu, env, and nef regions, respectively. In the gag-pol regions, three NFLGs had only one CRF07_BC gene fragment inserted into gene points between 4250 and 4792. Our findings provide strong evidence that the surveillance of novel recombinant forms is necessary for the increase in better control of HIV.

Genetic diversity of HIV-1 at the current stage of the epidemic in the Russian Federation: an increase in the prevalence of recombinant forms

The aim of the study: assessment of genetic diversity and prevalence of recombinant forms of HIV-1 at the current stage of the epidemic in the Russian Federation.Materials and methods. The study used collections of blood and its components obtained from 3178 HIV-infected patients of federal and regional «Centers for the Prevention and Control of AIDS» in the period from 2011 to 2020. Next, the extraction of proviral DNA or HIV-1 viral RNA was carried out, followed by amplification of the pol gene region and sequencing of the ampli fication products. Then, the obtained nucleotide sequences were analyzed to determine their subtype and the prevalence of recombinant forms of the virus was estimated.Results and discussion. It was found that sub-subtype A6 remains the dominant (82.9%) genetic variant of HIV-1 at the current stage of the epidemic in the Russian Federation. The second most common was subtype B — 7.14%. The share of each of the recombinant forms of HIV-1 — CRF02_AG and CRF03_AB accounted for about 1% of all analyzed samples, CRF63_02A6 — about 3.59%. In addition to circulating recombinant forms of HIV-1, 87 unique recombinants (2.74%) were identified. A significant (p<0.001) increase in the frequency of occurrence of HIV-1 recombinant forms of over time was revealed. The largest proportion of recombinant forms of HIV-1 was detected in the Siberian (35.83%) and Northwestern (15.98%) federal districts, the smallest — in the Volga (1.99%) and Ural (2.36%) federal districts.Conclusion. The results obtained indicate the growing genetic diversity of HIV-1 in the Russian Federation, along with the spread of HIV infection beyond vulnerable groups, as well as an increase in the frequency of occurrence of recombinant forms of HIV-1 over time and their involvement in the epidemic process.

Genome mosaic structure of two novel HIV-1 recombinant forms (CRF01_AE/B) in men who have sex with men in Hebei, China

BackgroundHomosexual contact is the main route of human immunodeficiency virus type one (HIV-1) transmission in Cangzhou Prefecture, Hebei, China. Moreover, the number of circulating recombinant forms (CRFs) and unique recombinant forms (URFs) in this key population is ever increasing.MethodsIn this study, we identified two novel URFs (hcz0017 and hcz0045) from two men who have sex with men (MSM) based in Cangzhou Prefecture. Phylogenetic and recombinant breakpoint analyses, based on the near full-length genomes (NFLGs) of the two novel URFs, showed that they originated from a recombination between HIV-1 CRF01_AE and subtype B.ResultsHXB2 numbering revealed that the NFLGs of hcz0017 and hcz0045 each contained the following seven subregions: hcz0017: IB (790–1,171 nt), IICRF01_AE (1,172–2,022 nt), IIIB (2,023–4,469 nt), IVCRF01_AE (4,470–5,866 nt), VB (5,867–7,462 nt), VICRF01_AE (7,463–8,379 nt), VIIB (8,380–9,411 nt); hcz0045: ICRF01_AE (790–5,147 nt), IIB (5,148–5,614 nt), IIICRF01_AE (5,615–6,035 nt), IVB (6,036–6,241 nt), VCRF01_AE (6,242–7,325nt), VIB (7,326–8,254 nt), VIICRF01_AE (8,255–9,411 nt). Moreover, the two MSM from whom the novel URFs originated from were diagnosed as recently HIV-1-infected, suggesting that the high prevalence of HIV-1 among MSM was related to high-risk sexual activity such as unprotected anal sex and multiple sexual partners.ConclusionsOur results highlight the need to continually monitor HIV-1 diversity in Hebei and its neighboring provinces to achieve a more effective control of HIV-1 spread within the MSM community.

Prevalence of Transmitted Drug Resistance among HIV-1 Patients in the Aegean Region: Results from the Western part of Turkey.

This study aimed to analyze the antiretroviral drug resistance in antiretroviral treatment-naïve HIV-positive patients in the Aegean Region of Turkey from 2012 to 2019. The study included 814 plasma samples from treatment-naïve HIV-positive patients. Drug resistance analysis was performed by Sanger sequencing (SS) between 2012-2017 and by next-generation sequencing sequencing (NGS) between 2018-2019. SS was used to analyze resistance mutations in the protease (PR) and reverse transcriptase (RT) gene regions using a ViroSeq HIV-1 Genotyping System. PCR products were analyzed with an ABI3500 GeneticAnalyzer (Applied Biosystems). The sequencing of the HIV genome in the PR, RT, and integrase gene regions was carried out using MiSeq NGS technology. Drug resistance mutations and subtypes were interpreted using the Stanford University HIV-1 drug resistance database. Transmitted drug resistance (TDR) mutation was detected in 34/814 ( 4.1 %) samples. Non-nucleoside reverse transcriptase inhibitor (NNRTI), nucleoside reverse transcriptase inhibitor (NRTI), and protease inhibitor (PI) mutations were identified in 1.4 % (n =12), 2.4 % (n =20), and 0.3 % (n = 3) of samples, respectively. The most common subtypes were B (53.1 % ), A (10.9%), CRF29_BF (10.6%), and B + CRF02_AG (8,2%). The most common TDR mutations were E138A (3.4%), T215 revertants (1.7%), M41L (1.5%), and K103N (1.1%). Transmitted drug resistance rate in the Aegean Region is compatible with national and regional data. Routine surveillance of resistance mutations may guide the safe and correct selection of initial drug combinations for antiretroviral therapy. The identification of HIV-1 subtypes and recombinant forms in Turkey may contribute to international molecular epidemiological data.

Identification of two novel HIV-1 recombinant forms originated from CRF01_AE and subtype B in the sexual contact population in Hebei province, China.

Two near full-length genome (NFLG) sequences of HIV-1 with undefined subtypes were analyzed to confirm the recombinant characteristics. In order to analyze the gene recombination patterns and breakpoints of these two NFLGs, the phylogenetic trees based on the NFLG sequences and their subregions were constructed, respectively. Sequences 233 and 953 are novel second-generation recombinant forms of HIV-1 CRF01_AE and subtype B. The NFLG phylogenetic tree analysis showed that these two NFLG sequences formed a unique monophyletic branch, respectively. The recombination breakpoints analysis showed that the recombination pattern of both sequences was that a subtype B fragment was inserted into a CRF01_AE backbone. Subregions I, II and III were from CRF01_AE, subtype B and CRF01_AE, respectively. The recombination breakpoints relative to HXB2 of sequences 233 and 953 were 2400 and 4870, and 3363 and 4828, respectively. The emergence of novel recombinant forms of CRF01_AE/B demonstrates that we should carry out the ongoing surveillance of HIV-1 recombinant forms in sexually transmitted population.

Global and regional epidemiology of HIV-1 recombinants in 1990–2015: a systematic review and global survey

Global HIV-1 genetic diversity and evolution form a major challenge to treatment and prevention efforts. An increasing number of distinct HIV-1 recombinants have been identified worldwide, but their contribution to the global epidemic is unknown. We aimed to estimate the global and regional distribution of HIV-1 recombinant forms during 1990-2015. We assembled a global HIV-1 molecular epidemiology database through a systematic literature review and a global survey. We searched the PubMed, Embase (Ovid), CINAHL (Ebscohost), and Global Health (Ovid) databases for HIV-1 subtyping studies published from Jan 1, 1990, to Dec 31, 2015. Unpublished original HIV-1 subtyping data were collected through a survey among experts in the field who were members of the WHO-UNAIDS Network for HIV Isolation and Characterisation. We included prevalence studies with HIV-1 subtyping data collected during 1990-2015. Countries were grouped into 14 regions and analyses were done for four time periods (1990-99, 2000-04, 2005-09, and 2010-15). The distribution of circulating recombinant forms (CRFs) and unique recombinant forms (URFs) in individual countries was weighted according to the UNAIDS estimates of the number of people living with HIV in each country to generate regional and global estimates of numbers and proportions of HIV-1 recombinants in each time period. The systematic review is registered with PROSPERO, CRD42017067164. Our global data collection yielded an HIV-1 molecular epidemiology database of 383 519 samples from 116 countries in 1990-2015. We found that the proportion of recombinants increased over time, both globally and in most regions, reaching 22·8% (7 978 517 of 34 921 639) of global HIV-1 infections in 2010-15. Both the proportion and the number of distinct CRFs detected increased over time to 16·7% and 57 CRFs in 2010-15. The global and regional distribution of HIV-1 recombinants was diverse and evolved over time, and we found large regional variation in the numbers (0-44 CRFs), types (58 distinct CRFs), and proportions (0-80·5%) of HIV-1 recombinants. Globally, CRF02_AG was the most prevalent recombinant, accounting for 33·9% (2 701 364 of 7 978 517) of all recombinant infections in 2010-15. URFs accounted for 26·7% (2 131 450 of 7 978 517), CRF01_AE for 23·0% (1 838 433), and other CRFs for 16·4% (1 307 270) of all recombinant infections in 2010-15. Although other CRFs accounted for small proportions of infections globally (<1% each), they were prominent in regional epidemics, including in east and southeast Asia, west and central Africa, Middle East and north Africa, and eastern Europe and central Asia. In addition, in 2010-15, central Africa (21·3% [243 041 of 1 143 531]), west Africa (15·5% [838 476 of 5 419 010]), east Africa (12·6% [591 140 of 4 704 986]), and Latin America (9·6% [153 069 of 1 586 605]) had high proportions of URFs. HIV-1 recombinants are increasingly prominent in global and regional HIV epidemics, which has important implications for the development of an HIV vaccine and the design of diagnostic, resistance, and viral load assays. Continued and improved surveillance of the global molecular epidemiology of HIV is crucial. None.

Genetic source completeness of HIV-1 circulating recombinant forms (CRFs) predicted by multi-label learning.

Infection with strains of different subtypes and the subsequent crossover reading between the two strands of genomic RNAs by host cells' reverse transcriptase are the main causes of the vast HIV-1 sequence diversity. Such inter-subtype genomic recombinants can become circulating recombinant forms (CRFs) after widespread transmissions in a population. Complete prediction of all the subtype sources of a CRF strain is a complicated machine learning problem. It is also difficult to understand whether a strain is an emerging new subtype and if so, how to accurately identify the new components of the genetic source. We introduce a multi-label learning algorithm for the complete prediction of multiple sources of a CRF sequence as well as the prediction of its chronological number. The prediction is strengthened by a voting of various multi-label learning methods to avoid biased decisions. In our steps, frequency and position features of the sequences are both extracted to capture signature patterns of pure subtypes and CRFs. The method was applied to 7185 HIV-1 sequences, comprising 5530 pure subtype sequences and 1655 CRF sequences. Results have demonstrated that the method can achieve very high accuracy (reaching 99%) in the prediction of the complete set of labels of HIV-1 recombinant forms. A few wrong predictions are actually incomplete predictions, very close to the complete set of genuine labels. https://github.com/Runbin-tang/The-source-of-HIV-CRFs-prediction. Supplementary data are available at Bioinformatics online.

HIV-1 recombinant forms in immigrants regularly residing in Milan, northern Italy

To assess the HIV -1subtypes distribution in HIV-1 positive migrants living in Milan we studied 77 HIV-1 patients followed at the San Raffaele Hospital of Milan. Twenty subjects were born in Europe, 43 in the Americas, 10 in Africa and 4 in Asia. Unsafe heterosexual activity prevailed in migrants born in Africa and male homosexuality in those born in European, American and Asian countries (p = 0.05). The phylogeny showed that 38/77 (49.3%) subjects carried HIV-B subtype while the remaining strains were classified as not pure HIV-1 B subtypes 13/77 (16.9%) or recombinant forms 26/77 (33.8%). Female gender more frequently showed HIV-1 non-B strains and rarely HIV-1 B subtypes (12/39, 30.8% vs. 3/38, 7.9%, p = 0.02). Transmitted drug resistance was identified in 10/77 (13%) patients predominately with B subtype. Our data underscore a large heterogeneity in HIV-1 subtypes and a large proportion of recombinant forms.

MOLECULAR EPIDEMIOLOGICAL ANALYSIS OF THE TRANSMISSION CLUSTERS OF THE HIV-1 CIRCULATING RECOMBINANT FORMS CRF01_AE AND CRF02_ AG IN BULGARIA

Background. The purpose of this study was to analyse the underlying HIV transmission clusters of individuals from different vulnerable groups infected with the recombinant forms of HIV-1 – CRF01_AE and CRF02_AG, between 1986 and 2011 using sequencing and phylogenetic analysis.&#x0D; Material and methods. Blood samples from randomly selected 242 individuals diagnosed with HIV-1 CRF01_AE and CRF02_AG in Bulgaria were analysed. HIV-1 pol gene fragment was sequenced using the ViroSeq HIV-1 Genotyping Test (Abbott) and/or TruGene DNA Sequencing System. The phylogenetic tree reconstruction was performed with the IQ-TREE program. Identification of the phylogenetic clusters was performed using the ClusterPicker program with two parameters to identify recent and distant infection. &#x0D; Results.Two main local independent epidemics confined to different geographical regions of the country were caused by HIV-1 CRF01_AE and CRF02_AG. The various viral strains circulate predominantly in two major separate regions – CRF01_AE in Sofia and CRF02_AG in Plovdiv. Most of the individuals infected with viral strains analysed in this study were people who inject drugs (PWID) or heterosexuals and only a few were men who have sex with men. The phylogenetic analysis revealed transmission clusters in both recombinant forms, few in number when confined within a short period of time and multiple clusters over an extended timeframe. &#x0D; Conclusions. The introduction and rapid spread of two different strains of HIV-1 into geographically distant groups of PWID triggered local epidemic outbreaks. The phylogenetic analysis indicated the accelerated transmission of HIV, which is a characteristic of the spread through injection practices. Our study demonstrated that transmission cluster monitoring is important for better understanding of the development of epidemic and could be used as a tool for the identification of risk indicator populations.

Near Full-Length Genomic Characterization of a Novel Unique Recombinant (CRF01_AE/CRF07_BC) in Fuyang City of China.

Recombinant forms contribute substantially to the genetic diversity of HIV-1. Recent studies have also revealed that three major viral strains (CRF07_BC, CRF01_AE, and subtype B) have been cocirculating among men who have sex with men (MSM) in Anhui, suggesting a high probability of generating new recombinants. In this study, we reported a novel CRF01_AE and CRF07_BC HIV-1 recombinant form in MSM in Fuyang city of China. Two near full-length genome (NFLG) named FY184 and FY208 were successfully obtained. The genomic composition analysis of the NFLG reveals that it was divided into four segments by three breakpoints, with two regions of CRF07_BC inserted into a CRF01_AE backbone's gag and pol regions. The CRF01_AE regions were originated from a subcluster lineage of CRF01_AE, which is mainly circulating among MSM in China. The emergence of a novel recombinant of CRF01_AE/CRF07_BC is indicative of the increasing genetic diversity of the HIV epidemic in MSM in Anhui.

HIV-1 genetic diversity and recombinant forms among men who have sex with men at a sentinel surveillance site in Xi'an City, China

HIV-1 genetic distribution and recombinant patterns are important in understanding the HIV epidemic among men who have sex with men (MSM). In this study, 83 HIV-positive MSM infections were confirmed at a sentinel surveillance site in Xi'an city, China in 2018. HIV-1 genotypes were determined by phylogenetic analyses of HIV-1 gag, pol and env gene fragments, including CRF07_BC (51.8%), CRF01_AE (30.1%), subtype B (3.6%), CRF55_01B (3.6%), CRF104_0107 (1.2%) and unique recombinant forms (URFs) (9.6%). Transmitted drug resistance mutations were detected in 2.4% (2/82) of HIV-infected MSM individuals. The phylogenetic analyses of near full-length genome (NFLG) of HIV-1 URFs were performed. A new circulating recombinant form (CRF), designated as CRF104_0107, was found in three epidemiologically unlinked individuals in Shaanxi province, China. The CRF104_0107 is composed of genomes CRF01_AE and CRF07_BC, with six recombinant breakpoints in the gag, pol, vif and vpr genes. This second-generation CRF has a breakpoint (HXB2 nt 3011) in common with CRF07_BC. The emergence of novel CRF and multiple URFs reflected HIV-1 genetic complexity among the local key populations in Xi'an city, China.

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-1 Second-Generation Recombinant Form (CRF01_AE/B) from Men Who Have Sex with Men in Guangxi Zhuang Autonomous Region, China.

We report here a novel HIV-1 recombinant form (18GXD4705) composed of CRF01_AE and subtype B, acquired from an unmarried HIV-positive young man subject infected through homosexual contact in Guangxi Province of eastern China. The phylogenetic analysis of the near full-length genome of 18GXD4705 indicated that one subtype B segment was inserted into the CRF01_AE backbone, with one recombinant breakpoint demonstrated in the pol region. The CRF01_AE region (I and III) of recombinant correlated with a previously reported subcluster 4 lineage. The B subregions (II) are greatly clustered together, with B strain references. The continued generation of this novel recombinant increases the genetic complexity and diversity of the HIV epidemic in Guangxi. In addition, further molecular epidemiological investigations should be conducted to continuously monitor the dynamic transmission of HIV-1 in the region.

Characterization of a Novel HIV-1 CRF01_AE/CRF07_BC Recombinant Virus Form in Guizhou, China.

We identified a novel CRF01_AE and 07_BC HIV-1 recombinant form in Guizhou province in southwest China. The phylogenetic analysis of the near full-length sequence reveals that it was divided into five segments by four breakpoints, and the CRF01_AE regions of the recombinant were clustered with subcluster 4 lineage of CRF01_AE, which mainly circulated among men who have sex with men (MSM) in China. The CRF07_BC regions of the recombinant were clustered with CRF07_BC lineage, which circulated among Chinese MSM. This is the first detection of a novel HIV-1 second-generation recombinant form (CRF07_BC/CRF01_AE) in Guizhou, which shows the increasing significance of heterosexual transmission contributing to the complexity of the HIV-1 epidemic in southwest China, and more effort measures should be taken to monitor the genetic evolution of HIV-1 strains and prevent HIV-1 transmissions.

Molecular genetic characteristics of HIV-1 variants isolated in the subjects of the Russian Far East.

Molecular-genetic monitoring of human immunodeficiency virus (HIV) drug-resistant strains circulation as well as analysis of territorial peculiarities of different genetic variants prevalence of the virus is a crucial part of epidemiological surveillance over HIV-infection spread. Objective of the research - to analyze the prevalence of HIV-1 genetic variants among HIV-positive people living in different constituent entities of the Far Eastern Federal District. Molecular-genetic analysis of the Pol-gene that is coding protease and a part of reverse transcriptase of HIV-1 was performed for a total number of 206 blood plasma samples. The biological material was collected from HIV-positive people living in Sakhalin, Magadan and Amur regions, Jewish Autonomous District, Khabarovsk region, Republic of Sakha (Yakutia) and Chukotka Autonomous Region (constituent entities of the Russian Federation in the Russian Far East). The research demonstrated that HIV-1 sub-subtype A6 continues to be dominant and comprises 72.1±3.1% of all isolated subtypes in the regions of the Russian Far East. HIV-1 subtype B was identified in 14 cases (6.8±1.8%) and subtype C in 4 cases (1.9±1.0%). Spectrum of HIV-1 recombinant forms was determined for some regions. We identified five types of HIV-1 circulating recombinant forms (CRF): CRF03_AB - 2 (0.9±0.7%), CRF02_AG - 8 (3.9±1.3%), CRF63_02A1 - 27 (13.1±2.4%), CRF11_cpx - 1 (0.5±0.5%), CRF01_AE - 3 (1.5±0.8%). High heterogeneity of the virus was registered in the Jewish Autonomous District. The conducted research revealed genetic differences in the landscape of HIV-1 subtypes circulation as well as differences in HIV-1 recombinant forms distribution frequency in the Russian Far East. Current findings are due to expansion of migration flows that promote cross-border importation and further spread of different HIV-1 genetic variants among population of the Far Eastern Federal District. The conducted research revealed that the molecular-genetic monitoring of HIV-1 genovariants should involve not only regions with high HIV-abundance but also with low HIV-prevalence and incidence.

Genomic Characterization of a Novel HIV-1 Second-Generation Recombinant Form (CRF01_AE/07_BC) from a Married Man Who Has Sex with Men in Zhejiang, China.

We report here a novel HIV-1 recombinant form detected from a married HIV-positive man infected through homosexual behavior in Zhejiang, China. The breakpoint analysis of near full-length genome demonstrated a complex genome organization comprising two circulating recombinant forms (CRFs), CRF01_AE and CRF07_BC, both well-known CRFs in China. The parental CRF01_AE region (II) of recombinant clustered together with a previously reported cluster 4 lineage. The CRF07_BC regions (I and III) clustered within CRF07_BC references. The ongoing generation of intersubtype recombinant viruses increases the complexity of the HIV-1 epidemic and illustrates the necessity of persistent surveillance of the transmission of HIV-1.

Near Full-Length Genome Sequence of a Novel HIV-1 Second-Generation Recombinant Form (CRF01_AE/CRF07_BC) Detected Among Men Who Have Sex with Men in Tianjin, China.

In recent years, men who have sex with men (MSM) have been the most affected population with fastest growing human immunodeficiency virus (HIV) prevalence in China. In our study, a novel CRF01_AE/07_BC HIV-1 recombinant form (TJIH0069), with four unique breakpoints in the pol, vpr, and nef gene regions, was identified among MSM in Tianjin City in north China. The CRF01_AE regions (regions I, III, and V) of the recombinant are all clustered together with a previously described sequence (HQ215555), which was exclusively circulating among MSM in Shijiazhuang city of Hebei Province in north China. The CRF07_BC regions (II and IV) are clustered with BJ070032 and JX960600, which were discovered from MSM population in north China. The continuous emergence of a similar pattern of recombinant strain between the two MSM-adapted existing circulating recombinant forms (CRFs) highlights the importance to monitor potential new CRFs for early and precise control and prevention.

Near Full-Length Genome Sequence of a Novel HIV-1 Recombinant Form (CRF01_AE/07_BC) Detected Among Men Who Have Sex with Men in Zhejiang, China.

The prevalence of HIV type 1 among men who have sex with men (MSM) is increasing in China. We report here a novel HIV-1 recombinant form (CRF01_AE/CRF07_BC) detected from a male patient infected with HIV-1 by homosexual behavior in Zhejiang Province of eastern China. The near full-length genome analyses showed that the unique HIV-1 recombinant isolate (16ZJ305) has two recombinant breakpoints observed in the env and tat/rev gene regions. To date, several novel CRF01_AE/CRF07_BC recombinant forms have been identified, which may imply an active transmission network of HIV-1 infection among MSM. Further studies of the molecular epidemiology of the HIV-1 epidemic among MSM are necessary to gain a better understanding of the transmission network and track the genetic evolution.

Near Full-Length Genomic Characterization of HIV-1 CRF01_AE/B Recombinant Strains Identified in Hebei, China.

This study reports a novel HIV-1 recombinant form of CRF01_AE/B that was isolated from a 22-year-old male individual (HE150308) residing in Hebei province, China. The near full-length genome (NFLG) phylogenetic tree showed that the strain was clustered with CRF01_AE reference sequences and placed at the peripheral position within the branch of CRF01_AE strains. The bootscaning and similarity plot analysis revealed that the NFLG of this novel recombinant was composed of eight interlaced segments, including four CRF01_AE and four subtype B segments separated by seven breakpoints observed in the gag, pol, and nef regions of HIV-1 genome. Phylogenetic analysis demonstrated that the CRF01_AE subregions were from the previously identified CRF01_AE cluster 5, and the B subregions were correlated with the B strains originated from Europe and America. They were all the lineages widely prevalent in men who have sex with men (MSM) population in China. In recent years, a large number of recombinants between CRF01_AE and B strains are constantly emerging in the MSM population in China. This continual and recurrent recombination between CRF01_AE and B in high-risk group people deserves more attention and further monitoring.