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Introduction: HIV-1 subtype B, as once one of the earliest strains introduced into mainland China rapidly spread in commercial plasma donors and heterosexuals in 1990s. Here, we aim to investigate the origin and evolutionary history of HIV-1 subtype B in Fuyang city, China., Methods: We collected sequences tested from Fuyang in the east of China where higher prevalence of HIV-1 among commercial plasma donors and heterosexuals to construct a phylogenetic tree using the Markov chain Monte Carlo (MCMC) algorithm, infer molecular transmission network using TN93 model and visualize it with Cytoscape software., Results and Discussion: Our results showed that >99% of subtype B sequences belonged to Thai B. The sequences from Fuyang often cluster closer to those from other its adjacent cities, which clustered together and formed a monophyletic cluster. HIV-1 B circulating in Fuyang dates back to approximately 1990. Among the 1,437 sequences, 166 clustered at a genetic distance of ≤1.2%, resulting in 73 clusters. The degree of clustering with at least one other person was 11.55%. Among the transmission clusters, 50 (80.65%) comprised two individuals. Most clusters consisted of both heterosexual transmission routes and men who have sex with men. Phylogenetic and molecular network analyses revealed a common origin with neighboring regions in mainland China, local onwards transmission after its introduction, and a limited clustering degree. However, at least two co-existing transmission routes in most transmission clusters imply a greater challenge in controlling the spread of HIV-1. Our findings highlight the value on tailoring prevention interventions by combination of molecular surveillance and epidemiology., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Pan, Gao, Hu, Yin, Shen, Yang, Wei, Ni, Dai, Miao, Qin, Jin, Guo and Wu.)

Introduction: A large number of unique recombinant forms have been found in China in recent years. This study aimed to report on a cluster of novel HIV-1 recombinants., Methods: We constructed phylogenetic trees using the maximum likelihood (ML) method with 1,000 bootstrap replicates in IQ-TREE 1.6.8 software and determined recombination break points using SimPlot 3.5.1., Results: Overall, 9 near-full-length genome (NFLG) sequences were reported in this study, including 1 circulation recombinant form (CRF)01_AE NFLG sequence and 8 highly similar novel HIV-1 second-generation recombinants composed of CRF01_AE and CRF07_BC (CRF105_0107) isolated from a cluster HIV-positive male subjects infected among men who have sex with men (MSM) in Nanjing, eastern China. The phylogenetic analysis of NFLG showed 1 sequence named "nj16" to have at least 11 breakpoints inner virus and 7 other sequences to have at least 10 breakpoints inner virus. Our findings further showed as follows: first, this is the first time that a cluster of novel CRF105_0107 HIV-1 strains were identified among MSM in Nanjing, Jiangsu. Second, the Chinese "4a" cluster of CRF01_AE which mainly circulating in northern China has spread in Jiangsu for more than 15 years. Third, HIV-1 recombination events were active in Nanjing city, and novel recombinants could spread rapidly through some small-scale transmission networks., Conclusion: The continued emergence of novel recombinant HIV-1 strains in Nanjing suggests dynamics and complexity in the HIV epidemic among MSM in Jiangsu province. Further investigations and molecular epidemiological research should be taken to monitor and understand transmission networks among MSM., (© 2021 The Author(s). Published by S. Karger AG, Basel.)

Background: To infer transmission direction of a HIV transmission chain is helpful not only in legal jurisdiction but also in precise intervention to prevent HIV spread. Recently, the direction of transmission is inferred by whether paraphyletic-monophyletic (PM) or a combination of paraphyletic and polyphyletic (PP) topologies is observed or not between the sequences of source and recipient in the phylogenetic tree. However, paraphyly between them often declines over time and may disappear between spouses due to bidirectional transmission after primary infection. In this study, our aim is to test the reliability of inferring HIV transmission direction between epidemiologically linked HIV-1 positive couples using whether or not paraphyly is observed in phylogenetic tree., Methods: HIV quasi-species were sequenced using PCR product clones, and then Bayesian analysis of molecular sequences with MCMC was employed to construct phylogenetic relationship of env, gag, pol gene fragments of HIV-1 positive couples using BEAST software., Results: Our results showed that all sequences of seven couples except pol sequences of couple 12 and 13 form their own monophyletic cluster in phylogenetic tree including the closest control sequences from GenBank or other studies on local samples, which are supported by significant Bayesian posterior probabilities more than 0.9932. Of seven couples, paraphyly is only observed in phylogenetic tree constructed with env and pol gene sequences of three couples and gag gene sequences of four couples. Paraphyly is not observed in half of HIV positive couples. Pol sequences of couple 13 is separated by Blast selected controls; pol sequences of couple 12 in phylogenetic tree is supported by a lower Bayesian posterior value., Conclusion: Paraphyly relationship between sequences of donator and recipient is only observed among partial HIV-1 positive couples with epidemiological link. Phylogenetic relationship is not always the same when various gene regions of HIV are used to conduct phylogenetic analysis. The combination of phylogenetic analysis based on various gene regions of HIV and enough epidemiology investigation is essential when inferring transmission direction of HIV in a transmission chain or in one couple. However, while observed paraphyly can be used to infer transmission direction in HIV-1 positive couple, no observed paraphyly cannot deny it.

CRF07_BC is one of the most prevalent HIV-1 strains in China, and Xinjiang Uygur Autonomous Region has ever been considered to be a second epidemic center after Yunnan Province in previous studies. Here we use HIV-1 pol gene sequences identified from Hetian Prefecture located in Xinjiang Autonomous Region to reconstruct the epidemic history of HIV CRF07_BC strain circulating in this region. We found that CRF07_BC is the predominant HIV-1 form in Hetian Prefecture, and the estimated tMRCA analysis shows that there is no enough evidence supporting Xinjiang Autonomous Region as a second epidemic center of spreading HIV-1. It may imply that every city may be only a point among the HIV spreading network because of the frequent migration of population in the whole country nowadays.

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.

Background: Prevalence of The transmitted HIV drug resistance (THDR) has been reported in many countries. In China, the low level THDR was found in only a few provinces. To know the transmitted HIV drug resistance in east of China, we investigated THDR during 2009-2011 in Jiangsu province of China., Methods: Between January and August of 2009, 2010, and 2011, we consecutively collected 50, 54, 53 blood specimens respectively from qualified individuals at surveillance sentinel sites in Jiangsu province according to protocol of HIV Drug Resistance Threshold Survey (HIVDR-TS) recommended by WHO. The region of pol gene including protease and partial retro-transcriptase was amplified, sequenced and edited. Then the sequences were submitted to HIV drug resistance database to analysis transmitted HIV drug resistance mutations using Calibrated Population Resistance tool. The reference sequences of different HIV-1 subtypes were downloaded from HIV database and Genebank. The phylogenetic trees were inferred using the neighbor-joining method., Results: Our results show that THDR has been at low level from 2009 to 2011, only K101E and V179D mutation was detected which did not belong to the major HIV-1 drug resistance mutations. Phylogenetic analysis showed that CRF01_AE is the predominant subtype, and followed by CRF07_BC and B subtype. Subtype B consists of the two distinct clusters., Conclusions: The low level of THDR suggests that anti-retroviral treatment was implemented more effectively and THDR surveillance should be conducted two years later in Jiangsu province of China. CRF01_AE has become the predominant subtype and dual infection of HIV may be common in Jiangsu province.

CRF01_AE and subtype B are the two major HIV-1 clades circulating in China. Heterosexual transmission is the predominant route for the spread of HIV and heterosexuals often include men who have sex with men and intravenous drug users. Furthermore, many kinds of circulating recombinant forms (CRF) and unique recombinant forms (URF) between CRF01_AE and subtype B were recently identified in Southeast Asia. Therefore it is inevitable that the new recombinant of CRF01_AE/B will emerge among them. Here we identified a novel recombinant of CRF01_AE/B, isolated from heterosexuals, which has a distinctly different genome structure from other CRF01Bs and URFs reported before. The analysis of the near full-length sequence of JS2011001 shows that it is composed of at least five interlaced CRF01_AE and B segments. Recently, many kinds of URFs and CRFs began to prevail within a short period in China, which implies that a mix of HIV-1 infections is common in China and more attention should focus on it.

CRF01_AE and subtype B are the two of major HIV-1 clades circulating in China. HIV spread more rapidly among men who have sex with men (MSM) than among populations with other risk behaviors. In Jiangsu province in China, the HIV-1 incidence among MSM was more than 3.8%. Our previous study showed that almost equal proportions of CRF01_AE, B, and CRF07_BC were circulating among MSM. Moreover, many kinds of CRF01Bs have been identified among MSM in Southeast Asia in recent years. It is therefore inevitable that recombination between CRF01_AE and subtype B will emerge among MSM in Jiangsu province in China. Here we identify a novel recombinant of CRF01_AE/B that has a distinctly different genome structure from other CRF01Bs and unique recombinant forms (URFs) previously identified. An analysis of the near full-length sequence of JS2010001 showed that it is composed of at least three interlaced CRF01_AE and B segments. Recently, many kinds of URFs and C circulating recombinant forms (CRFs) have emerged among MSM in China within a short period of time, which suggests that dual infection of HIV-1 among MSM in China is very common and that more effective intervening measures to prevent the spread of HIV among MSM should be taken.

The occurrence of a novel CRF01_AE-associated recombinant in Jiangsu implies the importance of characterizing full-length CRF01_AE genomic sequence from injecting drug users (IDUs). Here, we reported a near full-length CRF01_AE sequence 07JSWX045 obtained from a Jiangsu IDU, using a modified method. The sequence analyses of 07JSWX045 revealed several interesting findings. First, 07JSWX045 was phylogenetically close to CRF01_AE strains circulating among Jiangsu men who have sex with men (MSM), implying a recent common ancestor. Second, 07JSWX045 was not genetically associated with the CRF01_AE part of the new CRF01_AE/07_BC recombinant found in Jiangsu. Third, both 07JSWX045 and the CRF01_AE parent of CRF01/07 recombinant phylogenetically clustered with two different CRF01_AE subgroups circulating in Fujian, respectively. It suggests that at least two genetically independent CRF01_AE descendants are circulating in Jiangsu possibly via two independent introductions from Fujian. Fourth, two AZT resistance mutations in the RT gene were detected within patient JSWX045, who did not receive any antiviral therapy before sampling, providing valuable bioinformatics sites for investigating the epidemic origin and molecular properties of Jiangsu CRF01_AE strains. Furthermore, patient JSWX045 had two high-risk behaviors including injection drug use and heterosexual contact. He might have been initially infected with CRF01_AE via heterosexual contact, and then introduced this subtype to other people via injection drug use. Therefore, increasing concern is urgently needed for those persons who often have more than two high-risk behaviors.

Our recent study showed that almost equal proportions of B, CRFs_BC, and CRF01_AE were circulating among MSM in Jiangsu, suggesting that there is a very high likelihood of generating new intersubtypes/CRFs recombinants. Here, we report an epidemiologically linked cohort including 22 HIV-1-positive IDUs in Jiangsu. Fifteen blood samples were collected to investigate HIV-1 subtype characterization. The analyses of gag-RT regions showed that 14 of these samples belonged to CRF07_BC. Importantly, we detected, for the first time, a novel second-generation HIV-1 recombinant (07JSNJ001) between CRF01_AE and CRF07_BC. The analyses of the near full-length genomic sequence of 07JSNJ001 (GenBank accession number FJ238521) showed that 07JSNJ001 is composed of at least 10 interlaced CRF07_BC and CRF01_AE segments, quite distinct from any previously identified CRF and URF around the world. The detection of the CRF01_AE/CRF07_BC recombinant may be a harbinger of more new intersubtypes/CRFs recombinants occurring in Jiangsu Province.

Objectives: To investigate the prevalence of HIV, hepatitis B (HBV), hepatitis C (HCV), and syphilis among men who have sex with men (MSM) in 2 cities of Jiangsu, China, and to characterize the HIV-1 subtypes prevalent among this population., Methods: During September 2006 and July 2007, 296 and 173 MSM were recruited from Nanjing and Yangzhou, respectively. Sera samples were collected and tested for HIV, HBV, HCV, and syphilis infections. The nucleotide sequences of p17 and C2V3 regions were determined by RT-nested-PCR and sequencing. HIV-1 subtypes were characterized by phylogenetic analysis., Results: The prevalence of HIV, HBV, HCV, and syphilis infections among MSM was 5.8%, 11.1%, 0.7%, and 27.7%, respectively. The prevalence of HIV and syphilis was significantly higher in 2006-2007 than in 2003 (P 0.05). The phylogenetic tree of p17 showed that HIV-1 subtypes B, CRF01&#95;AE, and CRF07&#95;BC accounted for 35.7%, 35.7%, and 28.6%, respectively. The result of C2V3 showed that 45.5%, 36.4%, and 18.2% sequences belonged to HIV-1 subtype B, CRF01&#95;AE, and BC recombinants, respectively. The subtype characterization in Jiangsu was significantly different from those in Beijing (P <0.05). Furthermore, Jiangsu HIV-1 B strains were different from majority of China B' strains and originated from Beijing., Conclusions: The rapidly increasing prevalence and complex subtypes of HIV-1 suggest that effective prevention and intervention strategies are urgently needed for MSM in Jiangsu.

Summary: Background: The co-receptor tropism of any given HIV-1 isolate is closely associated with the progression of AIDS. Understanding the co-receptor tropism and genetic diversity of circulating HIV-1 strains is critical for AIDS treatment and vaccine development. Methods: All available China HIV-1 V3 sequences with known subtypes/circulating recombinant forms (CRFs) and transmission routes were retrieved from the Los Alamos HIV Sequence Database. HIV-1 co-receptor tropism was predicted using online tool HIV-1 PhenoPred. Results: All C/CRF07_BC/CRF08_BC strains appeared to use CCR5 for cell entry (R5 strains), while 61.1% of subtype B and 38.7% of CRF01_AE were also R5, indicating a higher prevalence of R5 (76.9%) than X4. The prevalence of R5 remained relatively stable over the different sample years regardless of C/CRF07_BC/CRF08_BC, B, or CRF01_AE subtypes. The co-receptor usage of HIV-1 appeared to be associated with the different subtypes, rather than transmission route. Furthermore, the V3 sequences of C/CRF07_BC/CRF08_BC were more genetically homogeneous relative to both subtypes B and CRF01_AE. Conclusions: The higher prevalence of R5 and higher level of homogeneity of V3 sequences in C/CRF07_BC/CRF08_BC suggest that CCR5 antagonists will be promising drugs for future AIDS treatment in China, and that circulating R5 strains are valuable candidates for AIDS vaccine development. [Copyright &y& Elsevier]