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

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.

Genetic Characteristics of Three Unique Recombinant Forms of HIV-1 in Yunnan, China

To explore the molecular epidemiological status of human immunodeficiency virus type 1 (HIV-1) in Yunnan, China, three HIV-1 near full-length genomes were amplified and sequenced from plasma samples that were collected from Burmese patients newly diagnosed with HIV-1 in Dehong Prefecture in Yunnan Province in 2017. Phylogenetic and bootscanning analyses revealed that all the sequences might be HIV-1 second-generation recombinant forms of circulating recombinant forms (CRF07_BC and CRF83_cpx) and unique recombinant forms. One of the sequences contained six CRF01_AE fragments, five subtype C fragments, and two subtype B fragments, which were separated by 12 breakpoints. These results revealed that the second-generation recombination of HIV-1 within different strains is still ongoing in Dehong, China. Systematic surveys and immediate interventions are urgently needed to prevent the formation of increasingly complex HIV-1 recombinant forms.

Identification of a Novel HIV-1 Unique CRF01_AE/C Recombinant in Yan'an City, Shaanxi Province

A wide variety of HIV-1 recombinants are constantly discovered in China. Comprehensively monitoring the genetic diversity of HIV-1 is very essential for understanding the molecular epidemiology and controlling the spread of the HIV-1 epidemic. In this study, we presented a novel HIV-1 unique CRF01_AE/C recombinant (19YA001) isolated from a female patient infected HIV-1 through heterosexual transmission in Yan'an city, Shaanxi province. The near full-length genome analyses showed 19YA001 was divided into two CRF01_AE and one C segments by two breakpoints observed in the vif/vpr region. To date, this is the first report revealing the characteristic of HIV-1 subtype in Yan'an city. And this unique recombinant strain might imply that the genetic diversity of HIV-1 in Yan'an city is complex. However, the sample size is too small. Further larger studies of HIV-1 molecular epidemiology are urgently needed to provide a better understanding of HIV-1 diversity and transmission in this region.

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.

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.

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.

Near-Full-Length Genome Sequences of a Novel HIV-1 Circulating Recombinant Form, CRF01_AE/B'/C (CRF78_cpx), in Yunnan, China

We report a novel HIV circulating recombinant form (CRF78_cpx) composed mainly of CRF01_AE with inserts from subtypes B and C identified from three epidemiologically unlinked individuals in Yunnan province, China. Two of the subjects are heterosexual men and one is a male intravenous drug user. Sequencing and analyzing the near-full-length genome of these three isolates (YNTC88, YNTC19, and YNTC35) revealed identical recombination breakpoints in all three viruses, but considerable genetic diversity between them, across the genomes, indicating that this is not a newly created CRF, only newly detected. CRF78_cpx differs from previously documented CRF01-AE/B'/C forms in its distinct backbone, inserted fragment size, and breakpoints, and is not related to other described recombinants in the region such as CRF07_BC or CRF65_cpx (also composed of CRF01_AE, B', and C). Our present findings further enrich the diversity of the prevalent HIV-1 CRFs in Yunnan, which is considered as an epicenter of HIV-1 infections in China.