Identification of new, emerging HIV-1 unique recombinant forms and drug resistant viruses circulating in Cameroon.
ABSTRACT: BACKGROUND: The HIV epidemic in Cameroon is characterized by a high degree of viral genetic diversity with circulating recombinant forms (CRFs) being predominant. The goal of our study was to determine recent trends in virus evolution and emergence of drug resistance in blood donors and HIV positive patients. METHODOLOGY: Blood specimens of 73 individuals were collected from three cities and a few villages in Cameroon and viruses were isolated by co-cultivation with PBMCs. Nested PCR was performed for gag p17 (670 bp) pol (840 bp) and Env gp41 (461 bp) genes. Sequences were phylogenetically analyzed using a reference set of sequences from the Los Alamos database. RESULTS: Phylogenetic analysis based on partial sequences revealed that 65% (n = 48) of strains were CRF02_AG, 4% (n = 3) subtype F2, 1% each belonged to CRF06 (n = 1), CRF11 (n = 1), subtype G (n = 1), subtype D (n = 1), CRF22_01A1 (n = 1), and 26% (n = 18) were Unique Recombinant Forms (URFs). Most URFs contained CRF02_AG in one or two HIV gene fragments analyzed. Furthermore, pol sequences of 61 viruses revealed drug resistance in 55.5% of patients on therapy and 44% of drug naïve individuals in the RT and protease regions. Overall URFs that had a primary HIV subtype designation in the pol region showed higher HIV-1 p24 levels than other recombinant forms in cell culture based replication kinetics studies. CONCLUSIONS: Our results indicate that although CRF02_AG continues to be the predominant strain in Cameroon, phylogenetically the HIV epidemic is continuing to evolve as multiple recombinants of CRF02_AG and URFs were identified in the individuals studied. CRF02_AG recombinants that contained the pol region of a primary subtype showed higher replicative advantage than other variants. Identification of drug resistant strains in drug-naïve patients suggests that these viruses are being transmitted in the population studied. Our findings support the need for continued molecular surveillance in this region of West Central Africa and investigating impact of variants on diagnostics, viral load and drug resistance assays on an ongoing basis.
Project description:HIV-1 group M is classified into 9 subtypes, as well as recombinants favored by coinfection and superinfection events with different variants. Although HIV-1 subtype B is predominant in Europe, intersubtype recombinants are increasing in prevalence and complexity. In this study, phylogenetic analyses of pol sequences were performed to detect the HIV-1 circulating and unique recombinant forms (CRFs and URFs, respectively) in a Spanish cohort of antiretroviral treatment-naïve HIV-infected patients included in the Research Network on HIV/AIDS (CoRIS). Bootscanning and other methods were used to define complex recombinants not assigned to any subtype or CRF. A total of 670 available HIV-1 pol sequences from different patients were collected, of which 588 (87.8%) were assigned to HIV-1 subtype B and 82 (12.2%) to HIV-1 non-B variants. Recombinants caused the majority (71.9%) of HIV-1 non-B infections and were found in 8.8% of CoRIS patients. Eleven URFs (accounting for 13.4% of HIV-1 non-B infections), presenting complex mosaic patterns, were detected. Among them, 10 harbored subtype B fragments. Four of the 11 URFs were found in Spanish natives. A cluster of three B/CRF02_AG recombinants was detected. We conclude that complex variants, including unique recombinant forms, are being introduced into Spain through both immigrants and natives. An increase in the frequency of mosaic viruses, reflecting the increasing heterogeneity of the HIV epidemic in our country, is expected.
Project description:BACKGROUND:The high genetic diversity of HIV-1 has been shown to influence the global distribution, disease progression, treatment success, and the development of an effective vaccine. Despite the low HIV prevalence in Cameroon, all the major HIV subtypes alongside several circulating recombinant forms (CRFs) and unique recombinant forms (URFs) have been reported in Cameroon. To date, HIV-1 diversity in some parts of Cameroon has been largely studied however, information on circulating HIV-1 subtypes in the Northwest region (NWR) of Cameroon is dearth. Therefore the aim of this study was to determine the current circulating HIV-1 subtypes among adults in the NWR of Cameroon. METHODS:The genetic analysis of the reverse transcriptase region of the pol gene was performed on 81 samples. The samples were collected from drug naïve patients aged between 18 and 61?years residing within the rural and urban towns in the NWR during the period between February and April 2016. Viral RNA was extracted from plasma, reverse-transcribed, further amplified by nested-PCR before sequencing using an in-house protocol. Generated sequences were then phylogenetically analyzed together with references using MEGA 7. RESULTS:Phylogenetic analysis revealed a broad viral diversity including CRF02 _AG (74.1%), F2 (7.4%), D (7.4%), G (3.7%), A1 (1.2%), CRF22_01A1 (2.5%), CRF06_cpx (1.2%), CRF09_cpx (1.2%), CRF11_cpx (1.2%). Three close epidemic clusters were found among F2 (1) and CRF02_AG (2) variants. For the first time we are reporting the CRF22_01A1 subtype in this region. CONCLUSION:Our findings update HIV-1 subtypes information in Cameroon and uphold previous studies that CRF02_AG is the most prevalent subtype. This CRF02_AG subtype may have important public health, research, and clinical consequences.
Project description:INTRODUCTION:In Cameroon, a manifold diversity of HIV strains exists with CRF02_AG and unique recombinant forms (URFs) being the predominant strains. In recent years, a steady increase in URFs and clade F2 viruses has been monitored through partial genome sequencing. There is an information gap in the characterization of emerging URFs along the full genome, which is needed to address the challenges URFs pose towards diagnosis, treatment and HIV-1 vaccine design. METHOD:Eighteen Cameroonian URFs from samples collected between the years 2000 and 2015 were studied using a newly developed near full genome sequencing (NFGS) protocol based on variable nested RT-PCRs with a versatile primer set. Near full genomes were characterized for recombination patterns and sequence signatures with possible impact on antiretroviral treatment or Env-directed immune responses. Third-generation sequencing (3GS) of near full or half genomes (HGs) gave insight into intra-patient URF diversity. RESULTS:The characterized URFs were composed of a broad variety of subtypes and recombinants including A, F, G, CRF01_AE, CRF02_AG and CRF22_01A1. Phylogenetic analysis unveiled dominant CRF02_AG and F2 recombination patterns. 3GS indicated a high intra-patient URF diversity with up to four distinct viral sub-populations present in plasma at the same time. URF pol genomic analysis revealed a number of accessory drug resistance mutations (DRMs) in the ART-naïve participants. Genotypic env analysis suggests CCR5 usage in 14/18 samples and identified deviations at residues, critical for gp120/gp41 interphase and CD4 binding site broadly neutralizing antibodies in more than half of the studied URFs. V1V2 sites of immune pressure in the human RV144 vaccine study varied in more than a third of URFs. CONCLUSIONS:This study identified novel mosaic patterns in URFs in Cameroon. In line with the regional predominance of CRF_02AG and the increased prevalence of clade F2, prominent CRF_02AG and F2 background patterns were observed underlying the URFs. In the context of the novel mosaic genomes, the impact of the identified accessory DRMs and Env epitope variations on treatment and immune control remains elusive. The evolving diversity of HIV-1 URFs in Cameroon requires continuous monitoring to respond to the increasing challenges for diagnosis, antiretroviral treatment and prevention.
Project description:<b>Background & methods: </b>The ICONIC project has developed an automated high-throughput pipeline to generate HIV nearly full-length genomes (NFLG, i.e. from gag to nef) from next-generation sequencing (NGS) data. The pipeline was applied to 420 HIV samples collected at University College London Hospitals NHS Trust and Barts Health NHS Trust (London) and sequenced using an Illumina MiSeq at the Wellcome Trust Sanger Institute (Cambridge). Consensus genomes were generated and subtyped using COMET, and unique recombinants were studied with jpHMM and SimPlot. Maximum-likelihood phylogenetic trees were constructed using RAxML to identify transmission networks using the Cluster Picker.<br><br><b>Results: </b>The pipeline generated sequences of at least 1Kb of length (median = 7.46Kb, IQR = 4.01Kb) for 375 out of the 420 samples (89%), with 174 (46.4%) being NFLG. A total of 365 sequences (169 of them NFLG) corresponded to unique subjects and were included in the down-stream analyses. The most frequent HIV subtypes were B (n = 149, 40.8%) and C (n = 77, 21.1%) and the circulating recombinant form CRF02_AG (n = 32, 8.8%). We found 14 different CRFs (n = 66, 18.1%) and multiple URFs (n = 32, 8.8%) that involved recombination between 12 different subtypes/CRFs. The most frequent URFs were B/CRF01_AE (4 cases) and A1/D, B/C, and B/CRF02_AG (3 cases each). Most URFs (19/26, 73%) lacked breakpoints in the PR+RT pol region, rendering them undetectable if only that was sequenced. Twelve (37.5%) of the URFs could have emerged within the UK, whereas the rest were probably imported from sub-Saharan Africa, South East Asia and South America. For 2 URFs we found highly similar pol sequences circulating in the UK. We detected 31 phylogenetic clusters using the full dataset: 25 pairs (mostly subtypes B and C), 4 triplets and 2 quadruplets. Some of these were not consistent across different genes due to inter- and intra-subtype recombination. Clusters involved 70 sequences, 19.2% of the dataset.<br><br><b>Conclusions: </b>The initial analysis of genome sequences detected substantial hidden variability in the London HIV epidemic. Analysing full genome sequences, as opposed to only PR+RT, identified previously undetected recombinants. It provided a more reliable description of CRFs (that would be otherwise misclassified) and transmission clusters.
Project description:Abstract Multiple HIV-1 subtypes and circulating recombinant forms (CRFs) are known to cocirculate in Africa. In West Africa, the high prevalence of CRF02_AG, and cocirculation of subtype A, CRF01_AE, CRF06_cpx, and other complex intersubtype recombinants has been well documented. Mali, situated in the heart of West Africa, is likely to be affected by the spread of recombinant subtypes. However, the dynamics of the spread of HIV-1 recombinant subtypes as well as nonrecombinant HIV-1 group M subtypes in this area have not been systematically assessed. Herein, we undertook genetic analyses on full-length env sequences derived from HIV-1-infected individuals living in the capital city of Mali, Bamako. Of 23 samples we examined, 16 were classified as CRF02_AG and three had a subsubtype A3. Among the remaining HIV-1 strains, CRF06_cpx and CRF09_cpx were each found in two patients. Comparison of phylogenies for six matched pol and full-length env sequences revealed that two strains had discordant subtype/CRF designations between the pol and env regions: one had A3(pol)CRF02_AG(env) and the other had CRF02_AG(pol)A3(env). Taken together, our study demonstrated the high prevalence of CRF02_AG and complexity of circulating HIV-1 strains in Mali. It also provided evidence of ongoing virus evolution of CRF02_AG, as illustrated by the emergence of more complex CRF02_AG/A3 intersubtype recombinants in this area.
Project description:West-Central Africa is an epicenter of the HIV pandemic; endemic to Cameroon are HIV-1 viruses belonging to all (sub)subtypes and numerous Circulating Recombinant Forms (CRFs). The rural villages of Cameroon harbor many strains of HIV-1, though these areas are not as well monitored as the urban centers. In the present study, 82 specimens obtained in 2000 and 2001 from subjects living in the rural villages of the South and West Regions of Cameroon were subtyped in gag, pol, and env and compared to 90 specimens obtained in 2006-2008 in the same regions, in order to analyze HIV-1 evolution in these rural areas. It was found that in the South Region, the proportion of unique recombinant forms (URFs) remained constant (~40%), while the amount of URFs containing fragments of a CRF increased by 25%. (Sub)subtypes A1, F2, H, and K, and CRF09_cpx, identified in 2000 and 2001, were replaced by CRFs 01_AE, 13_cpx, 14_BG, and 18_cpx in 2006-2008. In the West Region, (sub)subtypes A2, C, G, and H, and CRFs 01_AE and 09_cpx, identified in 2000-2001, were replaced by sub-subtype A1 and CRFs 25_cpx and 37_cpx in 2006-2008. The proportion of URFs in the West Region dropped significantly over the time period by 43%. In both Regions, the proportion of CRF02_AG increased at all loci. These findings demonstrate that the evolution of HIV-1 is distinct for each endemic region, and suggests that the proportion of URFs containing CRF fragments is increasing as the genetic identity of the virus continues to shift dramatically. This highlights the concern that subtype-specific vaccines may not be relevant in Cameroon, and that the distribution of viral diversity in these regions of Cameroon must be carefully monitored.
Project description:Cameroon is a West African country where high genetic diversity of HIV-1 has been reported. The predominant CRF02_AG is involved in the emergence of more complex intersubtype recombinants. In this study, we sequenced the full-length genome of a novel unique recombinant form of HIV-1, 02CAMLT04 isolated in blood donors in urban Cameroon. Phylogenetic tree and bootscan analysis showed that 02CAMLT04 was complex and seemed to be a secondary recombinant derived from CRF02_AG and CRF22_01A1. The genomic composition of 02CAMLT04 strain showed that it is composed of 3 segments; 24% of the genome is classified as CRF02_AG, spanning most of the envelope gene. The remaining 76% of the genome is classified as CRF22_01A1. In addition, the sequence analysis of 13 full-length sequences from HIV-1-positive specimens received from Cameroon between 2002 and 2010 indicated that 5 specimens are pure CRF22_01A1 viruses, and 6 others have homology with CRF22_01A1 sequences in either gag, pol, or env region, whereas 6% of strains contain portions of CRF22_01A1. Further study demonstrated that CRF22_01A1 is a primary prevalence strain co-circulating in Cameroon and is involved in complex intersubtype recombination events with subtypes (D or F), subsubtypes (A1 or F2), and CRFs (CRF01_AE or CRF02_AG). Our studies show that novel recombinants between CRF22_01A1 and other clades and recombinant forms may be emerging in Cameroon that could contribute to the future global diversity of HIV-1 in this region and worldwide.
Project description:To estimate the global and regional distribution of HIV-1 subtypes and recombinants between 2000 and 2007.Country-specific HIV-1 molecular epidemiology data were combined with estimates of the number of HIV-infected people in each country.Cross-sectional HIV-1 subtyping data were collected from 65 913 samples in 109 countries between 2000 and 2007. The distribution of HIV-1 subtypes in individual countries was weighted according to the number of HIV-infected people in each country to generate estimates of regional and global HIV-1 subtype distribution for the periods 2000-2003 and 2004-2007.Analysis of the global distribution of HIV-1 subtypes and recombinants in the two periods indicated a broadly stable distribution of HIV-1 subtypes worldwide with a notable increase in the proportion of circulating recombinant forms (CRFs), a decrease in unique recombinant forms (URFs) and an overall increase in recombinants. In 2004-2007, subtype C accounted for nearly half (48%) of all global infections, followed by subtypes A (12%) and B (11%), CRF02_AG (8%), CRF01_AE (5%), subtype G (5%) and D (2%). Subtypes F, H, J and K together cause fewer than 1% of infections worldwide. Other CRFs and URFs are each responsible for 4% of global infections, bringing the combined total of worldwide CRFs to 16% and all recombinants (CRFs along with URFs) to 20%.The global and regional distributions of individual subtypes and recombinants are broadly stable, although CRFs may play an increasing role in the HIV pandemic. The global diversity of HIV-1 poses a formidable challenge to HIV vaccine development.
Project description:<h4>Background</h4>The first case of HIV infection in Sri Lanka was reported in 1987 and at the end of 2018 there were 3500 people living with HIV. There have been commendable efforts made towards the detection, treatment, and prevention of HIV in the country. Even though the genetic diversity of HIV has been shown to affect the parameters ranging from detection to vaccine development, there is no data available with respect to the molecular epidemiology of HIV-1 in Sri Lanka.<h4>Methods</h4>In this report we have performed the ancillary analysis of pol gene region sequences (n = 85) obtained primarily for the purpose of HIV-1 drug resistance genotyping. Briefly, dried blood spot specimens (DBS) collected from HIV-1 infected individuals between December 2015 and August 2018 were subjected to pol gene amplification and sequencing. These pol gene sequences were used to interpret the drug resistance mutation profiles. Further, sequences were subjected to HIV-1 subtyping using REGA 3.0, COMET, jPHMM and, RIP online subtyping tools. Moreover, Bayesian phylogenetic analysis was employed to estimate the evolutionary history of HIV-1 subtype C in Sri Lanka.<h4>Results</h4>Our analysis revealed that the majority (51.8%) of pol gene sequences were subtype C. Other than subtype C, there were sequences categorized as subtypes A1, B, D and G. In addition to pure subtypes there were sequences which were observed to be circulating recombinant forms (CRFs) and a few of the recombinants were identified as potential unique recombinants (URFs). We also observed the presence of drug resistance mutations in 56 (65.9%) out of 85 sequences. Estimates of the Bayesian evolutionary analysis suggested that the HIV-1 subtype C was introduced to Sri Lanka during the early 1970s (1972.8).<h4>Conclusion</h4>The findings presented here indicate the presence of multiple HIV-1 subtypes and the prevalence of drug resistance mutations in Sri Lanka. The majority of the sequences were subtype C, having their most recent common ancestor traced back to the early 1970s. Continuous molecular surveillance of HIV-1 molecular epidemiology will be crucial to keep track of drug resistance, genetic diversity, and evolutionary history of HIV-1 in Sri Lanka.
Project description:Broad HIV-1 genetic diversity in Cameroon provides a unique opportunity to monitor HIV-1 evolution and allows the detection of novel strains. We have genetically characterized the HIV-1 subtypes found in 156 samples from 90 drug-naive subjects in Yaoundé, Cameroon collected from 2011 to 2013, using phylogenetic analysis of regions in gag and pol. We identified subtypes CRF02_AG (64.9%), CRF22_01A1 (7.1%), D (4.5%), F2 (3.9%), G (3.2%), CRF18_cpx (3.2%), CRF37_cpx (3.2%), CRF11_cpx (2.6%), CRF13_cpx (1.9%), A1 (1.3%), CRF01_AE (1.3%), CRF09_cpx (1.3%), A2 (0.6%), and H (0.6%). Sequence data for both the gag and pol regions were obtained from 62 subjects; for 59 of these subjects the two regions were identified as the same viral subtype while three subjects were discordant, A1/CRF02_AG (subject MDC006), CRF02_AG/F2 (subject MDC179), and a dual infection with CRF02_AG/F2 (subject MDC131). Longitudinal sequence data were obtained for 28 of these 62 subjects and confirmed the cross-sectional results. These data update subtype information for this area and highlight the necessity of such studies due to the numerous circulating subtypes, the ongoing superinfection, and the risk of emerging novel recombinant viruses.