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Weaver S, Dávila-Conn V, Ji D, Verdonk H, Ávila-Ríos S, Leigh Brown AJ, Wertheim JO, Kosakovsky Pond SL. AUTO-TUNE: SELECTING THE DISTANCE THRESHOLD FOR INFERRING HIV TRANSMISSION CLUSTERS. bioRxiv 2024:2024.03.11.584522. [PMID: 38559140 PMCID: PMC10979987 DOI: 10.1101/2024.03.11.584522] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
Molecular surveillance of viral pathogens and inference of transmission networks from genomic data play an increasingly important role in public health efforts, especially for HIV-1. For many methods, the genetic distance threshold used to connect sequences in the transmission network is a key parameter informing the properties of inferred networks. Using a distance threshold that is too high can result in a network with many spurious links, making it difficult to interpret. Conversely, a distance threshold that is too low can result in a network with too few links, which may not capture key insights into clusters of public health concern. Published research using the HIV-TRACE software package frequently uses the default threshold of 0.015 substitutions/site for HIV pol gene sequences, but in many cases, investigators heuristically select other threshold parameters to better capture the underlying dynamics of the epidemic they are studying. Here, we present a general heuristic scoring approach for tuning a distance threshold adaptively, which seeks to prevent the formation of giant clusters. We prioritize the ratio of the sizes of the largest and the second largest cluster, maximizing the number of clusters present in the network. We apply our scoring heuristic to outbreaks with different characteristics, such as regional or temporal variability, and demonstrate the utility of using the scoring mechanism's suggested distance threshold to identify clusters exhibiting risk factors that would have otherwise been more difficult to identify. For example, while we found that a 0.015 substitutions/site distance threshold is typical for US-like epidemics, recent outbreaks like the CRF07_BC subtype among men who have sex with men (MSM) in China have been found to have a lower optimal threshold of 0.005 to better capture the transition from injected drug use (IDU) to MSM as the primary risk factor. Alternatively, in communities surrounding Lake Victoria in Uganda, where there has been sustained hetero-sexual transmission for many years, we found that a larger distance threshold is necessary to capture a more risk factor-diverse population with sparse sampling over a longer period of time. Such identification may allow for more informed intervention action by respective public health officials.
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Affiliation(s)
- Steven Weaver
- Center for Viral Evolution, Temple University, Philadelphia, PA, USA
| | - Vanessa Dávila-Conn
- Center for Research in Infectious Diseases, National Institute of Respiratory Diseases, Mexico City, Mexico
| | - Daniel Ji
- Department of Computer Science & Engineering, UC San Diego, La Jolla, CA 92093, USA
| | - Hannah Verdonk
- Center for Viral Evolution, Temple University, Philadelphia, PA, USA
| | - Santiago Ávila-Ríos
- Center for Research in Infectious Diseases, National Institute of Respiratory Diseases, Mexico City, Mexico
| | - Andrew J Leigh Brown
- School of Biological Sciences, University of Edinburgh, Edinburgh, Scotland, United Kingdom
| | - Joel O Wertheim
- Department of Medicine, University of California San Diego, La Jolla, CA 92093, USA
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Sanaubarova A, Pujol-Hodge E, Dzissyuk N, Lemey P, Vermund SH, Leigh Brown AJ, Ali S. High-Level Drug-Resistant Mutations among HIV-1 Subtype A6 and CRF02_AG in Kazakhstan. Viruses 2023; 15:1407. [PMID: 37515095 PMCID: PMC10384832 DOI: 10.3390/v15071407] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2023] [Revised: 05/30/2023] [Accepted: 05/31/2023] [Indexed: 07/30/2023] Open
Abstract
HIV incidence in Kazakhstan increased by 73% between 2010 and 2020, with an estimated 35,000 people living with HIV (PLHIV) in 2020. The development of antiretroviral drug resistance is a major threat to effective antiretroviral therapy (ART), yet studies on the prevalence of drug resistance in Kazakhstan are sparse. In this study on the molecular epidemiology of HIV in Kazakhstan, we analyzed 968 partial HIV-1 pol sequences that were collected between 2017 and 2020 from PLHIV across all regions of Kazakhstan, covering almost 3% of PLHIV in 2020. Sequences predominantly represented subtypes A6 (57%) and CRF02_AG (41%), with 32% of sequences exhibiting high-level drug resistance. We further identified distinct drug-resistant mutations (DRMs) in the two subtypes: subtype A6 showed a propensity for DRMs A62V, G190S, K101E, and D67N, while CRF02_AG showed a propensity for K103N and V179E. Codon usage analysis revealed that different mutational pathways for the two subtypes may explain the difference in G190S and V179E frequencies. Phylogenetic analysis highlighted differences in the timing and geographic spread of both subtypes within the country, with A62V-harboring subtype A6 sequences clustering on the phylogeny, indicative of sustained transmission of the mutation. Our findings suggest an HIV epidemic characterized by high levels of drug resistance and differential DRM frequencies between subtypes. This emphasizes the importance of drug resistance monitoring within Kazakhstan, together with DRM and subtype screening at diagnosis, to tailor drug regimens and provide effective, virally suppressive ART.
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Affiliation(s)
- Ainur Sanaubarova
- Department of Biomedical Sciences, Nazarbayev School of Medicine, Nazarbayev University, Astana 010000, Kazakhstan;
| | - Emma Pujol-Hodge
- School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3FL, UK; (E.P.-H.); (A.J.L.B.)
| | - Natalya Dzissyuk
- Kazakh Scientific Center of Dermatology and Infectious Diseases, Almaty 010000, Kazakhstan;
| | - Philippe Lemey
- Department of Microbiology and Immunology, Rega Institute, Katholieke Universiteit Leuven, 3000 Leuven, Belgium;
| | - Sten H. Vermund
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT 06510, USA;
| | - Andrew J. Leigh Brown
- School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3FL, UK; (E.P.-H.); (A.J.L.B.)
| | - Syed Ali
- Department of Biomedical Sciences, Nazarbayev School of Medicine, Nazarbayev University, Astana 010000, Kazakhstan;
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Pujol-Hodge E, Salazar-Gonzalez JF, Ssemwanga D, Charlebois ED, Ayieko J, Grant HE, Liegler T, Atkins KE, Kaleebu P, Kamya MR, Petersen M, Havlir DV, Leigh Brown AJ. Detection of HIV-1 Transmission Clusters from Dried Blood Spots within a Universal Test-and-Treat Trial in East Africa. Viruses 2022; 14:1673. [PMID: 36016295 PMCID: PMC9414799 DOI: 10.3390/v14081673] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Revised: 07/15/2022] [Accepted: 07/25/2022] [Indexed: 11/24/2022] Open
Abstract
The Sustainable East Africa Research in Community Health (SEARCH) trial was a universal test-and-treat (UTT) trial in rural Uganda and Kenya, aiming to lower regional HIV-1 incidence. Here, we quantify breakthrough HIV-1 transmissions occurring during the trial from population-based, dried blood spot samples. Between 2013 and 2017, we obtained 549 gag and 488 pol HIV-1 consensus sequences from 745 participants: 469 participants infected prior to trial commencement and 276 SEARCH-incident infections. Putative transmission clusters, with a 1.5% pairwise genetic distance threshold, were inferred from maximum likelihood phylogenies; clusters arising after the start of SEARCH were identified with Bayesian time-calibrated phylogenies. Our phylodynamic approach identified nine clusters arising after the SEARCH start date: eight pairs and one triplet, representing mostly opposite-gender linked (6/9), within-community transmissions (7/9). Two clusters contained individuals with non-nucleoside reverse transcriptase inhibitor (NNRTI) resistance, both linked to intervention communities. The identification of SEARCH-incident, within-community transmissions reveals the role of unsuppressed individuals in sustaining the epidemic in both arms of a UTT trial setting. The presence of transmitted NNRTI resistance, implying treatment failure to the efavirenz-based antiretroviral therapy (ART) used during SEARCH, highlights the need to improve delivery and adherence to up-to-date ART recommendations, to halt HIV-1 transmission.
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Affiliation(s)
- Emma Pujol-Hodge
- Ashworth Laboratories, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3FL, UK; (E.P.-H.); (H.E.G.)
| | - Jesus F. Salazar-Gonzalez
- Medical Research Council (MRC)/Uganda Virus Research Institute (UVRI) and London School of Hygiene and Tropical Medicine (LSHTM) Uganda Research Unit, Entebbe P.O. Box 49, Uganda; (J.F.S.-G.); (D.S.); (P.K.)
| | - Deogratius Ssemwanga
- Medical Research Council (MRC)/Uganda Virus Research Institute (UVRI) and London School of Hygiene and Tropical Medicine (LSHTM) Uganda Research Unit, Entebbe P.O. Box 49, Uganda; (J.F.S.-G.); (D.S.); (P.K.)
- Uganda Virus Research Institute, Entebbe P.O. Box 49, Uganda
| | - Edwin D. Charlebois
- Division of Prevention Science, Department of Medicine, University of California, San Francisco, CA 94158, USA;
| | - James Ayieko
- Kenya Medical Research Institute, Nairobi P.O. Box 54840-00200, Kenya;
| | - Heather E. Grant
- Ashworth Laboratories, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3FL, UK; (E.P.-H.); (H.E.G.)
| | - Teri Liegler
- Division of HIV, Infectious Diseases and Global Medicine, Department of Medicine, University of California, San Francisco, CA 94110, USA; (T.L.); (D.V.H.)
| | - Katherine E. Atkins
- Usher Institute, University of Edinburgh, Edinburgh EH8 9AG, UK;
- Department of Infectious Disease Epidemiology, Faculty of Epidemiology and Population Health, LSHTM, London WC1E 7HT, UK
- Centre for Mathematical Modelling of Infectious Diseases, LSHTM, London WC1E 7HT, UK
| | - Pontiano Kaleebu
- Medical Research Council (MRC)/Uganda Virus Research Institute (UVRI) and London School of Hygiene and Tropical Medicine (LSHTM) Uganda Research Unit, Entebbe P.O. Box 49, Uganda; (J.F.S.-G.); (D.S.); (P.K.)
- Uganda Virus Research Institute, Entebbe P.O. Box 49, Uganda
| | - Moses R. Kamya
- School of Medicine, Makerere University, Kampala P.O. Box 7072, Uganda;
| | - Maya Petersen
- Division of Biostatistics, School of Public Health, University of California, Berkeley, CA 94720, USA;
| | - Diane V. Havlir
- Division of HIV, Infectious Diseases and Global Medicine, Department of Medicine, University of California, San Francisco, CA 94110, USA; (T.L.); (D.V.H.)
| | - Andrew J. Leigh Brown
- Ashworth Laboratories, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3FL, UK; (E.P.-H.); (H.E.G.)
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4
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Kayondo HW, Ssekagiri A, Nabakooza G, Bbosa N, Ssemwanga D, Kaleebu P, Mwalili S, Mango JM, Leigh Brown AJ, Saenz RA, Galiwango R, Kitayimbwa JM. Employing phylogenetic tree shape statistics to resolve the underlying host population structure. BMC Bioinformatics 2021; 22:546. [PMID: 34758743 PMCID: PMC8579572 DOI: 10.1186/s12859-021-04465-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Accepted: 10/29/2021] [Indexed: 12/24/2022] Open
Abstract
Background Host population structure is a key determinant of pathogen and infectious disease transmission patterns. Pathogen phylogenetic trees are useful tools to reveal the population structure underlying an epidemic. Determining whether a population is structured or not is useful in informing the type of phylogenetic methods to be used in a given study. We employ tree statistics derived from phylogenetic trees and machine learning classification techniques to reveal an underlying population structure. Results In this paper, we simulate phylogenetic trees from both structured and non-structured host populations. We compute eight statistics for the simulated trees, which are: the number of cherries; Sackin, Colless and total cophenetic indices; ladder length; maximum depth; maximum width, and width-to-depth ratio. Based on the estimated tree statistics, we classify the simulated trees as from either a non-structured or a structured population using the decision tree (DT), K-nearest neighbor (KNN) and support vector machine (SVM). We incorporate the basic reproductive number (\documentclass[12pt]{minimal}
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\begin{document}$$R_0$$\end{document}R0) in our tree simulation procedure. Sensitivity analysis is done to investigate whether the classifiers are robust to different choice of model parameters and to size of trees. Cross-validated results for area under the curve (AUC) for receiver operating characteristic (ROC) curves yield mean values of over 0.9 for most of the classification models. Conclusions Our classification procedure distinguishes well between trees from structured and non-structured populations using the classifiers, the two-sample Kolmogorov-Smirnov, Cucconi and Podgor-Gastwirth tests and the box plots. SVM models were more robust to changes in model parameters and tree size compared to KNN and DT classifiers. Our classification procedure was applied to real -world data and the structured population was revealed with high accuracy of \documentclass[12pt]{minimal}
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\begin{document}$$92.3\%$$\end{document}92.3% using SVM-polynomial classifier.
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Affiliation(s)
- Hassan W Kayondo
- Institute of Basic Sciences, Technology and Innovation (PAUSTI), Pan African University, Nairobi, Kenya. .,Department of Mathematics, Makerere University, Kampala, Uganda.
| | - Alfred Ssekagiri
- Uganda Virus Research Institute (UVRI), Entebbe, Uganda.,Department of Immunology and Molecular Biology, Makerere University, Kampala, Uganda
| | - Grace Nabakooza
- Department of Immunology and Molecular Biology, Makerere University, Kampala, Uganda.,UVRI Centre of Excellence in Infection and Immunity Research and Training (MUII-Plus), Makerere University, Entebbe, Uganda.,Centre for Computational Biology, Uganda Christian University, Mukono, Uganda
| | - Nicholas Bbosa
- Medical Research Council (MRC)/Uganda Virus Research Institute (UVRI) and London School of Hygiene and Tropical Medicine (LSHTM) Uganda Research Unit, Entebbe, Uganda
| | - Deogratius Ssemwanga
- Uganda Virus Research Institute (UVRI), Entebbe, Uganda.,Medical Research Council (MRC)/Uganda Virus Research Institute (UVRI) and London School of Hygiene and Tropical Medicine (LSHTM) Uganda Research Unit, Entebbe, Uganda
| | - Pontiano Kaleebu
- Uganda Virus Research Institute (UVRI), Entebbe, Uganda.,Medical Research Council (MRC)/Uganda Virus Research Institute (UVRI) and London School of Hygiene and Tropical Medicine (LSHTM) Uganda Research Unit, Entebbe, Uganda
| | - Samuel Mwalili
- Department of Statistics and Actuarial Sciences, Jomo Kenyatta University of Agriculture and Technology, Nairobi, Kenya
| | - John M Mango
- Department of Mathematics, Makerere University, Kampala, Uganda
| | | | | | - Ronald Galiwango
- Centre for Computational Biology, Uganda Christian University, Mukono, Uganda
| | - John M Kitayimbwa
- Centre for Computational Biology, Uganda Christian University, Mukono, Uganda
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5
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Grant HE, Hodcroft EB, Ssemwanga D, Kitayimbwa JM, Yebra G, Esquivel Gomez LR, Frampton D, Gall A, Kellam P, de Oliveira T, Bbosa N, Nsubuga RN, Kibengo F, Kwan TH, Lycett S, Kao R, Robertson DL, Ratmann O, Fraser C, Pillay D, Kaleebu P, Leigh Brown AJ. Pervasive and non-random recombination in near full-length HIV genomes from Uganda. Virus Evol 2020; 6:veaa004. [PMID: 32395255 PMCID: PMC7204518 DOI: 10.1093/ve/veaa004] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Recombination is an important feature of HIV evolution, occurring both within and between the major branches of diversity (subtypes). The Ugandan epidemic is primarily composed of two subtypes, A1 and D, that have been co-circulating for 50 years, frequently recombining in dually infected patients. Here, we investigate the frequency of recombinants in this population and the location of breakpoints along the genome. As part of the PANGEA-HIV consortium, 1,472 consensus genome sequences over 5 kb have been obtained from 1,857 samples collected by the MRC/UVRI & LSHTM Research unit in Uganda, 465 (31.6 per cent) of which were near full-length sequences (>8 kb). Using the subtyping tool SCUEAL, we find that of the near full-length dataset, 233 (50.1 per cent) genomes contained only one subtype, 30.8 per cent A1 (n = 143), 17.6 per cent D (n = 82), and 1.7 per cent C (n = 8), while 49.9 per cent (n = 232) contained more than one subtype (including A1/D (n = 164), A1/C (n = 13), C/D (n = 9); A1/C/D (n = 13), and 33 complex types). K-means clustering of the recombinant A1/D genomes revealed a section of envelope (C2gp120-TMgp41) is often inherited intact, whilst a generalized linear model was used to demonstrate significantly fewer breakpoints in the gag-pol and envelope C2-TM regions compared with accessory gene regions. Despite similar recombination patterns in many recombinants, no clearly supported circulating recombinant form (CRF) was found, there was limited evidence of the transmission of breakpoints, and the vast majority (153/164; 93 per cent) of the A1/D recombinants appear to be unique recombinant forms. Thus, recombination is pervasive with clear biases in breakpoint location, but CRFs are not a significant feature, characteristic of a complex, and diverse epidemic.
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Affiliation(s)
- Heather E Grant
- Institute of Evolutionary Biology, University of Edinburgh, Edinburgh, UK
| | - Emma B Hodcroft
- Biozentrum, University of Basel, Basel, Switzerland
- Swiss Institute of Bioinformatics, Basel, Switzerland
| | - Deogratius Ssemwanga
- Medical Research Council (MRC)/Uganda Virus Research Institute (UVRI) and London School of Hygiene and Tropical Medicine (LSHTM) Uganda Research Unit, Entebbe, Uganda
- Uganda Virus Research Institute, Entebbe, Uganda
| | | | - Gonzalo Yebra
- The Roslin Institute, University of Edinburgh, Edinburgh, UK
| | | | - Dan Frampton
- Division of Infection and Immunity, University College London, London, UK
| | - Astrid Gall
- European Molecular Biology Laboratory-European Bioinformatics Institute (EMBL-EBI), Wellcome Genome Campus, Hinxton, UK
| | - Paul Kellam
- European Molecular Biology Laboratory-European Bioinformatics Institute (EMBL-EBI), Wellcome Genome Campus, Hinxton, UK
| | - Tulio de Oliveira
- Nelson R. Mandela School of Medicine, Africa Health Research Institute, Durban, South Africa
| | - Nicholas Bbosa
- Medical Research Council (MRC)/Uganda Virus Research Institute (UVRI) and London School of Hygiene and Tropical Medicine (LSHTM) Uganda Research Unit, Entebbe, Uganda
| | - Rebecca N Nsubuga
- Medical Research Council (MRC)/Uganda Virus Research Institute (UVRI) and London School of Hygiene and Tropical Medicine (LSHTM) Uganda Research Unit, Entebbe, Uganda
| | - Freddie Kibengo
- Medical Research Council (MRC)/Uganda Virus Research Institute (UVRI) and London School of Hygiene and Tropical Medicine (LSHTM) Uganda Research Unit, Entebbe, Uganda
| | - Tsz Ho Kwan
- Stanley Ho Centre for Emerging Infectious Diseases, The Chinese University of Hong Kong, Shatin, Hong Kong
| | - Samantha Lycett
- The Roslin Institute, University of Edinburgh, Edinburgh, UK
| | - Rowland Kao
- The Roslin Institute, University of Edinburgh, Edinburgh, UK
| | | | - Oliver Ratmann
- Department of Mathematics, Imperial College London, London, UK
| | - Christophe Fraser
- Nuffield Department of Medicine, Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, UK
| | - Deenan Pillay
- European Molecular Biology Laboratory-European Bioinformatics Institute (EMBL-EBI), Wellcome Genome Campus, Hinxton, UK
- Nelson R. Mandela School of Medicine, Africa Health Research Institute, Durban, South Africa
| | - Pontiano Kaleebu
- Medical Research Council (MRC)/Uganda Virus Research Institute (UVRI) and London School of Hygiene and Tropical Medicine (LSHTM) Uganda Research Unit, Entebbe, Uganda
- Uganda Virus Research Institute, Entebbe, Uganda
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6
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Ragonnet-Cronin M, Jackson C, Bradley-Stewart A, Aitken C, McAuley A, Palmateer N, Gunson R, Goldberg D, Milosevic C, Leigh Brown AJ. Recent and Rapid Transmission of HIV Among People Who Inject Drugs in Scotland Revealed Through Phylogenetic Analysis. J Infect Dis 2019; 217:1875-1882. [PMID: 29546333 DOI: 10.1093/infdis/jiy130] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Accepted: 03/08/2018] [Indexed: 11/13/2022] Open
Abstract
Background Harm reduction has dramatically reduced HIV incidence among people who inject drugs (PWID). In Glasgow, Scotland, <10 infections/year have been diagnosed among PWID since the mid-1990s. However, in 2015 a sharp rise in diagnoses was noted among PWID; many were subtype C with 2 identical drug-resistant mutations and some displayed low avidity, suggesting the infections were linked and recent. Methods We collected Scottish pol sequences and identified closely related sequences from public databases. Genetic linkage was ascertained among 228 Scottish, 1820 UK, and 524 global sequences. The outbreak cluster was extracted to estimate epidemic parameters. Results All 104 outbreak sequences originated from Scotland and contained E138A and V179E. Mean genetic distance was <1% and mean time between transmissions was 6.7 months. The average number of onward transmissions consistently exceeded 1, indicating that spread was ongoing. Conclusions In contrast to other recent HIV outbreaks among PWID, harm reduction services were not clearly reduced in Scotland. Nonetheless, the high proportion of individuals with a history of homelessness (45%) suggests that services were inadequate for those in precarious living situations. The high prevalence of hepatitis C (>90%) is indicative of sharing of injecting equipment. Monitoring the epidemic phylogenetically in real time may accelerate public health action.
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Affiliation(s)
| | | | | | | | - Andrew McAuley
- Health Protection Scotland, Glasgow.,Glasgow Caledonian University, United Kingdom
| | - Norah Palmateer
- Health Protection Scotland, Glasgow.,Glasgow Caledonian University, United Kingdom
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7
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Kosakovsky Pond SL, Weaver S, Leigh Brown AJ, Wertheim JO. HIV-TRACE (TRAnsmission Cluster Engine): a Tool for Large Scale Molecular Epidemiology of HIV-1 and Other Rapidly Evolving Pathogens. Mol Biol Evol 2019; 35:1812-1819. [PMID: 29401317 DOI: 10.1093/molbev/msy016] [Citation(s) in RCA: 162] [Impact Index Per Article: 32.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
In modern applications of molecular epidemiology, genetic sequence data are routinely used to identify clusters of transmission in rapidly evolving pathogens, most notably HIV-1. Traditional 'shoe-leather' epidemiology infers transmission clusters by tracing chains of partners sharing epidemiological connections (e.g., sexual contact). Here, we present a computational tool for identifying a molecular transmission analog of such clusters: HIV-TRACE (TRAnsmission Cluster Engine). HIV-TRACE implements an approach inspired by traditional epidemiology, by identifying chains of partners whose viral genetic relatedness imply direct or indirect epidemiological connections. Molecular transmission clusters are constructed using codon-aware pairwise alignment to a reference sequence followed by pairwise genetic distance estimation among all sequences. This approach is computationally tractable and is capable of identifying HIV-1 transmission clusters in large surveillance databases comprising tens or hundreds of thousands of sequences in near real time, that is, on the order of minutes to hours. HIV-TRACE is available at www.hivtrace.org and from www.github.com/veg/hivtrace, along with the accompanying result visualization module from www.github.com/veg/hivtrace-viz. Importantly, the approach underlying HIV-TRACE is not limited to the study of HIV-1 and can be applied to study outbreaks and epidemics of other rapidly evolving pathogens.
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Affiliation(s)
| | - Steven Weaver
- Institute for Genomics and Evolutionary Medicine, Temple University, Philadelphia, PA
| | - Andrew J Leigh Brown
- Institute of Evolutionary Biology, University of Edinburgh, Edinburgh, United Kingdom
| | - Joel O Wertheim
- Department of Medicine, University of California, San Diego, CA
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8
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Ragonnet-Cronin M, Hué S, Hodcroft EB, Tostevin A, Dunn D, Fawcett T, Pozniak A, Brown AE, Delpech V, Brown AJL. Non-disclosed men who have sex with men in UK HIV transmission networks: phylogenetic analysis of surveillance data. Lancet HIV 2019; 5:e309-e316. [PMID: 29893244 DOI: 10.1016/s2352-3018(18)30062-6] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2017] [Revised: 03/23/2018] [Accepted: 03/27/2018] [Indexed: 11/18/2022]
Abstract
BACKGROUND Patients who do not disclose their sexuality, including men who do not disclose same-sex behaviour, are difficult to characterise through traditional epidemiological approaches such as interviews. Using a recently developed method to detect large networks of viral sequences from time-resolved trees, we localised non-disclosed men who have sex with men (MSM) in UK transmission networks, gaining crucial insight into the behaviour of this group. METHODS For this phylogenetic analysis, we obtained HIV pol sequences from the UK HIV Drug Resistance Database (UKRDB), a central repository for resistance tests done as part of routine clinical care throughout the UK. Sequence data are linked to demographic and clinical data held by the UK Collaborative HIV Cohort study and the national HIV/AIDS reporting system database. Initially, we reconstructed maximum likelihood phylogenies from these sequences, then sequences were selected for time-resolved analysis in BEAST if they were clustered with at least one other sequence at a genetic distance of 4·5% or less with support of at least 90%. We used time-resolved phylogenies to create networks by linking together nodes if sequences shared a common ancestor within the previous 5 years. We identified potential non-disclosed MSM (pnMSM), defined as self-reported heterosexual men who clustered only with men. We measured the network position of pnMSM, including betweenness (a measure of connectedness and importance) and assortativity (the propensity for nodes sharing attributes to link). FINDINGS 14 405 individuals were in the network, including 8452 MSM, 1743 heterosexual women and 1341 heterosexual men. 249 pnMSM were identified (18·6% of all clustered heterosexual men) in the network. pnMSM were more likely to be black African (p<0·0001), less likely to be infected with subtype B (p=0·006), and were slightly older (p=0·002) than the MSM they clustered with. Mean betweenness centrality was lower for pnMSM than for MSM (1·31, 95% CI 0·48-2·15 in pnMSM vs 2·24, 0·98-3·51 in MSM; p=0·002), indicating that pnMSM were in peripheral positions in MSM clusters. Assortativity by risk group was higher than expected (0·037 vs -0·037, p=0·01) signifying that pnMSM were linked to each other. We found that self-reported heterosexual men were more likely to link MSM and heterosexual women than heterosexual women were to link MSM and heterosexual men (Fisher's exact test p=0·0004; OR 2·24) but the number of such transmission chains was small (only 54 in total vs 32 in women). INTERPRETATION pnMSM are a subgroup distinct from both MSM and from heterosexual men. They are more likely to choose sexual partners who are also pnMSM and might exhibit lower-risk sexual behaviour than MSM (eg, choosing low-risk partners or consistently using condoms). Heterosexual men are the group most likely to be diagnosed with late-stage disease (ie, low CD4 counts) and non-disclosed MSM might put female partners at higher risk than heterosexual men because non-disclosed MSM have male partners. Hence, pnMSM require specific consideration to ensure they are included in public health interventions. FUNDING National Institutes of Health.
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Affiliation(s)
| | - Stéphane Hué
- Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, London, UK
| | - Emma B Hodcroft
- Institute of Evolutionary Biology, Ashworth Laboratories, University of Edinburgh, Edinburgh, UK
| | - Anna Tostevin
- Institute for Global Health, University College London, London, UK
| | - David Dunn
- Institute for Global Health, University College London, London, UK
| | - Tracy Fawcett
- Virology, Old Medical School, Leeds General Infirmary, Leeds, UK
| | | | | | | | - Andrew J Leigh Brown
- Institute of Evolutionary Biology, Ashworth Laboratories, University of Edinburgh, Edinburgh, UK
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Yebra G, Frampton D, Gallo Cassarino T, Raffle J, Hubb J, Ferns RB, Waters L, Tong CYW, Kozlakidis Z, Hayward A, Kellam P, Pillay D, Clark D, Nastouli E, Leigh Brown AJ. A high HIV-1 strain variability in London, UK, revealed by full-genome analysis: Results from the ICONIC project. PLoS One 2018; 13:e0192081. [PMID: 29389981 PMCID: PMC5794160 DOI: 10.1371/journal.pone.0192081] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Accepted: 12/28/2017] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND & METHODS 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. RESULTS 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. CONCLUSIONS 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.
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Affiliation(s)
- Gonzalo Yebra
- Institute of Evolutionary Biology, University of Edinburgh, Edinburgh, United Kingdom
| | - Dan Frampton
- UCL Division of Infection and Immunity, Faculty of Medical Sciences, London, United Kingdom
| | | | - Jade Raffle
- UCL Division of Infection and Immunity, Faculty of Medical Sciences, London, United Kingdom
- Department of Clinical Virology, UCL Hospital NHS Foundation Trust, London, United Kingdom
| | - Jonathan Hubb
- Department of Virology, Barts Health NHS Trust, London, United Kingdom
| | - R. Bridget Ferns
- Department of Clinical Virology, UCL Hospital NHS Foundation Trust, London, United Kingdom
- NIHR UCLH/UCL Biomedical Research Centre, London, United Kingdom
| | - Laura Waters
- Department of HIV Medicine, Mortimer Market Centre, Central & North West London NHS Trust, London, United Kingdom
| | - C. Y. William Tong
- Department of Virology, Barts Health NHS Trust, London, United Kingdom
- Queen Mary University, London, United Kingdom
| | - Zisis Kozlakidis
- UCL Division of Infection and Immunity, Faculty of Medical Sciences, London, United Kingdom
- UCL Institute of Disease Informatics, Farr Institute of Health Informatics Research, London, United Kingdom
| | - Andrew Hayward
- UCL Institute of Epidemiology and Health Care, London, United Kingdom
| | - Paul Kellam
- Division of Infectious Diseases, Department of Medicine, Imperial College London, London, United Kingdom
| | - Deenan Pillay
- UCL Division of Infection and Immunity, Faculty of Medical Sciences, London, United Kingdom
| | - Duncan Clark
- Department of Virology, Barts Health NHS Trust, London, United Kingdom
- School of Life Sciences, University of Glasgow. Glasgow, United Kingdom
| | - Eleni Nastouli
- Department of Clinical Virology, UCL Hospital NHS Foundation Trust, London, United Kingdom
- Department of Population, Policy and Practice, UCL GOS Institute of Child Health, London, United Kingdom
| | - Andrew J. Leigh Brown
- Institute of Evolutionary Biology, University of Edinburgh, Edinburgh, United Kingdom
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10
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Lu L, Leigh Brown AJ, Lycett SJ. Quantifying predictors for the spatial diffusion of avian influenza virus in China. BMC Evol Biol 2017; 17:16. [PMID: 28086751 PMCID: PMC5237338 DOI: 10.1186/s12862-016-0845-3] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Accepted: 12/08/2016] [Indexed: 11/18/2022] Open
Abstract
Background Avian influenza virus (AIV) causes both severe outbreaks and endemic disease among poultry and has caused sporadic human infections in Asia, furthermore the routes of transmission in avian species between geographic regions can be numerous and complex. Using nucleotide sequences from the internal protein coding segments of AIV, we performed a Bayesian phylogeographic study to uncover regional routes of transmission and factors predictive of the rate of viral diffusion within China. Results We found that the Central area and Pan-Pearl River Delta were the two main sources of AIV diffusion, while the East Coast areas especially the Yangtze River delta, were the major targets of viral invasion. Next we investigated the extent to which economic, agricultural, environmental and climatic regional data was predictive of viral diffusion by fitting phylogeographic discrete trait models using generalised linear models. Conclusions Our results highlighted that the economic-agricultural predictors, especially the poultry population density and the number of farm product markets, are the key determinants of spatial diffusion of AIV in China; high human density and freight transportation are also important predictors of high rates of viral transmission; Climate features (e.g. temperature) were correlated to the viral invasion in the destination to some degree; while little or no impacts were found from natural environment factors (such as surface water coverage). This study uncovers the risk factors and enhances our understanding of the spatial dynamics of AIV in bird populations. Electronic supplementary material The online version of this article (doi:10.1186/s12862-016-0845-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Lu Lu
- Institute of Evolutionary Biology, Ashworth Laboratories, University of Edinburgh, Edinburgh, EH9 3JT, UK
| | - Andrew J Leigh Brown
- Institute of Evolutionary Biology, Ashworth Laboratories, University of Edinburgh, Edinburgh, EH9 3JT, UK
| | - Samantha J Lycett
- The Roslin Institute, University of Edinburgh, Easter Bush Campus, Midlothian, EH25 9RG, UK.
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11
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Yebra G, Hodcroft EB, Ragonnet-Cronin ML, Pillay D, Brown AJL. Using nearly full-genome HIV sequence data improves phylogeny reconstruction in a simulated epidemic. Sci Rep 2016; 6:39489. [PMID: 28008945 PMCID: PMC5180198 DOI: 10.1038/srep39489] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Accepted: 11/21/2016] [Indexed: 01/09/2023] Open
Abstract
HIV molecular epidemiology studies analyse viral pol gene sequences due to their availability, but whole genome sequencing allows to use other genes. We aimed to determine what gene(s) provide(s) the best approximation to the real phylogeny by analysing a simulated epidemic (created as part of the PANGEA_HIV project) with a known transmission tree. We sub-sampled a simulated dataset of 4662 sequences into different combinations of genes (gag-pol-env, gag-pol, gag, pol, env and partial pol) and sampling depths (100%, 60%, 20% and 5%), generating 100 replicates for each case. We built maximum-likelihood trees for each combination using RAxML (GTR + Γ), and compared their topologies to the corresponding true tree’s using CompareTree. The accuracy of the trees was significantly proportional to the length of the sequences used, with the gag-pol-env datasets showing the best performance and gag and partial pol sequences showing the worst. The lowest sampling depths (20% and 5%) greatly reduced the accuracy of tree reconstruction and showed high variability among replicates, especially when using the shortest gene datasets. In conclusion, using longer sequences derived from nearly whole genomes will improve the reliability of phylogenetic reconstruction. With low sample coverage, results can be highly variable, particularly when based on short sequences.
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Affiliation(s)
- Gonzalo Yebra
- Institute of Evolutionary Biology, University of Edinburgh, Edinburgh, UK
| | - Emma B Hodcroft
- Institute of Evolutionary Biology, University of Edinburgh, Edinburgh, UK
| | | | - Deenan Pillay
- Wellcome Trust-Africa Centre for Health and Population Studies, University of KwaZulu-Natal, Durban, South Africa
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12
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Ratmann O, Hodcroft EB, Pickles M, Cori A, Hall M, Lycett S, Colijn C, Dearlove B, Didelot X, Frost S, Hossain ASMM, Joy JB, Kendall M, Kühnert D, Leventhal GE, Liang R, Plazzotta G, Poon AFY, Rasmussen DA, Stadler T, Volz E, Weis C, Leigh Brown AJ, Fraser C. Phylogenetic Tools for Generalized HIV-1 Epidemics: Findings from the PANGEA-HIV Methods Comparison. Mol Biol Evol 2016; 34:185-203. [PMID: 28053012 PMCID: PMC5854118 DOI: 10.1093/molbev/msw217] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Viral phylogenetic methods contribute to understanding how HIV spreads in populations, and thereby help guide the design of prevention interventions. So far, most analyses have been applied to well-sampled concentrated HIV-1 epidemics in wealthy countries. To direct the use of phylogenetic tools to where the impact of HIV-1 is greatest, the Phylogenetics And Networks for Generalized HIV Epidemics in Africa (PANGEA-HIV) consortium generates full-genome viral sequences from across sub-Saharan Africa. Analyzing these data presents new challenges, since epidemics are principally driven by heterosexual transmission and a smaller fraction of cases is sampled. Here, we show that viral phylogenetic tools can be adapted and used to estimate epidemiological quantities of central importance to HIV-1 prevention in sub-Saharan Africa. We used a community-wide methods comparison exercise on simulated data, where participants were blinded to the true dynamics they were inferring. Two distinct simulations captured generalized HIV-1 epidemics, before and after a large community-level intervention that reduced infection levels. Five research groups participated. Structured coalescent modeling approaches were most successful: phylogenetic estimates of HIV-1 incidence, incidence reductions, and the proportion of transmissions from individuals in their first 3 months of infection correlated with the true values (Pearson correlation > 90%), with small bias. However, on some simulations, true values were markedly outside reported confidence or credibility intervals. The blinded comparison revealed current limits and strengths in using HIV phylogenetics in challenging settings, provided benchmarks for future methods' development, and supports using the latest generation of phylogenetic tools to advance HIV surveillance and prevention.
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Affiliation(s)
- Oliver Ratmann
- Department of Infectious Disease Epidemiology, MRC Centre for Outbreak Analyses and Modelling, School of Public Health, Imperial College London, London, United Kingdom
| | - Emma B Hodcroft
- School of Biological Sciences, Institute of Evolutionary Biology, University of Edinburgh, Edinburgh, United Kingdom
| | - Michael Pickles
- Department of Infectious Disease Epidemiology, MRC Centre for Outbreak Analyses and Modelling, School of Public Health, Imperial College London, London, United Kingdom
| | - Anne Cori
- Department of Infectious Disease Epidemiology, MRC Centre for Outbreak Analyses and Modelling, School of Public Health, Imperial College London, London, United Kingdom
| | - Matthew Hall
- School of Biological Sciences, Institute of Evolutionary Biology, University of Edinburgh, Edinburgh, United Kingdom.,Nuffield Department of Medicine, Li Ka Shing Centre for Health Information and Discovery, Oxford Big Data Institute, University of Oxford, Oxford, United Kingdom
| | - Samantha Lycett
- School of Biological Sciences, Institute of Evolutionary Biology, University of Edinburgh, Edinburgh, United Kingdom.,The Roslin Institute, University of Edinburgh, Edinburgh, United Kingdom
| | - Caroline Colijn
- Department of Mathematics, Imperial College London, London, United Kingdom
| | - Bethany Dearlove
- Department of Veterinary Medicine, Cambridge Veterinary School, Cambridge, United Kingdom
| | - Xavier Didelot
- Department of Infectious Disease Epidemiology, MRC Centre for Outbreak Analyses and Modelling, School of Public Health, Imperial College London, London, United Kingdom
| | - Simon Frost
- Department of Veterinary Medicine, Cambridge Veterinary School, Cambridge, United Kingdom
| | | | - Jeffrey B Joy
- Department of Medicine, University of British Columbia, Vancouver, BC, Canada.,British Columbia Centre for Excellence in HIV/AIDS, Vancouver, BC, Canada
| | - Michelle Kendall
- Department of Mathematics, Imperial College London, London, United Kingdom
| | - Denise Kühnert
- Department of Environmental Systems Science, ETH Zürich, Zürich, Switzerland.,Department of Biosystems Science and Engineering, ETH Zürich, Basel, Switzerland
| | - Gabriel E Leventhal
- Department of Environmental Systems Science, ETH Zürich, Zürich, Switzerland.,Department of Civil and Environmental Engineering, Massachusetts Institute of Technology (MIT), Cambridge, MA
| | - Richard Liang
- British Columbia Centre for Excellence in HIV/AIDS, Vancouver, BC, Canada
| | - Giacomo Plazzotta
- Department of Mathematics, Imperial College London, London, United Kingdom
| | - Art F Y Poon
- Department of Pathology & Laboratory Medicine, Western University, Ontario, Canada
| | - David A Rasmussen
- Department of Biosystems Science and Engineering, ETH Zürich, Basel, Switzerland
| | - Tanja Stadler
- Department of Biosystems Science and Engineering, ETH Zürich, Basel, Switzerland
| | - Erik Volz
- Department of Infectious Disease Epidemiology, MRC Centre for Outbreak Analyses and Modelling, School of Public Health, Imperial College London, London, United Kingdom
| | - Caroline Weis
- Department of Biosystems Science and Engineering, ETH Zürich, Basel, Switzerland
| | - Andrew J Leigh Brown
- School of Biological Sciences, Institute of Evolutionary Biology, University of Edinburgh, Edinburgh, United Kingdom
| | - Christophe Fraser
- Department of Infectious Disease Epidemiology, MRC Centre for Outbreak Analyses and Modelling, School of Public Health, Imperial College London, London, United Kingdom.,Nuffield Department of Medicine, Li Ka Shing Centre for Health Information and Discovery, Oxford Big Data Institute, University of Oxford, Oxford, United Kingdom
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13
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Yebra G, Kalish ML, Leigh Brown AJ. Reconstructing the HIV-1 CRF02_AG and CRF06_cpx epidemics in Burkina Faso and West Africa using early samples. Infect Genet Evol 2016; 46:209-218. [PMID: 27063411 DOI: 10.1016/j.meegid.2016.03.038] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Revised: 03/28/2016] [Accepted: 03/31/2016] [Indexed: 11/28/2022]
Abstract
BACKGROUND HIV-1 circulating recombinant forms (CRFs) represent viral recombinant lineages that play a significant role in the global epidemic. Two of them dominate the epidemic in Burkina Faso: CRF06_cpx (first described in this country) and CRF02_AG. We reconstructed the phylodynamics of both recombinant viruses in Burkina Faso and throughout West Africa. METHODS We analysed CRF06_cpx and CRF02_AG sequences (protease/gp41) from early samples collected in Burkina Faso in 1986 together with other GenBank sequences (1984-2013) in 4 datasets: African CRF06_cpx (210/60); down-sampled CRF06_cpx (146/45); Burkina Faso CRF02_AG (130/39) and West/Central African CRF02_AG (691/298). For each dataset, we analysed both protease and gp41 jointly using the BEAST multilocus analysis and conducted phylogeographic analysis to reconstruct the early migration routes between countries. RESULTS The time to the most recent common ancestor (tMRCA) of CRF06_cpx was 1979 (1973-1983) for protease and 1981 (1978-1983) for gp41. The gp41 analysis inferred the origin of CRF06_cpx (or at least its parental subtype G lineage) in the Democratic Republic of Congo but migrated to Burkina Faso soon after (1982). Both genes showed that CRF06_cpx radiated to the rest of West Africa predominantly after around 1990. These results were robust to the oversampling of Burkina Faso sequences as they were confirmed in the down-sampled dataset. The tMRCA of the Burkina Faso CRF02_AG lineage was 1979 (1977-1983) for protease and 1980 (1978-1981) for gp41. However, we reconstructed its presence in West Africa much earlier (mid-1960s), with an initial origin in Cameroon and/or Nigeria, and its phylogeographic analysis revealed much interconnection within the region with a lack of country-specific phylogenetic patterns, which prevents tracking its exact migration routes. CONCLUSIONS Burkina Faso presents a relatively young HIV epidemic, with the diversification of the current in-country CRF02_AG and CRF06_cpx lineages taking place around 1980. This country represents the main source of CRF06_cpx in West Africa. The CRF02_AG epidemic started at least a decade earlier and showed much interchange between West African countries (especially involving coastal countries) suggesting great population mobility and an extensive viral spread in the region.
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Affiliation(s)
- Gonzalo Yebra
- Institute of Evolutionary Biology, University of Edinburgh, Edinburgh, UK.
| | - Marcia L Kalish
- Institute for Global Health, Vanderbilt University, Nashville, TN, USA
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14
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Ragonnet-Cronin M, Lycett SJ, Hodcroft EB, Hué S, Fearnhill E, Brown AE, Delpech V, Dunn D, Leigh Brown AJ. Transmission of Non-B HIV Subtypes in the United Kingdom Is Increasingly Driven by Large Non-Heterosexual Transmission Clusters. J Infect Dis 2015; 213:1410-8. [PMID: 26704616 PMCID: PMC4813743 DOI: 10.1093/infdis/jiv758] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Accepted: 12/10/2015] [Indexed: 12/02/2022] Open
Abstract
Background. The United Kingdom human immunodeficiency virus (HIV) epidemic was historically dominated by HIV subtype B transmission among men who have sex with men (MSM). Now 50% of diagnoses and prevalent infections are among heterosexual individuals and mainly involve non-B subtypes. Between 2002 and 2010, the prevalence of non-B diagnoses among MSM increased from 5.4% to 17%, and this study focused on the drivers of this change. Methods. Growth between 2007 and 2009 in transmission clusters among 14 000 subtype A1, C, D, and G sequences from the United Kingdom HIV Drug Resistance Database was analysed by risk group. Results. Of 1148 clusters containing at least 2 sequences in 2007, >75% were pairs and >90% were heterosexual. Most clusters (71.4%) did not grow during the study period. Growth was significantly lower for small clusters and higher for clusters of ≥7 sequences, with the highest growth observed for clusters comprising sequences from MSM and people who inject drugs (PWID). Risk group (P < .0001), cluster size (P < .0001), and subtype (P < .01) were predictive of growth in a generalized linear model. Discussion. Despite the increase in non-B subtypes associated with heterosexual transmission, MSM and PWID are at risk for non-B infections. Crossover of subtype C from heterosexuals to MSM has led to the expansion of this subtype within the United Kingdom.
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Affiliation(s)
| | | | | | | | | | | | | | - David Dunn
- MRC Clinical Trials Unit at University College London
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15
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Yebra G, Ragonnet-Cronin M, Ssemwanga D, Parry CM, Logue CH, Cane PA, Kaleebu P, Brown AJL. Analysis of the history and spread of HIV-1 in Uganda using phylodynamics. J Gen Virol 2015; 96:1890-8. [PMID: 25724670 PMCID: PMC4635457 DOI: 10.1099/vir.0.000107] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
HIV prevalence has decreased in Uganda since the 1990s, but remains substantial within high-risk groups. Here, we reconstruct the history and spread of HIV subtypes A1 and D in Uganda and explore the transmission dynamics in high-risk populations. We analysed HIV pol sequences from female sex workers in Kampala (n = 42), Lake Victoria fisher-folk (n = 46) and a rural clinical cohort (n = 74), together with publicly available sequences from adjacent regions in Uganda (n = 412) and newly generated sequences from samples taken in Kampala in 1986 (n = 12). Of the sequences from the three Ugandan populations, 60 (37.1 %) were classified as subtype D, 54 (33.3 %) as subtype A1, 31 (19.1 %) as A1/D recombinants, six (3.7 %) as subtype C, one (0.6 %) as subtype G and 10 (6.2 %) as other recombinants. Among the A1/D recombinants we identified a new candidate circulating recombinant form. Phylodynamic and phylogeographic analyses using BEAST indicated that the Ugandan epidemics originated in 1960 (1950-1968) for subtype A1 and 1973 (1970-1977) for D, in rural south-western Uganda with subsequent spread to Kampala. They also showed extensive interconnection with adjacent countries. The sequence analysis shows both epidemics grew exponentially during the 1970s-1980s and decreased from 1992, which agrees with HIV prevalence reports in Uganda. Inclusion of sequences from the 1980s indicated the origin of both epidemics was more recent than expected and substantially narrowed the confidence intervals in comparison to previous estimates. We identified three transmission clusters and ten pairs, none of them including patients from different populations, suggesting active transmission within a structured transmission network.
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Affiliation(s)
- Gonzalo Yebra
- 1Institute of Evolutionary Biology, University of Edinburgh, Edinburgh, UK
| | | | | | - Chris M Parry
- 2MRC/UVRI, Uganda Research Unit on AIDS, Entebbe, Uganda
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16
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Hodcroft E, Hadfield JD, Fearnhill E, Phillips A, Dunn D, O'Shea S, Pillay D, Leigh Brown AJ. The contribution of viral genotype to plasma viral set-point in HIV infection. PLoS Pathog 2014; 10:e1004112. [PMID: 24789308 PMCID: PMC4006911 DOI: 10.1371/journal.ppat.1004112] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2013] [Accepted: 03/22/2014] [Indexed: 12/24/2022] Open
Abstract
Disease progression in HIV-infected individuals varies greatly, and while the environmental and host factors influencing this variation have been widely investigated, the viral contribution to variation in set-point viral load, a predictor of disease progression, is less clear. Previous studies, using transmission-pairs and analysis of phylogenetic signal in small numbers of individuals, have produced a wide range of viral genetic effect estimates. Here we present a novel application of a population-scale method based in quantitative genetics to estimate the viral genetic effect on set-point viral load in the UK subtype B HIV-1 epidemic, based on a very large data set. Analyzing the initial viral load and associated pol sequence, both taken before anti-retroviral therapy, of 8,483 patients, we estimate the proportion of variance in viral load explained by viral genetic effects to be 5.7% (CI 2.8-8.6%). We also estimated the change in viral load over time due to selection on the virus and environmental effects to be a decline of 0.05 log10 copies/mL/year, in contrast to recent studies which suggested a reported small increase in viral load over the last 20 years might be due to evolutionary changes in the virus. Our results suggest that in the UK epidemic, subtype B has a small but significant viral genetic effect on viral load. By allowing the analysis of large sample sizes, we expect our approach to be applicable to the estimation of the genetic contribution to traits in many organisms.
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Affiliation(s)
- Emma Hodcroft
- Institute of Evolutionary Biology, University of Edinburgh, Ashworth Laboratories, Edinburgh, United Kingdom
| | - Jarrod D. Hadfield
- Institute of Evolutionary Biology, University of Edinburgh, Ashworth Laboratories, Edinburgh, United Kingdom
| | | | - Andrew Phillips
- Infection and Population Health, University College London, Royal Free Hospital, London, United Kingdom
| | - David Dunn
- MRC Clinical Trials Unit Aviation House, London, United Kingdom
| | - Siobhan O'Shea
- Department of Infectious Diseases, King's College London, London, United Kingdom
| | - Deenan Pillay
- Research Department of Infection, University College London, London, United Kingdom
| | - Andrew J. Leigh Brown
- Institute of Evolutionary Biology, University of Edinburgh, Ashworth Laboratories, Edinburgh, United Kingdom
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17
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Lu L, Lycett SJ, Leigh Brown AJ. Reassortment patterns of avian influenza virus internal segments among different subtypes. BMC Evol Biol 2014; 14:16. [PMID: 24456010 PMCID: PMC3905155 DOI: 10.1186/1471-2148-14-16] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2013] [Accepted: 01/14/2014] [Indexed: 01/26/2023] Open
Abstract
Background The segmented RNA genome of avian Influenza viruses (AIV) allows genetic reassortment between co-infecting viruses, providing an evolutionary pathway to generate genetic innovation. The genetic diversity (16 haemagglutinin and 9 neuraminidase subtypes) of AIV indicates an extensive reservoir of influenza viruses exists in bird populations, but how frequently subtypes reassort with each other is still unknown. Here we quantify the reassortment patterns among subtypes in the Eurasian avian viral pool by reconstructing the ancestral states of the subtypes as discrete states on time-scaled phylogenies with respect to the internal protein coding segments. We further analyzed how host species, the inferred evolutionary rates and the dN/dS ratio varied among segments and between discrete subtypes, and whether these factors may be associated with inter-subtype reassortment rate. Results The general patterns of reassortment are similar among five internal segments with the exception of segment 8, encoding the Non-Structural genes, which has a more divergent phylogeny. However, significant variation in rates between subtypes was observed. In particular, hemagglutinin-encoding segments of subtypes H5 to H9 reassort at a lower rate compared to those of H1 to H4, and Neuraminidase-encoding segments of subtypes N1 and N2 reassort less frequently than N3 to N9. Both host species and dN/dS ratio were significantly associated with reassortment rate, while evolutionary rate was not associated. The dN/dS ratio was negatively correlated with reassortment rate, as was the number of negatively selected sites for all segments. Conclusions These results indicate that overall selective constraint and host species are both associated with reassortment rate. These results together identify the wild bird population as the major source of new reassortants, rather than domestic poultry. The lower reassortment rates observed for H5N1 and H9N2 may be explained by the large proportion of strains derived from domestic poultry populations. In contrast, the higher rates observed in the H1N1, H3N8 and H4N6 subtypes could be due to their primary origin as infections of wild birds with multiple low pathogenicity strains in the large avian reservoir.
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Affiliation(s)
| | | | - Andrew J Leigh Brown
- University of Edinburgh, Institute of Evolutionary Biology, Ashworth Laboratories, West Mains Road, Edinburgh EH9 3JT, UK.
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18
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Ragonnet-Cronin M, Hodcroft E, Hué S, Fearnhill E, Delpech V, Brown AJL, Lycett S. Automated analysis of phylogenetic clusters. BMC Bioinformatics 2013; 14:317. [PMID: 24191891 PMCID: PMC4228337 DOI: 10.1186/1471-2105-14-317] [Citation(s) in RCA: 251] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2013] [Accepted: 10/30/2013] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND As sequence data sets used for the investigation of pathogen transmission patterns increase in size, automated tools and standardized methods for cluster analysis have become necessary. We have developed an automated Cluster Picker which identifies monophyletic clades meeting user-input criteria for bootstrap support and maximum genetic distance within large phylogenetic trees. A second tool, the Cluster Matcher, automates the process of linking genetic data to epidemiological or clinical data, and matches clusters between runs of the Cluster Picker. RESULTS We explore the effect of different bootstrap and genetic distance thresholds on clusters identified in a data set of publicly available HIV sequences, and compare these results to those of a previously published tool for cluster identification. To demonstrate their utility, we then use the Cluster Picker and Cluster Matcher together to investigate how clusters in the data set changed over time. We find that clusters containing sequences from more than one UK location at the first time point (multiple origin) were significantly more likely to grow than those representing only a single location. CONCLUSIONS The Cluster Picker and Cluster Matcher can rapidly process phylogenetic trees containing tens of thousands of sequences. Together these tools will facilitate comparisons of pathogen transmission dynamics between studies and countries.
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Abstract
Human immunodeficiency virus type 1 (HIV-1) is pandemic, but its contemporary global transmission network has not been characterized. A better understanding of the properties and dynamics of this network is essential for surveillance, prevention, and eventual eradication of HIV. Here, we apply a simple and computationally efficient network-based approach to all publicly available HIV polymerase sequences in the global database, revealing a contemporary picture of the spread of HIV-1 within and between countries. This approach automatically recovered well-characterized transmission clusters and extended other clusters thought to be contained within a single country across international borders. In addition, previously undescribed transmission clusters were discovered. Together, these clusters represent all known modes of HIV transmission. The extent of international linkage revealed by our comprehensive approach demonstrates the need to consider the global diversity of HIV, even when describing local epidemics. Finally, the speed of this method allows for near-real-time surveillance of the pandemic's progression.
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Ward MJ, Lycett SJ, Avila D, Bollback JP, Leigh Brown AJ. Evolutionary interactions between haemagglutinin and neuraminidase in avian influenza. BMC Evol Biol 2013; 13:222. [PMID: 24103105 PMCID: PMC3854068 DOI: 10.1186/1471-2148-13-222] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2013] [Accepted: 09/16/2013] [Indexed: 02/07/2023] Open
Abstract
Background Reassortment between the RNA segments encoding haemagglutinin (HA) and neuraminidase (NA), the major antigenic influenza proteins, produces viruses with novel HA and NA subtype combinations and has preceded the emergence of pandemic strains. It has been suggested that productive viral infection requires a balance in the level of functional activity of HA and NA, arising from their closely interacting roles in the viral life cycle, and that this functional balance could be mediated by genetic changes in the HA and NA. Here, we investigate how the selective pressure varies for H7 avian influenza HA on different NA subtype backgrounds. Results By extending Bayesian stochastic mutational mapping methods to calculate the ratio of the rate of non-synonymous change to the rate of synonymous change (dN/dS), we found the average dN/dS across the avian influenza H7 HA1 region to be significantly greater on an N2 NA subtype background than on an N1, N3 or N7 background. Observed differences in evolutionary rates of H7 HA on different NA subtype backgrounds could not be attributed to underlying differences between avian host species or virus pathogenicity. Examination of dN/dS values for each subtype on a site-by-site basis indicated that the elevated dN/dS on the N2 NA background was a result of increased selection, rather than a relaxation of selective constraint. Conclusions Our results are consistent with the hypothesis that reassortment exposes influenza HA to significant changes in selective pressure through genetic interactions with NA. Such epistatic effects might be explicitly accounted for in future models of influenza evolution.
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Affiliation(s)
- Melissa J Ward
- Institute for Evolutionary Biology, University of Edinburgh, Ashworth Building, West Mains Road, Edinburgh EH9 3JT, Scotland, UK.
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Schuh AJ, Ward MJ, Leigh Brown AJ, Barrett ADT. Phylogeography of Japanese encephalitis virus: genotype is associated with climate. PLoS Negl Trop Dis 2013; 7:e2411. [PMID: 24009790 PMCID: PMC3757071 DOI: 10.1371/journal.pntd.0002411] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2013] [Accepted: 07/26/2013] [Indexed: 11/18/2022] Open
Abstract
The circulation of vector-borne zoonotic viruses is largely determined by the overlap in the geographical distributions of virus-competent vectors and reservoir hosts. What is less clear are the factors influencing the distribution of virus-specific lineages. Japanese encephalitis virus (JEV) is the most important etiologic agent of epidemic encephalitis worldwide, and is primarily maintained between vertebrate reservoir hosts (avian and swine) and culicine mosquitoes. There are five genotypes of JEV: GI-V. In recent years, GI has displaced GIII as the dominant JEV genotype and GV has re-emerged after almost 60 years of undetected virus circulation. JEV is found throughout most of Asia, extending from maritime Siberia in the north to Australia in the south, and as far as Pakistan to the west and Saipan to the east. Transmission of JEV in temperate zones is epidemic with the majority of cases occurring in summer months, while transmission in tropical zones is endemic and occurs year-round at lower rates. To test the hypothesis that viruses circulating in these two geographical zones are genetically distinct, we applied Bayesian phylogeographic, categorical data analysis and phylogeny-trait association test techniques to the largest JEV dataset compiled to date, representing the envelope (E) gene of 487 isolates collected from 12 countries over 75 years. We demonstrated that GIII and the recently emerged GI-b are temperate genotypes likely maintained year-round in northern latitudes, while GI-a and GII are tropical genotypes likely maintained primarily through mosquito-avian and mosquito-swine transmission cycles. This study represents a new paradigm directly linking viral molecular evolution and climate. Although Japanese encephalitis virus (JEV) is a major cause of death and disability throughout tropical and temperate Asia, little is known about the evolution, geographical distribution and epidemiology of the five JEV genotypes (genetically distinct groups). To address this gap in our knowledge, we performed a genetic-based geographical analysis using the largest JEV sequence dataset assembled to date, including 487 viral sequences sampled from 12 countries over 75 years. We showed that both the newly and previously dominant genotypes of JEV are associated with temperate climates and are maintained throughout the cold winter months in northern Asia, likely by hibernating mosquitoes (survive throughout the winter), vertical transmission in mosquitoes (female to offspring), cold-blooded vertebrates and/or bats.
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Affiliation(s)
- Amy J. Schuh
- Center for Biodefense and Emerging Infectious Diseases, University of Texas Medical Branch, Galveston, Texas, United States of America
- Center for Tropical Diseases, University of Texas Medical Branch, Galveston, Texas, United States of America
- Sealy Center for Vaccine Development, University of Texas Medical Branch, Galveston, Texas, United States of America
- Institute for Human Infections and Immunity University of Texas Medical Branch, Galveston, Texas, United States of America
- Department of Pathology, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Melissa J. Ward
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, Scotland
| | - Andrew J. Leigh Brown
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, Scotland
| | - Alan D. T. Barrett
- Center for Biodefense and Emerging Infectious Diseases, University of Texas Medical Branch, Galveston, Texas, United States of America
- Center for Tropical Diseases, University of Texas Medical Branch, Galveston, Texas, United States of America
- Sealy Center for Vaccine Development, University of Texas Medical Branch, Galveston, Texas, United States of America
- Institute for Human Infections and Immunity University of Texas Medical Branch, Galveston, Texas, United States of America
- Department of Pathology, University of Texas Medical Branch, Galveston, Texas, United States of America
- * E-mail:
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Ward MJ, Lycett SJ, Kalish ML, Rambaut A, Leigh Brown AJ. Estimating the rate of intersubtype recombination in early HIV-1 group M strains. J Virol 2013; 87:1967-73. [PMID: 23236072 PMCID: PMC3571495 DOI: 10.1128/jvi.02478-12] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2012] [Accepted: 12/06/2012] [Indexed: 11/20/2022] Open
Abstract
West Central Africa has been implicated as the epicenter of the HIV-1 epidemic, and almost all group M subtypes can be found there. Previous analysis of early HIV-1 group M sequences from Kinshasa in the Democratic Republic of Congo, formerly Zaire, revealed that isolates from a number of individuals fall in different positions in phylogenetic trees constructed from sequences from opposite ends of the genome as a result of recombination between viruses of different subtypes. Here, we use discrete ancestral trait mapping to develop a procedure for quantifying HIV-1 group M intersubtype recombination across phylogenies, using individuals' gag (p17) and env (gp41) subtypes. The method was applied to previously described HIV-1 group M sequences from samples obtained in Kinshasa early in the global radiation of HIV. Nine different p17 and gp41 intersubtype recombinant combinations were present in the data set. The mean number of excess ancestral subtype transitions (NEST) required to map individuals' p17 subtypes onto the gp14 phylogeny samples, compared to the number required to map them onto the p17 phylogenies, and vice versa, indicated that excess subtype transitions occurred at a rate of approximately 7 × 10(-3) to 8 × 10(-3) per lineage per year as a result of intersubtype recombination. Our results imply that intersubtype recombination may have occurred in approximately 20% of lineages evolving over a period of 30 years and confirm intersubtype recombination as a substantial force in generating HIV-1 group M diversity.
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Affiliation(s)
- Melissa J. Ward
- University of Edinburgh, Institute of Evolutionary Biology, Ashworth Laboratories, Edinburgh, United Kingdom
| | - Samantha J. Lycett
- University of Edinburgh, Institute of Evolutionary Biology, Ashworth Laboratories, Edinburgh, United Kingdom
| | - Marcia L. Kalish
- Vanderbilt University, Vanderbilt Institute for Global Health, Nashville, Tennessee, USA
| | - Andrew Rambaut
- University of Edinburgh, Institute of Evolutionary Biology, Ashworth Laboratories, Edinburgh, United Kingdom
- Fogarty International Center, National Institutes of Health, Bethesda, Maryland, USA
| | - Andrew J. Leigh Brown
- University of Edinburgh, Institute of Evolutionary Biology, Ashworth Laboratories, Edinburgh, United Kingdom
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Lycett S, McLeish NJ, Robertson C, Carman W, Baillie G, McMenamin J, Rambaut A, Simmonds P, Woolhouse M, Leigh Brown AJ. Origin and fate of A/H1N1 influenza in Scotland during 2009. J Gen Virol 2012; 93:1253-1260. [PMID: 22337637 PMCID: PMC3755513 DOI: 10.1099/vir.0.039370-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The spread of influenza has usually been described by a ‘density’ model, where the largest centres of population drive the epidemic within a country. An alternative model emphasizing the role of air travel has recently been developed. We have examined the relative importance of the two in the context of the 2009 H1N1 influenza epidemic in Scotland. We obtained genome sequences of 70 strains representative of the geographical and temporal distribution of H1N1 influenza during the summer and winter phases of the pandemic in 2009. We analysed these strains, together with another 128 from the rest of the UK and 292 globally distributed strains, using maximum-likelihood phylogenetic and Bayesian phylogeographical methods. This revealed strikingly different epidemic patterns within Scotland in the early and late parts of 2009. The summer epidemic in Scotland was characterized by multiple independent introductions from both international and other UK sources, followed by major local expansion of a single clade that probably originated in Birmingham. The winter phase, in contrast, was more diverse genetically, with several clades of similar size in different locations, some of which had no particularly close phylogenetic affinity to strains sampled from either Scotland or England. Overall there was evidence to support both models, with significant links demonstrated between North American sequences and those from England, and between England and East Asia, indicating that major air-travel routes played an important role in the pattern of spread of the pandemic, both within the UK and globally.
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Affiliation(s)
- Samantha Lycett
- Institute of Evolutionary Biology, University of Edinburgh, Ashworth Laboratories, Edinburgh EH9 3JT, UK
| | - Nigel J McLeish
- Centre for Immunity, Infection and Evolution, Ashworth Laboratories, West Mains Rd, Edinburgh EH9 3JT, UK
| | - Christopher Robertson
- Health Protection Scotland (HPS), 3 Clifton Place, Glasgow G3 7LN, UK
- Department of Mathematics and Statistics, University of Strathclyde, 26 Richmond Street, Glasgow G1 1XH, UK
| | - William Carman
- West of Scotland Specialist Virology Centre, Gartnavel General Hospital, Glasgow, UK
| | - Gregory Baillie
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, CB10 1SA, UK
| | - James McMenamin
- Health Protection Scotland (HPS), 3 Clifton Place, Glasgow G3 7LN, UK
| | - Andrew Rambaut
- Institute of Evolutionary Biology, University of Edinburgh, Ashworth Laboratories, Edinburgh EH9 3JT, UK
| | - Peter Simmonds
- Centre for Immunity, Infection and Evolution, Ashworth Laboratories, West Mains Rd, Edinburgh EH9 3JT, UK
| | - Mark Woolhouse
- Centre for Immunity, Infection and Evolution, Ashworth Laboratories, West Mains Rd, Edinburgh EH9 3JT, UK
| | - Andrew J Leigh Brown
- Institute of Evolutionary Biology, University of Edinburgh, Ashworth Laboratories, Edinburgh EH9 3JT, UK
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Leigh Brown AJ, Lycett SJ, Weinert L, Hughes GJ, Fearnhill E, Dunn DT. Transmission network parameters estimated from HIV sequences for a nationwide epidemic. J Infect Dis 2011; 204:1463-9. [PMID: 21921202 PMCID: PMC3182313 DOI: 10.1093/infdis/jir550] [Citation(s) in RCA: 162] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2011] [Accepted: 06/20/2011] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Many studies of sexual behavior have shown that individuals vary greatly in their number of sexual partners over time, but it has proved difficult to obtain parameter estimates relating to the dynamics of human immunodeficiency virus (HIV) transmission except in small-scale contact tracing studies. Recent developments in molecular phylodynamics have provided new routes to obtain these parameter estimates, and current clinical practice provides suitable data for entire infected populations. METHODS A phylodynamic analysis was performed on partial pol gene sequences obtained for routine clinical care from 14,560 individuals, representing approximately 60% of the HIV-positive men who have sex with men (MSM) under care in the United Kingdom. RESULTS Among individuals linked to others in the data set, 29% are linked to only 1 individual, 41% are linked to 2-10 individuals, and 29% are linked to ≥10 individuals. The right-skewed degree distribution can be approximated by a power law, but the data are best fitted by a Waring distribution for all time depths. For time depths of 5-7 years, the distribution parameter ρ lies within the range that indicates infinite variance. CONCLUSIONS The transmission network among UK MSM is characterized by preferential association such that a randomly distributed intervention would not be expected to stop the epidemic.
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Affiliation(s)
- Andrew J Leigh Brown
- Institute of Evolutionary Biology, University of Edinburgh, London, United Kingdom.
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Hughes GJ, Fearnhill E, Dunn D, Lycett SJ, Rambaut A, Leigh Brown AJ. Molecular phylodynamics of the heterosexual HIV epidemic in the United Kingdom. PLoS Pathog 2009; 5:e1000590. [PMID: 19779560 PMCID: PMC2742734 DOI: 10.1371/journal.ppat.1000590] [Citation(s) in RCA: 142] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2009] [Accepted: 08/25/2009] [Indexed: 11/25/2022] Open
Abstract
The heterosexual risk group has become the largest HIV infected group in the United Kingdom during the last 10 years, but little is known of the network structure and dynamics of viral transmission in this group. The overwhelming majority of UK heterosexual infections are of non-B HIV subtypes, indicating viruses originating among immigrants from sub-Saharan Africa. The high rate of HIV evolution, combined with the availability of a very high density sample of viral sequences from routine clinical care has allowed the phylodynamics of the epidemic to be investigated for the first time. Sequences of the viral protease and partial reverse transcriptase coding regions from 11,071 patients infected with HIV of non-B subtypes were studied. Of these, 2774 were closely linked to at least one other sequence by nucleotide distance. Including the closest sequences from the global HIV database identified 296 individuals that were in UK-based groups of 3 or more individuals. There were a total of 8 UK-based clusters of 10 or more, comprising 143/2774 (5%) individuals, much lower than the figure of 25% obtained earlier for men who have sex with men (MSM). Sample dates were incorporated into relaxed clock phylogenetic analyses to estimate the dates of internal nodes. From the resulting time-resolved phylogenies, the internode lengths, used as estimates of maximum transmission intervals, had a median of 27 months overall, over twice as long as obtained for MSM (14 months), with only 2% of transmissions occurring in the first 6 months after infection. This phylodynamic analysis of non-B subtype HIV sequences representing over 40% of the estimated UK HIV-infected heterosexual population has revealed heterosexual HIV transmission in the UK is clustered, but on average in smaller groups and is transmitted with slower dynamics than among MSM. More effective intervention to restrict the epidemic may therefore be feasible, given effective diagnosis programmes. Since 1995, HIV among heterosexuals in the UK increased to the point where the total number of heterosexuals infected with HIV, predominantly of non-B subtypes, exceeds the number of HIV-positive homosexual men. To understand the dynamics of this epidemic, we have applied the novel technique of phylodynamics to the analysis of viral sequences taken in the course of routine clinical care from approximately 40% of the HIV-infected heterosexual population in the UK. Phylodynamics reconstructs the pattern of viral sequence divergence in time, revealing the size of transmission clusters and the dynamics of transmission within them. Of 11,071 patients studied, 296 were linked to at least two others in the UK. There were 8 clusters comprising 10 or more individuals among these, yielding a total of 143 or 5% of all individuals with links, much lower than seen earlier among homosexual men (25%). Viral transmissions within clusters also occurred less rapidly, only 2% being dated to the first 6 months of infection, compared to 25% among homosexual men. Overall, transmission clusters exist in the UK heterosexual HIV epidemic but they are generally smaller than among homosexuals; onward transmission occurs less rapidly and is not associated with acute HIV infection.
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Affiliation(s)
- Gareth J. Hughes
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, Scotland, United Kingdom
| | - Esther Fearnhill
- Medical Research Council Clinical Trials Unit, London, United Kingdom
| | - David Dunn
- Medical Research Council Clinical Trials Unit, London, United Kingdom
| | - Samantha J. Lycett
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, Scotland, United Kingdom
| | - Andrew Rambaut
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, Scotland, United Kingdom
| | - Andrew J. Leigh Brown
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, Scotland, United Kingdom
- * E-mail:
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Kosakovsky Pond SL, Poon AFY, Leigh Brown AJ, Frost SDW. A maximum likelihood method for detecting directional evolution in protein sequences and its application to influenza A virus. Mol Biol Evol 2008; 25:1809-24. [PMID: 18511426 DOI: 10.1093/molbev/msn123] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
We develop a model-based phylogenetic maximum likelihood test for evidence of preferential substitution toward a given residue at individual positions of a protein alignment--directional evolution of protein sequences (DEPS). DEPS can identify both the target residue and sites evolving toward it, help detect selective sweeps and frequency-dependent selection--scenarios that confound most existing tests for selection, and achieve good power and accuracy on simulated data. We applied DEPS to alignments representing different genomic regions of influenza A virus (IAV), sampled from avian hosts (H5N1 serotype) and human hosts (H3N2 serotype), and identified multiple directionally evolving sites in 5/8 genomic segments of H5N1 and H3N2 IAV. We propose a simple descriptive classification of directionally evolving sites into 5 groups based on the temporal distribution of residue frequencies and document known functional correlates, such as immune escape or host adaptation.
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Abstract
BACKGROUND The structure of sexual contact networks plays a key role in the epidemiology of sexually transmitted infections, and their reconstruction from interview data has provided valuable insights into the spread of infection. For HIV, the long period of infectivity has made the interpretation of contact networks more difficult, and major discrepancies have been observed between the contact network and the transmission network revealed by viral phylogenetics. The high rate of HIV evolution in principle allows for detailed reconstruction of links between virus from different individuals, but often sampling has been too sparse to describe the structure of the transmission network. The aim of this study was to analyze a high-density sample of an HIV-infected population using recently developed techniques in phylogenetics to infer the short-term dynamics of the epidemic among men who have sex with men (MSM). METHODS AND FINDINGS Sequences of the protease and reverse transcriptase coding regions from 2,126 patients, predominantly MSM, from London were compared: 402 of these showed a close match to at least one other subtype B sequence. Nine large clusters were identified on the basis of genetic distance; all were confirmed by Bayesian Monte Carlo Markov chain (MCMC) phylogenetic analysis. Overall, 25% of individuals with a close match with one sequence are linked to 10 or more others. Dated phylogenies of the clusters using a relaxed clock indicated that 65% of the transmissions within clusters took place between 1995 and 2000, and 25% occurred within 6 mo after infection. The likelihood that not all members of the clusters have been identified renders the latter observation conservative. CONCLUSIONS Reconstruction of the HIV transmission network using a dated phylogeny approach has revealed the HIV epidemic among MSM in London to have been episodic, with evidence of multiple clusters of transmissions dating to the late 1990s, a period when HIV prevalence is known to have doubled in this population. The quantitative description of the transmission dynamics among MSM will be important for parameterization of epidemiological models and in designing intervention strategies.
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Affiliation(s)
- Fraser Lewis
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, Scotland
| | - Gareth J Hughes
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, Scotland
| | - Andrew Rambaut
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, Scotland
| | - Anton Pozniak
- Chelsea and Westminster Hospital, London, United Kingdom
| | - Andrew J. Leigh Brown
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, Scotland
- * To whom correspondence should be addressed. E-mail:
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Poon AFY, Kosakovsky Pond SL, Bennett P, Richman DD, Leigh Brown AJ, Frost SDW. Adaptation to human populations is revealed by within-host polymorphisms in HIV-1 and hepatitis C virus. PLoS Pathog 2007; 3:e45. [PMID: 17397261 PMCID: PMC1839164 DOI: 10.1371/journal.ppat.0030045] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2006] [Accepted: 02/11/2007] [Indexed: 11/18/2022] Open
Abstract
CD8(+) cytotoxic T-lymphocytes (CTLs) perform a critical role in the immune control of viral infections, including those caused by human immunodeficiency virus type 1 (HIV-1) and hepatitis C virus (HCV). As a result, genetic variation at CTL epitopes is strongly influenced by host-specific selection for either escape from the immune response, or reversion due to the replicative costs of escape mutations in the absence of CTL recognition. Under strong CTL-mediated selection, codon positions within epitopes may immediately "toggle" in response to each host, such that genetic variation in the circulating virus population is shaped by rapid adaptation to immune variation in the host population. However, this hypothesis neglects the substantial genetic variation that accumulates in virus populations within hosts. Here, we evaluate this quantity for a large number of HIV-1- (n > or = 3,000) and HCV-infected patients (n > or = 2,600) by screening bulk RT-PCR sequences for sequencing "mixtures" (i.e., ambiguous nucleotides), which act as site-specific markers of genetic variation within each host. We find that nonsynonymous mixtures are abundant and significantly associated with codon positions under host-specific CTL selection, which should deplete within-host variation by driving the fixation of the favored variant. Using a simple model, we demonstrate that this apparently contradictory outcome can be explained by the transmission of unfavorable variants to new hosts before they are removed by selection, which occurs more frequently when selection and transmission occur on similar time scales. Consequently, the circulating virus population is shaped by the transmission rate and the disparity in selection intensities for escape or reversion as much as it is shaped by the immune diversity of the host population, with potentially serious implications for vaccine design.
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Affiliation(s)
- Art F Y Poon
- Department of Pathology, University of California San Diego, La Jolla, California, United States of America.
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Kosakovsky Pond SL, Frost SDW, Grossman Z, Gravenor MB, Richman DD, Brown AJL. Adaptation to different human populations by HIV-1 revealed by codon-based analyses. PLoS Comput Biol 2006; 2:e62. [PMID: 16789820 PMCID: PMC1480537 DOI: 10.1371/journal.pcbi.0020062] [Citation(s) in RCA: 180] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2005] [Accepted: 04/21/2006] [Indexed: 12/18/2022] Open
Abstract
Several codon-based methods are available for detecting adaptive evolution in protein-coding sequences, but to date none specifically identify sites that are selected differentially in two populations, although such comparisons between populations have been historically useful in identifying the action of natural selection. We have developed two fixed effects maximum likelihood methods: one for identifying codon positions showing selection patterns that persist in a population and another for detecting whether selection is operating differentially on individual codons of a gene sampled from two different populations. Applying these methods to two HIV populations infecting genetically distinct human hosts, we have found that few of the positively selected amino acid sites persist in the population; the other changes are detected only at the tips of the phylogenetic tree and appear deleterious in the long term. Additionally, we have identified seven amino acid sites in protease and reverse transcriptase that are selected differentially in the two samples, demonstrating specific population-level adaptation of HIV to human populations. Despite the efforts devoted to surveying HIV genetic diversity and the development of an effective vaccine, there is still no consensus on the extent to which the former prejudices the latter. Experimental studies show that escape from cell-mediated immunity is selected for in HIV and SIV, and sometimes very quickly. Conversely, escape mutants may be selected against at transmission, so how much does this selection within individuals influence the genotype of the circulating HIV population overall? Kosakovsky Pond, Leigh Brown, and colleagues have developed a new statistical approach to address this question. Using sequences from the globally most abundant HIV subtype (subtype C), the authors directly compared virus of the same subtype infecting genetically different human populations. They show at least half of the amino acid sites selected within individuals are not selected at a population level, and they identify six amino acid sites in the RT gene that are selected differentially between populations. We can now partition molecular adaptation between individual and population components for whatever genes may be included in candidate vaccines, in the target populations themselves. The methods are also important beyond the HIV world, where analogous issues arise in the more general question of the evolution of virulence in pathogens.
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Affiliation(s)
- Sergei L Kosakovsky Pond
- Department of Pathology, University of California San Diego, La Jolla, California, United States of America
| | - Simon D. W Frost
- Department of Pathology, University of California San Diego, La Jolla, California, United States of America
| | - Zehava Grossman
- National HIV Reference Lab, Public Health Laboratory, Ministry of Health, Tel Hashomer, Israel
| | - Michael B Gravenor
- School of Medicine, University of Swansea, Swansea, Wales, United Kingdom
| | - Douglas D Richman
- Department of Pathology, University of California San Diego, La Jolla, California, United States of America
- VA San Diego Health Care System, San Diego, California, United States of America
| | - Andrew J. Leigh Brown
- Institute for Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, Scotland, United Kingdom
- * To whom correspondence should be addressed. E-mail:
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Martinez-Picado J, Wrin T, Frost SDW, Clotet B, Ruiz L, Brown AJL, Petropoulos CJ, Parkin NT. Phenotypic hypersusceptibility to multiple protease inhibitors and low replicative capacity in patients who are chronically infected with human immunodeficiency virus type 1. J Virol 2005; 79:5907-13. [PMID: 15857976 PMCID: PMC1091704 DOI: 10.1128/jvi.79.10.5907-5913.2005] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Increased susceptibility to the protease inhibitors saquinavir and amprenavir has been observed in human immunodeficiency virus type 1 (HIV-1) with specific mutations in protease (V82T and N88S). Increased susceptibility to ritonavir has also been described in some viruses from antiretroviral agent-naive patients with primary HIV-1 infection in association with combinations of amino acid changes at polymorphic sites in the protease. Many of the viruses displaying increased susceptibility to protease inhibitors also had low replication capacity. In this retrospective study, we analyze the drug susceptibility phenotype and the replication capacity of virus isolates obtained at the peaks of viremia during five consecutive structured treatment interruptions in 12 chronically HIV-1-infected patients. Ten out of 12 patients had at least one sample with protease inhibitor hypersusceptibility (change </=0.4-fold) to one or more protease inhibitor. Hypersusceptibility to different protease inhibitors was observed at variable frequency, ranging from 38% to amprenavir to 11% to nelfinavir. Pairwise comparisons between susceptibilities for the protease inhibitors showed a consistent correlation among all pairs. There was also a significant relationship between susceptibility to protease inhibitors and replication capacity in all patients. Replication capacity remained stable over the course of repetitive cycles of structured treatment interruptions. We could find no association between in vitro replication capacity and in vivo plasma viral load doubling time and CD4(+) and CD8(+) T-cell counts at each treatment interruption. Several mutations were associated with hypersusceptibility to each protease inhibitor in a univariate analysis. This study extends the association between hypersusceptibility to protease inhibitors and low replication capacity to virus isolated from chronically infected patients and highlights the complexity of determining the genetic basis of this phenomenon. The potential clinical relevance of protease inhibitor hypersusceptibility and low replication capacity to virologic response to protease inhibitor-based therapies deserves to be investigated further.
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Affiliation(s)
- Javier Martinez-Picado
- IrsiCaixa Foundation Hospital Germans Trias i Pujol, Ctra. de Canyet, s/n 08916 Badalona, Spain.
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Yang OO, Daar ES, Jamieson BD, Balamurugan A, Smith DM, Pitt JA, Petropoulos CJ, Richman DD, Little SJ, Brown AJL. Human immunodeficiency virus type 1 clade B superinfection: evidence for differential immune containment of distinct clade B strains. J Virol 2005; 79:860-8. [PMID: 15613314 PMCID: PMC538553 DOI: 10.1128/jvi.79.2.860-868.2005] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Sequential infection with different strains of human immunodeficiency virus type 1 (HIV-1) is a rarely identified phenomenon with important implications for immunopathogenesis and vaccine development. Here, we identify an individual whose good initial control of viremia was lost in association with reduced containment of a superinfecting strain. Subject 2030 presented with acute symptoms of HIV-1 infection with high viremia and an incomplete seroconversion as shown by Western blotting. A low set point of viremia (approximately 1,000 HIV-1 copies/ml) was initially established without drug therapy, but a new higher set point (approximately 40,000 HIV-1 copies/ml) manifested about 5 months after infection. Drug susceptibility testing demonstrated a multidrug-resistant virus initially but a fully sensitive virus after 5 months, and an analysis of pol genotypes showed that these were two phylogenetically distinct strains of virus (strains A and B). Replication capacity assays suggested that the outgrowth of strain B was not due to higher fitness conferred by pol, and env sequences indicated that the two strains had the same R5 coreceptor phenotype. Delineation of CD8+-T-lymphocyte responses against HIV-1 showed a striking pattern of decay of the initial cellular immune responses after superinfection, followed by some adaptation of targeting to new epitopes. An examination of targeted sequences suggested that differences in the recognized epitopes contributed to the poor immune containment of strain B. In conclusion, the rapid overgrowth of a superinfecting strain of HIV-1 of the same subtype raises major concerns for effective vaccine development.
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Affiliation(s)
- Otto O Yang
- 37-121 Center for Health Sciences, Division of Infectious Diseases, 10833 LeConte Ave., UCLA Medical Center, Los Angeles, CA 90095, USA.
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Leigh Brown AJ, Frost SDW, Good B, Daar ES, Simon V, Markowitz M, Collier AC, Connick E, Conway B, Margolick JB, Routy JP, Corbeil J, Hellmann NS, Richman DD, Little SJ. Genetic basis of hypersusceptibility to protease inhibitors and low replicative capacity of human immunodeficiency virus type 1 strains in primary infection. J Virol 2004; 78:2242-6. [PMID: 14963120 PMCID: PMC369210 DOI: 10.1128/jvi.78.5.2242-2246.2004] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The initial virus strains from as many as 12% of individuals with primary human immunodeficiency virus (HIV) infection have a 50% inhibitory concentration </=0.4-fold that of HIV type 1(NL4-3) (HIV-1(NL4-3)) to ritonavir (hypersusceptibility [HS]). There is also substantial variation in replicative capacity (RC) or an in vitro assay of the contributions of protease (PR) and reverse transcriptase to viral fitness. In chronically infected antiretrovirally treated patients, amprenavir HS has been associated with the mutation N88S in PR, but this mutation is not seen in untreated patients. In this study, virus strains from 182 cases of primary HIV infection were analyzed, and a highly significant association between HS and low RC (</=10% that of HIV-1(NL4-3)) was observed (P < 10(-6)). Multivariate analysis was used to determine the genotypic basis of ritonavir HS, analyzing all polymorphic amino acid sites and insertions from p7gag through PR. Decision tree models developed on the entire Gag-plus-PR data set and on PR alone gave overall correct classifications of 73 and 72%, respectively, on cross-validation. They were also able to predict low RC, with sensitivities of 69 and 62% and specificities of 84 and 70%, respectively. The analysis shows that ritonavir HS in untreated primary HIV infection is not associated with single mutations but with combinations of amino acids at polymorphic sites and that the same genotypes which confer HS to PR inhibitors confer low RC. This supports the view that variation in PR function is directly responsible for variation in fitness among strains in primary infection.
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De Pasquale MP, Leigh Brown AJ, Uvin SC, Allega-Ingersoll J, Caliendo AM, Sutton L, Donahue S, D'Aquila RT. Differences in HIV-1 pol Sequences From Female Genital Tract and Blood During Antiretroviral Therapy. J Acquir Immune Defic Syndr 2003; 34:37-44. [PMID: 14501791 DOI: 10.1097/00126334-200309010-00005] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE To determine whether HIV-1 replicates locally in the female genital tract during therapy, and to study whether endocervix is the dominant source of virus in cervicovaginal lavage fluid. DESIGN Sequence analyses of HIV-1 pol were performed from cervicovaginal secretions and blood plasma of HIV-infected women failing antiretroviral therapy with detectable viral load in both compartments, as well as from drug-naive subjects. METHODS Viral RNA was extracted from cervicovaginal lavage fluid, endocervical secretions collected by Sno-strips, and blood plasma. Population sequencing of HIV-1 pol was performed using cycle sequencing. Drug resistance mutations were analyzed. Phylogenies were constructed based on synonymous positions in the sequences. RESULTS Resistant virus was detected concordantly in blood and genital tract specimens, consistent with drug selection pressure in both compartments. However, drug-selected mutations often differed in each compartment, and phylogenetic analysis showed differences in virus lineage in these compartments, consistent with local replication in female genital tract. Viruses in cervicovaginal lavage and endocervical secretions were genetically distinguishable, suggesting that endocervix is not the only source of virus found in cervicovaginal lavage. CONCLUSION These data support the hypothesis that HIV replication is compartmentalized within the female genital tract during antiretroviral therapy, which has implications for pathogenesis and for epidemiologic surveillance of drug-resistant virus.
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Affiliation(s)
- Maria Pia De Pasquale
- Division of Infectious Diseases, Vanderbilt University Medical Center, Nashville, Tennessee 37232-2372, USA.
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Leigh Brown AJ, Frost SDW, Mathews WC, Dawson K, Hellmann NS, Daar ES, Richman DD, Little SJ. Transmission fitness of drug-resistant human immunodeficiency virus and the prevalence of resistance in the antiretroviral-treated population. J Infect Dis 2003; 187:683-6. [PMID: 12599087 DOI: 10.1086/367989] [Citation(s) in RCA: 135] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2002] [Revised: 10/14/2002] [Indexed: 11/03/2022] Open
Abstract
Although the prevalence of drug-resistant strains in primary human immunodeficiency virus (HIV) infection in North America has recently increased, their transmission fitness remains unknown. The present study estimated the frequency of transmission of drug-resistant HIV from patients receiving antiretroviral therapy using retrospective surveys of clinic data. It revealed that resistant virus was transmitted only approximately 20% as frequently as expected from these patients. Individuals with primary resistance may become a significant source of resistant strains.
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Quigg M, Frost SDW, McDonagh S, Burns SM, Clutterbuck D, McMillan A, Leen CS, Brown AJL. Association of antiretroviral resistance genotypes with response to therapy--comparison of three models. Antivir Ther 2002; 7:151-7. [PMID: 12487381] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/28/2023]
Abstract
Genotype-based resistance assays are commonly used to aid treatment in HIV-infected individuals failing antiretroviral therapy. The relationship between genotype and antiretroviral therapy comes mostly from in vitro assays of the response to a single drugs although there is a need for a prediction of clinical response to combination therapy. We have compared three different methods of analysing genotype data as a predictor of clinical response in a small clinical cohort of highly antiretroviral-experienced individuals failing therapy. No method performed well beyond 8 weeks into a new therapeutic regimen. A model based on the number of 'primary' mutations was statistically significant, but a multiple regression model, which identified specific mutations explained threefold more variation in response. Optimal prediction in this dataset was given by a model obtained from a classification tree analysis, in which genotype at amino acid sites 135 and 202 were combined with amino acid site 184, which explained over 50% of the deviance in the data and had a classification success of 86%.
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Affiliation(s)
- Marlynne Quigg
- Centre for HIV Research, Institute of Cell, Animal and Population Biology, University of Edinburgh, Edinburgh, UK
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Quigg M, Frost SDW, McDonagh S, Burns SM, Clutterbuck D, McMillan A, Leen CS, Brown AJL. Association of Antiretroviral Resistance Genotypes with Response to Therapy – Comparison of Three Models. Antivir Ther 2002. [DOI: 10.1177/135965350200700303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Genotype-based resistance assays are commonly used to aid treatment in HIV-infected individuals failing anti-retroviral therapy. The relationship between genotype and antiretroviral therapy comes mostly from in vitro assays of the response to a single drugs although there is a need for a prediction of clinical response to combination therapy. We have compared three different methods of analysing genotype data as a predictor of clinical response in a small clinical cohort of highly antiretro-viral-experienced individuals failing therapy. No method performed well beyond 8 weeks into a new therapeutic regimen. A model based on the number of ‘primary’ mutations was statistically significant, but a multiple regression model, which identified specific mutations explained threefold more variation in response. Optimal prediction in this dataset was given by a model obtained from a classification tree analysis, in which genotype at amino acid sites 135 and 202 were combined with amino acid site 184, which explained over 50% of the deviance in the data and had a classification success of 86%.
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Affiliation(s)
- Marlynne Quigg
- Centre for HIV Research, Institute of Cell, Animal and Population Biology, University of Edinburgh, Edinburgh, UK
| | - Simon DW Frost
- Centre for HIV Research, Institute of Cell, Animal and Population Biology, University of Edinburgh, Edinburgh, UK
| | | | | | | | | | - Clifford S Leen
- Regional Infectious Diseases Unit, Western General Hospital, Edinburgh, UK
| | - Andrew J Leigh Brown
- Centre for HIV Research, Institute of Cell, Animal and Population Biology, University of Edinburgh, Edinburgh, UK
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Frost SDW, Martinez-Picado J, Ruiz L, Clotet B, Brown AJL. Viral dynamics during structured treatment interruptions of chronic human immunodeficiency virus type 1 infection. J Virol 2002; 76:968-79. [PMID: 11773372 PMCID: PMC135793 DOI: 10.1128/jvi.76.3.968-979.2002] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Although antiviral agents which block human immunodeficiency virus (HIV) replication can result in long-term suppression of viral loads to undetectable levels in plasma, long-term therapy fails to eradicate virus, which generally rebounds after a single treatment interruption. Multiple structured treatment interruptions (STIs) have been suggested as a possible strategy that may boost HIV-specific immune responses and control viral replication. We analyze viral dynamics during four consecutive STI cycles in 12 chronically infected patients with a history (>2 years) of viral suppression under highly active antiretroviral therapy. We fitted a simple model of viral rebound to the viral load data from each patient by using a novel statistical approach that allows us to overcome problems of estimating viral dynamics parameters when there are many viral load measurements below the limit of detection. There is an approximate halving of the average viral growth rate between the first and fourth STI cycles, yet the average time between treatment interruption and detection of viral loads in the plasma is approximately the same in the first and fourth interruptions. We hypothesize that reseeding of viral reservoirs during treatment interruptions can account for this discrepancy, although factors such as stochastic effects and the strength of HIV-specific immune responses may also affect the time to viral rebound. We also demonstrate spontaneous drops in viral load in later STIs, which reflect fluctuations in the rates of viral production and/or clearance that may be caused by a complex interaction between virus and target cells and/or immune responses.
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Affiliation(s)
- Simon D W Frost
- Department of Pathology, University of California, San Diego, California 92103, USA.
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