1
|
Fan R, Geritz SAH. Evolution of pathogens with cross-immunity in response to healthcare interventions. J Theor Biol 2023; 572:111575. [PMID: 37423484 DOI: 10.1016/j.jtbi.2023.111575] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 06/22/2023] [Accepted: 07/03/2023] [Indexed: 07/11/2023]
Abstract
Cross-immunity, as an evolutionary driver, can contribute to pathogen evolution, particularly pathogen diversity. Healthcare interventions aimed at reducing disease severity or transmission are commonly used to control diseases and can also induce pathogen evolution. Understanding pathogen evolution in the context of cross-immunity and healthcare interventions is crucial for infection control. This study starts by modelling cross-immunity, the extent of which is determined by strain traits and host characteristics. Given that all hosts have the same characteristics, full cross-immunity between residents and mutants occurs when mutation step sizes are small enough. Cross-immunity can be partial when the step size is large. The presence of partial cross-immunity reduces pathogen load and shortens the infectious period inside hosts, reducing transmission between hosts and improving host population survival and recovery. This study focuses on how pathogens evolve through small and large mutational steps and how healthcare interventions affect pathogen evolution. Using the theory of adaptive dynamics, we found that when mutational steps are small (only full cross-immunity is present), pathogen diversity cannot occur because it maximises the basic reproduction number. This results in intermediate values for both pathogen growth and clearance rates. However, when large mutational steps are allowed (with full and partial cross-immunity present), pathogens can evolve into multiple strains and induce pathogen diversity. The study also shows that different healthcare interventions can have varying effects on pathogen evolution. Generally, low levels of intervention are more likely to induce strain diversity, while high levels are more likely to result in strain reduction.
Collapse
Affiliation(s)
- Ruili Fan
- Department of Mathematics and Statistics, University of Helsinki, FIN-00014, Finland.
| | - Stefan A H Geritz
- Department of Mathematics and Statistics, University of Helsinki, FIN-00014, Finland
| |
Collapse
|
2
|
Stockdale JE, Liu P, Colijn C. The potential of genomics for infectious disease forecasting. Nat Microbiol 2022; 7:1736-1743. [PMID: 36266338 DOI: 10.1038/s41564-022-01233-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Accepted: 08/18/2022] [Indexed: 11/09/2022]
Abstract
Genomic technologies have led to tremendous gains in understanding how pathogens function, evolve and interact. Pathogen diversity is now measurable at high precision and resolution, in part because over the past decade, sequencing technologies have increased in speed and capacity, at decreased cost. Alongside this, the use of models that can forecast emergence and size of infectious disease outbreaks has risen, highlighted by the coronavirus disease 2019 pandemic but also due to modelling advances that allow for rapid estimates in emerging outbreaks to inform monitoring, coordination and resource deployment. However, genomics studies have remained largely retrospective. While they contain high-resolution views of pathogen diversification and evolution in the context of selection, they are often not aligned with designing interventions. This is a missed opportunity because pathogen diversification is at the core of the most pressing infectious public health challenges, and interventions need to take the mechanisms of virulence and understanding of pathogen diversification into account. In this Perspective, we assess these converging fields, discuss current challenges facing both surveillance specialists and modellers who want to harness genomic data, and propose next steps for integrating longitudinally sampled genomic data with statistical learning and interpretable modelling to make reliable predictions into the future.
Collapse
Affiliation(s)
- Jessica E Stockdale
- Department of Mathematics, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Pengyu Liu
- Department of Mathematics, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Caroline Colijn
- Department of Mathematics, Simon Fraser University, Burnaby, British Columbia, Canada.
| |
Collapse
|
3
|
Hendrickx DM, Delva W, Hens N. Influence of sexual risk behaviour and STI co-infection dynamics on the evolution of HIV set point viral load in MSM. Epidemics 2021; 36:100474. [PMID: 34153622 DOI: 10.1016/j.epidem.2021.100474] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Revised: 03/17/2021] [Accepted: 06/07/2021] [Indexed: 11/27/2022] Open
Abstract
HIV viral load (VL) is an important predictor of HIV progression and transmission. Anti-retroviral therapy (ART) has been reported to reduce HIV transmission by lowering VL. However, apart from this beneficial effect, increased levels of population mean set-point viral load (SPVL), an estimator for HIV virulence, have been observed in men who have sex with men (MSM) in the decade following the introduction of ART in The Netherlands. Several studies have been devoted to explain these counter-intuitive trends in SPVL. However, to our knowledge, none of these studies has investigated an explanation in which it arises as the result of a sexually transmitted infection (STI) co-factor in detail. In this study, we adapted an event-based, individual-based model to investigate how STI co-infection and sexual risk behaviour affect the evolution of HIV SPVL in MSM before and after the introduction of ART. The results suggest that sexual risk behaviour has an effect on SPVL and indicate that more data are needed to test the effect of STI co-factors on SPVL. Furthermore, the observed trends in SPVL cannot be explained by sexual risk behaviour and STI co-factors only. We recommend to develop mathematical models including also factors related to viral evolution as reported earlier in the literature. However, this requires more complex models, and the collection of more data for parameter estimation than what is currently available.
Collapse
Affiliation(s)
- Diana M Hendrickx
- I-BioStat, Data Science Institute, Hasselt University, Hasselt, Belgium.
| | - Wim Delva
- I-BioStat, Data Science Institute, Hasselt University, Hasselt, Belgium; The South African Department of Science and Technology-National Research Foundation (DST-NRF) Centre of Excellence in Epidemiological Modelling and Analysis (SACEMA), Stellenbosch University, Stellenbosch, South Africa; Department of Global Health, Faculty of Medicine and Health, Stellenbosch University, Stellenbosch, South Africa; International Centre for Reproductive Health, Ghent University, Ghent, Belgium; Rega Institute for Medical Research, KU Leuven, Leuven, Belgium; School for Data Science and Computational Thinking, Stellenbosch University, Stellenbosch, South Africa
| | - Niel Hens
- I-BioStat, Data Science Institute, Hasselt University, Hasselt, Belgium; Centre for Health Economics Research and Modelling Infectious Diseases, Vaccine & Infectious Disease Institute, University of Antwerp, Antwerp, Belgium
| |
Collapse
|
4
|
Stansfield SE, Herbeck JT, Gottlieb GS, Abernethy NF, Murphy JT, Mittler JE, Goodreau SM. Test-and-treat coverage and HIV virulence evolution among men who have sex with men. Virus Evol 2021; 7:veab011. [PMID: 33633867 PMCID: PMC7893213 DOI: 10.1093/ve/veab011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
HIV set point viral load (SPVL), the viral load established shortly after initial infection, is a proxy for HIV virulence: higher SPVLs lead to higher risk of transmission and faster disease progression. Three models of test-and-treat scenarios, mainly in heterosexual populations, found that increasing treatment coverage selected for more virulent viruses. We modeled virulence evolution in a population of men who have sex with men (MSM) with increasing test-and-treat coverage. We extended a stochastic, dynamic network model (EvoNetHIV). We varied relationship patterns (MSM vs. heterosexual), HIV transmission models (increasing vs. plateauing probability of transmission at very high viral loads), and treatment roll-out (with explicit testing or fixed intervals between infection and treatment). In scenarios most similar to previous models (longer relational durations and the plateauing transmission function), we replicated trends previously found: increasing treatment coverage led to increased virulence (0.12 log10 increase in mean population SPVL between 20% and 100% treatment coverage). In scenarios reflecting MSM behavioral data using the increasing transmission function, increasing treatment coverage selected for viruses with lower virulence (0.16 log10 decrease in mean population SPVL between 20% and 100% treatment coverage). These findings emphasize the impact of sexual network conditions and transmission function details on predicted epidemiological and evolutionary outcomes. Varying these features creates very different evolutionary environments, which in turn lead to opposite effects in mean population SPVL evolution. Our results suggest that, under some realistic conditions, effective test-and-treat strategies may not face the previously reported tradeoff in which increasing coverage leads to evolution of greater virulence. This suggests instead that a virtuous cycle of increasing treatment coverage and diminishing virulence is possible.
Collapse
Affiliation(s)
- Sarah E Stansfield
- Department of Biomedical Informatics and Medical Education, University of Washington, Seattle, WA 98195, USA
| | - Joshua T Herbeck
- Department of Global Health, University of Washington, Seattle, WA 98195, USA
| | - Geoffrey S Gottlieb
- Departments of Medicine & Global Health, University of Washington, Seattle, WA 98195, USA
| | - Neil F Abernethy
- Department of Biomedical Informatics and Medical Education, University of Washington, Seattle, WA 98195, USA
| | - James T Murphy
- Department of Microbiology, University of Washington, Seattle, WA 98195, USA
| | - John E Mittler
- Department of Microbiology, University of Washington, Seattle, WA 98195, USA
| | - Steven M Goodreau
- Department of Anthropology, University of Washington, Seattle, WA 98195, USA
| |
Collapse
|
5
|
Nijmeijer BM, Geijtenbeek TBH. Negative and Positive Selection Pressure During Sexual Transmission of Transmitted Founder HIV-1. Front Immunol 2019; 10:1599. [PMID: 31354736 PMCID: PMC6635476 DOI: 10.3389/fimmu.2019.01599] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Accepted: 06/26/2019] [Indexed: 12/21/2022] Open
Abstract
Sexual transmission of HIV-1 consists of processes that exert either positive or negative selection pressure on the virus. The sum of these selection pressures lead to the transmission of only one specific HIV-1 strain, termed the transmitted founder virus. Different dendritic cell subsets are abundantly present at mucosal sites and, interestingly, these DC subsets exert opposite pressure on viral selection during sexual transmission. In this review we describe receptors and cellular compartments in DCs that are involved in HIV-1 communication leading to either viral restriction by the host or further dissemination to establish a long-lived reservoir. We discuss the current understanding of host antiretroviral restriction factors against HIV-1 and specifically against the HIV-1 transmitted founder virus. We will also discuss potential clinical implications for exploiting these intrinsic restriction factors in developing novel therapeutic targets. A better understanding of these processes might help in developing strategies against HIV-1 infections by targeting dendritic cells.
Collapse
Affiliation(s)
- Bernadien M Nijmeijer
- Department of Experimental Immunology, Amsterdam University Medical Centers, Amsterdam Infection and Immunity Institute, University of Amsterdam, Amsterdam, Netherlands
| | - Teunis B H Geijtenbeek
- Department of Experimental Immunology, Amsterdam University Medical Centers, Amsterdam Infection and Immunity Institute, University of Amsterdam, Amsterdam, Netherlands
| |
Collapse
|
6
|
Childs LM, El Moustaid F, Gajewski Z, Kadelka S, Nikin-Beers R, Smith JW, Walker M, Johnson LR. Linked within-host and between-host models and data for infectious diseases: a systematic review. PeerJ 2019; 7:e7057. [PMID: 31249734 PMCID: PMC6589080 DOI: 10.7717/peerj.7057] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Accepted: 04/28/2019] [Indexed: 12/17/2022] Open
Abstract
The observed dynamics of infectious diseases are driven by processes across multiple scales. Here we focus on two: within-host, that is, how an infection progresses inside a single individual (for instance viral and immune dynamics), and between-host, that is, how the infection is transmitted between multiple individuals of a host population. The dynamics of each of these may be influenced by the other, particularly across evolutionary time. Thus understanding each of these scales, and the links between them, is necessary for a holistic understanding of the spread of infectious diseases. One approach to combining these scales is through mathematical modeling. We conducted a systematic review of the published literature on multi-scale mathematical models of disease transmission (as defined by combining within-host and between-host scales) to determine the extent to which mathematical models are being used to understand across-scale transmission, and the extent to which these models are being confronted with data. Following the PRISMA guidelines for systematic reviews, we identified 24 of 197 qualifying papers across 30 years that include both linked models at the within and between host scales and that used data to parameterize/calibrate models. We find that the approach that incorporates both modeling with data is under-utilized, if increasing. This highlights the need for better communication and collaboration between modelers and empiricists to build well-calibrated models that both improve understanding and may be used for prediction.
Collapse
Affiliation(s)
- Lauren M Childs
- Department of Mathematics, Virginia Polytechnic Institute and State University (Virginia Tech), Blacksburg, VA, USA
| | - Fadoua El Moustaid
- Department of Biological Sciences, Virginia Polytechnic Institute and State University (Virginia Tech), Blacksburg, VA, USA.,Global Change Center, Virginia Polytechnic Institute and State University (Virginia Tech), Blacksburg, VA, USA
| | - Zachary Gajewski
- Department of Biological Sciences, Virginia Polytechnic Institute and State University (Virginia Tech), Blacksburg, VA, USA.,Global Change Center, Virginia Polytechnic Institute and State University (Virginia Tech), Blacksburg, VA, USA.,Department of Statistics, Virginia Polytechnic Institute and State University (Virginia Tech), Blacksburg, VA, USA
| | - Sarah Kadelka
- Department of Mathematics, Virginia Polytechnic Institute and State University (Virginia Tech), Blacksburg, VA, USA
| | - Ryan Nikin-Beers
- Department of Mathematics, Virginia Polytechnic Institute and State University (Virginia Tech), Blacksburg, VA, USA.,Department of Mathematics, University of Florida, Gainesville, FL, USA
| | - John W Smith
- Department of Statistics, Virginia Polytechnic Institute and State University (Virginia Tech), Blacksburg, VA, USA
| | - Melody Walker
- Department of Mathematics, Virginia Polytechnic Institute and State University (Virginia Tech), Blacksburg, VA, USA
| | - Leah R Johnson
- Department of Biological Sciences, Virginia Polytechnic Institute and State University (Virginia Tech), Blacksburg, VA, USA.,Global Change Center, Virginia Polytechnic Institute and State University (Virginia Tech), Blacksburg, VA, USA.,Department of Statistics, Virginia Polytechnic Institute and State University (Virginia Tech), Blacksburg, VA, USA.,Computational Modeling and Data Analytics, Virginia Polytechnic Institute and State University (Virginia Tech), Blacksburg, VA, USA
| |
Collapse
|
7
|
Domínguez-Rodríguez S, Rojas P, Fernández McPhee C, Pagán I, Navarro ML, Ramos JT, Holguín Á. Effect of HIV/HCV Co-Infection on the Protease Evolution of HIV-1B: A Pilot Study in a Pediatric Population. Sci Rep 2018; 8:2347. [PMID: 29403002 PMCID: PMC5799169 DOI: 10.1038/s41598-018-19312-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Accepted: 12/29/2017] [Indexed: 12/28/2022] Open
Abstract
This pilot study evaluates in pediatric patients the impact of HIV/HCV coinfection in the molecular evolution of the HIV-1 subtype B protease (HIV-1BPR). For this study, HIV-1B/HCV coinfected (15) and HIV-1B monoinfected (56) patients with available HIV-1B pol sequences were enrolled. Both groups of patients had comparable gender frequencies and average age, time of infection, antiretroviral treatment (ART) exposure and time under ART. Prevalence of drug resistance mutations (DRM), genetic diversity, number of synonymous (dS) and non-synonymous (dN) mutations per site and selection pressures (dN - dS) in the HIV-1BPR were estimated and compared between mono- and coinfected patients. Both HIV-1B populations presented similar genetic diversity (0.050 ± 0.02 vs. 0.045 ± 0.01) and dS (0.074 ± 0.03 vs. 0.078 ± 0.04). In turn, in coinfected patients the HIV-1BPR had higher dN (0.045 ± 0.01 vs. 0.024 ± 0.01) and dN-dS (-0.026 ± 0.02 vs. -0.048 ± 0.04) values, and less amino acid sites under purifying selection (4.2% vs. 42.1%) than in monoinfected patients. Accordingly, in co-infection with HCV, the HIV-1BPR sites 50, 53, 82, 84 and 88 - associated with resistance to PIs - were under neutral evolution, whereas these sites were under purifying selection in monoinfected patients. This pilot study suggests that HIV-1B may evolve differently in the presence than in the absence of HCV.
Collapse
Affiliation(s)
- Sara Domínguez-Rodríguez
- HIV-1 Molecular Epidemiology Laboratory, Microbiology and Parasitology Department, Hospital Ramón y Cajal-IRYCIS and CIBER-ESP, Madrid, 28034, Spain
| | - Patricia Rojas
- HIV-1 Molecular Epidemiology Laboratory, Microbiology and Parasitology Department, Hospital Ramón y Cajal-IRYCIS and CIBER-ESP, Madrid, 28034, Spain
| | - Carolina Fernández McPhee
- Department of Pediatric Infectious Diseases, Hospital Universitario Gregorio Marañón-IisGM-UCM-RITIP-CoRISPe, Madrid, 28009, Spain
| | - Israel Pagán
- Centro de Biotecnología y Genómica de Plantas (UPM-INIA), Campus Montegancedo, Pozuelo de Alarcón, 28223, Madrid, Spain
| | - María Luisa Navarro
- Department of Pediatric Infectious Diseases, Hospital Universitario Gregorio Marañón-IisGM-UCM-RITIP-CoRISPe, Madrid, 28009, Spain
| | - José Tomás Ramos
- Pediatric Department, Hospital Clínico Universitario and Universidad Complutense, Madrid, 28040, Spain
| | - África Holguín
- HIV-1 Molecular Epidemiology Laboratory, Microbiology and Parasitology Department, Hospital Ramón y Cajal-IRYCIS and CIBER-ESP, Madrid, 28034, Spain.
| |
Collapse
|
8
|
Theys K, Libin P, Pineda-Peña AC, Nowé A, Vandamme AM, Abecasis AB. The impact of HIV-1 within-host evolution on transmission dynamics. Curr Opin Virol 2017; 28:92-101. [PMID: 29275182 DOI: 10.1016/j.coviro.2017.12.001] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Revised: 11/23/2017] [Accepted: 12/03/2017] [Indexed: 11/17/2022]
Abstract
The adaptive potential of HIV-1 is a vital mechanism to evade host immune responses and antiviral treatment. However, high evolutionary rates during persistent infection can impair transmission efficiency and alter disease progression in the new host, resulting in a delicate trade-off between within-host virulence and between-host infectiousness. This trade-off is visible in the disparity in evolutionary rates at within-host and between-host levels, and preferential transmission of ancestral donor viruses. Understanding the impact of within-host evolution for epidemiological studies is essential for the design of preventive and therapeutic measures. Herein, we review recent theoretical and experimental work that generated new insights into the complex link between within-host evolution and between-host fitness, revealing temporal and selective processes underlying the structure and dynamics of HIV-1 transmission.
Collapse
Affiliation(s)
- Kristof Theys
- KU Leuven, University of Leuven, Department of Microbiology and Immunology, Rega Institute for Medical Research, Clinical and Epidemiological Virology, Leuven, Belgium.
| | - Pieter Libin
- KU Leuven, University of Leuven, Department of Microbiology and Immunology, Rega Institute for Medical Research, Clinical and Epidemiological Virology, Leuven, Belgium; Articial Intelligence Lab, Department of Computer Science, Vrije Universiteit Brussel, Brussels, Belgium
| | - Andrea-Clemencia Pineda-Peña
- Molecular Biology and Immunology Department, Fundacion Instituto de Immunologia de Colombia (FIDIC), Basic Sciences Department, Universidad del Rosario, Bogota, Colombia; Global Health and Tropical Medicine, GHTM, Institute for Hygiene and Tropical Medicine, IHMT, University Nova de Lisboa, UNL, Lisbon, Portugal
| | - Ann Nowé
- Articial Intelligence Lab, Department of Computer Science, Vrije Universiteit Brussel, Brussels, Belgium
| | - Anne-Mieke Vandamme
- KU Leuven, University of Leuven, Department of Microbiology and Immunology, Rega Institute for Medical Research, Clinical and Epidemiological Virology, Leuven, Belgium
| | - Ana B Abecasis
- KU Leuven, University of Leuven, Department of Microbiology and Immunology, Rega Institute for Medical Research, Clinical and Epidemiological Virology, Leuven, Belgium; Global Health and Tropical Medicine, GHTM, Institute for Hygiene and Tropical Medicine, IHMT, University Nova de Lisboa, UNL, Lisbon, Portugal
| |
Collapse
|
9
|
Trimpert J, Groenke N, Jenckel M, He S, Kunec D, Szpara ML, Spatz SJ, Osterrieder N, McMahon DP. A phylogenomic analysis of Marek's disease virus reveals independent paths to virulence in Eurasia and North America. Evol Appl 2017; 10:1091-1101. [PMID: 29151863 PMCID: PMC5680632 DOI: 10.1111/eva.12515] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Accepted: 07/01/2017] [Indexed: 12/28/2022] Open
Abstract
Virulence determines the impact a pathogen has on the fitness of its host, yet current understanding of the evolutionary origins and causes of virulence of many pathogens is surprisingly incomplete. Here, we explore the evolution of Marek's disease virus (MDV), a herpesvirus commonly afflicting chickens and rarely other avian species. The history of MDV in the 20th century represents an important case study in the evolution of virulence. The severity of MDV infection in chickens has been rising steadily since the adoption of intensive farming techniques and vaccination programs in the 1950s and 1970s, respectively. It has remained uncertain, however, which of these factors is causally more responsible for the observed increase in virulence of circulating viruses. We conducted a phylogenomic study to understand the evolution of MDV in the context of dramatic changes to poultry farming and disease control. Our analysis reveals evidence of geographical structuring of MDV strains, with reconstructions supporting the emergence of virulent viruses independently in North America and Eurasia. Of note, the emergence of virulent viruses appears to coincide approximately with the introduction of comprehensive vaccination on both continents. The time‐dated phylogeny also indicated that MDV has a mean evolutionary rate of ~1.6 × 10−5 substitutions per site per year. An examination of gene‐linked mutations did not identify a strong association between mutational variation and virulence phenotypes, indicating that MDV may evolve readily and rapidly under strong selective pressures and that multiple genotypic pathways may underlie virulence adaptation in MDV.
Collapse
Affiliation(s)
- Jakob Trimpert
- Institut für Virologie Freie Universität Berlin Berlin Germany
| | - Nicole Groenke
- Institut für Virologie Freie Universität Berlin Berlin Germany
| | - Maria Jenckel
- Institute of Diagnostic Virology Friedrich-Loeffler-Institut Greifswald-Insel Riems Germany
| | - Shulin He
- Institut für Biologie Freie Universität Berlin Berlin Germany.,Department for Materials and Environment BAM Federal Institute for Materials Research and Testing Berlin Germany
| | - Dusan Kunec
- Institut für Virologie Freie Universität Berlin Berlin Germany
| | - Moriah L Szpara
- Department of Biochemistry and Molecular Biology Center for Infectious Disease Dynamics and the Huck Institutes of the Life Sciences Pennsylvania State University University Park PA USA
| | - Stephen J Spatz
- United States Department of Agriculture US National Poultry Research Center Athens GA USA
| | | | - Dino P McMahon
- Institut für Biologie Freie Universität Berlin Berlin Germany.,Department for Materials and Environment BAM Federal Institute for Materials Research and Testing Berlin Germany
| |
Collapse
|
10
|
Smith DRM, Mideo N. Modelling the evolution of HIV-1 virulence in response to imperfect therapy and prophylaxis. Evol Appl 2017; 10:297-309. [PMID: 28250813 PMCID: PMC5322411 DOI: 10.1111/eva.12458] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Accepted: 12/15/2016] [Indexed: 12/11/2022] Open
Abstract
Average HIV-1 virulence appears to have evolved in different directions in different host populations since antiretroviral therapy first became available, and models predict that HIV drugs can select for either higher or lower virulence, depending on how treatment is administered. However, HIV virulence evolution in response to "leaky" therapy (treatment that imperfectly suppresses viral replication) and the use of preventive drugs (pre-exposure prophylaxis) has not been explored. Using adaptive dynamics, we show that higher virulence can evolve when antiretroviral therapy is imperfectly effective and that this evolution erodes some of the long-term clinical and epidemiological benefits of HIV treatment. The introduction of pre-exposure prophylaxis greatly reduces infection prevalence, but can further amplify virulence evolution when it, too, is leaky. Increasing the uptake rate of these imperfect interventions increases selection for higher virulence and can lead to counterintuitive increases in infection prevalence in some scenarios. Although populations almost always fare better with access to interventions than without, untreated individuals could experience particularly poor clinical outcomes when virulence evolves. These findings predict that antiretroviral drugs may have underappreciated evolutionary consequences, but that maximizing drug efficacy can prevent this evolutionary response. We suggest that HIV virulence evolution should be closely monitored as access to interventions continues to improve.
Collapse
Affiliation(s)
- David R. M. Smith
- Department of Ecology and Evolutionary BiologyUniversity of TorontoTorontoONCanada
| | - Nicole Mideo
- Department of Ecology and Evolutionary BiologyUniversity of TorontoTorontoONCanada
| |
Collapse
|