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Consequences of immunopathology for pathogen virulence evolution and public health: malaria as a case study

Evolutionary theories explaining virulence—the fitness damage incurred by infected hosts—often focus on parasite strategies for within-host exploitation. However, much virulence can be caused by the host's own immune response: for example, pro-inflammatory cytokines, although essential for kill...

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Autores principales: Long, Gráinne H, Graham, Andrea L
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Blackwell Publishing Ltd 2011
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3352548/
https://www.ncbi.nlm.nih.gov/pubmed/25567973
http://dx.doi.org/10.1111/j.1752-4571.2010.00178.x
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author Long, Gráinne H
Graham, Andrea L
author_facet Long, Gráinne H
Graham, Andrea L
author_sort Long, Gráinne H
collection PubMed
description Evolutionary theories explaining virulence—the fitness damage incurred by infected hosts—often focus on parasite strategies for within-host exploitation. However, much virulence can be caused by the host's own immune response: for example, pro-inflammatory cytokines, although essential for killing malaria parasites, also damage host tissue. Here we argue that immune-mediated virulence, or ‘immunopathology,’ may affect malaria virulence evolution and should be considered in the design of medical interventions. Our argument is based on the ability of immunopathology to disrupt positive virulence-transmission relationships assumed under the trade-off theory of virulence evolution. During rodent malaria infections, experimental reduction of inflammation using reagents approved for field use decreases virulence but increases parasite transmission potential. Importantly, rodent malaria parasites exhibit genetic diversity in the propensity to induce inflammation and invest in transmission-stage parasites in the presence of pro-inflammatory cytokines. If immunopathology positively correlates with malaria parasite density, theory suggests it could select for relatively low malaria virulence. Medical interventions which decrease immunopathology may therefore inadvertently select for increased malaria virulence. The fitness consequences to parasites of variations in immunopathology must be better understood in order to predict trajectories of parasite virulence evolution in heterogeneous host populations and in response to medical interventions.
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spelling pubmed-33525482012-05-24 Consequences of immunopathology for pathogen virulence evolution and public health: malaria as a case study Long, Gráinne H Graham, Andrea L Evol Appl Perspective Evolutionary theories explaining virulence—the fitness damage incurred by infected hosts—often focus on parasite strategies for within-host exploitation. However, much virulence can be caused by the host's own immune response: for example, pro-inflammatory cytokines, although essential for killing malaria parasites, also damage host tissue. Here we argue that immune-mediated virulence, or ‘immunopathology,’ may affect malaria virulence evolution and should be considered in the design of medical interventions. Our argument is based on the ability of immunopathology to disrupt positive virulence-transmission relationships assumed under the trade-off theory of virulence evolution. During rodent malaria infections, experimental reduction of inflammation using reagents approved for field use decreases virulence but increases parasite transmission potential. Importantly, rodent malaria parasites exhibit genetic diversity in the propensity to induce inflammation and invest in transmission-stage parasites in the presence of pro-inflammatory cytokines. If immunopathology positively correlates with malaria parasite density, theory suggests it could select for relatively low malaria virulence. Medical interventions which decrease immunopathology may therefore inadvertently select for increased malaria virulence. The fitness consequences to parasites of variations in immunopathology must be better understood in order to predict trajectories of parasite virulence evolution in heterogeneous host populations and in response to medical interventions. Blackwell Publishing Ltd 2011-03 /pmc/articles/PMC3352548/ /pubmed/25567973 http://dx.doi.org/10.1111/j.1752-4571.2010.00178.x Text en © 2011 Blackwell Publishing Ltd
spellingShingle Perspective
Long, Gráinne H
Graham, Andrea L
Consequences of immunopathology for pathogen virulence evolution and public health: malaria as a case study
title Consequences of immunopathology for pathogen virulence evolution and public health: malaria as a case study
title_full Consequences of immunopathology for pathogen virulence evolution and public health: malaria as a case study
title_fullStr Consequences of immunopathology for pathogen virulence evolution and public health: malaria as a case study
title_full_unstemmed Consequences of immunopathology for pathogen virulence evolution and public health: malaria as a case study
title_short Consequences of immunopathology for pathogen virulence evolution and public health: malaria as a case study
title_sort consequences of immunopathology for pathogen virulence evolution and public health: malaria as a case study
topic Perspective
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3352548/
https://www.ncbi.nlm.nih.gov/pubmed/25567973
http://dx.doi.org/10.1111/j.1752-4571.2010.00178.x
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