Plasticity in transmission strategies of the malaria parasite, Plasmodium chabaudi: environmental and genetic effects

Authors

  • Angus Cameron,

    1. Boyd Orr Centre for Population and Ecosystem Health, Institute of Biodiversity, Animal Health and Comparative Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
    2. Department of Systems and Computational Biology, Albert Einstein College of Medicine, Bronx, NY, USA
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  • Sarah E. Reece,

    1. Centre for Immunity, Infection & Evolution, Institutes of Evolution, Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh, UK
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  • Damien R. Drew,

    1. Centre for Immunity, Infection & Evolution, Institutes of Evolution, Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh, UK
    2. Burnet Institute, Melbourne, Vic., Australia
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  • Daniel T. Haydon,

    1. Boyd Orr Centre for Population and Ecosystem Health, Institute of Biodiversity, Animal Health and Comparative Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
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  • Andrew J. Yates

    Corresponding author
    1. Department of Systems and Computational Biology, Albert Einstein College of Medicine, Bronx, NY, USA
    2. Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY, USA
    • Boyd Orr Centre for Population and Ecosystem Health, Institute of Biodiversity, Animal Health and Comparative Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
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Correspondence

Andrew J. Yates, Department of Systems and Computational Biology, Albert Einstein College of Medicine, Bronx, NY 10461, USA.

Tel.: +1 718 678 1198;

fax: +1 718 678 1018;

e-mail: andrew.yates@einstein.yu.edu

Abstract

Parasites may alter their behaviour to cope with changes in the within-host environment. In particular, investment in transmission may alter in response to the availability of parasite resources or host immune responses. However, experimental and theoretical studies have drawn conflicting conclusions regarding parasites' optimal (adaptive) responses to deterioration in habitat quality. We analyse data from acute infections with six genotypes of the rodent malaria species Plasmodium chabaudi to quantify how investment in transmission (gametocytes) is influenced by the within-host environment. Using a minimum of modelling assumptions, we find that proportional investment in gametocytogenesis increases sharply with host anaemia and also increases at low parasite densities. Further, stronger dependence of investment on parasite density is associated with greater virulence of the parasite genotype. Our study provides a robust quantitative framework for studying parasites' responses to the host environment and whether these responses are adaptive, which is crucial for predicting the short-term and evolutionary impact of transmission-blocking treatments for parasitic diseases.

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