Evolution of parasite virulence when host responses cause disease

Troy Day, Andrea L. Graham, Andrew Fraser Read

Research output: Contribution to journalArticle

70 Citations (Scopus)

Abstract

The trade-off hypothesis of virulence evolution rests on the assumption that infection-induced mortality is a consequence of host exploitation by parasites. This hypothesis lies at the heart of many empirical and theoretical studies of virulence evolution, despite growing evidence that infection-induced mortality is very often a by-product of host immune responses. We extend the theoretical framework of the trade-off hypothesis to incorporate such immunopathology and explore how this detrimental aspect of host defence mechanisms affects the evolution of pathogen exploitation and hence infection-induced mortality. We argue that there are qualitatively different ways in which immunopathology can arise and suggest ways in which empirical studies can tease apart these effects. We show that immunopathology can cause infection-induced mortality to increase or decrease as a result of pathogen evolution, depending on how it covaries with pathogen exploitation strategies and with parasite killing by hosts. Immunopathology is thus an important determinant of whether public and animal health programmes will drive evolution in a clinically beneficial or detrimental direction. Immunopathology complicates our understanding of disease evolution, but can nevertheless be readily accounted for within the framework of the trade-off hypothesis.

Original languageEnglish (US)
Pages (from-to)2685-2692
Number of pages8
JournalProceedings of the Royal Society B: Biological Sciences
Volume274
Issue number1626
DOIs
StatePublished - Nov 7 2007

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immunopathology
Pathogens
virulence
Virulence
parasite
Parasites
parasites
Mortality
Infection
trade-off
mortality
pathogen
infection
Byproducts
pathogens
Animals
Health
Theoretical Models
defense mechanism
Public Health

All Science Journal Classification (ASJC) codes

  • Biochemistry, Genetics and Molecular Biology(all)
  • Immunology and Microbiology(all)
  • Environmental Science(all)
  • Agricultural and Biological Sciences(all)

Cite this

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Evolution of parasite virulence when host responses cause disease. / Day, Troy; Graham, Andrea L.; Read, Andrew Fraser.

In: Proceedings of the Royal Society B: Biological Sciences, Vol. 274, No. 1626, 07.11.2007, p. 2685-2692.

Research output: Contribution to journalArticle

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