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Multiple infections, kin selection and the evolutionary epidemiology of parasite traits

S Lion1

  • 1CEFE UMR 5175-1919, Montpellier Cedex 5, France.

Journal of Evolutionary Biology
|September 14, 2013
PubMed

Insights

Coinfection dynamics reveal how parasite competition influences virulence. The study shows that parasite relatedness within hosts impacts virulence evolution, with complex outcomes depending on infection strategies.

Area of Science:

  • Evolutionary Biology
  • Parasitology
  • Epidemiology

Background:

  • Coinfection by multiple parasite strains shapes host exploitation strategies.
  • Existing models link kin selection to virulence and epidemiology to multiple infections.

Purpose of the Study:

  • To develop a general model of coinfections integrating kin selection and epidemiological approaches.
  • To analyze the invasion fitness of mutant parasites under varying infection multiplicities.

Main Methods:

  • Developed a general mathematical model for coinfections.
  • Derived an analytical expression for mutant invasion fitness.
  • Analyzed the evolutionarily stable strategies for virulence and host exploitation.

Main Results:

  • Evolutionarily stable virulence depends on the average within-host relatedness across all infection levels (multiplicity of infection).
  • When exploitation strategies vary by infection level, virulence depends on parasite reproductive values between infection classes.
  • Lower within-host relatedness can lead to either increased or decreased virulence.

Conclusions:

  • The study provides a generalized framework for understanding virulence evolution in coinfections.
  • Parasite competition and varying exploitation strategies create complex relationships between relatedness and virulence.
  • Findings challenge previous assumptions about the direct correlation between relatedness and virulence levels.
Keywords:
coinfectionepidemiologyrelatednessreproductive valuevirulence

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