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Evolution and virulence

We study the evolution of parasites and pathogens (including those which jump to novel host species, causing emerging disease), and how this affects their pathogenicity and virulence. We are also investigating coevolution between hosts and disease agents, and between interacting parasites and pathogens of different strains and species. Findings are relevant to disease surveillance and control policies.

Characterizing evolution

CIDD researchers are:

  • Conducting large-scale genomic analyses to detect patterns of parasite and pathogen evolution.
  • Modeling evolutionary processes to gain insights about evolutionary mechanisms and reconstruct evolutionary histories.

We mostly focus on:

  • RNA viruses, which demonstrate particularly high rates of genetic change.
  • Pathogenic bacteria and related strains and species that are less pathogenic. For example, the subspecies Bordetella pertussis and B. parapertussis are both human pathogens but appear to have evolved independently: they are more closely related to B. bronchiseptica (infects mice and other animals) than to each other.
  • A few DNA viruses. For instance, Cattadori et al. are investigating evolution of virulence in the myxoma virus in natural populations of European rabbits (Oryctolagus cuniculus) in the U.K.

Identifying gene function and expression

Once genetic differences between related microorganisms have been identified, we are looking in more detail at some of them to investigate the function and expression of particular genes. This can enable us to identify the genes involved in virulence and the circumstances under which they are expressed.

Investigating coevolution

Hosts and pathogens can exert powerful selective pressures on each other. CIDD researchers are investigating coevolution of hosts and disease agents in a variety of systems. 

Next step phylodynamics

Information about patterns, mechanisms and causes of evolution is at the core of the emerging discipline of phylodynamics, which is being pioneered by CIDD researchers.

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Sample papers

Mackinnon MJ, Gandon S & Read AF (2008) Virulence evolution in response to vaccination: the case of malaria. Vaccine 26S: C42-C52

Chen R & Holmes EC (2007) Avian influenza virus exhibits rapid evolutionary dynamics. Molecular Biology and Evolution 23: 2336-2341.

Poss M, Adoine A, Ross HA, Terwee JA, VandeWoude S & Rodrigo A (2007) Recombination in feline lentiviral genomes following experimental cross-species infection. Virology 359: 146-151.

Koelle K, Cobey S, Grenfell B & Pascual M (2006) Epochal evolution shapes the phylodynamics of influenza A (H3N2) in humans. Science 314: 1898-1903

Luis AD & Hudson PJ (2006). Hibernation patterns in mammals: a role for bacterial growth? Functional Ecology 20: 471

Bjornstad ON & Harvill ET (2005). Evolution and emergence of Bordetella in humans. Trends in Microbiology 13: 355-359


 
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