Format

Send to

Choose Destination
See comment in PubMed Commons below
Proc Biol Sci. 2004 Dec 7;271(1556):2431-8.

The impact of cross-immunity, mutation and stochastic extinction on pathogen diversity.

Author information

1
Department of Infectious Disease Epidemiology, Imperial College London, St Marys Campus, Norfolk Place, London W2 1PG, UK. l.aburaddad@imperial.ac.uk

Abstract

We examine the dynamics of antigenically diverse infectious agents using a mathematical model describing the transmission dynamics of arbitrary numbers of pathogen strains, interacting via cross-immunity, and in the presence of mutations generating new strains and stochastic extinctions of existing ones. Equilibrium dynamics fall into three classes depending on cross-immunity, transmissibility and host population size: systems where global extinction is likely, stable single-strain persistence, and multiple-strain persistence with stable diversity. Where multi-strain dynamics are stable, a diversity threshold region separates a low-prevalence, low-diversity region of parameter space from a high-diversity, high-prevalence region. The location of the threshold region is determined by the reproduction number of the pathogen and the intensity of cross-immunity, with the sharpness of the transition being determined by the manner in which immunity accrues with repeated infections. Host population size and cross-immunity are found to be the most decisive factors in determining pathogen diversity. While the model framework developed is simplified, we show that it can capture essential aspects of the complex evolutionary dynamics of pathogens such as influenza.

PMID:
15590592
PMCID:
PMC1691886
DOI:
10.1098/rspb.2004.2877
[Indexed for MEDLINE]
Free PMC Article
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for HighWire Icon for PubMed Central
    Loading ...
    Support Center