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Genetic diversity in the SIR model of pathogen evolution
Isabel Gordo1, M Gabriela M Gomes, Daniel G Reis
1Instituto Gulbenkian de Ciência, Oeiras, Portugal. igordo@igc.gulbenkian.pt
Plos One
|March 17, 2009
Summary
This study presents a model for pathogen genetic diversity, showing variation increases with infection duration and is influenced by host transmission dynamics. Invasion probability of new strains depends on fitness advantages, with signatures compared to influenza A.
Area of Science:
- Epidemiology
- Evolutionary Biology
- Population Genetics
Background:
- Pathogen populations evolve under host-pathogen interactions.
- Understanding genetic diversity is crucial for disease control and evolution.
- The susceptible-infected-recovered (SIR) model describes disease spread.
Purpose of the Study:
- To develop a model for assessing genetic diversity in pathogen populations.
- To analyze the factors influencing pathogen variation and evolution.
- To investigate the invasion dynamics of new pathogenic strains.
Main Methods:
- Developed a metapopulation model for pathogen replication and mutation within infected hosts.
- Utilized analytical expressions to predict pathogen neutral molecular variation.
- Introduced selection to model the invasion probability of fitter strains.
- Analyzed molecular signatures during strain replacement and compared with influenza A data.
Main Results:
- Pathogen neutral molecular variation is bounded by infection levels and increases with infection duration.
- Invasion probability of a novel pathogenic strain is determined by its relative fitness increase (s).
- Identified molecular signatures of strain replacement, consistent with influenza A patterns.
Conclusions:
- The developed model accurately predicts pathogen genetic diversity based on epidemiological parameters.
- Fitness differences are key drivers for the invasion and spread of new pathogen strains.
- The study provides insights into pathogen evolution and molecular signatures relevant to influenza surveillance.
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