Punctuated virus-driven succession generates dynamical alternations in CRISPR-mediated microbe-virus coevolution.
Armun Liaghat1,2, Jiayue Yang3, Rachel Whitaker3,4
1Department of Ecology and Evolution, University of Chicago, Chicago, IL, USA.
Journal of the Royal Society, Interface
|August 21, 2024
Summary
Viral epidemics emerge when host competition weakens microbial defenses against viruses. This study models how host-pathogen dynamics shift from control to widespread outbreaks, driven by ecological and evolutionary feedbacks.
Area of Science:
- Ecology
- Evolutionary Biology
- Microbiology
- Epidemiology
Background:
- Coevolution between viruses and microbes with CRISPR-Cas immunity shows alternating dynamics of host control and viral epidemics in models.
- These alternating dynamics are not yet observed in other host-pathogen systems.
- Understanding the transition from controlled host-pathogen interactions to large outbreaks is crucial.
Purpose of the Study:
- To investigate the breakdown of host control and the transition to large viral outbreaks using a stochastic eco-evolutionary model.
- To establish the role of host density-dependent competition in virus-driven succession and diversity.
- To derive viral emergence probability and explore alternation probabilities based on key parameters.
Main Methods:
- Developed a stochastic eco-evolutionary model incorporating host density-dependent competition.
- Utilized infection and escape networks to analyze host-pathogen interactions.
- Derived viral emergence probability and analyzed alternation probabilities as a function of non-dimensional parameters.
Main Results:
- Host density-dependent competition drives punctuated virus-driven succession and concentrates viral escape pathways during control phases.
- Fluctuations in viral emergence probability, increasing in size and frequency, characterize the approach to large outbreaks.
- Emergent feedbacks between host competition and viral diversification create a fragile host immune structure.
Conclusions:
- The study demonstrates how ecological factors (host competition) and evolutionary dynamics (viral diversification) interact to destabilize host immunity.
- These interactions potentiate a dynamical transition from controlled host-pathogen interactions to large-scale epidemics.
- The findings highlight the importance of considering eco-evolutionary feedbacks in understanding epidemic dynamics.
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