Evolution and spread of multiadapted pathogens in a spatially heterogeneous environment

Area of Science:

• Evolutionary biology
• Epidemiology
• Population genetics

Background:

• Pathogen adaptation to varied selective pressures complicates disease control.
• Understanding pathogen evolution in heterogeneous environments is crucial.

Purpose of the Study:

• Analyze pathogen evolutionary dynamics in spatially varying host populations.
• Determine conditions favoring generalist vs. specialist pathogen spread.
• Investigate the impact of spatial heterogeneity, adaptation costs, and population size on epidemic profiles.

Main Methods:

• Modeling pathogen spread and evolution in heterogeneous host populations.
• Analysis of transient (epidemic front) and long-term (behind the front) dynamics.
• Examination of factors including spatial heterogeneity, adaptation costs, mutation rates, and genetic drift.

Main Results:

• Identified five distinct epidemic profiles based on spatial heterogeneity and adaptation costs.
• Generalist pathogens can outcompete specialists under certain conditions, particularly in finite populations.
• Demographic stochasticity in finite populations favors generalists by increasing local maladapted pathogen extinction.
• Higher mutation rates can benefit specialist coalitions, accelerating epidemics in moderately heterogeneous environments.

Conclusions:

• Pathogen spread and evolution are significantly influenced by the interplay of migration, selection, mutation, and drift.
• Generalist strategies can be favored over specialist ones, with implications for disease control.
• Findings inform the development of durable control strategies against multi-adapted pathogens in agriculture and public health.