Virulence management: Closing the feedback loop between healthcare interventions and virulence evolution

Area of Science:

• Epidemiology
• Evolutionary Biology
• Mathematical Modeling

Background:

• Endemic pathogens pose significant societal burdens.
• Healthcare interventions impact pathogen transmission and host recovery dynamics.
• Understanding pathogen evolutionary responses to interventions is key for long-term control.

Purpose of the Study:

• To investigate the evolution of pathogen virulence under varying healthcare interventions.
• To determine optimal intervention strategies for different management objectives.
• To analyze the impact of intervention implementation speed on pathogen evolution.

Main Methods:

• Utilized Adaptive Dynamics techniques within an SIS (Susceptible-Infected-Susceptible) model.
• Modeled interventions affecting host recovery and pathogen transmission rates (density-independent and dependent).
• Optimized interventions for minimizing virulence, mortality, and achieving eradication.

Main Results:

• Optimal intervention strategy is objective-dependent.
• Minimizing virulence requires minimal healthcare intervention.
• Minimizing mortality is achievable with both low and high intervention levels.
• Rapid intervention changes are preferred over gradual ones to prevent pathogen evolutionary shifts.

Conclusions:

• Healthcare interventions can be tailored to specific control goals, but may have counterintuitive effects on virulence.
• Rapid implementation of interventions is essential to avoid complex pathogen evolutionary trajectories.
• Adaptive Dynamics provides a framework for predicting and managing pathogen evolution in response to public health strategies.