Novel methods for quantifying individual host response to infectious pathogens for genetic analyses.

Area of Science:

• Ecology
• Evolutionary Biology
• Quantitative Genetics

Background:

• Understanding host responses to pathogens is crucial for ecology and evolution.
• Quantifying individual host variation in resistance and tolerance is challenging.
• Existing methods often focus on population-level responses, masking individual differences.

Purpose of the Study:

• To introduce two novel quantitative approaches for assessing individual host responses to pathogen challenge.
• To provide methods for measuring infection severity and impact on host performance at the individual level.
• To generate new individual phenotypes for genetic analyses and to clarify concepts of host tolerance.

Main Methods:

• Extending group tolerance estimation to individual host level.
• Developing a dynamic approach to capture individual resistance and tolerance over infection time course.
• Utilizing repeated measurements of host performance and pathogen burden.

Main Results:

• Two distinct approaches are proposed: one extending group tolerance to individuals, and another capturing dynamic individual resistance and tolerance.
• The first approach disentangles host resistance from tolerance, while the second focuses on their combined effects.
• Both methods require repeated individual-level data on performance and pathogen burden over infection episodes.

Conclusions:

• The proposed methods offer new ways to phenotype individual host responses to pathogens.
• These approaches provide valuable tools for genetic analyses of disease resistance and tolerance.
• Considering individual tolerance reveals assumptions and limitations in current group tolerance concepts.