Figure 1.

Resistance and disease tolerance to infection. As host pathogen load increases during infection, disease symptoms become apparent and give rise to the clinical signs of infectious diseases. After an initial phase where both pathogen load and disease severity increase, the three possible outcomes are: (i) host homeostasis prevails based on resistance and disease tolerance mechanisms that eliminate pathogens and sustain vital metabolic outputs (green), (ii) resistance mechanisms reduce pathogen load but tissue damage control mechanisms fail to establish disease tolerance, compromising host homeostasis (blue); (iii) resistance mechanisms fail to control pathogen burden and tissue damage control mechanisms fail to establish diseases tolerance, compromising host homeostasis (red).