Within-host dynamics and evolution

Abstract

Infections typically spread from a primary site to target organs. Rapid early defences are critical to contain an infection. However, recognition is not error-free and shows a trade-off between specificity and sensitivity. The within-host dynamics of an infection can be studied in various ways, e.g. with target cell-limited models. The disease space can trace within-host infection trajectories and predict the eventual outcome. Also, computational and systems immunology identify important defence elements and predict the course of an infection. Infecting populations evolve within their hosts. Horizontal transfer of genetic elements, recombination, and mutations thereby allow pathogens to escape host defences; examples are escape mutants or antigenic variation. The evolution of antimicrobial resistance is of special concern. Co-infecting parasites, such as bacteria, can cooperate to exploit a host (e.g. by production of siderophores) or compete for access (e.g. by releasing bacteriocins). Multiscale models combine within- and between-host episodes.