Evolution of infectious diseases in heterogeneous environments
Monday, March 6, 2017 - 12:00pm
Joseph Henry Room, Jadwin Hall
Physics and the Lewis-Sigler Institute

Infectious diseases caused by viruses, bacteria, and other parasites remain a major cause of illness and death worldwide. A major barrier to effective control of infections is the rapid rate at which they evolve to avoid natural immunity, cross between species, and resist medical interventions. The goal of my work is to better understand the factors that influence the direction and pace of this evolution using mathematical models. In this talk I will present our recent work examining how the structure of host contact networks - that is, the set of interactions through which the disease may be transmitted between individuals in a population - influences the emergence of new disease strains. We show that counter-intuitively, network structures that facilitate the spread of initial outbreaks often hinder the selection of newly evolved strains. Only some types of higher-order contact structure influence the rate of adaptation, and we examine these effects in real-world networks from schools, hospitals, and the community. Beyond this example, I will also discuss how fluctuating environments - such as periodically administered antimicrobial drugs - create unique selective pressures for drug resistant strains that cannot be predicted from time-averaged approximations, and can potentially even lead to evolution of synchronization between the pathogen and the therapy.