Mechanistic models of host movement to understand disease dynamics in variable environments

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In Canada, over the last two decades new wildlife diseases have emerged and patterns of existing diseases have changed substantially. These changes highlight the need for research that investigates disease dynamics. Diseases are spread when a susceptible host contacts an infectious host or a parasite. These rates of encounter depend strongly on how hosts move, and yet, most mathematical models of disease spread do not explicitly consider host movement. In addition, temperature, humidity and other abiotic factors affect both the infectivity of parasites and the rate of maturation through parasite life stages. Both the strength and mechanisms of seasonality will affect disease dynamics. Parasites affect how hosts move and this affects parasite spread and the evolution of characteristics such as parasite virulence. My research group will investigate how host movement affects the types of epidemics that result. We will consider different types of movement models including correlated and biased random walks and state-space models. We will investigate the effect of fluctuating environmental conditions on the spread of free-living parasites. We will also investigate the evolution of parasite virulence by deriving and analyzing mathematical models where a trade-off exists between the rate of host movement and/or parasite infectivity, the parasite shedding rate, and the disease-induced death rate. In all cases, the models will be analyzed using mathematical and computational techniques.This research will capitalize on recent progress in developing mechanistic models of animal movement and will contribute new conceptual, quantitative, and computational tools to the study of infectious disease spread. The models that we will derive improve the biological realism of existing theory and are likely to lead to a better understanding of disease dynamics. For a specific case study, we will apply the theory we develop to understand the spread of brain worm in declining herds of caribou in Newfoundland. This research program will support the training of 1 PhD student, 4 MSc students and 4 undergraduate researchers. These students will be trained in mathematical modelling and theoretical biology and will gain valuable experience in interdisciplinary research.