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Epidemiology and Modelling

Head of Group: Professor Chris Gilligan

Chris Gilligan

Our research is focused on developing and testing a theoretical framework to understand the mechanisms that control invasion, persistence, scaling and variability of epidemics within changing agricultural and natural landscapes. Our models are used to predict the spread of disease and to identify and optimise economically and ecologically sustainable strategies for disease management, encompassing genetical, chemical, biological and cultural methods. The research involves a synthesis of epidemiological theory, population and evolutionary genetics, landscape ecology and economic modelling. The models are tested using data from laboratory microcosms and extensive field and regional data-sets.

Current projects include:

Optimising disease control strategies

Cassava mosaic disease
Cassava mosaic disease
We use a range of mathematical, statistical and computational techniques to predict the spread of disease through heterogeneous host populations. Examples of current questions include: is there a critical density of susceptible crops that is necessary for invasion by a virulent race of the pathogen? How is this affected by the geometry of the susceptible crops relative to the dispersal mechanisms of the parasite? How can we match the scale of control with the inherent temporal and spatial scales of the epidemic?

Estimation of epidemiological parameters

brown rust of wheat
Brown rust of wheat
One of the principal challenges in dealing with emerging epidemics is to estimate parameters for dispersal and transmission soon enough to use them to inform models that are then used to compare the effectiveness of different control strategies before it is too late to act. We use advanced statistical methods to infer these from successive snapshots of disease while allowing for uncertainties in disease reporting. Current applications of the models in protecting agricultural crops include: cassava virus disease, citrus canker and citrus greening and novel strains of wheat stem rust in Africa and Asia. Applications for disease in forest and semi-natural environments include sudden oak death, acute oak decline and ash dieback.