Hierarchical models for the spatio-temporal dynamics in*

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We shall develop an evidence-based hierarchical family of paradigmatic model frameworks for the temporal and spatial spread of two directly transmitted infections of farm animals: Avian Influenza (Al) and Foot and Mouth Disease(FMD. With respect to modeling disease systems we shall create both local (within herd/flock), county, state and national models of Al and FMD. The heirarchical strategy is important because the simpler models can be completed more quickly and parameterized more readily and are therefore more likely to be available for use than the more complicated models. Their behavior can more easily be generalized to other systems and can inform response measures in a strategic (if not tactical) sense. The more complicated models are essential tactical instruments but will take longer to complete and their behavior may not be so easily generalized to other infections. Our proposal represents a compromise between the need to provide useful strategic information about a range of potential threats - and the requirement that we can inform tactical decisions about prevention, response and recovery. Among other things, we shall investigate the appropriate level of granularity (scale) for each of these models. There are few regions in the USA where farms locations are mapped to level of detail required for most existing types of models for spatial and temporal spread at state or national scales. We shall devise models (metapopulation/ Patch/ Gravity models) based on other spatial resolutions (eg data based on zip codes, counties, or a national grid system). We shall test and calibrate these approximations using detailed spatial stochastic models developed using detailed and extensive GIS data bases on farm location in Pennsylvania and then extend their use to other regions in the USA. We shall use the models to devise and refine strategies for prevention, response and recovery. Avian Influenza and Foot and Mouth Disease are potential agents of bio/agroterrorism in addition to being devastating animal epidemic diseases in their own right which have have dramatic adverse effects on the well-being (social, economic and psycholgical) of human populations. The models proposed here will assist in planning strategies for prevention, control and response. In the case of Avian Influenza especially, controlling the infection in birds is a pre-emptive strategy for control in people.