African swine fever virus (ASFv) is endemic in wild boar in Eastern Europe, challenging elimination in domestic swine. Estimates of the distances between transmission events are crucial for predicting rates of disease spread to guide allocation of surveillance and control resources. Transmission distances are mainly defined by spatial and social processes in hosts, but effects of these processes on spread are poorly understood, and inferences often include only one process. To understand

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... of spatial and social processes on disease dynamics we developed spatially-explicit transmission models with different assumptions about social and/or spatial contact processes. We fit the models to ASFv surveillance data from Eastern Poland from 2014-2015 and evaluated how inclusion of social structure affected inference. The model that accounted for social along with spatial processes provided better inference of spatial spread and predicted that ~80% of transmission events are within the same family group. The models predicted dramatically different effective reproductive numbers, both in magnitude and variation. Specifying contact structure with spatial but not social processes can lead to very different disease dynamics and inference of epidemiological parameters. Uncertainty in these processes should be accounted for in predicting spatial spread in social species.