Abstract
Management response to contagious disease outbreaks requires rapid application of appropriate control measures (for example, quarantine and vaccination), but with little current or empirical data about how the disease may spread. This means that modelling is one of the few available options for making important decisions, and geographical modelling is a key approach. While there are many models that deal with disease spread within livestock populations, there are few that deal explicitly with widely dispersed animal populations such as unfenced livestock and wild and feral animals. It is for this purpose that we have developed a geographic automata model, Sirca, to simulate possible outbreaks of disease in wild and unfenced animal populations.