The pathogenesis, epidemiology and options for control of Johne's disease in sheep were reviewed and mathematical models developed to simulate the spread of Johne’s disease within infected flocks, and between flocks on a regional basis. The models (the OJD Flock Model and the OJD Regional Model) also allow the evaluation and comparison of various control options at both flock and regional levels. Adequate data is still unavailable to allow accurate estimates of the true values for many of the models' parameters. However, as more precise estimates of the values of key parameters become available, the models will allow a rapid assessment of the likely impact of these values on our understanding of the disease
