Figure 1

Susceptible - Infected – Low susceptible - Infected (SILI) model of severe footrot among sheep flocks. The simulation model was developed to estimate the potential spread of severe footrot in Norway if no elimination programme was initiated and to estimate the relative importance of the different spreading routes. The figure shows the transmission dynamics of severe footrot within one county (i) for one time step with possible introduction from other counties (j) through sheep movement, cattle movement and sharing of common pastures. The model was used to calculate all the 19 counties separately.