Fig. 3.

The attack rates of 21,000 ordered simulated epidemics with farm #663 as the index farm and epidemic parameters δ* = 3×10⁻⁶ and ρ^* = 2. There were 14,443 ‘mild’ simulations (epidemics with early stochastic extinction for which 5 or fewer farms out of 946 were infected) and 6557 ‘severe’ epidemics (all with 276 or more infected farms). The jump is at 0.6878 and the mean of the attack rate for the severe epidemics is 0.30. The inset map is a histogram of the 6557 severe epidemics.