Figure 1.

Population size and disease prevalence along a gradient of increasing death rate. Solid thick line, total population size; solid thin line, number diseased; dashed line, prevalence (scaled from 0 to 100% on y-axis); thin dotted line, disease-free deterministic population size. (a) Classical model with density-dependent transmission and disease induced mortality; α=0.25, b=2, β=0.3. (b) Sterilizing disease with density-dependent transmission; b=1, β=0.3. (c) Sterilizing disease with frequency-dependent transmission; b=1, β=3. Throughout: d (min)=0.5, m=0.2, K=100, lattice=10×50 cells.