Global Stability of an SEIS Epidemic Model with General Saturation Incidence

Figure 2

Movement paths of 𝑆, 𝐸, and 𝐼 as functions of time 𝑡. For (a), we have 𝑅₀=0.85 and 𝑃₀ is globally stable. The disease is extinct. For (b), we have 𝑅₀=1.4 and 𝑃^∗ is globally stable. The disease spreads to be endemic.

(a)

(b)