Dynamical Behavior of a New Epidemiological Model

Figure 2

When 𝜏=0, 𝑏=3, 𝛼=𝑑=𝑘=𝑐=𝑢₁=1, 𝑢₂=2, and the initial value is (3,1,1), then 𝑅₀=1, and the solution (𝑆(𝑡),𝐼(𝑡),𝐷(𝑡)) approaches to the disease-free equilibrium 𝐸₀=(3,0,0) as 𝑡→∞.