Fig. 3.

Simulations of system (1) for Q = 100, μ = 0.04, π₃ = 0.03, γ = 0.288, ρ = 0.02, σ = 0.04, δ = 0.8, α = 0.81. (a) is the solution of S_p versus time (days) and (b) is S_n versus time t. (c) is the projected I_p − I_n phase plane space and (d) is the projected S_n − S_p phase plane of the phase space