Figure 8.

Co-dimension two bifurcation diagrams in terms of the wt and mutant virus infection rates α_w and α_m when backwards mutation is possible. The mutation rates are (a) μ_m = 10⁻³ and μ_w = 10⁻¹ and (b) μ_m = 10⁻¹ and μ_w = 10⁻¹. All other parameters are given by (3.12). Dashed and solid lines correspond to transcritical and Hopf bifurcations, respectively. Blue denotes biologically feasible equilibria undergoing the bifurcations (all components non-negative), while colour orange denotes bifurcations of equilibria with negative components. The non-patterned, polka-dot and checkerboard regions correspond to virus-free, stationary coexisting, and oscillatory coexisting states, respectively.