Dynamical behavior and bifurcation analysis for a theoretical model of dengue fever transmission with incubation period and delayed recovery

Both the paper and the candidate solution reach the same threshold and uniqueness conclusions. However, for global stability of the disease-free equilibrium, the paper plugs Sh=1 and Sv=1/c1v (DFE values) directly into L' along trajectories to infer negativity and global stability, which is not justified; one needs bounds (Sh≤1, Sv≤1/c1v) and LaSalle’s invariance principle, as the model rightly provides. The model’s treatment of infection delays (τh, τv) via a clean characteristic equation and a modulus bound is also correct and sharper than what the paper explicitly states. Hence, the result is correct, but the paper’s argument is incomplete; the model’s proof closes the gap.