This study focused on the existence and uniqueness(EU) and stability of the solution for a system of fractional differential equations(FDEs) via Atangana-Baleanu derivative in the sense of Caputo (ABC) with \(\phi_{p}\)-Laplacian operator. Green function \( \mathcal{G}^{\eth}(t,s)\), \(m<\eth<m+1\), \(m\geq4\) used for converting the suggested problem to an integral equation. Guo-Krasnoselskii theorem used for proving the EU of solution for the suggested problem. The stability of the solution was derived by Hyers-Ulam stability method(HUS). One illustrative example is used for manifesting the results.

This work focuses on an HIV infection model with intracellular delay and immune response delay, in which the former delay refers to the time it takes for healthy cells to become infectious after infection, and the latter delay refers to the time when immune cells are activated and induced by infected cells. By investigating the properties of the associated characteristic equation, we derive sufficient criteria for the asymptotic stability of the equilibria and the existence of Hopf bifurcation to the delayed model. Based on normal form theory and center manifold theorem, the stability and the direction of the Hopf bifurcating periodic solutions are studied. The results reveal that the intracellular delay cannot affect the stability of the immunity-present equilibrium, but the immune response delay can destabilize the stable immunity-present equilibrium through the Hopf bifurcation. Numerical simulations are provided to support the theoretical results.

In this paper, we consider a diffusive epidemic model with latent period and vaccination strategy. The well-posedness of solutions is first investigated for such a system. Then, in terms of the basic reproduction number and the critical wave speed, we establish a complete threshold result which reveals the existence and nonexistence of the strong traveling waves connecting the disease-free equilibrium to the endemic steady state. Finally, some numerical simulations are performed to illustrate our theoretical analysis. Our results implies that (i) the diffusion ability of the infected individuals can accelerate the minimal wave speed; and (ii) the latent period and vaccination strategy would slow down the spread of the disease.