Dynamics and spreading speed of a reaction-diffusion system with advection modeling West Nile virus

摘要

This paper aims to explore the temporal-spatial spreading and asymptotic behaviors of West Nile virus (WNv) by a reaction-advection-diffusion system with free boundaries, especially considering the impact of advection term on the extinction and persistence of West Nile virus. We define the spatial-temporal risk index R-0(F) (t) with the advection rate (mu) and the general basic disease reproduction number R-0(D) to get the vanishing-spreading dichotomy regimes of West Nile virus. We show that there exists a threshold value mu* of the advection rate, and obtain the threshold results of mu*. When the spreading occurs, we investigate the asymptotic dynamical behaviors of the solution in the long run and first give an estimate that the asymptotic spreading speed of the leftward front is less than or equal to the rightward front in the case of 0 < mu < mu*. At last, we give some numerical simulations to identify the significant effects of the advection. (c) 2020 Elsevier Inc. All rights reserved.