| In this paper,we propose a periodic dengue disease transmission model with vaccination and two time delays.We first introduce the basic reproduction ratio R0 for this model and then prove that R0 serves as a threshold value for the global extinction and uniform persistence of the disease.More precisely,the disease will die out if R0<1;the system admits a positive periodic solution and the disease will persist if R0>1.Numerically,we derive the algorithm to compute R0 and study the dengue transmission case in Brazil.Our numerical simulation results are consistent with the theoretical results that we have obtained.In addition,we analyze the effects of the vaccination on the transmission of dengue and suggest the strategies to the prevention and control of dengue. |