“…As stated in [41], one of the significant features of malicious codes is their latent characteristics, which implies that the nodes are infected at time t − τ and they are surviving in the latent period τ and then become infective at time t. In addition, too large time delay may lead to large number of infected nodes, because of which malicious codes propagation persists in the system. Therefore, compared with the model proposed in [33], the delayed model in our paper is more general. It should be also pointed out that there are some proposed epidemic models for propagation of malicious code in a wireless sensor network such as the models in [5,6,9,42,43], but the authors did not consider the characteristics of networks like communication radius and distributed density of nodes in wireless sensor network.…”