“…The deterministic SIRS models (1.1) have been extended in several different ways into stochastic or random counterparts. One of them is to perturb the deterministic models by white noises, see, for instance, [3,16,22,26,32] upon asymptotic analysis. Whereas, with regard to deterministic SIRS models or stochastic counterparts perturbed by white noises, the environment is assumed to be constant.…”