Аннотация:The system dynamics of the randomly perturbed SIS depend on a certain threshold RS. If RS < 1, the disease is removed from our community, whereas an epidemic will occur if RS > 1. However, what happens when RS = 1? In this paper, we give a solution to this problem. Furthermore, we make some improvements to the free disease equilibrium state E0 when RS < 1. Last, we give some computational simulations to explain our results.
