Human movement not only facilitates disease spread but also poses a serious challenge to disease control and eradication. In reality, disease eradication is rather difficult or even impossible for many infectious diseases. Thus, reducing disease prevalence (proportion of people being infected) to a low level is a more feasible and cost-effective goal. The basic reproduction number can serve as a threshold for disease persistence and extinction, but it usually cannot measure the endemic level. In this talk, based on an SIS (Susceptible-Infectious-Susceptible) patch model, I will explore the impact of the movement of susceptible and infected populations on the local and global disease prevalence. It is shown that there is an inconsistency between disease persistence and disease prevalence with respect to dispersal rate. In particular, for the two-patch case, two complete classifications of the model parameter space are given: one addressing when dispersal leads to larger or smaller global disease prevalence than no dispersal, and the other concerning how the global disease prevalence varies with dispersal rate. This is a joint work with Yuan Lou and Ailing Wang.