Adaptive dispersal effect on the spread of a disease in a patchy environment.

During outbreaks of a communicable disease, people intensely follow the media coverage of the epidemic. Most people attempt to minimize contact with others, and move themselves to avoid crowds. This dispersal may be adaptive regarding the intensity of media coverage and the population numbers in different patches. We propose an epidemic model with such adaptive dispersal rates to examine how appropriate adaption can facilitate disease control in connected groups or patches. Assuming dependence of the adaptive dispersal on the total population in the relevant patches, we derived an expression for the basic reproduction number to be related to the intensity of media coverage, and we show that the disease-free equilibrium is globally asymptotically stable if and it becomes unstable if . In the unstable case, we showed a uniform persistence of disease by using a perturbation theory and the monotone dynamics theory. Specifically, when the disease mildly affects the dispersal of infectious individuals and rarely induces death, a unique endemic equilibrium exists in the model, which is globally asymptotically stable in positive states. Moreover, we performed numerical calculations to explain how the intensity of media coverage causes competition among patches, and influences the final distribution of the population.