Dynamics Of Non-autonomous SEIS Epidemic Model With Bilinear Incidence Rate

Epidemics have been one of the diseases that are payed most attention by human-beings,so studies to rules of transmission and methods of protection are of great importance.Native and foreign scholars have payed great effort in studies of kinds of epidemics.In this paper,we discuss the permanence and extinction of non-autonomous SEIS epidemic model with bilinear incidence rate,and get the conditions when the epidemic is permanent or extinct,the explorations also involve the existence and stability of periodic solutions in the periodic case.