ANALYSIS OF AN SEIRS EPIDEMIC MODEL WITH TIME DELAYS AND PULSE VACCINATION

摘要

Pulse vaccination is an important strategy for the elimination of infectious diseases. An SEIRS epidemic model with time delays and pulse vaccination is formulated in this paper. By the comparison theorem in impulsive differential equations, we obtain that the infection-free periodic solution is globally attractive if the pulse vaccination rate is larger than θ~*. Moreover, we show that the disease is uniformly persistent if the pulse vaccination rate is less than θ~* under appropriate conditions. The permanence of the model is investigated analytically.