摘要：We incorporate the immigration of susceptible individuals into an SEIR epidemic model, assuming that the immigration rate decreases as the spread of infection increases. For this model, the basic reproduction number, 𝑅0, is found, which determines that the disease is either extinct or persistent ultimately. The obtained results show that the disease becomes extinct as 𝑅0<1 and persists in the population as 𝑅0>1.
