Before revision: In this work, we have developed a Coxian distributed SEIR model in incorporating an empirical incubation period since Coxian distribution approximately converges to any distribution. A basic reproduction number is found from the model .
After revision: In this work, we have developed a Coxian distributed SEIR model in incorporating an empirical incubation period . We show that the global dynamics are completely determined by a basic reproduction number is found from the model .