Thieme, Horst R.van den Driessche, P.2010-02-192010-02-1919982010-02-19http://hdl.handle.net/1828/2239A general disease transmission model of SIRS type is formulated and analyzed. There is constant recruitment into the susceptible class mass action incidence, and stage age in the removed class. Disease fatalities occur in the infective class and the removed stages. Sufficient conditions are given for the endemic equilibrium to be globally asymptotically stable. For example, if the disease confers permanent immunity, then global stability of the endemic equilibrium (for parameter values such that it exists) is assured. Other examples are given that exhibit this same assured behavior.enTechnical Report