Hethcote, Herbert W.Lewis, Mark A.van den Driessche, P.2009-08-202009-08-2019882009-08-20http://hdl.handle.net/1828/1547An epidemiological model with both a time delay in the removed class and a nonlinear incidence rate is analysed to determine the equilibria and their stability. This model is for diseases where individuals are first susceptible, then infected, then removed with temporary immunity and then susceptible again when they lose their immunity. There are multiple equilibria for some parameter values, and, for certain of these, periodic solutions arise by Hopf bifurcation from the large nontrivial equilibrium state.enepidemiological modelHopf bifurcationnonlinear incidencetime delaytechnical reports (mathematics and statistics)Technical ReportDepartment of MathematicsDepartment of Mathematics and Statistics