Threshold Dynamics for Compartmental EpidemicModels in Periodic Environments Introduction The basic reproduction ratio Three examples Threshold dynamics in a patchy model IntroductionThe basic reproduction ratio is the expected number of secondary cases produced,in a completely susceptible population,by a typical infective individual.Autonomous epidemic models 7,31Specific infectious diseasesSexual diseases 20Tuberculosis in possums 13Dengue fever 12SARS 15,24,33,40People travel among cities 1,2
