A demographic model of measles epidemics

Liverpool, U.K., 1863-1900, has been used as a model to explore the interac tion between measles epidemics and the population dynamics in an overcrowde d community with inadequate nutrition using a non-linear model which allows the estimation of certain underlying demographic parameters. The results a re consistent with a system that is driven by an oscillation in the transmi ssion parameter that is compounded of an oscillation in autumn temperatures (at the resonant frequency of the system, 2.4 years) and, secondarily, by an oscillation in wheat prices (wavelength = 5.3 years, twice that of the e pidemics).