Effects of population density on the spread of disease

The effect of population density on the epidemic outbreak of measles or measles‐like infectious diseases was evaluated. Using average‐number contacts with susceptible individuals per infectious individual as a measure of population density, an analytical model for the distribution of the nonstationary stochastic process of susceptible contact is presented. A 5‐dimensional lattice simulation model of disease spread was used to evaluate the effects of four different population densities. A zero‐inflated Poisson probability model was used to quantify the nonstationarity of the contact rate in the stochastic epidemic process. Analysis of the simulation results identified a decrease in a susceptible contact rate from four to three, resulted in a dramatic effect on the distribution of contacts over time, the magnitude of the outbreak, and, ultimately, the spread of disease.