A validation study of a simulation model for common source epidemics

We consider an environment and a population of individuals who are susceptible to a disease caused by a pathogen spread from a common source. We view the sequence of events resulting in the illness of some individuals as consisting of three components: the introduction of the pathogens and their dispersion through the environment, the movement of susceptible individuals through the environment, and the physiological effects of exposure of susceptible individuals to various pathogen levels. We identify four important parameters: two for each of the first and third components. A computer simulation of a model with these features is developed and implemented to study a 1977 outbreak of toxoplasmosis. Questions of parameter estimation and model validation are considered in detail.