A CONTINUUM MODEL OF THE WITHIN-ANIMAL POPULATION DYNAMICS OF E. COLI O157

Abstract

The high level of human morbidity caused by E. coli O157:H7 necessitates an improved understanding of the infection dynamics of this bacterium within the bovine reservoir. Until recently, a degree of uncertainty surrounded the issue of whether these bacteria colonize the bovine gut and as yet, only incomplete in-vivo datasets are available. Such data typically consist of bacterial counts from fecal samples. The development of a deterministic model, which has been devised to make good use of such data, is presented. A partial differential equation, which includes advection, diffusion and growth terms, is used to model the (unobserved) passage of bacteria through the bovine gut. A set of experimentally-obtained fecal count data is used to parameterize the model. Between-animal variability is found to be greater than between-strain variability, with some results adding further weight to the hypothesis that E. coli O157:H7 can colonize the bovine gastrointestinal tract.