Modeling Dose-Response for Illness from Salmonella Enteritidis in Eggs. A. R. Baker, Epidemiology and Risk Assessment, USDA-FSIS, Washington, DC; and R. M. McDowell, Risk Analysis Systems, USDA-APHIS, Riverdale, MD
Modeling dose-response for human illness from exposure to Salmonella enteritidis in internally contaminated eggs is the final module of the farm-to-table risk assessment of SE in eggs in USA. To account for differing susceptibility the exposed population was divided into two sub-populations: a susceptible population (very young, elderly, pregnant women, and others whose medical conditions have compromised their immune response) and a normal population. Probability of illness from specific exposures were computed using a beta-Poisson dose-response function fitted to a surrogate pathogen. The range of clinical outcomes included four mutually exclusive events: recovery without medical treatment; recovery following treatment by a physician; recovery following hospitalization; and death. In addition, the development of a post-illness sequel, reactive arthritis, was modeled for survivors. Based on published analyses of foodborne disease outbreaks, the probabilities of specific clinical outcomes were assumed to be independent of ingested dose, given person becomes ill. Total numbers of persons with specific clinical outcomes were modeled using the normal approximation to the binomial in a Monte Carlo framework where both numbers exposed and probabilities are random variables.
Go to . . .