Send to

Choose Destination
Epidemiol Infect. 2008 Jun;136(6):761-70. Epub 2007 Aug 3.

Hierarchical dose response of E. coli O157:H7 from human outbreaks incorporating heterogeneity in exposure.

Author information

National Institute of Public Health and the Environment, Antonie van Leeuwenhoeklaan 9, Bilthoven, The Netherlands.


The infectivity of pathogenic microorganisms is a key factor in the transmission of an infectious disease in a susceptible population. Microbial infectivity is generally estimated from dose-response studies in human volunteers. This can only be done with mildly pathogenic organisms. Here a hierarchical Beta-Poisson dose-response model is developed utilizing data from human outbreaks. On the lowest level each outbreak is modelled separately and these are then combined at a second level to produce a group dose-response relation. The distribution of foodborne pathogens often shows strong heterogeneity and this is incorporated by introducing an additional parameter to the dose-response model, accounting for the degree of overdispersion relative to Poisson distribution. It was found that heterogeneity considerably influences the shape of the dose-response relationship and increases uncertainty in predicted risk. This uncertainty is greater than previously reported surrogate and outbreak models using a single level of analysis. Monte Carlo parameter samples (alpha, beta of the Beta-Poisson model) can be readily incorporated in risk assessment models built using tools such as S-plus and @ Risk.

[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for Cambridge University Press Icon for PubMed Central
Loading ...
Support Center