Modern statistical models and computational methods can now incorporate uncertainty of the parameters used in Quantitative Microbial Risk Assessments (QMRA). Many QMRAs use Monte Carlo methods, but work from fixed estimates for means, variances and other parameters. We illustrate the ease of estimating all parameters contemporaneously with the risk assessment, incorporating all the parameter uncertainty arising from the experiments from which these parameters are estimated. A Bayesian approach is adopted, using Markov Chain Monte Carlo Gibbs sampling (MCMC) via the freely available software, WinBUGS. The method and its ease of implementation are illustrated by a case study that involves incorporating three disparate datasets into an MCMC framework. The probabilities of infection when the uncertainty associated with parameter estimation is incorporated into a QMRA are shown to be considerably more variable over various dose ranges than the analogous probabilities obtained when constants from the literature are simply ‘plugged’ in as is done in most QMRAs. Neglecting these sources of uncertainty may lead to erroneous decisions for public health and risk management.
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Research Article|
February 03 2011
Incorporating parameter uncertainty into Quantitative Microbial Risk Assessment (QMRA)
Margaret Donald;
1Queensland University of Technology, George Street, Brisbane, QLD 4000, Australia
Tel.: +617 3138 1292; E-mail: [email protected]
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Kerrie Mengersen;
Kerrie Mengersen
1Queensland University of Technology, George Street, Brisbane, QLD 4000, Australia
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Simon Toze;
Simon Toze
1Queensland University of Technology, George Street, Brisbane, QLD 4000, Australia
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Jatinder P.S. Sidhu;
Jatinder P.S. Sidhu
1Queensland University of Technology, George Street, Brisbane, QLD 4000, Australia
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Angus Cook
Angus Cook
1Queensland University of Technology, George Street, Brisbane, QLD 4000, Australia
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J Water Health (2011) 9 (1): 10–26.
Article history
Received:
July 20 2009
Accepted:
May 18 2010
Citation
Margaret Donald, Kerrie Mengersen, Simon Toze, Jatinder P.S. Sidhu, Angus Cook; Incorporating parameter uncertainty into Quantitative Microbial Risk Assessment (QMRA). J Water Health 1 March 2011; 9 (1): 10–26. doi: https://doi.org/10.2166/wh.2010.073
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