Quantitative Risk Assessment of Introducing Bovine Spongiform Encephalopathy into Taiwan through Importation of Bone-in Beef from North America
Date Issued
2010
Date
2010
Author(s)
Hsieh, Yi-Hsuen
Abstract
The study aims to assess bovine spongiform encephalopathy (BSE) risk of Taiwan incurred from North America (NA) bone-in beef importation which introduces risk materials including internal bone marrow as well as external spinal cord and dorsal root ganglia contamination. After importation, releasing of risk materials comes from plate waste recycling, processing factories and slaughterhouse wastewater treatment as well as rendered product input into cattle environment. A risk model is constructed to simulate BSE prevalence of NA, the estimation of product usage and distribution, and the probability of cattle oral transmission. After input the estimated values for all parameters and selection the most appropriate model, Latin Hypercube simulation for 10,000 times is conducted and the results reveal that the risk of BSE through importing NA bone-in beef is 3.08×10-11 ± 2.75×10-10 (95th percentile = 4.39×10-9) in 2010. The study provides not only a scenario of overall bone-in beef importation risk assessment for domestic cattle but also a flexible model to assess the BSE risk from other beef exporting countries. Moreover, the study introduces a new idea to extrapolate meat and bone meal contamination in animal feed via exponential distribution, takes bone marrow as the major resource of infectivity to process risk assessment, and considers the role of pigs in transmission of BSE. The results show that fertilizer is the most important routes of BSE transmission in our model. Although the simulated risk values are within negligible ranges of scientific acceptable scale, they should be interpreted carefully for the sake of uncertainties in current model. Thus, it is necessary to ascertain all the ambigulous parameters in current model and process for further simuations to adjust the risk in the future. Since BSE is an irreversible fatal zoonotic disease, it is essential to establish rigorous strategies through appropriate risk management to reduce BSE transmission risk.
Subjects
Quantitative risk assessment
Bovine spongiform encephalopathy
North America
Scenario tree
Bone-in beef
Type
thesis
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