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Bovine Spongiform Encephalopathy Risk Assessment on Bovine Spongiform
Encephalopathy in Cattle in Canada
Part C: Risk Estimation
Table of contents | List of tables | List
of figures
Main page |
Part A | Part B | Part C
TABLE OF CONTENTS
| 1. |
INTRODUCTION |
| 2. |
HAZARD IDENTIFICATION |
| 3. |
RELEASE ASSESSMENT |
|
3.1. Probability that the Imported Bovine Animal is BSE-Infected (f1) |
| 4. |
EXPOSURE ASSESSMENT |
|
4.1. Probability that the Animal was Slaughtered (f2) |
|
4.2. Probability that the Carcass was Rendered (f3) and the
Probability Inedible Parts of the Carcass were Rendered (f6) |
|
4.3. Probability of Contaminated Batch(es) Entering the Cattle Feed Chain
(f4, f7) |
|
4.4. Probability of at Least One Oral Transmission Infection (f5,
and f8) |
|
4.5. Number of ID50 s Presented by a BSE-Infected Rendered
Carcass |
|
4.6. Rendering Reduction in ID50s |
|
4.7. Average Daily Consumption of MBM by Age (months) |
|
4.8. Proportion of Dairy Cattle Population by Age (months) |
|
4.9. Age-Dependent Susceptibility of Cattle to BSE Infection (ps
) |
| 5. |
CONSEQUENCE ASSESSMENT |
|
5.1. Direct Consequences |
|
|
5.1.1. Animal Health Impact |
|
|
5.1.2. Public Health Impact |
|
5.2. Indirect Consequences |
|
|
5.2.1. Economic Considerations |
|
|
5.2.1.1. Surveillance, Control and Eradication cost |
|
|
5.2.2. Potential Trade Losses |
|
|
5.2.2.1. Trade Impact |
|
|
5.2.2.2. Impact on Industry |
| 6. |
RISK ESTIMATION |
|
6.1. Risk Estimate |
|
6.2. Mitigating Measures in Place Between 1997 and 2002 |
|
|
6.2.1. Import controls |
|
|
6.2.2. Surveillance |
|
|
6.2.3. Rendering practices |
|
|
6.2.4. Feed industry |
|
|
6.2.5. Farms |
| REFERENCES |
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LIST OF TABLES
| Table 1: |
Lifetime cumulative incidence of BSE clinical disease and infection in
birth cohorts in the Great Britain for the years 1974–1989, and the number of cattle
imported into Canada according to the year of birth (cattle that died or were slaughtered
and may have been rendered) |
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LIST OF FIGURES
| Figure 1 |
Release and exposure assessment scenario tree emanating from an
initiating failure event of importing cattle between 1979–1997 from the United
Kingdom, Austria, Denmark, France, Germany, the Republic of Ireland, Switzerland, and the
Netherlands, that were potentially infected with bovine spongiform encephalopathy |
| Figure 2 |
Distribution of the estimated number of BSE-infected cattle imported from
the United Kingdom, France, Switzerland, Denmark, the Republic of Ireland, Austria,
Germany, and the Netherlands that were slaughtered or died and may have been rendered
(binomial distribution output with 10,000 iterations of Latin hypercube sampling using the
risk analysis computer software @RISK (Palisade Corporation, New York)) |
| Figure 3 |
Total cattle oral ID50s of BSE infectivity according to month
post-infection (adapted from Cohen et al., 2001) |
| Figure 4 |
The relative susceptibility of cattle to BSE infection according to age
in months (Cohen et al., 2001) |
| Figure 5 |
Distribution of the probability of at least one infection as a simulation
output of the @RISK risk analysis software, 100,000 iterations of Latin hypercube sampling |
| Figure 6 |
Sensitivity analysis (@RISK tornado graph) of the output (probability of
at least one infection) and the model inputs |
|
