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Systemic modelling applied to studying outbreaks of exotic animal diseasesDelgado, Joao Pedro Correa January 2011 (has links)
Context and rationale – This work originates from policy priorities established within Defra to manage exotic animal diseases (EAD); specifically to understand the causes of low probability events, and to establish contingencies to manage outbreak incidents. Outbreaks of exotic animal diseases, e.g. FMD, CSF and HPAI, can cause economic and social impacts of catastrophic proportions. The UK’s government develops and implements policies and controls to prevent EAD and thus minimise these impacts. Control policies to achieve this are designed to address the vulnerabilities within the control systems. However, data are limited for both the introduction of an EAD as well as its resurgence following the disposal of infected carcasses, i.e. the pre-outbreak and post-outbreak phases of an EAD event. These lack of data compromises the development of policy interventions to improve protection. To overcome these data limitations, predictive models are used to predict system vulnerabilities. Cont/d.
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Three Essays on Bio-securityGao, Qi 2009 December 1900 (has links)
In this dissertation, several essays in the field of bio-security are presented.
The estimation of the probability of an FMD outbreak by type and location of
premises is important for decision making. In Essay I, we estimate and predict the
probability/risk of an FMD outbreak spreading to the various premises in the study area.
We first used a Poisson regression model with adjustment dispersion associated with
random simulation results from the AusSpead model to estimate the parameters of the
model. Our estimation and prediction show that large cattle loss could be concentrated in
three counties-Deaf Smith, Parmer, and Castro. These results are based on approximately
70% of the feedlots with over 10,000 cattle located in the three counties previously
mentioned.
In Essay II, our objective is to determine the best mitigation strategies in minimizing
animal loss based on AusSpead simulation model. We tested 15 mitigation strategies by
using multiple comparison. The results show that the best mitigation strategies for all four
scenarios are regular surveillance, slaughter of the infected animals, and early detection. We then used the Mixed Integer Programming to estimate costs of disposing of animal
carcasses and transportation. Results show that the unit disposal cost will vary with
carcass scale and the unit transportation cost also varies with the distribution of the
infected premises and disposal locations.
FMD seems to have varying impacts on equity markets. In Essay III, we studied
returns at three different levels of the stock market. We determined results in a structural
break, and then estimated the impact of the announcement of confirmed cases of FMD
disease on the volatility of stock market returns by using a GARCH-Mean model. Our
results show that the structure break occurs on the day with the largest number of
confirmed cases for meat product firms rather than the day of the first confirmed case.
We found that the conditional volatilities over the FMD period are higher than those over
the sample period. The announcement of confirmed cases had the largest marginal impact
on meat products. Investors may always consider maintaining a portfolio consisting of
index funds or hedge funds.
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