Thesis (Ph. D.)--University of California, San Diego, 2008. / Title from first page of PDF file (viewed December 1, 2008). Available via ProQuest Digital Dissertations. Vita. Includes bibliographical references (p. 297-318).

The quarantine of people suspected of being exposed to a disease, and the isolation of those with clinical symptoms of the disease, constitute what is probably the oldest infection control mechanism since the beginning of recorded human history. The thesis is based on using mathematical modelling and analysis to gain qualitative insight into the transmission dynamics of a disease that is controllable using quarantine and isolation. A basic model, which takes the form of an autonomous deterministic system of non-linear differential equations with standard incidence, is formulated first of all. Rigorous analysis of the basic model shows that its disease-free equilibrium is globally-asymptotically stable whenever a certain epidemiological threshold (denoted by Rc) is less than unity. The epidemiological implication of this result is that the disease will be eliminated from the community if the use of quarantine and isolation could result in making Rc < 1. The model has a unique endemic equilibrium whenever Rc > 1. Using a Lyapunov function of Goh-Volterra type, it is shown that the unique endemic equilibrium is globally-asymptotically stable for a special case. The basic model is extended to incorporate various epidemiological and biological aspects relating to the transmission dynamics and control of a communicable disease, such as the use of time delay to model the latency period, effect of periodicity (seasonality), the use of an imperfect vaccine and the use of multiple latent and infectious stages (coupled with gamma-distributed average waiting times in these stages). One of the main mathematical findings of this thesis is that adding time delay, periodicity and multiple latent and infectious stages to the basic quarantine/isolation model does not alter the essential qualitative features of the basic model (pertaining to the persistence or elimination of the disease). On the other hand, the use of an imperfect vaccine induces the phenomenon of backward bifurcation (a dynamical feature not present in the basic model), the consequence of which is that disease elimination becomes more difficult using quarantine and isolation (since, in this case, the epidemiological requirement Rc < 1 is, although necessary, no longer sufficient for disease elimination). Numerous numerical simulations are carried out, using parameter values relevant to the 2003 SARS outbreaks in the Greater Toronto Area of Canada, to illustrate some of the theoretical findings as well as to evaluate the population-level impact of quarantine/isolation and an imperfect vaccine. In particular, threshold conditions for which the aforementioned control measures could have a positive or negative population-level impact are determined.

The quarantine of people suspected of being exposed to a disease, and the isolation of those with clinical symptoms of the disease, constitute what is probably the oldest infection control mechanism since the beginning of recorded human history. The thesis is based on using mathematical modelling and analysis to gain qualitative insight into the transmission dynamics of a disease that is controllable using quarantine and isolation. A basic model, which takes the form of an autonomous deterministic system of non-linear differential equations with standard incidence, is formulated first of all. Rigorous analysis of the basic model shows that its disease-free equilibrium is globally-asymptotically stable whenever a certain epidemiological threshold (denoted by Rc) is less than unity. The epidemiological implication of this result is that the disease will be eliminated from the community if the use of quarantine and isolation could result in making Rc < 1. The model has a unique endemic equilibrium whenever Rc > 1. Using a Lyapunov function of Goh-Volterra type, it is shown that the unique endemic equilibrium is globally-asymptotically stable for a special case. The basic model is extended to incorporate various epidemiological and biological aspects relating to the transmission dynamics and control of a communicable disease, such as the use of time delay to model the latency period, effect of periodicity (seasonality), the use of an imperfect vaccine and the use of multiple latent and infectious stages (coupled with gamma-distributed average waiting times in these stages). One of the main mathematical findings of this thesis is that adding time delay, periodicity and multiple latent and infectious stages to the basic quarantine/isolation model does not alter the essential qualitative features of the basic model (pertaining to the persistence or elimination of the disease). On the other hand, the use of an imperfect vaccine induces the phenomenon of backward bifurcation (a dynamical feature not present in the basic model), the consequence of which is that disease elimination becomes more difficult using quarantine and isolation (since, in this case, the epidemiological requirement Rc < 1 is, although necessary, no longer sufficient for disease elimination). Numerous numerical simulations are carried out, using parameter values relevant to the 2003 SARS outbreaks in the Greater Toronto Area of Canada, to illustrate some of the theoretical findings as well as to evaluate the population-level impact of quarantine/isolation and an imperfect vaccine. In particular, threshold conditions for which the aforementioned control measures could have a positive or negative population-level impact are determined.

archives@tulane.edu / Losing My Dimension seeks to characterize the nature of spacetime during quarantine. Designed to be viewed in both 2D and 3D using red/cyan glasses, this body of work wields space as a medium in order to probe the dimensional qualities of our changing realities. Through a series of interactive web vignettes built with recognizable user interfaces, this work engages the viewer in an individualized reflection upon both the benefits and detriments of digital denizenship, particularly in the context of a global pandemic. / 1 / Jenna deBoisblanc

In this thesis I developed and analysed several mathematical models that describe the dynamics of infectious diseases spreading in a population simultaneously with people becoming aware of the presence of the disease and thus modifying their behaviour. This is achieved using compartmental models, with further extensions to models with time delays and the administration of vaccines. Resulting mathematical models were analysed using the techniques of dynamical systems and bifurcations theory, complemented by direct numerical simulations. Design of optimal strategies maximising the reduction of infection rates subject to logistical constraints were studied within the new modelling framework and with a view to be used in realistic contexts. Of particular interest is the design and analysis of the impact of local and global awareness campaigns, as well as the administration of vaccines to minimise the spread of infections.

The problem of invasive alien species (IAS) is recognized as the second most serious threat to loss of biodiversity after habitat destruction. It is a problem largely created by humans as they transport and introduce species, deliberately and accidentally, from one part of the globe to another. The pressures exerted on biodiversity by international trade are one of the most serious aspects of the IAS problem. Although states are under obligations in international environmental law to prevent the entry of, and control, those alien species that threaten biodiversity, to date state practice has often been found wanting. In particular, quarantine regulation, which can be a state??s first line of defence against IAS, is mainly used by states to protect their farming and agricultural product sectors rather than biodiversity at large. The reasons for this include lack of domestic resources and lack of guidance at the international level. However, even if states were to expand the purview of quarantine, the question arises whether they would be able to use quarantine regulation to protect biodiversity from IAS while simultaneously fulfilling their international trade law obligations. This study seeks to answer this question by examining international environmental law and international trade law in their application to quarantine regulation. In doing so, the study identifies many areas of conflict. The different policies that underpin environmental and trade regimes mean that environmental concepts, such as the precautionary principle and the ecosystem approach, are difficult to apply within the international trade law regime. A way of achieving a more harmonized international response to the problem of IAS is suggested by incorporating environmental considerations into the international standards used by states to design and implement domestic quarantine measures. To facilitate the practical implementation of international standards the study further recommends appropriate financial and institutional capacity building mechanisms.

The problem of invasive alien species (IAS) is recognized as the second most serious threat to loss of biodiversity after habitat destruction. It is a problem largely created by humans as they transport and introduce species, deliberately and accidentally, from one part of the globe to another. The pressures exerted on biodiversity by international trade are one of the most serious aspects of the IAS problem. Although states are under obligations in international environmental law to prevent the entry of, and control, those alien species that threaten biodiversity, to date state practice has often been found wanting. In particular, quarantine regulation, which can be a state??s first line of defence against IAS, is mainly used by states to protect their farming and agricultural product sectors rather than biodiversity at large. The reasons for this include lack of domestic resources and lack of guidance at the international level. However, even if states were to expand the purview of quarantine, the question arises whether they would be able to use quarantine regulation to protect biodiversity from IAS while simultaneously fulfilling their international trade law obligations. This study seeks to answer this question by examining international environmental law and international trade law in their application to quarantine regulation. In doing so, the study identifies many areas of conflict. The different policies that underpin environmental and trade regimes mean that environmental concepts, such as the precautionary principle and the ecosystem approach, are difficult to apply within the international trade law regime. A way of achieving a more harmonized international response to the problem of IAS is suggested by incorporating environmental considerations into the international standards used by states to design and implement domestic quarantine measures. To facilitate the practical implementation of international standards the study further recommends appropriate financial and institutional capacity building mechanisms.

The problem of invasive alien species (IAS) is recognized as the second most serious threat to loss of biodiversity after habitat destruction. It is a problem largely created by humans as they transport and introduce species, deliberately and accidentally, from one part of the globe to another. The pressures exerted on biodiversity by international trade are one of the most serious aspects of the IAS problem. Although states are under obligations in international environmental law to prevent the entry of, and control, those alien species that threaten biodiversity, to date state practice has often been found wanting. In particular, quarantine regulation, which can be a state??s first line of defence against IAS, is mainly used by states to protect their farming and agricultural product sectors rather than biodiversity at large. The reasons for this include lack of domestic resources and lack of guidance at the international level. However, even if states were to expand the purview of quarantine, the question arises whether they would be able to use quarantine regulation to protect biodiversity from IAS while simultaneously fulfilling their international trade law obligations. This study seeks to answer this question by examining international environmental law and international trade law in their application to quarantine regulation. In doing so, the study identifies many areas of conflict. The different policies that underpin environmental and trade regimes mean that environmental concepts, such as the precautionary principle and the ecosystem approach, are difficult to apply within the international trade law regime. A way of achieving a more harmonized international response to the problem of IAS is suggested by incorporating environmental considerations into the international standards used by states to design and implement domestic quarantine measures. To facilitate the practical implementation of international standards the study further recommends appropriate financial and institutional capacity building mechanisms.

The problem of invasive alien species (IAS) is recognized as the second most serious threat to loss of biodiversity after habitat destruction. It is a problem largely created by humans as they transport and introduce species, deliberately and accidentally, from one part of the globe to another. The pressures exerted on biodiversity by international trade are one of the most serious aspects of the IAS problem. Although states are under obligations in international environmental law to prevent the entry of, and control, those alien species that threaten biodiversity, to date state practice has often been found wanting. In particular, quarantine regulation, which can be a state??s first line of defence against IAS, is mainly used by states to protect their farming and agricultural product sectors rather than biodiversity at large. The reasons for this include lack of domestic resources and lack of guidance at the international level. However, even if states were to expand the purview of quarantine, the question arises whether they would be able to use quarantine regulation to protect biodiversity from IAS while simultaneously fulfilling their international trade law obligations. This study seeks to answer this question by examining international environmental law and international trade law in their application to quarantine regulation. In doing so, the study identifies many areas of conflict. The different policies that underpin environmental and trade regimes mean that environmental concepts, such as the precautionary principle and the ecosystem approach, are difficult to apply within the international trade law regime. A way of achieving a more harmonized international response to the problem of IAS is suggested by incorporating environmental considerations into the international standards used by states to design and implement domestic quarantine measures. To facilitate the practical implementation of international standards the study further recommends appropriate financial and institutional capacity building mechanisms.

Thesis (Ph. D. in engineering science)--Washington State University, December 2006. / Includes bibliographical references.