The application of spatial methods to epidemic estimation and prediction problems is a vibrant and active area of research. In many cases, however, well thought out and laboratory supported models for epidemic patterns may be easy to specify but extremely difficult to fit efficiently. While this problem exists in many scientific disciplines, epidemic modeling is particularly prone to this challenge due to the rate at which the problem scope grows as a function of the size of the spatial and temporal domains involved. An additional barrier to widespread use of spatiotemporal epidemic models is the lack of user friendly software packages capable of fitting them. In particular, compartmental epidemic models are easy to understand, but in most cases difficult to fit. This class of epidemic models describes a set of states, or compartments, which captures the disease progression in a population. This dissertation attempts to expand the problem scope to which spatio-temporal compartmental epidemic models are applicable both computationally and practically. In particular, a general family of spatially heterogeneous SEIRS models is developed alongside a software library with the dual goals of high computational performance and ease of use in fitting models in this class. We emphasize the task of model specification, and develop a framework describing the components of epidemic behavior. In addition, we establish methods to estimate and interpret reproductive numbers, which are of fundamental importance to the study of infectious disease. Finally, we demonstrate the application of these techniques both under simulation, and in the context of a diverse set of real diseases, including Ebola Virus Disease, Smallpox, Methicillin-resistant Staphylococcus aureus, and Influenza.

Cystic fibrosis (CF) is an autosomal recessive genetic disorder of which lung disease is the leading cause of morbidity and mortality. One attractive strategy for the treatment of CF lung disease is to directly deliver CF transmembrane conductance regulator gene to airway epithelia. Although promising results have been reported, barriers present in the lung make successful gene transfer to the respiratory tract difficult. In order to improve gene transfer strategies in the intrapulmonary airways, we need to identify the bottlenecks of transduction for the vector system. A previous study reported that feline immunodeficiency virus (FIV)-mediated gene transfer was more efficient in the nasal airways in mice than the intrapulmonary airways (Sinn, P.L. et al. 2008, J. Viol). Our first goal was to identify barriers to lentiviral gene transfer in the murine airways. We demonstrate that host immune response is not the major barrier preventing efficient FIV-mediated transduction in the intrapulmonary airways. We show that the FIV vector transduces murine primary nasal epithelial cell cultures with greater efficiency than murine primary tracheal epithelial cell cultures. In addition, GP64 pseudotyped vesicular stomatitis virus (VSV) transduces better in nasal epithelia compared to intrapulmonary airways in mice. On the other hand, we observed that VSVG glycoprotein-pseudotyped VSV transduces the intrapulmonary airway as well as nasal epithelia in mice with similar efficiency. Our results suggest that differentially expressed cellular factor(s) specific for GP64 or FIV vector may be the major barrier(s) for FIV vector-mediated gene transfer in the murine intrapulmonary airways. The recent development of CF porcine models prompted us to investigate possible barriers for lentiviral vector-mediated gene transfer in porcine cells. Our preliminary results showed that HIV transduction was restricted in porcine but not human lung-derived cell lines. Porcine TRIM5 has sequences similar to restrictive bovine TRIM5 orthologs. Therefore, our second goal was to investigate the possible restriction of lentiviral vectors by porcine TRIM5. We demonstrate that transient overexpression or knockdown of endogenously expressed porcine TRIM5 does not affect HIV or FIV transduction. Lastly, we characterized a mucin domain-deleted EBOV (EBOVΔO) glycoprotein mutant with increased transduction. This EBOVΔO 5-mer mutant was generated based on mutants with an increased transduction as identified by alanine scanning mutagenesis (Brindlay, M.A. et al. 2007. J. Viol). We show that VSV pseudotyped with the 5-mer mutant increased transduction both in vitro and in mice when compared to the wild-type EBOVΔO. Structural analysis demonstrated that 5 mutations were located proximal to the GP1-GP2 interface. Enhanced transduction likely results from a lower energy metastable state of the glycoprotein. FIV pseudotyped with 5-mer also shows increased transduction in multiple cell lines. Identification of barriers in intrapulmonary airways and improvements of vector systems will help the advancement of gene therapy for CF.

To enter cells, the filovirus, ebolavirus (EBOV), must bind to target cells and internalize into an endocytic vesicle. The properties surrounding filoviral entry into permissive cells remain poorly studied. To date, the kinetics associated with filoviral-glycoprotein (GP)-mediated entry have never been investigated past 6 hours. Our initial entry studies with filoviral-GP pseudotyped retrovirions at 37˚C indicated that virions entered permissive cells with a half time (T50) of ~8 hours. We found that 10 to 20% of retroviral based virions bound to cells in over a one hour period at 4˚C suggesting that virion binding was relatively inefficient. Surprisingly, we also observed that less than half of the retroviral based pseudovirions pre-bound to the cell surface were internalized by 7 hours at 37˚C indicating that virion internalization was a slow process. Consistent with slow internalization of retroviral particles, we observed that, while virus entry lost sensitivity to ammonium chloride treatment with time, 50% of the virions remained sensitive to low pH neutralization for at least 7 hours. These slow entry kinetics for filoviruses have not been appreciated thus far, and could have significant implications in the timing and types of treatments that could be administered to filoviral infected individuals. We also determined the impact of specific carbohydrate linkages on host cell plasma membrane proteins involved in filoviral entry, by using a series of Chinese hamster ovary (CHO) cell lines deficient in one or more enzymes required for N- and O- linked glycosylation. The LdlD CHO cell line that expresses normal surface N-linked glycans but has abbreviated O-linked surface glycans showed a 50% reduction in transduction by both Zaire (ZEBOV) and Lake Victoria MARV-GP pseudotyped particles as compared to the control wild type parental CHO cell line (Pro5). Use of the novel O-linked inhibitor drug 1-68A allowed us to confirm the necessity of O-linked glycans in efficient ZEBOV entry into additional permissive cells types. Interestingly, loss of terminal sialic acids (Lec2 cells) or galactose (Lec8 cells) on both N- and O- linked sugars resulted in a 2-fold enhancement of filoviral GP mediated entry compared to control. However, Lec1 cells that have wild type O-linked glycans but highly abbreviated N-linked glycans had similar levels of transduction to control Pro5 cells. Further studies indicated that binding of ZEBOV pseudovirions to Pro5 and all mutant CHO cells was equal, indicating that a post-binding defect or enhancement in ZEBOV internalization may be occurring. These data identify the importance of host cell O-linked glycosylation during the initial steps of filovirus infection. While the receptor(s) used by filoviruses for productive binding and entry into cells remains to be identified, several proteins have been shown to enhance filoviral entry into cells. Axl, a plasma membrane associated Tyro3/Axl/Mer (TAM) family member, is necessary for optimal ZEBOV-GP-dependent entry into some permissive cells, but not others. To date, the precise role of Axl in virion entry is unknown. Through the use of biochemical inhibitors, RNAi, and dominant-negative constructs, we set out to characterize entry pathways used for ZEBOV uptake in cells that require Axl for optimal transduction (Axl-dependent cells) and to define the role of Axl in these processes. We demonstrate that ZEBOV-GP-dependent entry into Axl-dependent cells occurs through multiple pathways including both clathrin-dependent and caveolae/lipid raft-mediated endocytosis. Surprisingly, both dynamin-dependent and -independent fluid-phase uptake (FPU) pathways mediated ZEBOV-GP entry into the Axl-dependent cells as well. Reduction of Axl expression by RNAi treatment resulted in abrogation of ZEBOV entry by FPU-dependent pathways, but had no effect on receptor-mediated endocytosis mechanisms. Our findings demonstrate for the first time that Axl enhances FPU, thereby increasing productive ZEBOV entry, and providing insight into the mechanisms surrounding filoviral entry.

Thesis (Ph.D.)--York University, 2008. Graduate Programme in Chemistry. / Typescript. Includes bibliographical references (leaves 279-288). Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:NR39054

Mucosal delivery of recombinant adenovirus serotype 5 (rAd5)-based vaccine preparations are appealing for vaccine development in terms of lowering toxicity induced by high viral loads and substantial liver accumulation following systemic injection of the vaccine. However, this mode of delivery is currently under-developed due to the relatively low T-cell mediated immune responses generated against the encoded transgene. The first study described in this thesis demonstrated that sublingual immunization induces rapid migration of MHCII+, CD11C+ antigen presenting cells to the delivery site and elicit antigen-specific T and B cell-mediated immune responses in naïve mice and those with pre-existing immunity (PEI) to Ad5 at a level higher than that achieved after oral immunization. More importantly, this strategy improved protection of animals with PEI to Ad in contrast to poor protection after IM injection. The second study was designed to establish a method for inducing PEI that most accurately reflects natural infection in rodents and identifies the immunologic parameters elicited by rAd5-based Ebola vaccine necessary for protection against lethal infection. When immunization occurred by the same route in which PEI was induced, the antigen-specific multifunctional CD8+ T cell and antibody responses were significantly reduced. This correlated with poor survival after challenge with a lethal dose of Ebola Zaire in rodents. The data suggests that 1) establishment of PEI by the same route used for immunization is the most stringent test for a novel formulation designed to be effective in those with PEI to Ad5, and 2) for a formulation to be effective in those with PEI, it must be capable of restoring antigen-specific multifunctional CD8+ T cell and antibody responses, compromised by PEI. The third study screened novel formulations for their ability to improve in vitro transduction efficiency and immunogenicity and efficacy in vivo in the presence of anti-Ad5 neutralizing antibodies. Formulations consisting of pharmaceutically acceptable, non-immunogenic excipients that can prime the arms of immune response compromised by PEI improved survival after lethal challenge with Ebola Zaire challenge for rAd5-based Ebola vaccine in rodents with PEI. Taken together, these studies provide insight on how to reconstitute necessary immune responses in vaccine protocols by establishing a reliable PEI model in rodents, testing routes of administration, and formulations of the rAd5-based Ebola vaccine. / text

Data management in resource-limited settings can be a mountainous problem if not approached with a thorough understanding of those limitations and a mindset prepared for rapid changes in the environment. Data management becomes even more challenging at multiple points of entry, where there are many interwoven parts working together in order to get a potential traveler from his/her first steps into an airport area to boarding a plane, all while ensuring that the traveler has been thoroughly screened for any signs or symptoms of a possible Ebola virus disease infection. This capstone describes the history of the International Health Regulations’ effects on control of disease spread and importation at points of entry, the Do Not Board/Lookout List’s role in disease control in the United States, and the CDC’s International Assistance Team’s unique task in creating and implementing country-specific databases to meet the needs of Ebola-affected countries. The most critical data management need at these countries’ points of entry is specifically to prevent the exportation of Ebola virus disease in order to keep each country’s airspace open and allow goods, personnel and services to continue to be imported into these countries during this sustained Ebola outbreak.

Thesis (Ph. D. in Chemistry)--Vanderbilt University, Dec. 2009. / Title from title screen. Includes bibliographical references.

Emerging infectious diseases (EIDs) constitute an important global health security problem. During EID outbreaks, patient centred research can play a significant role in informing evidence-based care for patients, in calibrating public health responses, and in directing effective policy and research. However, to date, this type of research has been limited in impact. This thesis sets out to improve the value of patient centred research in combating EID outbreaks. It provides a structured analysis of what has previously constrained efforts to rapidly accumulate high-quality evidence. It provides primary data from research conducted during an outbreak, and conducted in an outbreak vulnerable setting. And it provides recommendations that aim to facilitate high-quality data collection in future events. This thesis contains four results chapters. Chapter 2 systematically reviews elements of the research response to two EID outbreaks of public health importance. Chapter 3 provides findings of a phase II clinical trial of an investigational therapy for Ebola virus disease (EVD), contextualises the utility of this and comparable work in improving patient care, and discusses the operational feasibility of such work during an epidemic. Chapter 4 focuses specifically on improving one element - disease characterisation - during EID outbreaks. It achieves this through presenting a systematic analysis of bias in the characterisation of EVD and recommends how to prioritise data gathering for high-risk pathogens. Chapter 5 exemplifies how clinical data collection practices can progress between outbreaks. It is the first stage of work undertaken to improve the clinical characterisation of communicable diseases in the vulnerable environment of refugee camps. This thesis demonstrates progress towards having higher quality clinical research conducted during the time frame of an epidemic. Future work can focus on the most important barriers to accelerating research, now that these have been more clearly defined.

The global health system is ill prepared to handle communicable health crises, much less effectively communicate about them, as evidenced by the West African Ebola outbreak. Although some critics have argued that the delay in international response contributed to the fast spread of the disease, others place greater blame on local cultural practices. The current study investigated how risk/crisis communication was produced, deployed, and received. This is particularly critical as the World Health Organization guidance on crisis/risk communication is not based on systematic evidence-based research Again, risk communication on communicable diseases is still relatively new and the body of research lacks both rigorous empirical evidence and evaluation research on event-specific risk communication efforts. Guided by the protection motivation theory and social mobilization theory, and using a comparative case study approach, this study sought to examine how crisis risk communication was undertaken and received in Liberia and Ghana and the implications for health crisis risk communication. Data was collected via interviews with communication and social mobilization team representatives in the two countries, document reviews, surveys of a cross section of inhabitants in Margibi and Shai Osudoku districts, and focus group discussions with purposively selected participants in the two countries. The study finds that expert-led top-bottom communication interventions used at the start of the outbreak were ineffective in getting target audiences to make the recommended behavior changes in Liberia. Messages developed induced fear rather than action. Furthermore, one in five respondents today, cannot identify the main signs and symptoms of Ebola. Again, the more worried people were about Ebola, the more vulnerable they felt. Finally, respondents moved through a cycle from equilibrium to defense to protection and then back to equilibrium as they sought to make sense of the disease and the communication they received about Ebola. It is recommended that risk communication include bottom-up community-led communication approaches and systems that are embedded within community culture and reality and used by community members. Again, the research challenged the assumption in risk perception studies that increasing knowledge and self-efficacy lowers risk perception thus suggesting the need for further studies in this area. / 10000-01-01

The current study analyses the media strategies used by Sierra Leone to repair their destination image during and after crisis to attract international tourism. There is an academic study written by Avraham and Ketter (2017) that appears on this topic as well, but focusing on many Sub-Saharan African countries where Sierra Leone is mentioned. Therefore, it was chosen to study this country in more depth, to confirm or disregard Avraham and Ketters (2017) conclusions about this particular country and their media-strategies. The framework used in this research is the multi-step model for altering place image. The study was based on qualitative content analysis of online posts from two sources, which are two Sierra Leonian tourism webpages. The data was located between the years 2015-2017. The study’s conclusion shows that Sierra Leone’s marketers and policy makers used source-focused strategies to handle the crisis, which are (1) disregard for/partial acknowledgement of the crisis, (2) full acknowledgement of the crisis and moderate coping measures, (3) full acknowledgement of the crisis and extreme coping measures and (4) disengagement from the place’s main characteristics.