Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 20 of 81 for “"within host"”.
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Drivers of Dengue Within-Host Dynamics and Virulence Evolution
… chapter of my dissertation, I integrate these within-host models with a vector-borne epidemiological model to understand the potential for virulence evolution in dengue. Critically, I show that dengue is expected to evolve towards intermediate virulence, and that the optimal virulence of the …
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Analysis of within-host evolution of Plasmodium Falciparum during treatment
Antimalarial drugs impose strong selective pressure on Plasmodium falciparum parasite genomes and leave signatures of selection. The evolutionary basis of drug resistant malaria in endemic and epidemic settings continues to remain an ongoing scientific priority whose solution carries a significant …
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A cholera model linking between-host, within-host and environmental disease dynamics
… governed by human-human, environment-human, and within-human sub-dynamics. In this paper, a model is presented to incorporate all three of these dynamical components. The model is divided into three subgroups where the dynamics are analyzed according to their respective time scales. Specifically, …
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SARS-COV-2 EVOLUTION AND TRANSMISSION: WITHIN-HOST, BETWEEN-HOST, AND BETWEEN-SPECIES
… we investigate the evolution of SARS-CoV-2 within immunocompromised individuals with prolonged infections, compare viral adaptations between vaccinated and unvaccinated hosts, and explore interspecies transmission between humans and animals. We found that SARS-CoV-2 evolution rates are …
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Within-host population dynamics and collective interactions of SARS-CoV-2 and influenza virus
… genetically distinct viral genomes interact within a cell. Because every virus that circulates within a host population must initially emerge within a single individual, it is crucial to understand the factors that govern viral dynamics within a host. Intra-host viral populations are subject …
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Within Host and Multiscale Models of Usutu and SARS-CoV-2 Viral Infections with Animal Hosts
… dissertation explores the relationship between within-host virus dynamics, the environment and the between-host viral transmission. We will validate the models against data from SARS-CoV-2 infections, and data from infections with an emerging pathogen, the Usutu virus. Our models of SARS-CoV-2 …
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Integrating mathematical models with experimental data from in vivo studies to investigate the within-host dynamics of Salmonella Typhimurium
… innovation in the field is by understanding the host-bacteria interactions that take place in vivo and affect the clinical outcome of the disease, the response to treatment and the immunological response following vaccination. Mechanistic mathematical models are being increasingly used to advance …
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The Effect of Within-host Virus Population Growth and Interspecific Competition on Aphid Transmission and Population Structure of Barley Yellow Dwarf Virus
… similar in that they share aphid vectors and host species, but in agricultural fields in New York State we found that the prevalence of PAV was three times greater than that of PAS. To determine if differences in within-host population growth rate affect vector transmission efficiency, disease …
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Inferring Determinants of Viral Transmission using Short-Read Sequence Data
… spread, pathogens must not only be able to grow within an infected host, but also transmit to found new infections. In this thesis, I present a new population genetic framework generating insights into viral transmission events based upon genome sequence data collected before and after …
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A cross-scale model for the evolution of influenza within a single season
… cross-scale model for the evolution of influenza within a single season. We model evolution as the emergence and spread of a mutant strain in a population that is already invaded by a parent resident strain. This allows us to investigate both the emergence dynamics of a mutant strain as well as …
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Mathematical Modeling of Dengue Viral Infection
… severity, we develop mathematical models of within-host virus-cell interaction, epidemiological models of virus transmission, and a combination of the within-host and between-host models. The main results of this thesis focus on the within-host model. We model the effects of antibody …
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Exposure heterogeneity, host immunity and virulence evolution in a wild bird-bacterium system
… A major source of heterogeneity in free-living host populations is the degree of exposure to a pathogen, as well as a host's history of exposure to a pathogen, which can create variation in standing immunity. We sought to determine the role of exposure heterogeneity on host susceptibility and …
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Multiscale Modelling of Foodborne Diseases
… complex system wherein pathogens multiply within hosts, spread across people, and infect entire populations of hosts. The description of most biological processes involves multiple, interconnected phenomena occurring on different spatial and temporal scales in the human body. Traditional …
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Ecological and evolutionary aspects of interactions between microbes coinfecting plants
Coinfections of one host with multiple pathogen species are common, and have important implications for host health and pathogen fitness. In the research reported here, plant virus systems were used to explore the effects of coinfection on pathogen populations and host responses. Chapter 1 …
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Immunoepidemiological Modeling of Dengue Viral Infection
… To analyze these hypotheses, we developed within-host mathematical models. In previous work, we predicted a decreased non-neutralizing antibody effect during secondary infection. Since this effect accounts for decreased viral clearance and the virus is in quasi-equilibrium with infected …
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Mathematical modeling, analysis, and simulation of Cholera dynamics
… (SIR) model for the between-host transmission of cholera is employed. At the individual host level, the evolution of the pathogen within the human body is incorporated. The between-host and within-host dynamics are connected through an environmental equation that characterizes …
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Conversion intentions amongst South African interns in time of COVID-19: An application of the Theory of Planned Behavior
… alike, of what impacts intern conversion rates within host organisations. Drawing on the Theory of Planned Behaviour (TPB) (Ajzen, 1991) this study explored the intention toward conversion into full-time employment within host organisations of the South African intern. The study employed a …
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Pathogen evolution within and between hosts with applications to the pneumococcus and SARS-CoV-2
… of Streptococcus pneumoniae and SARS-CoV-2 within the host and during transmission. Initially, a fast solution to the problem of clustering pathogen genomes is presented. An approximation to a Dirichlet process mixture model is shown to produce accurate genome clusterings 10-100 times faster …
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Towards an understanding of symbiont natural history through studies of crayfish and their annelid associates
… throughout North America, Europe, and Asia host assemblages of obligate ectosymbiotic annelid worms called branchiobdellidans. The work presented here is a detailed experimental and observational study of the ecological interactions between crayfish and their worms. In a comprehensive …
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Estimation and Comparison of HIV-Specific Substitution Matrices
… substitution matrices are the between- and within-host matrices estimated using HIV sequences introduced by Nickle et al. (2007). This thesis focuses on constructing more granular HIV-specific matrices (clade-specific matrices and gene-specific matrices) and comparing the matrices in a way …
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