Digital Commons Network^™

Evaluation Of Protection Induced By Dna Vaccine Candidate Against Leishmania Mexicana In Balb/C Mice Model, Rosina Rodarte

Open Access Theses & Dissertations

Background and Significance. The leishmaniases are a diverse group of diseases with four major clinical manifestations: cutaneous, mucocutaneous, visceral, and diffuse. Approximately 21 Leishmania species and 30 sandfly vectors have been implicated in human leishmaniasis. Leishmaniasis is endemic in 88 countries, 72 are developing countries. Currently, 350 million people live in leishmaniasis-endemic areas around the world. The true incidence of the disease is not known. However, the estimated incidence for visceral leishmaniasis is 500,000 cases per year, and for cutaneous and mucocutaneous leishmaniasis 1.5-2 million cases per year. Visceral leishmaniasis causes 70,000 deaths each year. In the Americas region, …

Point Of Care Diagnostics: Status And Future, Vladimir Gubala, Leanne Harris, Antonio J. Ricco, Ming X. Tan, David Williams

Articles

The most commonly used test for monitoring heparin therapy is the activated partial thromboplastin time (aPTT). The response of available aPTT reagents to heparin varies significantly. The aim of this study was to highlight the differences between aPTT reagents stored in a dried format to select the most suitable formulations to be used for the development of point-of-care diagnostic devices used for monitoring of unfractionated heparin dose response.

METHODS:

Ten reagents were analysed in terms of their performance in liquid and in dried form after storage for 24 h and 14 days. Performance was assessed by measurement of the clotting …

Effects Of The Exotic Shrub Lonicera Maackii On The Plant Animal Interactions In The Invaded Habitat, Humberto De Paula Dutra

Dissertations

Invasive plants are an economical, political, social, and ecological problem. Some invasive species are a serious concern for society because some of them are diseases, some are agricultural pests, and some become major threats to the ecosystems. Most studies with invasive species are limited because they measure only the impact of the invasion via direct pathways. Unfortunately, the potential for non-native plant species to alter ecosystem functions via indirect pathways mediated by interactions with animals just recently became broadly recognized. This research investigates the interactions of Amur honeysuckle with native fauna and how these interactions indirectly affect other trophic levels …

Discrimination And Aggregative Patterns Among And Between Populations Of Entamoeba Spp., Katelyn M. Higgins

Honors Senior Capstones and Theses

Kin recognition facilitates the evolution of cooperation in animals, but its relevance in microorganisms and their behavior toward relatives remains unclear. The Entamoeba lineage constitutes an ideal model to determine the behavioral and signaling cues needed for aggregative preference. Chemical cues have been reported for E. histolytica but not E. dispar, suggesting cell-communication between con-specifics and behavioral differences with relevance for disease. Entamoeba varieties have been reported as ‘morphologically undistinguishable’. Two strains of E. invadens have been isolated from different hosts (VK-1: NS - Varanus komodoensis and IP1- serpentes) but were classified within the same ‘species’. Trophozoites …

Infectious Disease And The Worldwide Distribution Of Iq, Christopher Guiles Eppig

Biology ETDs

We show that infectious disease is a major contributor to the worldwide distribution of human cognitive ability, as measured by psychometric IQ. In areas where infectious disease is high, average human intelligence tends to be lower, and in areas where infectious disease is low, average human intelligence tends to be higher. In separate studies, we tested this across world nations (chapter 2) and across states of the USA (chapter 3). In efforts to disseminate our research to wider audiences, I reviewed the findings contained in chapters 2 and 3 using language that is accessible to non-biologists (chapter 4). Although it …

The Dynamics Of Stage Structured Prey-Predator Model Involving Parasitic Infectious Disease, Raid K. Naji, Dina S. Al-Jaf

Applications and Applied Mathematics: An International Journal (AAM)

In this paper a prey-predator model involving parasitic infectious disease is proposed and analyzed. It is assumed that the life cycle of predator species is divided into two stages immature and mature. The analysis of local and global stability of all possible subsystems is carried out. The dynamical behaviors of the model system around biologically feasible equilibria are studied. The global dynamics of the model are investigated with the help of Suitable Lyapunov functions. Conditions for which the model persists are established. Finally, to nationalize our analytical results, numerical simulations are worked out for a hypothetical set of parameter values.

Modeling Spread Of Polio With The Role Of Vaccination, Manju Agarwal, Archana S. Bhadauria

Applications and Applied Mathematics: An International Journal (AAM)

In this paper, we have proposed and analyzed a nonlinear mathematical model for the spread of Polio in a population with variable size structure including the role of vaccination. A threshold parameter, R , is found that completely determines the stability dynamics and outcome of the disease. It is found that if R 1, the disease free equilibrium is stable and the disease dies out. However, if R >1, there exists a unique endemic equilibrium that is locally asymptotically stable. Conditions for the persistence of the disease are determined by means of Fonda’s theorem. Moreover, numerical simulation of the proposed …

Influence Of Detritus Levels And Organic Pollution On Interspecific Resource Competition, Oviposition Behavior, And Larval Survival Of Two Tire-Inhabiting Mosquito Species (Diptera: Culicidae), David Wayne Allgood

Master's Theses

Mosquitoes (Diptera: Culicidae) are vectors of disease in the adult stage, but understanding the factors affecting distributions of the immature stages is important to the understanding and control of adult populations. Discarded automobile tires comprise important larval mosquito habitats. The Asian tiger mosquito (Aedes albopictus) and the southern house mosquito (Culex quinquefasciatus) are two medically important species commonly found in tires, but factors affecting their larval distributions in tires have not been studied, nor have their interspecific interactions. I investigated the effects of chemicals associated with organic pollution on oviposition preferences and larval survival of both …

Tick Infestations And Their Consequences For Migratory Songbirds During Spring Stopover, Johnny Michael Sellers Jr.

Master's Theses

Migratory birds face a number of challenges during their seasonal movement from tropical/sub-tropical Central and South America to more temperate North America. Maintaining health during migration is of particular concern. This study seeks to understand how haematophageous ectoparasites, such as ticks (Ixodida), impact host body condition as they feed on passerines during migration. We hypothesized that foraging location would impact tick acquisition by migrants and that tick burdens during migration would negatively impact body condition. We surveyed 2,064 birds during spring 2009 and 2010 and found that 2.4% of the surveyed birds were infested with one or more …

The Nih-Niaid Filariasis Research Reagent Resource Center, Michelle L. Michalski, Kathryn G. Griffiths, Steven A. Williams, Ray M. Kaplan, Andrew Moorhead

Biological Sciences: Faculty Publications

Filarial worms cause a variety of tropical diseases in humans; however, they are difficult to study because they have complex life cycles that require arthropod intermediate hosts and mammalian definitive hosts. Research efforts in industrialized countries are further complicated by the fact that some filarial nematodes that cause disease in humans are restricted in host specificity to humans alone. This potentially makes the commitment to research difficult, expensive, and restrictive. Over 40 years ago, the United States National Institutes of Health–National Institute of Allergy and Infectious Diseases (NIH-NIAID) established a resource from which investigators could obtain various filarial parasite species …

Laboratory Diagnosis Of Clostridium Difficile Infection: Can Molecular Amplification Methods Move Us Out Of Uncertainty?, Fred C. Tenover, Ellen Jo Baron, Lance R. Peterson, David Persing

Biology Faculty Publications

The laboratory diagnosis of Clostridium difficile infection (CDI) continues to be challenging. Recent guidelines from professional societies in the United States note that enzyme immunoassays for toxins A and B do not have adequate sensitivity to be used alone for detecting CDI, yet the optimal method for diagnosing this infection remains unclear. Nucleic acid amplification tests (NAATs) that target chromosomal toxin genes (usually the toxin B gene, tcdB) show high sensitivity and specificity, provide rapid results, and are amenable to both batch and on-demand testing, but these tests were not universally recommended for routine use in the recent guidelines. …

Use Of Optimal Control Models To Predict Treatment Time For Managing Tick-Borne Disease, Holly D. Gaff, Elsa Schaefer, Suzanne Lenhart

Biological Sciences Faculty Publications

Tick-borne diseases have been on the rise recently, and correspondingly, there is an increased interest in implementing control measures to decrease the risk. Optimal control provides an ideal tool to identify the best method for reducing risk while accounting for the associated costs. Using a previously published model, a variety of frameworks are assessed to identify the key factors influencing mitigation strategies. The level and duration of tick-reducing efforts are key metrics for understanding the successful reduction in tick-borne disease incidence. The results show that the punctuated nature of the tick's life history plays a critical role in reducing risk …

The Abundance And Infection Status Of Anopheles Spp. Mosquitoes At Three Sites In Loudoun County, Northern Virginia, Priya Krishnan

Theses and Dissertations

Malaria is a re-emerging infectious disease with approximately half of the world's population at risk. In the US, since the 1950’s the Center for Disease Control (CDC) has been reporting between 1,000 and 1,500 cases of malaria every year. A majority of these cases were among US travellers and were attributed to Plasmodium falciparum. In August 2002, two cases of human malaria due to Plasmodium vivax were reported in Loudoun County, Northern Virginia. The Center for Disease Control and Prevention concluded that these cases were acquired locally. This was because of an absence of other risk factors such as international …

No Evidence Of Association Between Hiv-1 And Malaria In Populations With Low Hiv-1 Prevalence, Diego F. Cuadros, Adam J. Branscum, Gisela García-Ramos

Biology Faculty Publications

BACKGROUND: The geographic overlap between HIV-1 and malaria has generated much interest in their potential interactions. A variety of studies have evidenced a complex HIV-malaria interaction within individuals and populations that may have dramatic effects, but the causes and implications of this co-infection at the population level are still unclear. In a previous publication, we showed that the prevalence of malaria caused by the parasite Plasmodium falciparum is associated with HIV infection in eastern sub-Saharan Africa. To complement our knowledge of the HIV-malaria co-infection, the objective of this work was to assess the relationship between malaria and HIV prevalence in …

Effect Of Variable Transmission Rate On The Dynamics Of Hiv In Sub-Saharan Africa, Diego F. Cuadros, Phillip H. Crowley, Ben Augustine, Sarah L. Stewart, Gisela García-Ramos

Biology Faculty Publications

BACKGROUND: The cause of the high HIV prevalence in sub-Saharan Africa is incompletely understood, with heterosexual penile-vaginal transmission proposed as the main mechanism. Heterosexual HIV transmission has been estimated to have a very low probability; but effects of cofactors that vary in space and time may substantially alter this pattern.

METHODS: To test the effect of individual variation in the HIV infectiousness generated by co-infection, we developed and analyzed a mathematical sexual network model that simulates the behavioral components of a population from Malawi, as well as the dynamics of HIV and the co-infection effect caused by other infectious diseases, …

Characterizing The Distribution Of Planktonic Fecal Bacteria In The James River, Richmond, Virginia, John Furry

Theses and Dissertations

Surface waters containing fecal bacteria present significant public health risks. Understanding the sources of and factors affecting the distribution of fecal-indicating bacteria is necessary to predict potential illnesses more effectively. This thesis presents two studies on the distribution of fecal bacteria in the James River through Richmond, Virginia. Chapter 1 describes nearly 11 years of water quality, climate, and hydrologic data that occurred with changes in Escherichia coli concentrations, concluding that Richmond contributes significant quantities of fecal bacteria to the James River, and that the distribution of these bacteria varies seasonally. Chapter 2 details the development of Polymerase Chain Reaction …

Spite And The Scale Of Competition In Pseudomonas Aeruginosa, R. Inglis, Patrick Roberts, Andy Gardner, Angus Buckling

Biology Department Faculty Works

Scale of competition has been shown to be an important factor in shaping the evolution of social interactions. Although many theoretical and experimental studies have examined its effect on altruistic cooperation, relatively little research effort has been focused on spiteful behaviors—actions that harm both the actor and the recipient. In this study, we expand on existing theory by investigating the importance of the global frequency of spiteful alleles, and we determine experimentally how the scale of competition affects selection for spite in the bacterial pathogen Pseudomonas aeruginosa under high and intermediate spatial relatedness. Consistent with our theoretical results, we found …

The Health Status, Concerns, And Reform In Uruguay With An Emphasis On Health Promotion Programs Geared Towards The Care And Development Of The Country's Children And Adolescents, Melissa Raquel Ramírez

Honors Scholar Theses

This study was conducted in Montevideo, Uruguay, where I examined the actions that the country and society as a whole, its various communities, the Uruguayan government, and the people take in order to prevent disease and promote a healthy society. An ethnographic experiential and evidence-based approach, including personal experience, interviews, and official government documents, was used to fully describe the way the system operates. Due to Uruguay's demographic characteristics, particular attention was paid to children and adolescents. For this thesis, Uruguay is described in terms of its history, physical and mental health issues, society's shared health concerns, and its vulnerable …

Avian Influenza In Migratory Birds In The United States, 2007–2009, And Effects Of September Hunting Seasons On Survival, Harvest, And Recovery Rates Of Canada Geese Banded In Southeast Nebraska, Scott R. Groepper

School of Natural Resources: Dissertations, Theses, and Student Research

Highly-pathogenic avian influenza virus (HPAIV H5N1) poses risks to wild birds, poultry, and humans. Personnel with the United States Department of Agriculture-Animal Plant Health Inspection Service-Wildlife Services, state, and tribal wildlife agencies collected 168,940 samples from migratory birds from 2007 to 2009 to test for presence of HPAIV H5N1. No HPAIV was found, but other subtypes were discovered, including H5 and H7. I estimated prevalence of avian influenza virus by flyway and found prevalence was lowest each year in the Atlantic Flyway (6.7%–8.3%), highest in the Pacific Flyway in 2007 (13.3%) and 2008 (13.4%), and highest in the Mississippi Flyway …

Role Of Porcine Reproductive And Respiratory Syndrome Virus Non-Structural Protein 1 In Viral Replications And Pathogenesis, Lalit Kumar Beura

School of Veterinary and Biomedical Sciences: Dissertations, Theses, and Student Research

Porcine reproductive and respiratory syndrome virus (PRRSV) is an infectious agent of significant concern to the global swine industry. PRRSV infection of pigs is initiated by a long viremia after which the virus enters in an extended persistent phase of 3-4 months that ultimately is resolved by the immune system. The delayed and weak host adaptive response is responsible for the protracted convalescence period. An initial sub-optimal innate immune response is postulated to be the reason behind such meager adaptive immune response. A major focus of the studies undertaken in this dissertation was to identify the viral non-structural proteins (nsps) …

Upregulation Of Reactive Oxygen Species During The Retrovirus Life Cycle And Their Roles In A Mutant Of Moloney Murine Leukemia Virus, Ts1-Mediated Neurodegeneration, Soo Jin Kim

Dissertations and Theses (Open Access)

Viral invasion of the central nervous system (CNS) and development of neurological symptoms is a characteristic of many retroviruses. The mechanism by which retrovirus infection causes neurological dysfunction has yet to be fully elucidated. Given the complexity of the retrovirus-mediated neuropathogenesis, studies using small animal models are extremely valuable. Our laboratory has used a mutant moloney murine leukemia retrovirus, ts1-mediated neurodegneration. We hypothesize that astrocytes play an important role in ts1-induced neurodegeneration since they are retroviral reservoirs and supporting cells for neurons. It has been shown that ts1 is able to infect astrocytes in vivo and in …

Lipid Metabolism In Trypanosoma Brucei: Molecular Characterization Of Fatty Acid Synthesis And Uptake, Patrick Vigueira

All Dissertations

My doctoral studies focused on the fatty acid metabolism of the deadly protozoan parasite, Trypanosoma brucei. Fatty acid metabolism in T. brucei can be broadly divided into two pathways, synthesis and uptake. In Chapters 2-4 I describe experiments investigating the parasite's fatty acid synthesis pathway. Chapter 2 contains the initial characterization of acetyl-CoA carboxylase (ACC) in T. brucei. Knockdown of TbACC by RNA interference (RNAi) reduced parasite virulence in a mouse model, suggesting that TbACC has the potential to be utilized as a drug target. Chapters 3 and 4 explore the effects of two known ACC inhibitors, the …

Diversity, Loss, And Gain Of Malaria Parasites In A Globally Invasive Bird, Alfonso Marzal, Robert Ricklefs, Gediminas Valkiunas, Tamer Albayrak, Elena Arriero, Camille Bonneaud, Gábor Czirják, John Ewen, Olof Hellgren, Dita Hořáková, Tatjana Iezhova, Henrik Jensen, Asta Križanauskienė, Marcos Lima, Florentino De Lope, Eyðfinn Magnussen, Lynn Martin, Anders Møller, Vaidas Palinauskas, Péter Pap, Javier Pérez-Tris, Ravinder Sehgal, Manuel Soler, Eszter Szöllősi, Helena Westerdahl, Pavel Zetindjiev, Staffan Bensch

Biology Department Faculty Works

Invasive species can displace natives, and thus identifying the traits that make aliens successful is crucial for predicting and preventing biodiversity loss. Pathogens may play an important role in the invasive process, facilitating colonization of their hosts in new continents and islands. According to the Novel Weapon Hypothesis, colonizers may out-compete local native species by bringing with them novel pathogens to which native species are not adapted. In contrast, the Enemy Release Hypothesis suggests that flourishing colonizers are successful because they have left their pathogens behind. To assess the role of avian malaria and related haemosporidian parasites in the global …

An Invasive Species Reduces Aquatic Insect Flux To Terrestrial Food Webs, Steven S. Merkley

Theses and Dissertations

Although it is well documented how introduced species can negatively affect native species, we only poorly understand how they may alter ecosystem functions. We investigated how an invasive fish affected the flux of aquatic insects to terrestrial food webs using mesocosms in a desert spring ecosystem. We compared aquatic insect emergence between alternative community states with monocultures and polycultures of two native species of fish, least chub (Iotichthys phlegethontis) and Utah chub (Gila atraria) plus, introduced western mosquitofish (Gambusia affinis). We tested three hypotheses: (1) aquatic insect biomass will be greater than terrestrial insect …

Changes In Life History Within An Individual's Lifetime, Eric J. Billman

Theses and Dissertations

A central goal of life history theory is to understand the selective factors that generate the diversity of reproductive patterns observed in nature. Within lifetime changes in reproductive investment will determine an organism's fitness; however, this area of life history theory has received less attention than comparisons among population that characterize life history traits as a single population mean. Reproductive allocation can be affected by multiple cues; the integration of these cues across an organism's lifetime generates the diversity in life history strategies observed in nature. Life history studies should examine the interacting effects of multiple cues on life history …

Exome-Wide Dna Capture And Next Generation Sequencing In Domestic And Wild Species, Albano Beja-Pereira, Shanyuan Chen, Theodore F. Cosart, Gordon Luikart, Sarah B. Ng, Jay Shendure

Biological Sciences Faculty Publications

Our understanding of the molecular, genetic basis of adaptations and phenotypic differentiation among individuals will advance quickly thanks to new molecular techniques. This understanding is crucial given that accelerating environmental change and human population growth are increasingly threatening natural populations of fish and wildlife as well as increasing demands for agricultural production in domesticated species. This makes it urgent in many wild and domestic species to investigate the genetic basis of fitness, adaptation, and disease resistance [1], and to discover adaptive genes and speciation genes, i.e., the "loci of evolution" [2].

Substratum Interfacial Energetic Effects On The Attachment Of Marine Bacteria, Linnea Kathryn Ista

Biology ETDs

Biofilms represent an ancient, ubiquitous and influential form of life on earth. They are interesting both scientifically and because of their impacts on our environment, health and technology. Biofilm formation is initiated by attachment of bacterial cells from an aqueous suspension onto a suitable attachment substratum. While in certain, well studied cases initial attachment and subsequent biofilm formation is mediated by specific ligand-receptor pairs on the bacteria and attachment substratum, in the open environment, including the ocean, it is assumed to be non-specific and mediated by processes similar to those that drive adsorption of colloids at the water-solid interface. Colloidal …

Mathematical Modeling And Dynamical Analysis Of The Operation Of The Hypothalamus - Pituitary - Thyroid (Hpt) Axis In Autoimmune (Hashimoto's) Thyroiditis, Balamurugan Pandiyan

Dissertations (1934 -)

This thesis is a mathematical modeling study of the operation of the negative feedback control through the hypothalamus-pituitary- thyroid (HPT) axis in autoimmune (Hashimoto's) thyroiditis. Negative feedback control through the HPT axis is a mechanism in which the high levels of thyroid hormone; free thyroxine (FT4) in the blood inhibits the secretion of the pituitary hormone, thyroid stimulating hormone (TSH) into the blood. Similarly, the low levels of free thyroxine (FT4) sensed by the pituitary gland and then it secretes thyroid stimulating hormone (TSH) into the blood. Autoimmune (Hashimoto's) thyroiditis is a disease in which the immune system turns against …

A Cellular Automata Model Of Infection Control On Medical Implants, Alicia Prieto-Langarica, Hristo Kojouharov, Benito Chen-Charpentier, Liping Tang

Applications and Applied Mathematics: An International Journal (AAM)

S. epidermidis infections on medically implanted devices are a common problem in modern medicine due to the abundance of the bacteria. Once inside the body, S. epidermidis gather in communities called biofilms and can become extremely hard to eradicate, causing the patient serious complications. We simulate the complex S. epidermidis-Neutrophils interactions in order to determine the optimum conditions for the immune system to be able to contain the infection and avoid implant rejection. Our cellular automata model can also be used as a tool for determining the optimal amount of antibiotics for combating biofilm formation on medical implants.

Fertilization Narratives In The Art Of Gustav Klimt, Diego Rivera And Frida Kahlo: Repression, Domination And Eros Among Cells, Scott F. Gilbert, S. Brauckmann

Biology Faculty Works

Fertilization narratives are powerful biological stories that can be used for social ends, and 20th-century artists have used fertilization-based imagery to convey political and social ideas. In Danae, Gustav Klimt used an esoteric stage of early human embryos to indicate successful fertilization and the inability of government repression to stifle creativity. In Man, Controller of the Universe, Diego Rivera painted a mural of a man controlling an ovulating ovary, depicting Trotsky's view that society will rationally regulate human fertilization. His former wife, Frida Kahlo, refuted this view in Moses: Nucleus of Creation, wherein she painted images of fertilization and embryo …