Parasitology Commons^™

Tick Extracellular Vesicles Enable Arthropod Feeding And Promote Distinct Outcomes Of Bacterial Infection, Adela S. Oliva Chávez, Xiaowei Wang, Liron Marnin, Nathan K. Archer, Holly L. Hammond, Erin E. Mcclure Carroll, Dana K. Shaw, Brenden G. Tully, Amanda D. Buskirk, Shelby L. Ford, L. Rainer Butler, Preeti Shahi, Kateryna Morozova, Cristina C. Clement, Lauren Lawres, Anya J. O'Neal, Choukri Ben Mamoun, Kathleen L. Mason, Brandi E. Hobbs, Glen A. Scoles, Eileen M. Barry, Daniel E. Sonenshine, Utpal Pal, Jesus G. Valenzuela, Marcelo B. Sztein, Marcela F. Pasetti, Michael L. Levin, Michail Kotsyfakis, Steven M. Jay, Jason F. Huntley, Lloyd S. Miller, Laura Santambrogio, Joao H.F. Pedra

Biological Sciences Faculty Publications

Extracellular vesicles are thought to facilitate pathogen transmission from arthropods to humans and other animals. Here, we reveal that pathogen spreading from arthropods to the mammalian host is multifaceted. Extracellular vesicles from Ixodes scapularis enable tick feeding and promote infection of the mildly virulent rickettsial agent Anaplasma phagocytophilum through the SNARE proteins Vamp33 and Synaptobrevin 2 and dendritic epidermal T cells. However, extracellular vesicles from the tick Dermacentor andersoni mitigate microbial spreading caused by the lethal pathogen Francisella tularensis. Collectively, we establish that tick extracellular vesicles foster distinct outcomes of bacterial infection and assist in vector feeding by acting …

Tick Ecdysteroid Hormone, Global Microbiota/Rickettsia Signaling In The Ovary Versus Carcass During Vitellogenesis In Part-Fed (Virgin) American Dog Ticks, Dermacentor Variabilis, Loganathan Ponnusamy, Haley Sutton, Robert D. Mitchell Iii, Daniel E. Sonenshine, Charles S. Apperson, Richard Michael Roe

Biological Sciences Faculty Publications

The transovarial transmission of tick-borne bacterial pathogens is an important mechanism for their maintenance in natural populations and transmission, causing disease in humans and animals. The mechanism for this transmission and the possible role of tick hormones facilitating this process have never been studied. Injections of physiological levels of the tick hormone, 20-hydroxyecdysone (20E), into part-fed (virgin) adult females of the American dog tick, Dermacentor variabilis, attached to the host caused a reduction in density of Rickettsia montanensis in the carcass and an increase in the ovaries compared to buffer-injected controls. This injection initiates yolk protein synthesis and uptake …

Molecular Studies On The Interactions Between Biomphalaria Snails And Schistosoma Mansoni, Lijun Lu

Biology ETDs

Biomphalaria snails serve as vectors for Schistosoma mansoni, a trematode causing human schistosomiasis. Control of Schistosoma mansoni involves chemotherapy of affected people, but new control methods built on improved understanding of schistosome-snail interactions are needed. My dissertation applies molecular and bioinformatics approaches to understand such interactions. Chapter 1 shows that significant differences exist among Biomphalaria species in Africa with respect to their ability to support schistosome development. Chapters 2 and 3 reveal the transcriptional responses of Biomphalaria glabrata susceptible (SUS) or resistant (RES) to Schistosoma mansoni. Chapter 2 identifies a new family of snail immune factors, the AIG …

Field Evaluation Of Recombinant Antigen Elisa In Detecting Zoonotic Schistosome Infection Among Water Buffaloes In Endemic Municipalities In The Philippines, Jose Ma. M. Angeles, Yasuyuki Goto, Masahi Kirinoki, Elena A. Villacorte, Kharleezelle J. Moendeg, Pilarita T. Rivera, Yuichi Chigusa, Shin-Ichiro Kawazu

Biology Faculty Publications

In this study, we investigated the use of recombinant antigens thioredoxin peroxidase-1 (rSjTPx-1) and tandem repeat rSj1TR in evaluating the antibody positivity rates of Schistosoma japonicum infection among water buffaloes from four endemic areas in the Philippines, two municipalities with high endemicity (Calatrava, Negros Occidental and Catarman, Northern Samar) and two municipalities nearing elimination with no cases of human schistosomiasis (Talibon and Trinidad, Bohol). These recombinant antigen ELISA assays were compared with other diagnostic tests including SEA-ELISA, FECT, and fecal-based PCR. Results showed that rSj1TR-ELISA has the highest agreement with PCR in all study areas. Furthermore, significant positivity rates among …

A Brain-Infecting Parasite Impacts Host Metabolism Both During Exposure And After Infection Is Established, Lauren E. Nadler, Erik Bengston, Erika J. Eliason, Cameron Hassibi, Siri H. Helland-Riise, Ida B. Johansen, Garfield T. Kwan, Martin Tresguerres, Andrew V. Turner, Kelly L. Weinersmith, Øyvind Øverli, Ryan F. Hechinger

Marine & Environmental Sciences Faculty Datasets

1. Metabolic costs associated with parasites should not be limited to established infections. Even during initial exposure to questing and attacking parasites, hosts can enact behavioural and physiological responses that could also incur metabolic costs. However, few studies have measured these costs directly. Hence, little is known about metabolic costs arising from parasite exposure.
2. Further, no one has yet measured whether and how previous infection history modulates metabolic responses to parasite exposure.
3. Here, using the California killifish (Fundulus parvipinnis) and its brain-infecting parasite (Euhaplorchis californiensis), we quantified how killifish metabolism, behaviour, and osmoregulatory phenotype changed upon acute …

Analyses Of The Expression, Immunohistochemical Properties And Serodiagnostic Potential Of Schistosoma Japonicum Peroxiredoxin-4, Minh-Anh Dang-Trinh, Jose Ma. M. Angeles, Kharleezelle J. Moendeg, Adrian Miki C. Macalanda, Thu-Thuy Nguyen, Luna Higuchi, Shotaro Nakagun, Masahi Kirinoki, Yuichi Chigusa, Yasuyuki Goto, Shin-Ichiro Kawazu

Biology Faculty Publications

Background

Schistosoma japonicum, which inhabits the mesenteric vein of the mammalian hosts for about 20 to 30 years, is subjected to the oxidative stresses from the host defense mechanism during their intra-mammalian stages. To counteract this host immune attack, the parasite utilizes their antioxidant system for survival inside the host. Peroxiredoxins (Prxs), thiol-specific antioxidant proteins, play an essential role for protecting the parasite against oxidative stress by reducing hydrogen peroxide to water. Only three types of 2-Cys Prxs have been previously characterized in S. japonicum whereas a fourth Prx has been identified for Schistosoma mansoni as Prx-4. A sequence …

Increased Diversity And Novel Subtypes Among Clinical Cryptosporidium Parvum And Cryptosporidium Hominis Isolates In Southern Ireland, Jennifer K. O'Leary, Liam Blake, Gerard D. Corcoran, Roy D. Sleator, Brigid Lucey

Department of Biological Sciences Publications

Reported incidence rates of cryptosporidiosis in Ireland are consistently among the highest in Europe. Despite the national prevalence of this enteric parasite and the compulsory nature of incidence surveillance and reporting, in-depth analyses seeking to genotype clinical isolates of Cryptosporidium on an intra-species level are rarely undertaken in Ireland. This molecular epidemiology study of 163 clinical Cryptosporidium isolates was conducted in Southern Ireland, from 2015 to 2018, in order to ascertain population subtype heterogeneity. Analysis was conducted via real-time PCR amplification and gp60 gene sequencing, which successfully determined the subtype designation of 149 of the 163 (91.4%) tested isolates. Overall, …

A Study On Ecological Distribution Of And Selected Gene Expression In Amblyomma Americanum: An Insight Into The Alpha-Galactose Allergy Caused By Tick Bites, Leah Cuthill

Electronic Theses & Dissertations

Ticks transmit a wide variety of pathogens including viruses, bacteria, protozoa, and helminthes to vertebrates. Their life cycle depends on blood meals from various hosts as well as on environmental conditions such as the temperature and habitat type. A newly recognized allergic disease has been identified and is characterized by a delayed reaction following the consumption of some mammalian meats. The allergy often results in life threatening reactions such as anaphylaxis, hives, and breathing problems 3-6 hours after the consumption of mammalian meat. Not everyone develops the allergy when they are bitten by a lone star tick, and the cause …

Presence Of Dirofilaria Immitis In Mosquitoes In Southeastern Georgia, Angelica C. Tumminello

Honors College Theses

Canine heartworm disease is caused by the filarial nematode Dirofilaria immitis, which is transmitted by at least 25 known species of mosquito vectors. This study sought to understand which species of mosquitoes are present in Bulloch County, Georgia, and which species are transmitting canine heartworm disease. This study also investigated whether particular canine demographics correlated with a greater risk of heartworm disease. Surveillance of mosquitoes was conducted in known heartworm-positive canine locations using traditional gravid trapping and vacuum sampling. Mosquito samples were frozen until deemed inactive, then identified by species and sex. The mosquitoes were then either dissected under …

A New Genus And Two New Species Of Unarmed Hymenolepidid Cestodes (Cestoda: Hymenolepididae) From Geomyid Rodents In Mexico And Costa Rica, Scott Lyell Gardner, Altangerel Tsogtsaikhan Dursahinhan, Mariel Campbell, S. Elizabeth Rácz

Scott L. Gardner Publications

Two new cestodes of the family Hymenolepididae are described from two species of rodents of the family Geomyidae collected in Mexico and Costa Rica. One new species of Hymenolepis is described from Cratogeomys planiceps Merriam 1895 from near Toluca, Mexico and another that we allocate to a new genus is described from Heterogeomys heterodus (Peters, 1865) from near Irazú Volcano, Costa Rica. Hymenolepis s. str. includes those Hymenolepididae with an apical organ, with no hooks on suckers or apical organ, and three testes. Hobergia irazuensis n. gen., n. sp. includes a hymenolepidid with an apical organ, unarmed scolex, small …

Before The Pandemic Ends: Making Sure This Never Happens Again, Daniel R. Brooks, Eric P. Hoberg, Walter A. Boeger, Scott Lyell Gardner, Sabrina B. L. Araujo, Katalin Bajer, Sebastian Botero-Cañola, Brian Byrd, Gábor Földvári, Joseph A. Cook, Jonathan L. Dunnum, Altangerel Tsogtsaikhan Dursahinhan, László Zsolt Garamszegi, Dávid Herczeg, Ferenc Jakab, Alicia Juarrero, Gábor Kemenesi, Kornélia Kurucz, Virginia León-Règagnon, Hugo H. Mejía-Madrid, Orsolya Molnár, Richard A. Nisbett, Wolfgang Preiser, Michael Stuart, Eors Szathmary, Valeria Trivellone

Scott L. Gardner Publications

Introduction

On 30 January 2020, the World Health Organization (WHO) declared a Global Health Emergency of international concern attendant to the emergence and spread of SARS-CoV-2, nearly two months after the first reported emergence of human cases in Wuhan, China. In the subsequent two months, global, national and local health personnel and infrastructures have been overwhelmed, leading to suffering and death for infected people, and the threat of socio-economic instability and potential collapse for humanity as a whole. This shows that our current and traditional mode of coping, anchored in responses after the fact, is not capable of dealing with …

Gaharitrema Droneni N. Gen., N. Sp. (Digenea: Zoogonidae: Lepidophyllinae) From The Pudgy Cuskeel, Spectrunculus Grandis (Ophidiiformes: Ophidiidae), From Deep Waters Off Oregon, With Updates Keys To Zoogonid Subfamilies And Genera, Charles K. Blend, Gábor R. Rácz, Scott Gardner

Scott L. Gardner Publications

Gaharitrema droneni n. gen., n. sp. (Digenea: Zoogonidae: Lepidophyllinae) is described from the intestine of the pudgy cuskeel, Spectrunculus grandis (Gu¨ nther, 1877) (Ophidiiformes: Ophidiidae), collected at 2,800 m depth from the northeastern Pacific Ocean off Oregon. The new genus is distinguished from Brachyenteron Manter, 1934 and Steganoderma Stafford, 1904, the 2 closest lepidophylline genera, and from 4 other zoogonid genera erected since 2007, the last major revision of the family, by a combination of diagnostic features including a pyriform or spindle-shaped body, smooth testes and ovary, narrow ceca that reach with the vitellarium into the hindbody, an unspecialized ventral …

Ticks On Lizards: Parasite-Host Interactions Of The Southern Alligator Lizard (Elgaria Multicarinata) In Washington State, Emma Houghton

Undergraduate Honors Theses

I investigated interactions between ectoparasites (ticks) and their host, the southern alligator lizard (Elgaria multicarinata). Alligator lizards are capable of complement-mediated killing of the Lyme disease spirochete carried by ticks and may potentially reduce Lyme disease prevalence by cleansing pathogenic organisms from ticks. Despite this, little is known about host-parasite dynamics in alligator lizards. My goals were to 1) assess patterns of tick presence (i.e. parasite load) on alligator lizards and 2) investigate potential negative effects of ticks on alligator lizards. I sampled lizards during the summer of 2019 near Catherine Creek, along the Columbia River Gorge in southern Washington. …

Ticks On Lizards: Parasite-Host Interactions Of The Southern Alligator Lizard (Elgaria Multicarinata) In Washington State, Emma Houghton

All Undergraduate Projects

I investigated interactions between ectoparasites (ticks) and their host, the southern alligator lizard (Elgaria multicarinata). Alligator lizards are capable of complement-mediated killing of the Lyme disease spirochete carried by ticks and may potentially reduce Lyme disease prevalence by cleansing pathogenic organisms from ticks. Despite this, little is known about host-parasite dynamics in alligator lizards. My goals were to 1) assess patterns of tick presence (i.e. parasite load) on alligator lizards and 2) investigate potential negative effects of ticks on alligator lizards. I sampled lizards during the summer of 2019 near Catherine Creek, along the Columbia River Gorge in southern Washington. …

Tick-Borne Flavivirus Inhibits Sphingomyelinase (Issmase), A Venomous Spider Ortholog To Increase Sphingomyelin Lipid Levels For Its Survival In Ixodes Scapularis Ticks, Pravesh Regmi, Supreet Khanal, Girish Neelakanta, Hameda Sultana

Biological Sciences Faculty Publications

Our previous study showed that cells from medically important arthropods, such as ticks, secrete extracellular vesicles (EVs) including exosomes that mediate transmission of flavivirus RNA and proteins to the human cells. Understanding the molecular determinants and mechanism(s) of arthropod-borne flavivirus transmission via exosome biogenesis is very important. In this current study, we showed that in the presence of tick-borne Langat Virus (LGTV; a member of tick-borne encephalitis virus complex), the expression of arthropod IsSMase, a sphingomyelinase D (SMase D) that catalyzes the hydrolytic cleavage of substrates like sphingomyelin (SM) lipids, was significantly reduced in both Ixodes scapularis ticks (in vivo) …

The Heat Is On: Comparison Of Thermoregulatory Behavior In Parasitised Versus Unparasitized Caterpillars Of The Tobacco Hornworm, Manduca Sexta (L.) [Lepidoptera: Sphingidae], Jessica M. Johnston

Theses and Dissertations

Insect thermoregulatory research has demonstrated evidence of variation occurring within and among species with respect to infection, pathogens, and parasitism, but few studies have examined differences in thermoregulatory behavior in a host-parasite system with a coevolved symbiotic virus. I investigated the role of parasitism by Cotesia congregata (Say) (Hymenoptera: Braconidae) on the thermoregulatory behavior of Manduca sexta (L.) (Lepidoptera: Sphingidae) using an experimental design in a thermal gradient chamber and a complementary observational field study on wild M. sexta collected from tobacco farms. Parasitism and larval age were not found to have a significant effect on the preferred body temperature …

Analysis Of Genetic Structure And Pathogen Dynamics Of Ixodes Scapularis In Southwestern Virginia, Leemu Jackson

Undergraduate Honors Theses

Ixodes scapularis, or the blacklegged tick, is the primary vector of Borrelia burgdorferi. This pathogen is the causative agent of Lyme disease, the most common vector-transmitted disease in the United States. Although I. scapularis is distributed throughout the eastern U.S., Lyme disease is only considered endemic in the northeastern region of the country. Prior to 2007, Lyme disease was uncommon in Virginia, but since then cases of Lyme disease have increased dramatically with a hotspot forming in the Roanoke-Blacksburg area. The purpose of the current study was to determine whether B. burgdorferi prevalence and the genetic structure of I. …

Getting Lost: The Fungal Hijacking Of Ant Foraging Behavior In Space And Time, Thienthanh Trinh

Electronic Theses and Dissertations, 2020-2023

Many parasites have evolved strategies to exploit host behavior such that it benefits parasite transmission. Ophiocordyceps manipulations of carpenter ant behavior represent an evident example. Manipulated ants are coerced to ascend vegetation and clamp down their mandibles in a stereotypical "death-grip" bite. The fungus then kills the ant, sprouts a stalk and releases infective spores. Research has focused on this ultimate manipulation, leaving the subtler behavioral changes pre-biting largely unexplored. Field and transcriptome data found that the host circadian clocks, olfaction, and communication may be disrupted, suggesting that the fungus is affecting ant foraging activity and effectivity. To test these …

An Efficient Microinjection Method To Generate Human Anaplasmosis Agent Anaplasma Phagocytophilum-Infected Ticks, Vikas Taank, Ellango Ramasamy, Hameeda Sultana, Girish Neelakanta

Biological Sciences Faculty Publications

Ticks are important vectors that transmit several pathogens including human anaplasmosis agent, Anaplasma phagocytophilum. This bacterium is an obligate intracellular rickettsial pathogen. An infected reservoir animal host is often required for maintenance of this bacterial colony and as a source for blood to perform needle inoculations in naïve animals for tick feeding studies. In this study, we report an efficient microinjection method to generate A. phagocytophilum-infected ticks in laboratory conditions. The dense-core (DC) form of A. phagocytophilum was isolated from in vitro cultures and injected into the anal pore of unfed uninfected Ixodes scapularis nymphal ticks. These ticks …

Host Relationships And Geographic Distribution Of Species Of Blanchard, 1848 (Onchoproteocephalidea, Onchobothriidae) In Elasmobranchs: A Metadata Analysis, Francisco Zaragoza-Tapia, Griselda Pulido-Flores, Scott L. Gardner, Scott Monks

Scott L. Gardner Publications

Species of Acanthobothrium have been documented as parasites of the spiral intestine of elasmobranchs. Results of a metadata analysis indicate that 114 species of elasmobranchs have been reported as hosts of 200 species of Acanthobothrium. The metadata analysis revealed that 3.7% of species of sharks and 14.9% of species of rays that have been reported as hosts to date; some species are parasitized by more than one species of Acanthobothrium. This work provides a Category designation, as proposed by Ghoshroy and Caira (2001), for each species of Acanthobothrium. These Category designations are a tool to facilitate comparisons …

Obituary: Sydney Anderson (1927–2018), Scott Lyell Gardner, Robert M. Timm, Nancy Olds, Hugh H. Genoways

Scott L. Gardner Publications

On August 12, 2018, the American Society of Mammalogists (ASM) lost one of its giants of the latter half of the 20th century when Sydney Anderson quietly passed away at his home in Birmingham, Alabama, at the age of 91. “Syd,” to his many friends and colleagues, was born on January 11, 1927 in Topeka, Kansas, to Robert Grant and Evelyn Fern (Hunt) Anderson.

Anderson began his professional career at the University of Kansas, where for four years (1955–1959) he served as Assistant Curator in charge of mammals in the Museum of Natural History, and Instructor in the Department of …

Discovery Of Exosomes From Tick Saliva And Salivary Glands Reveals Therapeutic Roles For Cxcl12 And Il-8 In Wound Healing At The Tick-Human Skin Interface, Wenshuo Zhou, Faizan Tahir, Joseph Che-Yen Wang, Michael Woodson, Michael B. Sherman, Shahid Karim, Girish Neelakanta, Hameeda Sultana

Biological Sciences Faculty Publications

Ticks secrete various anti-coagulatory, anti-vasoconstrictory, anti-inflammatory, and anti-platelet aggregation factors in their saliva at the bite site during feeding to evade host immunological surveillance and responses. For the first time, we report successful isolation of exosomes (small membrane-bound extracellular signaling vesicles) from saliva and salivary glands of partially fed or unfed ixodid ticks. Our data showed a novel role of these in vivo exosomes in the inhibition of wound healing via downregulation of C-X-C motif chemokine ligand 12 (CXCL12) and upregulation of interleukin-8 (IL-8). Cryo-electron microscopy (cryo-EM) analysis revealed that tick saliva and salivary glands are composed of heterogeneous populations …

A Simple, Inexpensive Method For Mark-Recapture Of Ixodid Ticks, Alexis White, Robin Minch, Lindsey Bidder, Holly Gaff

Biological Sciences Faculty Publications

Mark-recapture techniques have been widely used and specialized to study organisms throughout the field of biology. To mark-recapture ticks (Ixodida), we have created a simple method to mark ticks using nail polish applied with an insect pin secured in a pencil that allows for a variety of questions to be answered. For measuring tick control efficacy, estimating population estimates, or measuring movement of ticks, this inexpensive mark-recapture method has been easily applied in the field and in the lab to provide useful data to answer a variety of questions about ticks.

The Sucking Louse Fauna Of Mongolian Rodents: Host Associations, Molecular Phylogenetics And Description Of Two New Species, Chase N. Robinson

Honors College Theses

This study aimed to screen Mongolian rodents for sucking lice (Insecta: Phthiraptera: Anoplura) to better understand host-parasite associations for this understudied region. Nine species, including 3 previously undescribed, from 4 genera were identified. A molecular phylogeny based on 2 mitochondrial genes of collected louse specimens is included.

The Ecological Niche Of Echinococcus Multilocularis In North America: Understanding Biotic And Abiotic Determinants Of Parasite Distribution With New Records In New Mexico And Maryland, United States, Sebastian Botero-Cañola, Altangerel Tsogtsaikhan Dursahinhan, Sara E. Rácz, Parker V. Lowe, John E. Ubelaker, Scott Lyell Gardner

Scott L. Gardner Publications

English abstract: Understanding the factors shaping the niche of parasites and its expression over geographical space and through time continues to be a modern scientific challenge with the results of research in this area directly influencing both theoretical and applied biology. This is especially important for proactive management of zoonotic parasites such as Echinococcus multilocularis, the etiologic agent of alveolar echinococcosis. Echinococcus multilocularis has a Holarctic distribution; with its geographic range and prevalence increasing recently in areas of the western Palearctic, while its distribution dynamics are poorly understood in the Nearctic. In this paper, we use an ecological niche …

Taxonomic Revision Of The Haemaphysalis (Rhipistoma) Spinulosa Subgroup, Parasites Of Carnivores And Other Mammals In Sub-Saharan Africa, Jackson A. Tomlinson

College of Graduate Studies: Theses & Dissertations

Nine new species of Haemaphysalis are here described based on a morphological analysis of 7,077 adult specimens stored in the U.S. National Tick Collection (Georgia Southern, Statesboro, USA) and collected from various carnivores (Carnivora: Canidae, Felidae, Herpestidae, Hyaenidae, Mustelidae, Nandiniidae, Viverridae) and hedgehogs (Erinaceomorpha: Erinaceidae); few specimens were found on hares (Lagomorpha: Leporidae), various rodents (Rodentia: Bathyergidae, Cricetidae, Muridae, Nesomyidae, Pedetidae, Sciuridae, Spalacidae) and other mammals (Artiodactyla, Chiroptera, Hyracoidea, Perissodactyla, Primates, and Soricomorpha) in 29 sub-Saharan African countries. In addition to descriptions of new species, 4 species, namely H. spinulosa Neumann, 1906, H. muhsamae Santos Dias, 1954, H …

Multistate Survey Of American Dog Ticks (Dermacentor Variabilis) For Rickettsia Species, Joy A. Hecht, Michelle E.J. Allerdice, Elizabeth A. Dykstra, Laura Mastel, Rebecca J. Eisen, Tammi L. Johnson, Holly D. Gaff, Andrea S. Varela-Stokes, Jerome Goddard, Benedict B. Pagac, Christopher D. Paddock, Sandor E. Karpathy

Biological Sciences Faculty Publications

Dermacentor variabilis, a common human-biting tick found throughout the eastern half and along the west coast of the United States, is a vector of multiple bacterial pathogens. Historically, D. variabilis has been considered a primary vector of Rickettsia rickettsii, the causative agent of Rocky Mountain spotted fever. A total of 883 adult D. variabilis, collected between 2012 and 2017 from various locations in 12 states across the United States, were screened for rickettsial DNA. Tick extracts were evaluated using three real-time PCR assays; an R. rickettsii-specific assay, a Rickettsia bellii-specific assay, and a Rickettsia genus-specific …

Dynamics Of Two Pathogens In A Single Tick Population, Alexis White, Elsa Schaefer, Chelsea Wright-Thompson, Christopher M. Kribs, Holly Gaff

Biological Sciences Faculty Publications

A mathematical model for a two-pathogen, one-tick, one-host system is presented and explored. The goal of this model is to determine how long an invading pathogen persists within a tick population in which a resident pathogen is already established. The numerical simulations of the model demonstrate the parameter ranges that allow for coexistence of the two pathogens. Sensitivity analysis highlights the importance of vector-borne, tick-to-host, transmission rates on the invasion reproductive number and persistence of the pathogens over time. The model is then applied to a case study based on a reclaimed swampland field site in southeastern Virginia using field …

Parasitic Dinoflagellate Hematodinium Perezi Prevalence In Larval And Juvenile Blue Crabs Callinectes Sapidus From Coastal Bays Of Virginia, H. J. Small, J. P. Huchin-Mian, K. S. Reece, K. M. Pagenkopp Lohan, Mark J. Butler Iv, J. D. Shields

Biological Sciences Faculty Publications

The parasitic dinoflagellate Hematodinium perezi infects the American blue crab Callinectes sapidus and other decapods along the Eastern seaboard and Gulf of Mexico coast of the USA. Large juvenile and adult blue crabs experience high mortality during seasonal outbreaks of H. perezi, but less is known about its presence in the early life history stages of this host. We determined the prevalence of H. perezi in megalopae and early benthic juvenile crabs from multiple locations along the Virginia portion of the Delmarva Peninsula. The DNA of H. perezi was not detected in any megalopae collected from several locations within …

Trypanosoma Cruzi Trypomastigote Glycosylphosphatidylinositol-Anchored Mucins And A Synthetic Alpha-Gal-Containing Neoglycoprotein As Potential Biomarkers And Vaccines For Chagas Disease, Igor Leandro Estevao

Open Access Theses & Dissertations

Chagas disease (CD), caused by the protozoan Trypanosoma cruzi, is a neglected tropical disease that kills or permanently disable thousands of people annually. About 6-8 million people are estimated to be infected worldwide. Although many efforts have been made for the development of an effective immunotherapy, currently there is no vaccine to prevent or treat CD in humans. Despite their toxicity, the two current drugs for CD, benznidazole (BZN) and nifurtimox (NFX), have medium-to-high efficacy in the chronic stage of the disease and could save or improve the lives of thousands of patients. However, negative seroconversion in treated patients, as …