Medicine and Health Sciences Commons^™

Equine Fecal Microbiota Response To Short Term Antibiotic Administration, Jordan Lacey Parker

Theses and Dissertations--Veterinary Science

Though generally regarded as safe, research continues to demonstrate negative side effects of antibiotic administration on the gastrointestinal (GIT) microbiota across species. In horses, antibiotic associated diarrhea (AAD) is a life-threatening side effect linked to the GIT microbiota. This study tested the hypothesis that short term antibiotic administration to healthy horses would negatively impact the fecal microbiota as measured by their ability to digest nutrients and produce short chain fatty acids (SCFAs). Twenty-four horses were assigned to one of four treatments: control (CO); potassium penicillin/gentamicin sulfate (KPG); ceftiofur crystalline free acid (EX); trimethoprim/sulfamethoxazole (SMZ); and treated for 4 days. Fecal …

The Effects Of Cannabidiol On Senior Equine Health, Shelley Turner

Theses and Dissertations--Veterinary Science

Cannabis sativa L., has been revealed to produce hundreds of phytocannabinoids, of which cannabidiol (CBD) is one of the most desired. It has been revealed that CBD can potentially treat inflammation and act as an analgesic in humans without psychoactive effects of delta-9-tetrahydrocannabinol (THC). Recently, there has been interest in understanding the potential health benefits of CBD for horses. With an increasing senior horse population (< 15 years old), alternatives to the use of non-steroidal anti-inflammatory drugs (NSAIDs) such as phenylbutazone, firocoxib, and flunixin meglumine, are desired as these common anti-inflammatory treatments have negative side effects. Because senior horses may have chronic low-grade inflammation, termed inflamm-aging, they are a natural model to investigate the efficacy of CBD on inflammatory responses as well as other health parameters. Given this interest, and due to the lack of research conducted on CBD in the horse, the overall objective of this dissertation work was to conduct both basic and applied research investigating the effects of CBD on equine immune function and health. The first objective was to determine the in vitro effects of CBD as an anti-inflammatory. Peripheral blood mononuclear cells (PBMCs) from senior horses were cultured in vitro with increasing concentrations of pure CBD dissolved in dimethyl sulfoxide (DMSO). These cells were …

Muscle Mass And Immune Function In The Senior Horse, Alisa Christina Herbst

Theses and Dissertations--Veterinary Science

Senior horses (≥ 15 years) represent up to one-third of the global equine population, and the proportion of old horses (≥ 20 years) in the U.S. has been steadily increasing. Aging is associated with a loss of skeletal muscle mass in horses, and while age-related muscle loss is comparingly well characterized in humans, little is currently known concerning underlying mechanisms, adverse outcomes, or the prevalence of low muscle mass in senior horses. One factor proposed to play a role in the development of age-related muscle atrophy in humans is inflamm-aging, a low-grade inflammation that affects elderly people and that has …

An Assessment Of The Carrier State And A Novel Marker Of Leptospira And Abortion In Central Kentucky Horses, Gloria Louise Gellin

Theses and Dissertations--Veterinary Science

Leptospirosis is a reemerging zoonotic infection of worldwide importance and affects all mammals. The bacterium is transmitted to animals and humans by urine, fetal membranes and body fluids. Leptospira shedding in the urine contaminates both soil and water, exposing both humans and animals to the bacterium. Leptospirosis in horses can cause abortion and is one of the etiologies of equine recurrent uveitis which can lead to blindness. Equine leptospiral abortion in Central Kentucky is primarily caused by serovar Pomona, with occasional cases attributed to serovar Grippotyphosa. There are a few reports in the literature attributing abortion to serovar Bratislava in …

Host-Parasite Interaction In Horses: Mucosal Responses To Naturally Acquired Cyathostomin Infections And Anthelmintic Treatment, Ashley Elaine Steuer

Theses and Dissertations--Veterinary Science

Cyathostomins are ubiquitous parasites in equids. In rare cases, cyathostomins lead to a generalized typhlocolitis and death. In healthy horses, local reactions are noted to the mucosal larvae; however, the mechanisms and importance of these reactions have not been elucidated. It has been hypothesized that anthelmintics can alter these reactions. Currently, three drug classes are approved for use in horses against cyathostomins; while all products target the adults, only two products are labeled as larvicidal. Adulticidal therapy is implicated in triggering the typhlocolitis, however, current evidence is contradictory. There is also conjecture that the larvicidal drugs can increase the risk …

Evaluation Of Rhodococcus Equi Susceptibility To Silver Nanoparticle Antimicrobials, Elizabeth Boudaher

Theses and Dissertations--Veterinary Science

Rhodococcus equi is a significant cause of pneumonia in foals and immunocompromised humans. Antimicrobial resistance among R. equi isolates has developed as a consequence of inappropriate stewardship and bacterial evolution, leading to an increased rate of treatment failures that typically result in foal fatality. In the current study, we evaluated the efficacy of antimicrobial silver nanoparticle (AgNP) complexes in controlling R. equi growth. Previous studies characterizing AgNP-induced antibacterial effects in other Gram-positive pathogens led us to hypothesize that silver nanoparticle antimicrobials impact R. equi viability and intracellular replication. We therefore investigated the effect of silver nanoparticle complexes on R. equi …

Effects Of Pituitary Pars Intermedia Dysfunction And Prascend® Treatment On Endocrine And Immune Function In Senior Horses, Ashton B. Miller

Theses and Dissertations--Veterinary Science

Pituitary pars intermedia dysfunction (PPID) is one of the most common endocrine diseases affecting senior horses. PPID causes abnormally high concentrations of adrenocorticotropic hormone (ACTH) in the plasma and a very distinct, long, shaggy haircoat (hypertrichosis). At present, the recommended treatment for PPID is daily oral administration of pergolide mesylate. Due to the increased ACTH levels associated with PPID, it is commonly thought that these horses are immunosuppressed and at increased risk of opportunistic infections, although current research in this area is sparse. Additionally, it is not well-understood how treatment with Prascend^® (pergolide tablets) affects endocrine measures other than …

An Epidemiologic Study Of Antimicrobial Resistance Of Staphylococcus Species Isolated From Equine Samples Submitted To A Diagnostic Laboratory, Ronita Adams, Jackie Smith, Stephan Locke, Erica Phillips, Erdal Erol, Craig N. Carter, Agricola Odoi

Veterinary Science Faculty Publications

Background

Antimicrobial resistance limits traditional treatment options and increases costs. It is therefore important to estimate the magnitude of the problem so as to provide empirical data to guide control efforts. The aim of this study was to investigate the burden and patterns of antimicrobial resistance (AMR) among equine Staphylococcus samples submitted to the University of Kentucky Veterinary Diagnostic Laboratory (UKVDL) from 1993 to 2009. Retrospective data of 1711 equine Staphylococcus samples submitted to the UKVDL during the time period 1993 to 2009 were included in the study. Antimicrobial susceptibility testing, that included 16 drugs, were performed using cultures followed …

Cellular And Molecular Basis Of Equine Arteritis Virus Persistent Infection In The Stallion Reproductive Tract: Characterization Of Local Host-Pathogen Interactions Mediating Long-Term Viral Persistence, Mariano Carossino

Theses and Dissertations--Veterinary Science

Equine arteritis virus (EAV) has a global impact on the equine industry being the causative agent of equine viral arteritis (EVA), a reproductive, respiratory, and systemic disease of equids. A distinctive feature of EAV infection is that it establishes long-term persistent infection in the reproductive tract of stallions and is continuously shed in the semen (carrier state). Recent studies showed that long-term persistence is associated with a specific allele of the CXCL16 gene (CXCL16S). However, the cellular and molecular mechanisms underlying the establishment and maintenance of persistent infection are yet to be determined. The studies were undertaken herein …

Rhodococcus Equi In The Foal – Improving Diagnostic And Prevention Measures, Fernanda Bicudo Cesar

Theses and Dissertations--Veterinary Science

Although Rhodococcus equi (R. equi), previously known as Corynebacterium equi, was first isolated from pneumonic foals almost a century ago, it remains the most common cause of subacute or chronic granulomatous bronchopneumonia in foals. While the majority of foals exposed to R. equi develop a protective immune response (regressors), others exhibit a unique susceptibility to infection (progressors). The determinants for either outcome are not completely understood. Therefore, current diagnostic and preventive measures are suboptimal and require betterment. In light of this current need, we hypothesized that immunoglobulin G subisotype T [IgG(T)] against the virulence-associated protein A (VapA) …

Equine Arteritis Virus Elicits A Mucosal Antibody Response In The Reproductive Tract Of Persistently Infected Stallions, Mariano Carossino, Bettina Wagner, Alan T. Loynachan, R. Frank Cook, Igor F. Canisso, Lakshman Chelvarajan, Casey L. Edwards, Bora Nam, John F. Timoney, Peter J. Timoney, Udeni B. R. Balasuriya

Maxwell H. Gluck Equine Research Center Faculty Publications

Equine arteritis virus (EAV) has the ability to establish persistent infection in the reproductive tract of the stallion (carrier) and is continuously shed in its semen. We have recently demonstrated that EAV persists within stromal cells and a subset of lymphocytes in the stallion accessory sex glands in the presence of a significant local inflammatory response. In the present study, we demonstrated that EAV elicits a mucosal antibody response in the reproductive tract during persistent infection with homing of plasma cells into accessory sex glands. The EAV-specific immunoglobulin isotypes in seminal plasma included IgA, IgG1, IgG3/5, and IgG4/7. Interestingly, seminal …

Hops (Humulus Lupulus L.) Bitter Acids: Modulation Of Rumen Fermentation And Potential As An Alternative Growth Promoter, Michael D. Flythe, Isabelle A. Kagan, Yuxi Wang, Nelmy Narvaez

Animal and Food Sciences Faculty Publications

Antibiotics can improve ruminant growth and efficiency by altering rumen fermentation via selective inhibition of microorganisms. However, antibiotic use is increasingly restricted due to concerns about the spread of antibiotic-resistance. Plant-based antimicrobials are alternatives to antibiotics in animal production. The hops plant (Humulus lupulus L.) produces a range of bioactive secondary metabolites, including antimicrobial prenylated phloroglucinols, which are commonly called alpha- and beta-acids. These latter compounds can be considered phyto-ionophores, phytochemicals with a similar antimicrobial mechanism of action to ionophore antibiotics (e.g., monensin, lasalocid). Like ionophores, the hop beta-acids inhibit rumen bacteria possessing a classical Gram-positive cell envelope. This …

Equine Arteritis Virus Has Specific Tropism For Stromal Cells And Cd8+ T And Cd21+ B Lymphocytes But Not For Glandular Epithelium At The Primary Site Of Persistent Infection In The Stallion Reproductive Tract, Mariano Carossino, Alan T. Loynachan, Igor F. Canisso, Richard Frank Cook, Juliana Roberta Campos, Bora Nam, Yun Young Go, Edward L. Squires, Mats H. T. Troedsson, Thomas W. Swerczek, Fabio Del Piero, Ernest F. Bailey, Peter J. Timoney, Udeni B. R. Balasuriya

Veterinary Science Faculty Publications

Equine arteritis virus (EAV) has a global impact on the equine industry as the causative agent of equine viral arteritis (EVA), a respiratory, systemic, and reproductive disease of equids. A distinctive feature of EAV infection is that it establishes long-term persistent infection in 10 to 70% of infected stallions (carriers). In these stallions, EAV is detectable only in the reproductive tract, and viral persistence occurs despite the presence of high serum neutralizing antibody titers. Carrier stallions constitute the natural reservoir of the virus as they continuously shed EAV in their semen. Although the accessory sex glands have been implicated as …

Exogenous Lactobacilli Mitigate Microbial Changes Associated With Grain Fermentation (Corn, Oats, And Wheat) By Equine Fecal Microflora Ex Vivo, Brittany E. Harlow, Laurie M. Lawrence, Patricia A. Harris, Glen E. Aiken, Michael D. Flythe

Animal and Food Sciences Faculty Publications

Cereal grains are often included in equine diets. When starch intake exceeds foregut digestion starch will reach the hindgut, impacting microbial ecology. Probiotics (e.g., lactobacilli) are reported to mitigate GI dysbioses in other species. This study was conducted to determine the effect of exogenous lactobacilli on pH and the growth of amylolytic and lactate-utilizing bacteria. Feces were collected from 3 mature geldings fed grass hay with access to pasture. Fecal microbes were harvested by differential centrifugation, washed, and re-suspended in anaerobic media containing ground corn, wheat, or oats at 1.6% (w/v) starch and one of five …

Analysis Of Humoral Immune Responses In Horses With Equine Protozoal Myeloencephalitis, Catherine-Jane Angwin

Theses and Dissertations--Veterinary Science

Equine protozoal myeloencephalitis (EPM), caused by the protozoan parasite Sarcocystis neurona, is one of the most important neurological diseases of horses in the Americas. While seroprevalence of S. neurona in horses is high, clinical manifestation of EPM occurs in less than 1% of infected horses. Factors governing the occurrence and severity of EPM are largely unknown, although horse immunity might play an important role in clinical outcome. We hypothesize that EPM occurs due to an aberrant immune response, which will be discernable in the equine IgG subisotypes a, b, and (T) that recognize S. neurona in infected diseased horses versus …

Inflammation And Insulin Dysregulation In The Horse, Sarah E. Elzinga

Theses and Dissertations--Veterinary Science

Insulin dysregulation (ID) in the horse is receiving increasing attention as a serious health concern, in particular due to its association with the potentially career or life ending condition, laminitis. The role of inflammation and the immune system in ID as well as its associated health concerns has also been raised. However, the involvement of inflammation in and mechanisms behind ID in the horse remain unclear. Therefore, our overall hypothesis was that due in part to changes in their gut microbiota and plasma lipidome, horses with ID have changes in circulating proinflammatory markers, in particular in response to glycemic challenge, …

An Investigation Into Specific Seminal Plasma Proteins And Their Effect On The Innate Immune Response To Breeding In The Mare, Carleigh Elizabeth Fedorka

Theses and Dissertations--Veterinary Science

The mare experiences a transient innate immune response to breeding, the resolution of which is crucial for optimal fertility. The majority of mares are able to modulate this inflammation in a timely fashion, but a subpopulation exists which fail to do so and are considered susceptible to persistent breeding-induced endometritis (PBIE). Seminal plasma has been shown to modulate aspects of this inflammation. Recently, two seminal plasma proteins have garnered interest for their immune modulating properties: cysteine-rich secretory protein-3 (CRISP-3) and lactoferrin. These proteins have been found to alter the binding between sperm and neutrophils based on sperm viability in vitro …

Nonlinear Hierarchical Models For Longitudinal Experimental Infection Studies, Michael David Singleton

Theses and Dissertations--Epidemiology and Biostatistics

Experimental infection (EI) studies, involving the intentional inoculation of animal or human subjects with an infectious agent under controlled conditions, have a long history in infectious disease research. Longitudinal infection response data often arise in EI studies designed to demonstrate vaccine efficacy, explore disease etiology, pathogenesis and transmission, or understand the host immune response to infection. Viral loads, antibody titers, symptom scores and body temperature are a few of the outcome variables commonly studied. Longitudinal EI data are inherently nonlinear, often with single-peaked response trajectories with a common pre- and post-infection baseline. Such data are frequently analyzed with statistical methods …

Modulation Of Type-I Interferon Mediated Immune Response: A Novel Innate Immune Evasion Strategy Of Equine Herpesvirus 1, Sanjay Sarkar

Theses and Dissertations--Veterinary Science

Equine herpesvirus-1 (EHV-1) is one of the major viral pathogens causing respiratory disease, abortion, perinatal mortality and neurologic disease among horses resulting in significant economic losses to the equine industry. The virus can also remain latent in the horses and recrudesce at any time. Type-I interferons (IFNs) act as a first line of defense against many viral infections.

In this study we investigated the type-I IFN response against the neuropathogenic T953 strain of EHV-1 in equine endothelial cells (EECs). The results showed that after a transient induction of IFN-β mRNA as well as protein at an early time (3h) post …

Role Of Viral And Host Factors In Influenza Virus Mediated Inhibition Of Interleukin-23, Ashish Tiwari

Theses and Dissertations--Veterinary Science

Influenza virus is one of the major respiratory pathogens of humans as well as animals, including equines. There is an increasing evidence that bacterial infections are the most common cause of the death during influenza. In horses also, secondary bacterial pneumonia can lead to death, and surviving horses may take up to six months for the complete recovery resulting in heavy economic loss to the equine industry. Interleukin (IL)-23 mediated innate immune response has been shown to protect the host from various respiratory bacterial infections. However, studies to investigate the role of host and viral factors in the regulation of …

Determination Of Farm-Specific Lawsonia Intracellularis Seroprevalence In Central Kentucky Thoroughbreds And The Identification Of Factors Contributing To Equine Proliferative Enteropathy, Allen E. Page

Theses and Dissertations--Veterinary Science

Lawsonia intracellularis and the disease it causes in horses, equine proliferative enteropathy (EPE), is an emerging pathogen of increasing importance to the horse industry from both an economic and welfare standpoint. Long recognized as an economically important disease of swine, the hallmark of EPE is a protein-losing enteropathy, where affected horses suffer weight loss and some ultimately succumb to the disease despite aggressive treatment. There are currently no known EPE preventative measures and the epidemiology of the disease remains poorly defined. While EPE is a sporadic disease affecting less than 25% of exposed horses, some farms experience clinical cases year …

Molecular And Genomic Approaches To Understanding Host-Virus Interactions In Shaping The Outcome Of Equine Arteritis Virus Infection, Yun Young Go

University of Kentucky Doctoral Dissertations

Equine arteritis virus (EAV) is the causal agent of equine viral arteritis, a disease of equids. During natural outbreaks of the disease, EAV can cause abortion in pregnant mares and persistent infection in stallions. Understanding how host cellular proteins interact with viral RNA and viral proteins, as well as their role in viral infection, will enable better characterization of the pathogenesis of EAV and establishment of persistent infection in stallions. Accordingly, we hypothesized that both viral factors and host genetically related factors could influence the outcome of EAV infection in horses. To test this hypothesis, we first combined contemporary molecular …

Genetic Immunization In The Horse: The Potential For Enhanced Immune Responses With Deacylated Polyethyleneimine (Pei) And Immunostimulatory Cytokines As Vaccine Adjuvants, Deborah Lee Even

Theses and Dissertations--Veterinary Science

DNA vaccines in larger animals, such as horses, are generally less effective and elicit significantly weaker immune responses, than in small animal model systems. To provide optimal protection against pathogenic microorganisms, the induction of both humoral and cellular immune responses from DNA vaccination may be necessary. One limitation to DNA immunization in the horse is the difficulty in generating high levels of antigen-specific antibody and CTL responses. Previous work in the laboratory has demonstrated that expression constructs containing native sequences encoding the surface unit (SU) envelope glycoprotein (pCiSU) of the Equine Infectious Anemia Virus (EIAV) are ineffective at stimulating immune …