Pathogenesis in horses refers to the biological mechanisms that lead to the development and progression of diseases within equine species. This process involves a complex interaction between the horse's immune system, genetic predispositions, environmental factors, and infectious agents such as bacteria, viruses, or parasites. Understanding pathogenesis is essential for identifying how diseases manifest and progress in horses, which can inform diagnostic and therapeutic strategies. Research in this area often focuses on specific diseases, examining factors such as pathogen entry, immune response, tissue damage, and recovery processes. This page compiles peer-reviewed research studies and scholarly articles that explore the mechanisms, contributing factors, and implications of pathogenesis in equine health.
Gillen A, Archer D, Ireland J, Rocchigiani G.Strangulating lipomata are the most common cause of small intestinal strangulating obstruction. Evaluation of histological features of pathological and non-pathological lipomata, and the histological properties of omental and retroperitoneal fat have not been described. Objective: To characterise histological features of equine abdominal lipomata, omental and retroperitoneal adipose tissue, and associations between them. Methods: Prospective observational anatomic (gross and histological). Methods: Horses undergoing emergency laparotomy for management of abdominal pain in a single hospital wer...
Engiles JB, Stefanovski D, van Eps A.To examine the effects of prolonged preferential weight bearing (PWB) and reduced ambulation (RA) on hoof lamellae using a nonpainful in vivo experimental model. Unassigned: 12 healthy Standardbred horses were housed in stocks continuously for 92 hours. A platform shoe was placed on 1 forelimb in the PWB group (n = 6) to increase the load on the supporting limb (SL) by approximately 10% bodyweight, whereas the RA group (n = 6) had normal weight bearing. Archived healthy horse (n = 8) samples were used as controls. Histomorphometry and histochemistry (terminal deoxynucleotidyl transferase dUTP ...
Attia MM, Omar HM.This study aimed to collect data on the most common parasites of the family equidae which is spp. During this study we focused on the prevalence rate in the world; the distribution of the six known species: life cycle and the pathogenesis of the larvae inside the hosts were investigated around the world. Molecular as well as serological diagnoses were analyzed. Possible treatment strategies which were fully studied; are also, included. () and larvae are the main present larvae in equine; other species, such as , , and may be present. Although the female flies' egg-laying behavior can annoy...
Kozak S, Merda D, Chesnais V, Breuil MF, Harrison M, Zdovc I, Golob M, Petry S, Duquesne F.Taylorella equigenitalis is the causative agent of contagious equine metritis, an internationally regulated sexually-transmitted infection in horses, which is of great concern as it usually results in temporary infertility. Taylorella asinigenitalis, the second member of the genus, is mainly found in donkeys and is considered non-pathogenic, although a first natural outbreak was reported in 2019 in the United Arab Emirates. Multilocus sequence typing (MLST) is currently used to study the epidemiology of Taylorella spp. but, while highly transposable and reproducible, it only focuses on < 0.5...
Finno CJ.In the field of equine muscle disorders, many conditions have a genetic basis. Therefore, genetic testing is an important part of the diagnostic evaluation. Validated genetic tests are currently available for 5 equine muscle disorders: hyperkalemic periodic paralysis, malignant hyperthermia, glycogen branching enzyme disease, type 1 polysaccharide storage myopathy, and myosin heavy chain myopathy. These diseases should be tested for in the appropriate breeds with clinical signs of disease or as part of breeding management. Genetic testing in veterinary medicine is not regulated, and therefore,...
Durward-Akhurst SA, Valberg SJ.Several inflammatory myopathies have an infectious or immune-mediated basis in the horse. Myosin heavy chain myopathy is caused by a codominant missense variant in MYH1 and has 3 clinical presentations: immune-mediated myositis, calciphylaxis, and nonexertional rhabdomyolysis in Quarter Horse-related breeds. An infarctive form of purpura hemorrhagica affects numerous breeds, presenting with focal firm, painful muscle swelling, and subsequent infarction of multiple tissues. While Streptococcus equi equi is often the inciting cause, anaplasmosis, sarcocystis, piroplasmosis, viruses, and vaccines...
Pusterla N, Barnum S, Lawton K, Craig B, James K.Equid alphaherpesvirus 4 (EqAHV4; Orthoherpesviridae, Varicellovirus equidalpha4; equine rhinopneumonitis virus) has seldom been associated with complications such as abortion and myeloencephalopathy, given the low tendency of this virus to induce viremia. We investigated the frequency of EqAHV4 viremia in horses with fever and respiratory signs. Case selection included all equids with EqAHV4 quantitative real-time PCR (qPCR)-positive nasal secretions (defined as EqAHV4 qPCR-positive cases) submitted to a diagnostic laboratory. Controls consisted of each case submitted before and after each Eq...
Kublicka A, Lorek D, Mikołajczyk-Martinez A, Chodaczek G, Chwirot A, Bażanów B, Matczuk AK.The process of viral entry into host cells is crucial for the establishment of infection and the determination of viral pathogenicity. A comprehensive understanding of entry pathways is fundamental for the development of novel therapeutic strategies. Standard techniques for investigating viral entry include confocal microscopy and flow cytometry, both of which provide complementary qualitative and quantitative data. Imaging flow cytometry, which integrates the advantages of both methodologies, offers significant potential in virological studies. In this investigation, we employed imaging flow ...
Jurisic L, Auerswald H, Marcacci M, Di Giallonardo F, Coetzee LM, Curini V, Averaimo D, Ortiz-Baez AS, Cammà C, Di Teodoro G, Richt JA, Holmes EC....Members of the RNA virus order infect hosts ranging from marine invertebrates to terrestrial mammals. As such, understanding the determinants of host range in this group of viruses, as well as their patterns of emergence and disease potential, is of clear importance. The are a recently documented family within the . To date, mesoniviruses have only been associated with the infection of arthropod species, particularly mosquitoes, and hence are regarded as insect-specific viruses (ISVs). Herein, we report the first detection of a mesonivirus-Alphamesonivirus-1 -in mammals. Specifically, we uti...
Kabir A, Kelley WG, Glover C, Erol E, Helmy YA.Salmonella is a foodborne pathogen that poses a significant threat to global public health. It affects several animal species, including horses. Salmonella infections in horses can be either asymptomatic or cause severe clinical illness. Infections caused by Salmonella are presently controlled with antibiotics. Due to the formation of biofilms and the emergence of antimicrobial resistance, the treatment has become more complicated. Our study focused on investigating the prevalence of Salmonella enterica in necropsied horses, assessing the capability for biofilm formation, and motility, determi...
Jensen A, Clarke EJ, Nugent Z, Paice E, Gringel I, Yamamoto K, Rocchigiani G, Peffers AJ, Cooper L, Peffers MJ.Equine dental diseases significantly impact a horse's overall health, performance and quality of life. They can result in secondary infections and digestive disturbances, potentially leading to colic. A recently described disease affecting the incisors of horses is equine odontoclastic tooth resorption and hypercementosis (EOTRH). Understanding EOTRH is crucial for early diagnosis, effective management and prevention of its severe consequences. Objective: To determine proteomic differences in incisor cementum in horses with and without clinical EOTRH. Methods: Comparative and observational cli...
Carvalho Serena G, Marchezan Piva M, Viezzer Bianchi M, Fernandes da Fonseca HC, Chitolina Pupin R, Martins Basso R, Secorun Borges A....In horses, systemic calcinosis is a rare syndrome characterised by muscle lesion associated with the mineralisation of large muscle groups or other organs, in the absence of an alternative cause for the calcification, such as toxic, enzootic or metabolic. Molecular and histopathological aspects of the disease are still poorly elucidated. Objective: To describe the epidemiological, pathological and molecular aspects of systemic calcinosis in a convenience sample of six horses submitted to necropsy in the Southern and Midwestern regions of Brazil. Methods: Retrospective exploratory study. Method...
Gerras J, Young K, Roberts D, Waldman G, Salmon JH, Gilger BC.To describe the ocular findings, chronology of disease, and serum leptospiral titers in a group of horses, mules, and donkeys following an outbreak of leptospirosis. Unassigned: Fifty Equidae in central North Carolina had ophthalmic examinations and serum leptospiral microscopic agglutination test (MAT) titers performed every 3-6 months for 24 months followed by a final examination at 34 months. Unassigned: Throughout the nearly three-year study period, 17 horses (34%; 17/49 horses) developed signs of uveitis; 20 eyes (20/34; 58.8%) of these 17 horses were visual at the initial examinati...
Styková E, Valocký I, Kačírová J, Fecskeová LK.Equine pastern dermatitis (EPD) is a multifactorial disease with a change in the skin microbiome. The present study monitored the influence of Weissella cibaria Biocenol™ 4/8 D37 CCM 9015 stabilized on alginite on the skin microbiota of healthy horses and model patients with EPD. Based on clinical signs, EPD lesions were identified as exudative or proliferative forms. A comparison of the initial microbial community based on 16S rRNA amplicon sequencing revealed that there was a statistically significant difference between healthy vs. exudative (R = 0.52, p = 0.003) and exudative vs. ...
Ishikawa Y, Tufa SF, Keene DR, Bächinger HP, Winand NJ.Mutations in the collagen-modifying enzyme lysyl hydroxylase 1 (LH1) cause Warmblood Fragile Foal Syndrome (WFFS) in horses. We investigated the impact of this mutation on collagen structure and function. Our results show that LH1 deficiency leads to reduced lysine hydroxylation, altered collagen fibril organization, and tissue abnormalities resembling human Ehlers-Danlos syndrome. These findings highlight the critical role of LH1 in collagen biosynthesis and provide insights into the pathogenesis of WFFS.
Vinijkumthorn R, Kingkaw A, Yanyongsirikarn P, Phaonakrop N, Roytrakul S, Vongsangnak W, Tesena P.Equine melanocytic neoplasm (EMN) represents a form of skin tumor observed predominantly in grey horses aged over 15 years. Despite its prevalence, current therapeutic and preventive strategies for EMN have been subject to limited investigation. This study endeavors to shed light on potential phosphoproteins present in equine serum and fecal samples, potentially linked to EMN, with a specific focus on functional interactions in EMN pathogenesis. We examined 50 samples (25 serum, 25 feces), divided into three groups based on EMN severity: normal (n = 16), mild (n = 18), and severe EMN (...
Equine infectious anemia virus (EIAV) is the simplest described within the family, related to the human immunodeficiency viruses (HIV-1 and HIV-2). There is an important interplay between host cells and viruses. Viruses need to hijack cellular proteins for their viral cycle completion and some cellular proteins are antiviral agents interfering with viral replication. HIV cellular partners have been extensively studied and described, with a special attention to host proteins able to inhibit specific steps of the viral cycle, called restriction factors. Viruses develop countermeasures against ...
Koziy RV, Katselis GS, Yoshimura S, Simko E, Bracamonte JL.Prompt diagnosis of equine septic arthritis is crucial for successful treatment. Serum amyloid A (SAA) has been suggested as a reliable biomarker. However, we previously found that synovial fluid SAA increases in nonaffected joints of horses with septic arthritis. We hypothesized that systemic SAA may leak into the nonaffected joints. If this is the case, we also hypothesized that locally produced joint SAA isoforms may be better candidates for septic arthritis biomarkers. Thus, our objectives were 1) to evaluate the temporal kinetics of systemic and synovial fluid SAA in horses with septic ar...
Toft K, Honoré ML, Ripley N, Nielsen MK, Mardahl M, Fromm B, Hedberg-Alm Y, Tydén E, Nielsen LN, Nejsum P, Thamsborg SM, Cirera S, Pihl TH.The equine bloodworm, Strongylus vulgaris, is a common and highly pathogenic parasite in horses due to its migratory life cycle involving the intestinal arteries. Current diagnostic techniques cannot detect the prepatent migrating stages of S. vulgaris, highlighting the need for new biomarkers. Parasites release microRNAs (miRNAs) into their environment, which could potentially be detectable in host blood samples. Additionally, host miRNA expression patterns may change in response to infection. This study aimed to identify miRNAs associated with S. vulgaris infection by profiling the horse's m...
François AC, Renaud B, Kruse CJ, Marcillaud-Pitel C, Votion DM.Anne-Christine François, Benoît Renaud, Caroline-Julia Kruse, Christel Marcillaud-Pitel and Dominique-Marie Votion of the Atypical Myopathy Alert Group discuss insights from 20 years of research and surveillance on equine atypical myopathy.
Guest DJ, Birch HL, Thorpe CT.The suspensory ligament (SL) is a key component of the elaborate and highly adapted suspensory apparatus in the horse. In addition to contributing to stabilisation of the metacarpophalangeal joint, the SL has a spring like function to reduce the energetic cost of locomotion. Although the SL is highly prone to injury in horses of all ages and competing in a wide range of disciplines, knowledge regarding fundamental structure-function relationships in the SL is lacking, particularly compared with other injury-prone tendinous structures such as the superficial digital flexor tendon. In this revie...
Hain-Saunders N, Knight DR, Bruce M, Riley TV.Recent increases in community-associated Clostridioides difficile infections have highlighted the importance of monitoring toxigenic C. difficile from animal and environmental sources. We provide the complete circularized genomes of two toxigenic C. difficile strains isolated from feral horse faeces. Genome N64 (sequence type 964) consists of a single chromosome of 4,078,791 bp, while genome H251 (sequence type 963) comprises one chromosome (4,304,722 bp) and three plasmids (150,942 bp, 11,534 bp, and 9,074 bp).
Rodrigues GG, Alves DS, Bromberger CR, Nomelini QSS, Borges AS, de Oliveira-Filho JP, Delfiol DJZ.The association between aural plaques, Equus caballus papillomavirus (EcPV), and the different breeds of horses and risk factors is poorly described. The objective of this study was to determine the clinical prevalence of aural plaques in Mangalarga Marchador (MM) and Quarter Horse (QH) horses in Brazil, to evaluate the association of this prevalence with some risk factors, and to detect the presence of EcPV DNA (types 1-10) in aural plaques biopsies. A total of 400 MM and 425 QH horses, were clinically evaluated. For each horse, an identification form was completed, containing information on ...
Botía M, Martín-Cuervo M, Martínez-Subiela S, Cerón JJ, Ayala I, Hansen S, Muñoz-Prieto A.Equine Gastric Ulcer Syndrome (EGUS) is a widespread disease with a very high prevalence and importance in horses. It includes two conditions: Equine squamous gastric disease (ESGD), linked to acid disturbances, and Equine Glandular Gastric Disease (EGGD), associated with inflammation and immune system issues. In saliva, increased levels of immunological markers have been observed in this disease, indicating immune system involvement. In addition, changes in biomarkers of oxidative stress have been described. In horses, IgG and IgA are proteins that appear in saliva and serum and are considere...
Gagliardi R, Koch DW, Loeser R, Schnabel LV.Osteoarthritis (OA) is a debilitating disease that impacts millions of individuals and has limited therapeutic options. A significant hindrance to therapeutic discovery is the lack of in vitro OA models that translate reliably to in vivo preclinical animal models. An alternative to traditional inflammatory cytokine models is the matrikine stimulation model, in which fragments of matrix proteins naturally found in OA tissues and synovial fluid, are used to stimulate cells of the joint. The objective of this study was to determine if matrikine stimulation of equine synovial fibroblasts and chond...
Ryu SH, Jang B, Kim BS, Park KT.This is the first report describing the isolation and genome sequence of Flavobacterium ceti (F. ceti IJFC025) from a draining submandibular lymph node abscess in a 6-year-old mixed-breed mare in Korea. Since F. ceti is not a usual infectious pathogen that causes equine health problems, this study presents the complete genome sequence of F. ceti isolated from a submandibular lymph node abscess sample in Jeju, South Korea, in 2022. The entire genome sequence of F. ceti IJFC025 consisted of a 3,144,426-bp chromosome with 35.6 % G + C content. Gene prediction revealed that this strain possesse...
Luan Y, Zhong L, Li C, Yue X, Ye M, Wang J, Zhu Y, Wang Q.Polydactyly was recorded before 100 BCE and attracted widespread interest because of its relationship to limb health and ancestral traits in horses. However, the underlying reasons for the development of polydactyly remain unclear. To search for polydactyly-related genes, we utilize a paternal half-sib family and screen for variants that match the mode of inheritance. Through this screening process, 77 variants in 65 genes are filtered. A missense variant (EqCab3.0 chr4: <107353368> A > G) (rs1138485164) in the 3rd exon of LMBR1 is identified as a source of amino acid sequence variatio...
Muñoz-Prieto A, Rubić I, Rešetar Maslov D, González-Sánchez JC, Mrljak V, Cerón JJ, Hansen S.Equine gastric ulcer syndrome (EGUS) is a common condition in horses. This study explores the use of liquid proteomics to identify new biomarkers in saliva and serum to monitor EGUS treatment. The proteomes of horses with EGUS before and after a successful treatment with omeprazole were analysed. In saliva, 503 proteins were identified, with 7 upregulated and 6 downregulated post-treatment. Among the proteins that changed, there was an increase in vimentin, linked to wound healing, and a decrease in podocalyxin, associated with tissue damage. In serum, 206 proteins were found, with significant...
Kambayashi Y, Nemoto M, Ochi A, Kishi D, Ueno T, Tsujimura K, Bannai H, Kawanishi N, Ohta M, Suzuki T.In this study, equine intestinal enteroids (EIEs) were generated from the duodenum, jejunum, and ileum and inoculated with equine coronavirus (ECoV) to investigate their suitability as in vitro models with which to study ECoV infection. Immunohistochemistry revealed that the EIEs were composed of various cell types expressed in vivo in the intestinal epithelium. Quantitative reverse-transcription PCR (qRT-PCR) and virus titration showed that ECoV had infected and replicated in the EIEs. These results were corroborated by electron microscopy. This study suggests that EIEs can be novel in vitro ...
Manikantan V, Ripley NE, Nielsen MK, Dangoudoubiyam S.Parascaris spp. represent a significant threat to equine health worldwide, particularly in foals. The long-term survival of parasites in the host necessitates persistent modulation of the host immune response. Intercellular communication achieved through the exchange of molecules via extracellular vesicles (EVs) released from the parasite could be a crucial factor in this regard. This study aimed to isolate and characterize EVs released by adult male and female Parascaris worms and conduct a proteomic analysis to identify sex-specific proteins and potential immunomodulatory factors. Methods: L...
Venter M, Swanepoel R.West Nile virus (WNV) is widely distributed in South Africa, but since a few cases of neurological disease have been reported from this region, endemic lineage 2 strains were postulated to be of low virulence. Several cases of nonfatal encephalitis in humans as well as fatal cases in a foal, dog, and ostrich chicks have, however, been associated with lineage 2 WNV in South Africa. The pathogenesis of lineage 2 WNV strains was investigated using mouse neuroinvasive experiments, gene expression experiments, and genome sequence comparisons which indicated that lineage 2 strains that are highly pa...
Hoffmann C, Ellenberger C, Mattos RC, Aupperle H, Dhein S, Stief B, Schoon HA.This paper describes the histomorphological and immunohistochemical characterisation of phenotypic variations of endometrosis as well as potential etiological factors which may influence disease progression. In total, 779 endometrial biopsies were examined. These biopsies were taken in the breeding and non-breeding season (n=509), on defined days during the estrous cycle (n=70) and before and after experimentally induced bacterial endometritis (n=200). In addition to conventional histopathology, selected biopsies were investigated using alcianblue staining as well as immunohistochemical method...
Bian J, Khaychuk V, Angers RC, Fernández-Borges N, Vidal E, Meyerett-Reid C, Kim S, Calvi CL, Bartz JC, Hoover EA, Agrimi U, Richt JA, Castilla J....Adaptation of prions to new species is thought to reflect the capacity of the host-encoded cellular form of the prion protein (PrP) to selectively propagate optimized prion conformations from larger ensembles generated in the species of origin. Here we describe an alternate replicative process, termed nonadaptive prion amplification (NAPA), in which dominant conformers bypass this requirement during particular interspecies transmissions. To model susceptibility of horses to prions, we produced transgenic (Tg) mice expressing cognate PrP Although disease transmission to only a subset of infecte...
Dubey JP, Lindsay DS, Saville WJ, Reed SM, Granstrom DE, Speer CA.Equine protozoal myeloencephalitis (EPM) is a serious neurological disease of horses in the Americas. The protozoan most commonly associated with EPM is Sarcocystis neurona. The complete life cycle of S. neurona is unknown, including its natural intermediate host that harbors its sarcocyst. Opossums (Didelphis virginiana, Didelphis albiventris) are its definitive hosts. Horses are considered its aberrant hosts because only schizonts and merozoites (no sarcocysts) are found in horses. EPM-like disease occurs in a variety of mammals including cats, mink, raccoons, skunks, Pacific harbor seals, p...
Schaffartzik A, Hamza E, Janda J, Crameri R, Marti E, Rhyner C.Insect bite hypersensitivity (IBH) is an allergic dermatitis of the horse caused by bites of insects of the genus Culicoides and is currently the best characterized allergic disease of horses. This article reviews knowledge of the immunopathogenesis of IBH, with a particular focus on the causative allergens. Whereas so far hardly any research has been done on the role of antigen presenting cells in the pathogenesis of IBH, recent studies suggest that IBH is characterized by an imbalance between a T helper 2 (Th2) and regulatory T cell (T(reg)) immune response, as shown both locally in the skin...
Cantile C, Del Piero F, Di Guardo G, Arispici M.The pathologic and peroxidase immunohistochemical features of West Nile flavivirus (WNV) infection were compared in four horses from the northeastern United States and six horses from central Italy. In all 10 animals, there were mild to severe polioencephalomyelitis with small T lymphocyte and lesser macrophage perivascular infiltrate, multifocal glial nodules, neutrophils, and occasional neuronophagia. Perivascular hemorrhages, also noted macroscopically in two animals, were observed in 50% of the horses. In the four American horses, lesions extended from the basal nuclei through the brain st...
Hondalus MK.Inhalation of the soil-borne organism, Rhodococcus equi, can lead to a chronic and severe pyogranulomatous pneumonia in young horses and immunocompromised people. In addition, ulcerative colitis is a common sequela to infection in foals, and dissemination from the lung to other body sites is not uncommon in either the horse or man. Although the facultative intracellular bacterium is susceptible to neutrophil-mediated killing, it is able to resist innate macrophage defenses and establish residence within the intracellular environment of that phagocyte. Definitive virulence factors of R. equi ha...
Herholz C, Miserez R, Nicolet J, Frey J, Popoff M, Gibert M, Gerber H, Straub R.The incidence of a new, yet unassigned toxin type of Clostridium perfringens containing the genes for the alpha-toxin and the recently described beta2-toxin in horses with intestinal disorders is reported. The study included 18 horses suffering from typical typhlocolitis, 7 horses with atypical typhlocolitis, 16 horses with other intestinal disorders, and 58 horses without intestinal disease. In total, 20 samples of ingesta of the small and large intestines, five biopsy specimens of the intestinal wall, and 74 fecal samples were analyzed bacteriologically. C. perfringens isolates were typed fo...
David S, Abraham AM.Since the isolation of West Nile virus (WNV) in 1937, in Uganda, it has spread globally, causing significant morbidity and mortality. While birds serve as amplifier hosts, mosquitoes of the Culex genus function as vectors. Humans and horses are dead end hosts. The clinical manifestations of West Nile infection in humans range from asymptomatic illness to West Nile encephalitis. Methods: The laboratory offers an array of tests, the preferred method being detection of RNA and serum IgM for WNV, which, if detected, confirms the clinical diagnosis. Although no definitive antiviral therapy and vacc...
Muscatello G, Leadon DP, Klayt M, Ocampo-Sosa A, Lewis DA, Fogarty U, Buckley T, Gilkerson JR, Meijer WG, Vazquez-Boland JA.Infection with Rhodococcus (Corynebacterium) equi is a well-recognised condition in foals that represents a consistent and serious risk worldwide. The condition manifests itself primarily as one of pulmonary abscessation and bronchitis, hence the terminology of 'rattles' derived from its most obvious clinical sign, frequently terminal when first identified. This review addresses the clinical manifestation, bacteriology and pathogenesis of the condition together with recent developments providing knowledge of the organism in terms of virulence, epidemiology, transmission and immune responses. E...
Shirato K, Kimura T, Mizutani T, Kariwa H, Takashima I.West Nile (WN) virus is a mosquito-borne flavivirus that can cause lethal encephalitis in humans and horses. The WN virus endemic in New York City (NY) in 1999 caused large-scale mortality of wild birds that was not evident in endemic areas in other parts of the world, and the pathogenesis of the WN virus strain isolated in NY (NY strain) appears to differ from that of previously isolated strains. However, the pathogenesis of NY strain infection remains unclear. This study examined CC (RANTES/CCL5, MIP-1 alpha/CCL3, MIP-1 beta/CCL4) and CXC (IP-10/CXCL10, B lymphocyte chemoattractant (BLC/CXCL...
Komar N, Dohm DJ, Turell MJ, Spielman A.To determine whether eastern equine encephalitis (EEE) virus infection in starlings may be more fulminant than in various native candidate reservoir birds, we compared their respective intensities and durations of viremia. Viremias are more intense and longer lasting in starlings than in robins and other birds. Starlings frequently die as their viremia begins to wane; other birds generally survive. Various Aedes as well as Culiseta melanura mosquitoes can acquire EEE viral infection from infected starlings under laboratory conditions. The reservoir competence of a bird is described as the prod...
Hornig M, Briese T, Licinio J, Khabbaz RF, Altshuler LL, Potkin SG, Schwemmle M, Siemetzki U, Mintz J, Honkavuori K, Kraemer HC, Egan MF, Whybrow PC....In 1983, reports of antibodies in subjects with major depressive disorder (MDD) to an as-yet uncharacterized infectious agent associated with meningoencephalitis in horses and sheep led to molecular cloning of the genome of a novel, negative-stranded neurotropic virus, Borna disease virus (BDV). This advance has enabled the development of new diagnostic assays, including in situ hybridization, PCR and serology based on recombinant proteins. Since these assays were first implemented in 1990, more than 80 studies have reported an association between BDV and a wide range of human illnesses that i...
Fernandes F, Chen K, Ehrlich LS, Jin J, Chen MH, Medina GN, Symons M, Montelaro R, Donaldson J, Tjandra N, Carter CA.Phosphatidylinositol 4,5-biphosphate [PI(4,5)P(2) ], the predominant phosphoinositide (PI) on the plasma membrane, binds the matrix (MA) protein of human immunodeficiency virus type 1 (HIV-1) and equine infectious anemia virus (EIAV) with similar affinities in vitro. Interaction with PI(4,5)P(2) is critical for HIV-1 assembly on the plasma membrane. EIAV has been shown to localize in internal compartments; hence, the significance of its interaction with PI(4,5)P(2) is unclear. We therefore investigated the binding in vitro of other PIs to EIAV MA and whether intracellular association with comp...
Baer A, Lundberg L, Swales D, Waybright N, Pinkham C, Dinman JD, Jacobs JL, Kehn-Hall K.Venezuelan equine encephalitis virus (VEEV) is a previously weaponized arthropod-borne virus responsible for causing acute and fatal encephalitis in animal and human hosts. The increased circulation and spread in the Americas of VEEV and other encephalitic arboviruses, such as eastern equine encephalitis virus and West Nile virus, underscore the need for research aimed at characterizing the pathogenesis of viral encephalomyelitis for the development of novel medical countermeasures. The host-pathogen dynamics of VEEV Trinidad donkey-infected human astrocytoma U87MG cells were determined by car...
van der Geize R, Grommen AW, Hessels GI, Jacobs AA, Dijkhuizen L.Rhodococcus equi causes fatal pyogranulomatous pneumonia in foals and immunocompromised animals and humans. Despite its importance, there is currently no effective vaccine against the disease. The actinobacteria R. equi and the human pathogen Mycobacterium tuberculosis are related, and both cause pulmonary diseases. Recently, we have shown that essential steps in the cholesterol catabolic pathway are involved in the pathogenicity of M. tuberculosis. Bioinformatic analysis revealed the presence of a similar cholesterol catabolic gene cluster in R. equi. Orthologs of predicted M. tuberculosis vi...
Gilbertie JM, Schnabel LV, Hickok NJ, Jacob ME, Conlon BP, Shapiro IM, Parvizi J, Schaer TP.Bacterial invasion of synovial joints, as in infectious or septic arthritis, can be difficult to treat in both veterinary and human clinical practice. Biofilms, in the form of free-floating clumps or aggregates, are involved with the pathogenesis of infectious arthritis and periprosthetic joint infection (PJI). Infection of a joint containing an orthopedic implant can additionally complicate these infections due to the presence of adherent biofilms. Because of these biofilm phenotypes, bacteria within these infected joints show increased antimicrobial tolerance even at high antibiotic concentr...
Koop G, Vrieling M, Storisteanu DM, Lok LS, Monie T, van Wigcheren G, Raisen C, Ba X, Gleadall N, Hadjirin N, Timmerman AJ, Wagenaar JA, Klunder HM....Bicomponent pore-forming leukocidins are a family of potent toxins secreted by Staphylococcus aureus, which target white blood cells preferentially and consist of an S- and an F-component. The S-component recognizes a receptor on the host cell, enabling high-affinity binding to the cell surface, after which the toxins form a pore that penetrates the cell lipid bilayer. Until now, six different leukocidins have been described, some of which are host and cell specific. Here, we identify and characterise a novel S. aureus leukocidin; LukPQ. LukPQ is encoded on a 45 kb prophage (ΦSaeq1) found i...
Fielding CL, Higgins JK, Higgins JC, McIntosh S, Scott E, Giannitti F, Mete A, Pusterla N.Equine coronavirus (ECoV) is associated with clinical disease in adult horses. Outbreaks are associated with a low case fatality rate and a small number of animals with signs of encephalopathic disease are described. Objective: The aim of this study is to describe the epidemiological and clinical features of two outbreaks of ECoV infection that were associated with an high case fatality rate. Methods: 14 miniature horses and 1 miniature donkey testing fecal positive for ECoV from two related disease outbreaks. Methods: Retrospective study describing the epidemiological findings, clinicopatholo...
Ivester KM, Couëtil LL, Zimmerman NJ.Inhalant exposure to airborne irritants commonly encountered in horse stables is implicated in the pathogenesis of inflammatory airway disease (IAD) and recurrent airway obstruction (RAO), non-infectious, inflammatory pulmonary disorders that impact the health and performance of horses across all equine disciplines. IAD and RAO have overlapping clinical, cytological, and functional manifestations of the pulmonary response to organic dust and noxious gases encountered in the barn environment. Study of these diseases has provided important but incomplete understanding of the effect of air qualit...
Karikoski NP, McGowan CM, Singer ER, Asplin KE, Tulamo RM, Patterson-Kane JC.Laminitis in equids is a clinical syndrome usually associated with systemic disease. Endocrinopathies recently have been recognized as the most common cause of laminitis, with hyperinsulinemia playing a key role. Descriptions of laminitis-associated lesions have been confusing due to the wide range of experimental models used, failure of adequate clinical documentation for naturally occurring cases, lack of separate analysis of inflammatory and endocrinopathic laminitis, and uncertainty regarding normal morphological variation of lamellae. In this study, lamellar morphology and pathology were ...
Olstad K, Hendrickson EH, Carlson CS, Ekman S, Dolvik NI.To transect blood vessels within epiphyseal cartilage canals and observe whether this resulted in ischaemic chondronecrosis, an associated focal delay in enchondral ossification [osteochondrosis (OC)] and pathological cartilage fracture [osteochondrosis dissecans (OCD)] in the distal femur of foals, with potential translational value to the pathogenesis of juvenile osteochondritis dissecans (JOCD) in children. Methods: Ten Norwegian Fjord Pony foals were operated at the age of 13-15 days. Two vessels supplying the epiphyseal growth cartilage of the lateral trochlear ridge of the left distal fe...
Szóstek-Mioduchowska AZ, Lukasik K, Skarzynski DJ, Okuda K.Transforming growth factor (TGF)-β1 not only regulates cell growth, development, and tissue remodeling, but it also participates in the pathogenesis of tissue fibrosis. In the equine endometrium, the concentration of TGF-β1 is correlated with endometrosis (equine endometrial fibrosis). In other tissues, TGF-β1 induces differentiation of many cell types into myofibroblasts. These cells are characterized by α-smooth muscle actin (α-SMA) expression and an ability to deposit excessive amounts of extracellular matrix (ECM) components. The aim of the study was to determine whether TGF-β1 plays...
Kampen H, Holicki CM, Ziegler U, Groschup MH, Tews BA, Werner D.In 2018, West Nile virus (WNV) broke out for the first time in Germany, with continuation of the epidemic in 2019, involving birds, horses and humans. To identify vectors and characterize the virus, mosquitoes were collected in both years in zoological gardens and on a horse meadow immediately following the diagnosis of disease cases in birds and horses. Mosquitoes were identified and screened for WNV by qRT-PCR, with virus-positive samples being sequenced for the viral envelope protein gene. While no positive mosquitoes were found in 2018, seven mosquito pools tested positive for WNV in 2019 ...
Oue Y, Ishihara R, Edamatsu H, Morita Y, Yoshida M, Yoshima M, Hatama S, Murakami K, Kanno T.A new equine coronavirus was isolated from the feces of adult horses with pyrogenic and enteric disease. The disease outbreak was mainly observed among 2- to 4-year-old horses living in stables of a draft-horse racetrack in Japan. On comparing the isolated virus (isolate Tokachi09) with the equine coronavirus NC99 strain, no significant differences were observed in several biological properties such as hemagglutinating activity, antigenicity (in indirect immunofluorescence and neutralization tests), and one-step growth (in cell culture). The sequences of the nucleocapsid and spike genes of iso...
Fridell RA, Partin KM, Carpenter S, Cullen BR.Several members of the lentivirus family of complex retroviruses have been shown to encode proteins that are functionally equivalent to the Rev posttranscriptional regulatory protein of human immunodeficiency virus type 1 (HIV-1). Furthermore, the domain organization of HIV-1 Rev, featuring a highly basic N-terminal RNA binding domain and a leucin-rich C-terminal effector domain, has also been shown to be highly conserved among Rev proteins derived from not only the primate but also the ovine and caprine lentiviruses. Although it has therefore appeared highly probable that the lentivirus equin...
Ravichandran K, Anbazhagan S, Karthik K, Angappan M, Dhayananth B.Avian chlamydiosis is one of the important neglected diseases with critical zoonotic potential. Chlamydia psittaci, the causative agent, affects most categories of birds, livestock, companion animals, and humans. It has many obscured characters and epidemiological dimensions, which makes it unique among other bacterial agents. Recent reports on transmission from equine to humans alarmed the public health authorities, and it necessitates the importance of routine screening of this infectious disease. High prevalence of spill-over infection in equines was associated with reproductive losses. New...
Donadieu E, Bahuon C, Lowenski S, Zientara S, Coulpier M, Lecollinet S.West Nile virus (WNV) is a neurotropic flavivirus that cycles between mosquitoes and birds but that can also infect humans, horses, and other vertebrate animals. In most humans, WNV infection remains subclinical. However, 20%-40% of those infected may develop WNV disease, with symptoms ranging from fever to meningoencephalitis. A large variety of WNV strains have been described worldwide. Based on their genetic differences, they have been classified into eight lineages; the pathogenic strains belong to lineages 1 and 2. Ten years ago, Beasley et al. (2002) found that dramatic differences exist...
Kono Y, Hirasawa K, Fukunaga Y, Taniguchi T.Horses which had passed a few months to a few years asymptomatically after the last recurrence of equine infectious anemia (EIA) showed a typical febrile response after treatment with the immunosuppressive agent, dexamethasone (DM) or cyclophosphamide (CY). In horses showing a febrile response, EIA virus which had not been neutralized by neutralizing antibody previously produced was propagated. In DM-treated horses it disappeared from the blood soon after pyretolysis and antibody against the virus was produced promptly. In contrast, detectable viremia persisted in CY-treated horses for 10 to 8...
Pirie RS, Collie DD, Dixon PM, McGorum BC.Equine heaves is a naturally occurring organic dust-induced asthma characterized by airway neutrophilia, mucus hypersecretion and obstructive lung dysfunction. However, the relative role of different dust components in disease severity remains unclear. Objective: This study investigated the relative contribution of inhaled endotoxin and organic dust particulates (mainly mould spores) in inducing heaves in heaves-susceptible horses. Methods: Control and heaves-susceptible horses received inhalation challenges with hay dust suspension (HDS) before and after lipopolysaccharide (LPS) depletion. He...
