The study of diseases in horses encompasses a wide range of conditions affecting equine health, including infectious diseases, metabolic disorders, and genetic abnormalities. These diseases can impact various systems within the horse, such as respiratory, gastrointestinal, and musculoskeletal systems, and can lead to significant health challenges. Research in this area focuses on understanding the pathophysiology, diagnosis, prevention, and treatment of equine diseases. Common diseases studied include equine influenza, equine herpesvirus, and laminitis. This page provides access to peer-reviewed research studies and scholarly articles that explore the etiology, clinical presentation, and management strategies of diseases in horses, contributing to the advancement of equine veterinary medicine.
Tanabe M, Kelly R, de Lahunta A, Duffy MS, Wade SE, Divers TJ.Parasitic granulomatous eosinophilic inflammation was observed in the central nervous system (CNS) of a 6-month-old Arabian colt from New York state. Inflammation was associated with eggs, larvae, and adult nematodes in the cerebellum. Nematodes had histological characteristics of the superfamily Metastrongyloidea. The presence of dorsal-spined larvae in the CNS was further indicative of infection with a nematode in the family Protostrongylidae. Infections were most compatible with Parelaphostrongylus tenuis but specific diagnosis was not possible. This is the first definitive report of a prot...
Brown DL, Anderson M, Cullen JM.Mesenchymal hamartoma of the liver is a rare congenital disorder of biliary tract development. During the necropsy of a late-term equine fetus, a markedly enlarged liver of more than two times normal weight was found. Light microscopic review revealed that the normal hepatic parenchyma had been obliterated, replaced, and expanded by abnormal bile ducts surrounded by abundant, myxoid stroma. The lesion was diagnosed as a mesenchymal hamartoma. Small portions of the liver had bridging septa of fibrosis and proliferations of small-caliber abnormal bile ducts, resembling another congenital biliary...
Dietzel J, Kuhrt H, Stahl T, Kacza J, Seeger J, Weber M, Uhlig A, Reichenbach A, Grosche A, Pannicke T.Borna disease (BD) is a fatal disorder of horses, often characterized by blindness. Although degeneration of retinal neurons has been demonstrated in a rat model, there are controversial data concerning whether a similar degeneration occurs in the retina of infected horses. To investigate whether BD may cause degeneration of photoreceptors and possibly of other neuronal cells at least at later stages of the disease, we performed a detailed quantitative morphologic study of retinal tissue from Borna-diseased horses. BD was diagnosed by detection of pathognomonic Joest-Degen inclusion bodies in ...
Pei Y, Parreira V, Nicholson VM, Prescott JF.Rhodococcus equi can cause severe or fatal pneumonia in foals as well as in immunocompromised animals and humans. Its ability to persist in macrophages is fundamental to how it causes disease, but the basis of this is poorly understood. To examine further the general application of a recently developed system of targeted gene mutation and to assess the importance of different genes in resistance to innate immune defenses, we disrupted the genes encoding high-temperature requirement A (htrA), nitrate reductase (narG), peptidase D (pepD), phosphoribosylaminoimidazole-succinocarboxamide synthase ...
Moyaert H, Haesebrouck F, Baele M, Picavet T, Ducatelle R, Chiers K, Ceelen L, Decostere A.Recently, a new enterohepatic Helicobacter species, H. equorum, was isolated from faecal samples of two clinically healthy horses. At the onset of this study, nothing was known about the prevalence of this organism in horses, nor was there any information available on the possible zoonotic character of this agent. This study aimed to determine the prevalence of H. equorum in faecal samples from equine and human origin. Therefore, faecal samples of 120 healthy privately owned horses, 227 healthy riding-school horses and 239 hospitalised horses were screened for H. equorum-DNA by means of a PCR ...
Morales MA, Barrandeguy M, Fabbri C, Garcia JB, Vissani A, Trono K, Gutierrez G, Pigretti S, Menchaca H, Garrido N, Taylor N, Fernandez F, Levis S....West Nile virus (WNV) was isolated from the brains of 3 horses that died from encephalitis in February 2006. The horses were from different farms in central Argentina and had not traveled outside the country. This is the first isolation of WNV in South America.
Bagcigil FA, Moodley A, Baptiste KE, Jensen VF, Guardabassi L.beta-Lactams and macrolides are important antibiotics for treatment of staphylococcal infections in both humans and animals. The aim of the study was to investigate the occurrence, species distribution and clonality of methicillin- and erythromycin-resistant staphylococci in the nasal cavity of dogs, horses, pigs, and cattle in Denmark. Nasal swabs were collected from a total of 400 animals, including 100 individuals of each species. Methicillin- and erythromycin-resistant staphylococci were isolated on selective media, identified by 16S rDNA sequencing, and typed by pulsed field gel electroph...
Olds AM, Stewart AA, Freeman DE, Schaeffer DJ.To determine the rate of development of septic arthritis after elective arthroscopy and evaluate associations between various factors and development of this complication in horses. Methods: Retrospective case series. Methods: 682 horses that underwent arthroscopic procedures at the University of Illinois Veterinary Teaching Hospital from 1994 to 2003. Methods: Information pertaining to signalment, joints treated, whether antimicrobials were administered, and development of postoperative septic arthritis was collected from medical records. Horses with a primary problem of septic arthritis or w...
Murphy BA, Vick MM, Sessions DR, Cook RF, Fitzgerald BP.Peripheral clocks receive timing signals from the master mammalian pacemaker in the suprachiasmatic nucleus (SCN) and function to adaptively anticipate daily changes that influence local physiology. Evidence suggests that peripheral immune activation may act as a resetting signal for circadian clocks in peripheral tissues. We wished to investigate whether acute systemic inflammation could synchronize clock gene expression in equine peripheral blood, a tissue that does not normally oscillate in this species. We report that in vivo administration of lipopolysaccharide (LPS) results in significan...
Güleğen E, Cirak VY.Lice infestations of horses occur mainly during winter months and are characterized by severe pruritus and an unkempt coat. Two lice have been described for equines namely Bovicola (Damalinia) equi and Haemotopinus asini. There is a scarcity of data on the occurrence and prevalence rates of these horse pathogens in Turkey. This paper reports a thoroughbred farm, in which two horses were found to be infested with B. equi. The horses were treated with propoxur and no lice or nymphs could be found after treatment for10 days.
Cribb NC, Cote NM, Bouré LP, Peregrine AS.To retrospectively evaluate the medical and surgical records of horses with acute small intestinal obstructions associated with Parascaris equorum infection; to describe the gastrointestinal lesions; and to determine the outcome of cases with such lesions. Methods: Records of 25 horses with acute small intestinal obstruction associated with P. equorum between 1985 and 2004 were reviewed to determine signalment, history, physical examination, surgical or post-mortem findings, and outcome. Results: All horses except one were less than 12 months old. Standardbreds were over-represented in the pop...
Watts AE, Fubini SL, Vernier-Singer M, Golkowski C, Shin S, Todhunter RJ.To determine the effect of nonthermal plasma on Staphylococcus aureus, fibroblasts in monolayer culture, and clean and contaminated skin explants. Methods: Normal skin from euthanized horses. Methods: S aureus organisms were plated and treated with nonthermal plasma followed by bacterial culture to assess viability. Fibroblasts in monolayer culture and the epidermal and dermal surfaces of clean and S aureus-contaminated skin explants were treated. The effects of distance and duration on the response to treatment were compared. Results: Compared with controls, treatment with nonthermal plasma r...
Kornilova OA.Endobiotic ciliates of native Yakut horse are investigated. 57 ciliate species have been found. From 17 up to 43 species of ciliates have been revealed in each host specimen. The specimens of Alloiozona trizona Hsiung, 1930 and Triadinium caudatum Fiorentini, 1890 were present in 100 % of the horses. The endemic genus and species of allantosomides, Strelkowella urunbasiensis Kornilova, 2004, has been found in 11 horses. Allantoxena japonensis (Imai, 1979) and Cycloposthium ishikawai Gassovsky, 1919 being recorded previously in Japan only were found for the first time in Russia. The species Cyc...
Norrdin RW, Stover SM.Mechanical overload leads to a common arthrosis in the metacarpal condyle of the fetlock joint of racehorses. This is usually asymptomatic but severe forms can cause lameness. Subchondral bone failure is often present and the predictability of the site provided an opportunity to study of the progression of bone failure from microcracks to actual collapse of subchondral bone. Twenty-five fetlock condyles from racehorses with various stages of disease were selected. Stages ranged from mild through severe subchondral bone sclerosis, to the collapse of bone and indentation or loss of cartilage kno...
Masset A, Staszyk C, Gasse H.Corrosion casts of blood vessels in the periodontium of cheek teeth from eight horses were observed three-dimensionally with a dissection microscope. Selected specimens were examined in a scanning electron microscope. Periodontal blood vessels communicated with those from the gingiva, the alveolar bone, and the apical region. In the upper jaw, there were anastomoses with the blood vessels of the mucosa of the maxillary sinus. The periodontal vascular system was organized in two or three layers. The peripheral layer was mainly composed of large venules, the inner one consisted of capillaries. I...
Barsotti G, Sgorbini M, Nardoni S, Corazza M, Mancianti F.The fungal flora of the normal conjunctival fornix has been described for many animal species (Urban et al., 1972; Samuelson et al., 1984; Moore et al., 1988; Davidson et al., 1994; Cooper et at, 2001) and many environmental factors, such as age, geography, habitat and husbandry are reported to influence its composition (Samuelson at at, 1984; Andrew et at, 2003). Equine keratomycosis can be caused by saprophytic fungi following an underlying corneal pathology or improper use of topical antibiotics and/or topical corticosteroids (Andrew at al., 1998; Brooks, 1999). Knowledge of differences in ...
Ul Hasan M, Muhammad G, Gutierrez C, Iqbal Z, Shakoor A, Jabbar A.A cross-sectional study has been carried out in order to determine the prevalence of Trypanosoma evansi infection in susceptible hosts in the Punjab region (Pakistan). A total of 170 equines and 150 dromedary camels were examined. Five (3.3%) and 6 (4%) camels were positive at parasitological and serological examination, respectively. None of the equines tested positive at any method. These results seem to indicate that T. evansi infection has a relatively low prevalence in the Punjab region. However, efforts must be done in order to establish control measures in affected herds and avoid disse...
Lillini E, Macrì G, Proietti G, Scarpulla M.Ixodes ricinus (I. ricinus) is one of the vectors of Anaplasma phagocytophilum (A. phagocytophilum) in Europe, in which rates of infection range from 1.9% to 34%. In 1998, human granulocytic ehrlichiosis-like (HGE-like) Ehrlichia DNA was detected in Italy, by PCR technique in one I. ricinus nymph out of 55 ticks that were examined. In 1996, 6.3% of 310 human sera in high-risk subjects from Italy were found positive for antibodies to Ehrlichia phagocytophila (E. phagocytophila). In the same year, the authors reported the first case of equine granulocytic ehrlichiosis. In 1997, only 2 out of 563...
McCue PM, Roser JF, Munro CJ, Liu IK, Lasley BL.The granulosa cell tumor is the most common ovarian tumor in mares. A clinical diagnosis can be made based on the presence ofa unilaterally enlarged ovary and a small inactive contralateral ovary. Endocrine testing may be beneficial to confirm a diagnosis. Surgical removal of the tumor eliminates the adverse effect on pituitary function and results in resumption of follicular development and ovulation in the opposite ovary over time.
Bucca S.Identification of a compromised pregnancy in the mare requires the exhaustive collection of a database that includes past and recent reproductive and medical histories and a variety of parameters indicating fetal distress and possibly suggesting neonatal compromise.Judicious interpretation of findings and serial recording of data throughout gestation may help in the early detection of abnormal fetomaternal exchange pathways. Some sources of compromise may be identified, and the impact on fetomaternal well-being maybe calculated. Appropriate preventive or corrective measures may then be impleme...
Hodavance MS, Ralston SL, Pelczer I.Metabonomic analysis is a powerful tool for identifying and characterizing metabolic disorders, for example type 2 diabetes and the metabolic syndrome. Nuclear magnetic resonance (NMR) spectroscopy is an essential tool for such analysis, with special benefits. The review assesses the current status and potential of NMR-based metabonomics of type 2 diabetes. The horse is proposed as a possible model for studying this condition and disease. Some examples are shown of horse blood analyses by NMR.
Apprich V, Spergser J, Rosengarten R, Stanek C.The effects of two dermatophytes (Microsporum gypseum and Trichophyton mentagrophytes) and four moulds (Scopulariopsis brevicaulis, Alternaria alternata, Geotrichum candidum and Penicillium spp.) on living keratinocyte cultures were examined in vitro using primary human keratinocytes. Rates of apoptosis of infected cells were determined using a colorimetric TUNEL system which detects the characteristic nuclear DNA fragmentation of apoptotic cells. The cytotoxicity of the individual fungi was tested by quantitatively measuring cytosolic enzyme lactate dehydrogenase, released upon cell lysis, in...
Spoormakers TJ, Ensink JM, Goehring LS, Koeman JP, Ter Braake F, van der Vlugt-Meijer RH, van den Belt AJ.The occurrence of unexpectedly high numbers of horses with neurological signs during two outbreaks of strangles required prompt in-depth researching of these cases, including the exploration of magnetic resonance imaging (MRI) as a possible diagnostic technique. Objective: To describe the case series and assess the usefulness of MRI as an imaging modality for cases suspected of space-occupying lesions in the cerebral cavity. Methods: Four cases suspected of suffering from cerebral damage due to Streptococcus equi subsp. equi infection were examined clinically, pathologically, bacteriologically...
Wagner B, Overesch G, Sheoran AS, Holmes MA, Richards C, Leibold W, Radbruch A.Previous restriction analysis of cloned equine DNA and genomic DNA of equine peripheral blood mononuclear cells had indicated the existence of one c epsilon, one c alpha and up to six c gamma genes in the haploid equine genome. The c epsilon and c alpha genes have been aligned on a 30 kb DNA fragment in the order 5' c epsilon-c alpha 3'. Here we describe the alignment of the equine c mu and c gamma genes by deletion analysis of one IgM, four IgG and two equine light chain expressing heterohybridomas. This analysis establishes the existence of six c gamma genes per haploid genome. The genomic a...
Mullaney TP, Brown CM.Newborn Shetland foals died of acute hepatic failure following oral administration of approximately 16 mg/kg body weight ferrous fumarate. Lesions in these foals were indistinguishable from lesions in foals given an oral digestive inoculant containing ferrous fumarate and were also similar to the syndrome characterised as 'toxic hepatopathy' in foals in the United States in 1983. We conclude that foals are susceptible to toxicity from low doses of iron compounds in the first few days of life. Vitamin E and selenium deficiency may contribute to this susceptibility.
Colles CM.Twenty horses suffering from navicular disease were treated with warfarin given orally. The dosage was to effect, to give a 2 to 4 second prolongation of the one stage prothrombin time (OSPT). Dosage was initially at a rate of 0.018 mg/kg, changing the dose by amounts of 20 per cent until the required dose was achieved. Final dose rates varied from 0.012 mg/kg to 0.75 mg/kg. All the cases treated received warfarin daily throughout the trial. Seventeen of the animals became sound and the remaining 3 showed a marked improvement in their gait. The mean of the ages of the horses was 7.5 years, the...
Ruitenberg KM, Love DN, Gilkerson JR, Wellington JE, Whalley JM.We have shown previously that equine herpesvirus 1 (EHV-1) glycoprotein D (gD) DNA elicited protective immune responses against EHV-1 challenge in murine respiratory and abortion models of EHV-1 disease. In this study, 20 horses, all with pre-existing antibody to EHV-4 and two with pre-existing antibody to EHV-1, were inoculated intramuscularly with three doses each of 50, 200 or 500microg EHV-1 gD DNA or with 500microg vector DNA. In 8 of 15 horses, inoculation with EHV-1 gD DNA led to elevated gD-specific antibody and nine horses exhibited increased virus neutralising (VN) antibody titres co...
Anzai T, Wada R, Nakanishi A, Kamada M, Takai S, Shindo Y, Tsubaki S.The diagnostic value of tracheal aspiration was evaluated through comparison with other diagnostic methods using an experimental model of Rhodococcus equi (R. equi) pneumonia in foals. Pneumonia was induced by spraying of the virulent R. equi strain ATCC 33701 into the trachea of foals. All foals developed fever from 11 to 16 days after bacterial inoculation. One foal was euthanized on day 26 due to its poor prognosis, and other foals euthanized on day 43. During the experiment, some tests for diagnosis of Rhodococcus equi pneumonia such as tracheal aspiration, radiography, serodiagnosis and f...
Tanimoto T, Yamasaki S, Ohtsuki Y.A well-demarcated solitary splenic mass (20 x 20 x 15 cm in size) containing hemorrhagic and necrotic foci was observed in a 4-year-old Thoroughbred stallion. Histologically, the mass consisted of lymphoma cells of the diffuse large non-cleaved type, with a high mitotic index and scattered macrophages that formed a starry sky pattern. The lymphoma cells revealed diffuse positivity for acid phosphatase and alpha naphthyl butyrate esterase, and were also positive for intracytoplasmic IgM on occasion, and mostly for proliferating cell nuclear antigen. Ultrastructural examination revealed moderate...
Wilkins PA.Equine neonatal intensive care units have expanded knowledge and understanding of the normal and abnormal physiology of the equine neonate, resulting in successful treatment of critically ill equine neonates. The overall survival rate has increased tremendously since the early 1980s, from a little more than 50% to 80% or more for most facilities. The severely septic foal and the very premature foal still remain large treatment challenges, but less severely septic foals and foals challenged by adverse peripartum events such as dystocia and placentitis are surviving to hospital discharge and per...
Gericota B, Aleman M, Kozikowski TA, Pesavento P, Bollen AW, Madigan JE, Higgins RJ.A 4-year-old Dutch warmblood mare was presented with a 10-month history of ataxia and proprioceptive deficits. Computed tomography defined a large, non-contrast enhancing mass in the left cerebral hemisphere. Necropsy examination revealed a tumour that effaced much of the piriform and temporal lobes. Microscopically the lesion was classified as a grade IV glioblastoma with an oligodendroglial component (GBM-O). The tumour was composed of highly pleomorphic cells organized in different patterns within a fibrillary stroma. There were multiple foci of necrosis. At the periphery of the tumour neop...
Yu F, Chen Y, Liu B, Wang T, Ding Z, Yi Z, Zhu Y, Li J.Health monitoring is critical for newborn animals due to their vulnerability to diseases. Urine can be not only a useful and non-invasive tool (free-catch samples) to reflect the physiological status of animals but also to help monitor the progression of diseases. Proteomics involves the study of the whole complement of proteins and peptides, including structure, quantities, functions, variations and interactions. In this study, urinary proteomics of neonatal donkeys were characterized and compared to the profiles of adult donkeys to provide a reference database for healthy neonatal donkeys. T...
Hahn CN, Matiasek K, Syrja P, Jokinen TS, Macintyre N, Tulamo RM.A neurological disorder characterised by pelvic limb metatarsophalangeal joint extensor paresis has been observed in numerous horses in Scandinavia for the last decade. Very little has been formally reported and there have been no detailed assessments of the neurological signs or neuropathological lesions. Objective: To describe the epidemiological and pathological features of an outbreak of 'Scandinavian knuckling syndrome' in a riding stable in southern Finland. Methods: Clinical neurological examination of 4 cases and neuropathological assessment of tissues of one case were performed. Resul...
Wooldridge AA, Seahorn TL, Williams J, Taylor HW, Oliver JL, Kim DY, Vicek TJ.A 2-year-old quarter horse gelding presented for evaluation of polyuria and polydipsia. Azotemia was detected on serum chemistry profile. Small, misshapen, hyperechoic kidneys with decreased corticomedullary demarcation, hydronephrosis, and a right nephrolith were noted ultrasonographically. The diagnosis of end-stage kidney disease and dysplasia was made histopathologically using ultrasound-guided biopsy. Two ureteroliths were found in the right ureter via cystoscopy, and a nephrolith was seen in the right kidney at necropsy. Clinical, ultrasonographic, and pathologic features of equine uroli...
Collobert C, Bernard N, Lamidey C.The umbilical skin and ligamentum nuchae of 368 horses were examined post mortem for Onchocerca species. Only four of the horses were infected and pathological changes were observed on the skin of two of them. Thelazia lacrimalis was recovered from 38 (10.3 per cent) of the horses, and animals aged six months to two years were more frequently infected. No ocular lesions were observed. The prevalences of these two nematodes were low when compared with the infection rates reported in the United Kingdom and North America.
Evans TJ.During equine gestation, ergopeptine alkaloid exposure is not uncommon, and pregnant mares are particularly sensitive to the endocrine disruptive effects of these compounds on lactogenesis and steroidogenesis. Agalactia, prolonged gestation, abortion, dystocia, and placental and fetal abnormalities are all clinical manifestations of changes in the endocrine milieu induced by the ingestion of ergopeptine alkaloid-contaminated feedstuffs by mares during late gestation. An understanding of the endocrine disruptive effects of gestational exposure to ergopeptine alkaloids is necessary for the diagn...
Schediwy M, Mevissen M, Demuth D, Kupper J, Naegeli H.This retrospective study evaluated the frequency, etiology, therapy and prognosis of animal poisoning registered from 2003 to 2012. The relevant cases reported to the Swiss Toxicological Information Center (STIC) were compared with those from previously examined periods. Human medicines not approved for animals and pesticides represented the most common causes of poisoning in dogs. Novel cases occurred as a consequence of the exposure of dogs to ricinus fertilizers, grape residues from wineries, pepper lachrymatory spray and dry bouillon. Cats are still freequently poisoned by pyrethroid drugs...
Ringger NC, Edens L, Bain P, Raskin RE, Larock R.A 5-year-old Thoroughbred mare presented with a 4 week history of weight loss, fever and leukopenia. Rectally, a large active foetus, thickened spleen and an abdominal mass were palpated. Leukopenia, mild anaemia, marked thrombocytopenia and hyperfibrinogenaemia were found. Cytology and cytochemical staining of a bone marrow aspirate supported a diagnosis of acute myelogenous leukaemia. The mare deteriorated despite medical therapy and was humanely euthanased.
van Hoogmoed L, Yarbrough TB, Lecouteur RA, Hornof WJ.A 6 week old American Paint filly was admitted for evaluation of a dorsal thoracic mass suspected to be a meningocele. The diagnosis was confirmed by plain and contrast enhanced computed tomography. Surgical repair was performed by dissection of the base of the meningocele followed by ligation. No postoperative complications occurred. Contrast enhanced computed tomography was useful to confirm the diagnosis of meningocele and rule out a meningomyelocele.
van der Meulen KM, Nauwynck HJ, Pensaert MB.Equine herpesvirus-1 (EHV-1) is an important pathogen of horses, causing abortion and nervous system disorders, even in vaccinated animals. During the cell-associated viremia, EHV-1 is carried by peripheral blood mononuclear cells (PBMC), mainly lymphocytes. In vitro, monocytes are the most important fraction of PBMC in which EHV-1 replicates, however, mitogen stimulation prior to EHV-1 infection increases the percentage of infected lymphocytes. The role of the cell cycle in viral replication and the role of cluster formation in cell-to-cell transmission of the virus were examined in mitogen-s...