Neurological diseases in horses encompass a range of disorders affecting the central and peripheral nervous systems. These conditions can arise from various etiologies, including infectious agents, genetic predispositions, trauma, or metabolic imbalances. Common neurological diseases in horses include equine protozoal myeloencephalitis (EPM), equine herpesvirus myeloencephalopathy (EHM), and cervical vertebral stenotic myelopathy (CVSM), also known as wobbler syndrome. Clinical signs associated with these diseases may include ataxia, weakness, altered gait, and changes in behavior or mental status. Diagnosis typically involves a combination of clinical evaluation, imaging techniques, and laboratory testing. This page compiles peer-reviewed research studies and scholarly articles that investigate the pathophysiology, diagnostic approaches, and treatment options for neurological diseases in equine populations.
Finno CJ, Estell KE, Winfield L, Katzman S, Bordbari MH, Burns EN, Miller AD, Puschner B, Tran CK, Xu L.Equine neuroaxonal dystrophy/equine degenerative myeloencephalopathy (eNAD/EDM) is a neurodegenerative disorder affecting genetically predisposed foals maintained on an α-tocopherol (α-TOH) deficient diet. Currently no antemortem diagnostic test for eNAD/EDM is available. Objective: Because α-TOH deficiency is associated with increased lipid peroxidation, it was hypothesized that F2 -isoprostanes (F2 IsoP), F4 -neuroprostanes (F4 NP) and oxysterols derived from free radical oxidation would be increased in the cerebrospinal fluid (CSF) and neural tissue of eNAD/EDM affected horses and could ...
Aleman M, Costa LRR, Crowe C, Kass PH.Neuroglycopenia refers to a shortage of glucose in the brain resulting in neuronal dysfunction and death if left untreated. Presumed neuroglycopenia has not been described in horses. Objective: To report neurological signs in horses with presumed neuroglycopenia as the result of severe hypoglycemia. Methods: Ninety horses (hours to 28 years of age) diagnosed with hypoglycemia (blood glucose concentration < 75 mg/dL [< 4.2 mmol/L]). Methods: Retrospective study. Electronic medical records were searched. Signalment, history, complaint, clinical signs, laboratory findings including CSF analysis, ...
Bedenice D, Johnson AL.EPM, CVSM, and EDM are currently recognized as the 3 most common neurologic diseases in US horses, with the latter 2 conditions being most prevalent in young animals. Moreover, horses competing at shows and performance events are at greater risk for exposure to highly contagious, neurologic EHV-1 outbreaks. A clinical diagnosis of any neurologic disease should be based on a careful history, complete neurologic examination, and appropriate diagnostic testing and interpretation. However, mild or early neurologic signs can often mimic or be mistaken for an orthopedic condition when horses present...
Swinebroad EL.Given the variable clinical signs attributed to Borrelia burgdorferi, including infectious arthritis, neurologic disease, and behavioral changes, B burgdorferi is an important differential for decreased performance in sport horses. The primary vectors (Ixodes tick species) are expanding their range and thus Borrelia species are located in a wider area, making exposure more likely. Due to regionally high seroprevalence and vague clinical signs, diagnosis of Lyme disease in the horse is believed overestimated. Antibiotics are first-line treatment of confirmed Lyme disease. A single positive sero...
Estell K, Spriet M, Phillips KL, Aleman M, Finno CJ.Previously published myelographic studies do not report findings at the junction between the seventh cervical (C7) and first thoracic vertebrae (T1). Modern digital radiographic equipment allows improved visualization of C7-T1. Based on clinical experience, we hypothesized that 50% reduction of the dorsal myelographic column or 20% reduction of the dural diameter, criteria commonly used as a supportive finding for spinal cord compression in the cervical vertebral column, do not apply at C7-T1. A myelographic study was performed on 12 healthy, neurologically normal horses. Our hypothesis was co...
Hemmings A, Parker MO, Hale C, McBride SD.Spontaneous stereotypic behaviours are repetitive, compulsive, topographically invariant response patterns commonly observed in captive or domestic animals, which have been linked to dysfunction of basal ganglia input/output pathways. There is evidence that endogenous opioids play a key regulatory role in basal ganglia direct and indirect pathways, but their precise role, both causally and functionally, in spontaneous stereotypic behaviour is unclear. Here we examined the profile of mu- and delta-opioid receptors (density [Bmax] and affinity [Kd]) of basal ganglia structures in stereotypy (n...
Carrera JP, Bagamian KH, Travassos da Rosa AP, Wang E, Beltran D, Gundaker ND, Armien B, Arroyo G, Sosa N, Pascale JM, Valderrama A, Tesh RB....Members of the genera (family ) and (family ) are important zoonotic human and equine etiologic agents of neurologic diseases in the New World. In 2010, an outbreak of Madariaga virus (MADV; formerly eastern equine encephalitis virus) and Venezuelan equine encephalitis virus (VEEV) infections was reported in eastern Panamá. We further characterized the epidemiology of the outbreak by studying household contacts of confirmed human cases and of equine cases with neurological disease signs. Serum samples were screened using a hemagglutination inhibition test, and human results were confirmed u...
Draper ACE, Piercy RJ.Recurrent Laryngeal Neuropathy (RLN) is a highly prevalent and predominantly left-sided, degenerative disorder of the recurrent laryngeal nerves (RLn) of tall horses, that causes inspiratory stridor at exercise because of intrinsic laryngeal muscle paresis. The associated laryngeal dysfunction and exercise intolerance in athletic horses commonly leads to surgical intervention, retirement or euthanasia with associated financial and welfare implications. Despite speculation, there is a lack of consensus and conflicting evidence supporting the primary classification of RLN, as either a distal ("d...
Fortuna PRJ, Bielefeldt-Ohmann H, Ovchinnikov DA, Wolvetang EJ, Whitworth DJ.Horses are susceptible to a number of neurotropic viruses, including West Nile virus (WNV), which is a pathogen of global significance in both horses and humans. However, there are no in vitro models with which to study infectious neuropathic diseases in the horse. In an effort to redress this, we have generated neurons from equine induced pluripotent stem cells (equiPSCs) that express a range of cortical neuron-specific markers, in addition to the membrane-bound ligand ephrin B3, which plays an important role in axon guidance as well as functioning as the receptor through which henipaviruses,...
It is currently unknown if the intrathecal administration of a high dose of allogeneic mesenchymal stem cells (MSCs) is safe, how MSCs migrate throughout the vertebral canal after intrathecal administration, and whether MSCs are able to home to a site of injury. The aims of the study were: 1) to evaluate the safety of intrathecal injection of 100 million allogeneic adipose-derived MSCs (ASCs); 2) to assess the distribution of ASCs after atlanto-occipital (AO) and lumbosacral (LS) injection in healthy horses; and 3) to determine if ASCs homed to the site of injury in neurologically diseased hor...
Schale S, Howe D, Yeargan M, Morrow JK, Graves A, Johnson AL.Infection by 2 or more protozoa is linked with increased severity of disease in marine mammals with protozoan encephalitis. Objective: To assess whether horses with equine protozoal myeloencephalitis (EPM) caused by Sarcocystis neurona also have evidence of infection with Neospora hughesi or Toxoplasma gondii. We hypothesized that horses with EPM would be more likely than horses with cervical vertebral stenotic myelopathy (CVSM) to be positive for antibodies to multiple protozoan parasites. Methods: One hundred one horses with neurologic disease: 49 with EPM and 52 with CVSM. Methods: Case rev...
Kurz JP, Schoenhals KE, Hullinger GA, Van Wettere AJ.Syringomyelia is a form of myelodysplasia defined by the formation of one or more fluid-filled cavities within the spinal cord that do not communicate with the central canal. The defect may be congenital or acquired. Clinical signs correlate to the segment of spinal cord affected and include pain, paresis, proprioceptive deficits, alterations in sensation, scoliosis, and autonomic dysfunction. This report describes the clinical and pathologic changes in a case of acquired syringomyelia in a 10-year-old American Paint Horse mare. The horse had a six-week history of progressive proprioceptive de...
Zoll WM, Prakoso D, Dark M, Liu J, Stockdale-Walden H, Long MT.Eosinophils within the central nervous system are abnormal and are usually associated with fungal or parasitic infections in horses. Causative agents include Halicephalobus gingivalis, Sarcocystis neurona, and Neospora hughesi. Confirmation of these organisms via specific testing is typically not performed, and final diagnoses are often presumptive. With molecular technology, many of these organisms can now be confirmed. This is important for emerging and zoonotic pathogens, including Angiostrongylus cantonensis, an emerging parasite of interest in the southeastern United States. We retrospect...
Howe DK, Yeargan M, Simpson L, Dangoudoubiyam S.Sarcocystis neurona is a member of the important phylum Apicomplexa and the primary cause of equine protozoal myeloencephalitis (EPM). Moreover, S. neurona is the best-studied species in the genus Sarcocystis, one of the most successful parasite taxa, as virtually all vertebrate animals may be infected by at least one species. Consequently, scientific investigation of S. neurona will aid in the control of EPM and neurologic disease in sea mammals, while also improving our understanding of a prominent branch on the apicomplexan phylogenetic tree. These protocols describe methods that expand the...
Johnson AL, Johnstone LK, Stefanovski D.The accuracy of the Lyme multiplex assay for the diagnosis of neuroborreliosis in horses is unknown. Objective: To describe Lyme multiplex results in horses with a postmortem diagnosis of neuroborreliosis. The hypothesis was that paired serum and cerebrospinal fluid (CSF) results and a CSF : serum ratio would allow differentiation of horses with neuroborreliosis from those with other neurologic diseases. Methods: Ninety horses that had neurologic examinations, serum and CSF Lyme multiplex analyses, and postmortem examination of the nervous system performed. Methods: Retrospective study. Data...
Aman JE, Valberg SJ, Elangovan N, Nicholson A, Lewis SS, Konczak J.Cerebellar Purkinje cell axonal degeneration has been identified in horses with shivering but its relationship with abnormal hindlimb movement has not been elucidated. Objective: To characterise surface electromyographic (sEMG) hindlimb muscle activity in horses with shivering, correlate with clinical scores and examine horses for Purkinje axonal degeneration. Methods: Descriptive controlled clinical study. Methods: The hindlimb of seven shivering and six control draught horses were clinically scored. Biceps femoris (BF), vastus lateralis (VL), tensor fasciae latae and extensor digitorum longu...
Bryant NA, Wilkie GS, Russell CA, Compston L, Grafham D, Clissold L, McLay K, Medcalf L, Newton R, Davison AJ, Elton DM.Equine herpesvirus 1 (EHV-1) causes respiratory disease, abortion, neonatal death and neurological disease in equines and is endemic in most countries. The viral factors that influence EHV-1 disease severity are poorly understood, and this has hampered vaccine development. However, the N752D substitution in the viral DNA polymerase catalytic subunit has been shown statistically to be associated with neurological disease. This has given rise to the term "neuropathic strain," even though strains lacking the polymorphism have been recovered from cases of neurological disease. To broaden understan...
Mirra A, Klopfenstein Bregger MD, Levionnois OL.A 15-year-old Selle Francais gelding was presented to the equine referral hospital for treatment of a left guttural pouch mycosis previously diagnosed. After induction, the horse was shortly hoisted by all four feet, moved on a padded surgical table, and positioned in right lateral recumbency. In order to reduce the risk of bleeding during surgical manipulation of the carotid and maxillary arteries, a mean arterial pressure between 60 and 70 mmHg was targeted. After surgery, the horse was moved in a padded recovery box keeping the same lateral recumbency. Four unsuccessful attempts were perf...
McGorum BC, Pirie RS.Equine dysautonomia (ED; also known as equine grass sickness) is a neurological disease of unknown cause, which primarily affects grazing adult horses. The clinical signs reflect degeneration of specific neuronal populations, predominantly within the autonomic and enteric nervous systems, with disease severity and prognosis determined by the extent of neuronal loss. This review is primarily focused on the major clinical decision-making processes in relation to ED, namely, (1) clinical diagnosis, (2) selection of appropriate ancillary diagnostic tests, (3) obtaining diagnostic confirmation, (4)...
Whitehead AE, Whitty J, Scott M, Léguillette R.A gelding was diagnosed with dysphagia and left guttural pouch mycosis. Treatments included topical antifungal drugs, systemic voriconazole, and balloon occlusion of the internal carotid artery. Ongoing dysphagia of neurological origin necessitated extra-oral feeding through an esophagostomy tube. Complementary case management included acupuncture. Clinical remission occurred over 10 weeks. Dysphagie réversible secondaire à une mycose de la poche gutturale chez un hongre traité médicalement avec du voriconazole et chirurgicalement par l’occlusion de la carotide et l’œsophagostomie. Un...
MacDonald KD, Hart KA, Davis JL, Berghaus LJ, Giguère S.Seizures are a common manifestation of neurological disease in the neonatal foal and are an important cause of morbidity and mortality in this population. Current antiepileptic options are effective, but often have undesirable adverse effects, short duration of action and high cost. Levetiracetam has an ideal safety and pharmacokinetic profile in multiple species, including the adult horse, and may be a safe and cost-effective alternative anticonvulsant in neonatal foals. Due to differences in drug disposition and clearance dosages in neonates, dosing recommendations in other species or adult ...
Shakya AK, O'Callaghan DJ, Kim SK.Equine herpesvirus 1 (EHV-1) is a major pathogen affecting equines worldwide. The virus causes respiratory disease, abortion, and, in some cases, neurological disease. EHV-1 Kentucky A (KyA) is attenuated in the mouse and equine, whereas wild-type pathogenic strain RacL11 induces severe inflammatory infiltration of the lung, causing infected mice to succumb. The complete DNA sequencing of the KyA genome revealed that genes UL17 (ORF17), US6 (ORF73; gI), US7 (ORF74; gE), and US8 (ORF75; 10 K) are deleted as compared to the RacL11 and Ab4 genomes. In-frame deletions in the US1 (ORF68), US4 (OR...
Kumar R, Patil RD.The importance of horse (Equus caballus) to equine practitioners and researchers cannot be ignored. An unevenly distributed population of equids harbors numerous diseases, which can affect horses of any age and breed. Among these, the affections of nervous system are potent reason for death and euthanasia in equids. Many episodes associated with the emergence of equine encephalitic conditions have also pose a threat to human population as well, which signifies their pathogenic zoonotic potential. Intensification of most of the arboviruses is associated with sophisticated interaction between ve...
Hattori K, Matsuda N, Murakami T, Ito E, Ugawa Y.A 62-year-old man with acute paraplegia was transferred to our hospital. He had flaccid paraplegia and multiple cranial nerve palsies, such as mydriasis of the left pupil, abduction palsy of the left eye, hoarseness and dysphagia, but no meningeal irritation signs. MRI of the spinal canal showed swellings of the conus medullaris and the cauda equine, and also contrast enhancement of the spinal meninges. The cerebrospinal fluid (CSF) showed pleocytosis and protein increment. The lymph node was swollen in his right axilla. The biopsy specimen from the right axillary lymph node revealed metastasi...
Aleman M, Finno CJ, Weich K, Penedo MCT.The carrier status of lavender foal syndrome (LFS), cerebellar abiotrophy (CA), severe combined immunodeficiency (SCID), and occipitoatlantoaxial malformation (OAAM1) in foals with juvenile idiopathic epilepsy (JIE) is unknown. Objective: To determine the carrier status of LFS, CA, SCID, and OAAM1 in foals with JIE. Methods: Ten foals with JIE. Methods: Archived DNA samples were tested for known genetic mutations causing LFS, CA, SCID, and OAAM1. The inclusion criteria consisted of having been diagnosed with JIE by ruling out other causes of seizures in foals and supported by electroencephalog...
Venter M, Pretorius M, Fuller JA, Botha E, Rakgotho M, Stivaktas V, Weyer C, Romito M, Williams J.During 2008-2015 in South Africa, we conducted West Nile virus surveillance in 1,407 animals with neurologic disease and identified mostly lineage 2 cases in horses (7.4%, 79/1,069), livestock (1.5%, 2/132), and wildlife (0.5%, 1/206); 35% were fatal. Geographic correlation of horse cases with seropositive veterinarians suggests disease in horses can predict risk in humans.
Civello ANE, Dunkel B, Summers BA, Martineau HM.A neurofibroma of granular cell subtype is described in a 7-year-old horse. The horse had a 3-month history of ataxia affecting the forelimbs and hindlimbs, suggesting a C1-C6 neuroanatomical localization. Post-mortem examination revealed an intradural mass arising from the right sixth cervical spinal nerve and compressing the spinal cord. Histologically, the mass was composed largely of wavy spindle cells (a mixture of Schwann cells, perineurial cells and fibroblasts) intimately associated with ropy collagen fibres. Approximately 25% of the spindle cells were swollen and contained densely-pac...
Lacombe VA, Podell M, Furr M, Reed SM, Oglesbee MJ, Hinchcliff KW, Kohn CW.Electroencephalography (EEG) is a valuable diagnostic test to identify functional disturbances in brain activity. The purpose of this study was to assess the validity of EEG as a diagnostic indicator of intracranial diseases in horses. The validity of EEG was estimated by comparing clinical, clinicopathologic, and histopathologic findings to EEG findings in 20 horses examined for seizures. collapse, or abnormal behavior between 1984 and 1997. A bipolar left-to-right, back-to-front montage and a bipolar circular montage were recorded from sedated (4) and anesthetized (16) horses. Visual and sem...
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...
Jahns H, Callanan JJ, McElroy MC, Sammin DJ, Bassett HF.Brains from 100 horses, aged 2-25 years, were systematically examined by histopathology at 46 different neuroanatomical sites. The horses were sourced from a slaughterhouse (group A, n = 57), from a kennel that collected dead animals, and from 2 diagnostic laboratories (group B, n = 43). All horses from group A and 26 horses from group B were examined by a veterinarian in the period before death. None of the horses were known to exhibit clinical signs suggestive of neurologic disease. Among the main changes identified were vacuolation in the neuropil (n = 73), neurons (n = 32), white matter (n...
Boy MG, Galligan DT, Divers TJ.Medical records of 82 horses with clinical signs of neurologic disease and histologic lesions suggestive of protozoal encephalomyelitis were reviewed. The presence of a protozoan parasite in the CNS was not influenced by prior treatment of the horse with corticosteroids. Prior treatment of horses with trimethoprim-sulfonamide alone or in combination with pyrimethamine resulted in a decreased number of horses in which a protozoan parasite was detected in the CNS at necropsy. The mean age of affected horses was 3.62 +/- 2.78 years, with male and Standardbred horses being overrepresented, compare...
Chiocchetti R, Giancola F, Mazzoni M, Sorteni C, Romagnoli N, Pietra M.The lower esophageal sphincter (LES) is a specialized, thickened muscle region with a high resting tone mediated by myogenic and neurogenic mechanisms. During swallowing or belching, the LES undergoes strong inhibitory innervation. In the horse, the LES seems to be organized as a "one-way" structure, enabling only the oral-anal progression of food. We characterized the esophageal and gastric pericardial inhibitory and excitatory intramural neurons immunoreactive (IR) for the enzymes neuronal nitric oxide synthase (nNOS) and choline acetyltransferase. Large percentages of myenteric plexus (MP) ...
Hughes KJ, Laidlaw EH, Reed SM, Keen J, Abbott JB, Trevail T, Hammond G, Parkin TD, Love S.Sagittal ratio values (SRVs) of cervical vertebrae are used for ante-mortem diagnosis of cervical vertebral stenotic myelopathy, but intraobserver and interobserver variability in measurement may influence radiographic interpretation of vertebral stenosis in horses with neurological disease. Objective: To determine intraobserver repeatability in SRVs, intra- and interobserver agreement in SRVs and whether or not agreement was influenced by animal age. Methods: Forty-two horses (>1 year old) with neurological disease from which laterolateral computed radiographic images of C2-C7 were obtained. ...
Encheff JL, Armstrong C, Masterson M, Fox C, Gribble P.This study investigated the effects of a 10-week hippotherapy program on trunk, pelvis, and hip joint positioning during the stance phase of gait. Methods: Eleven children (6 boys and 5 girls; 7.9 ± 2.7 years) with neurological disorders and impaired ambulation participated. Joint range of motion data were collected via 3-dimensional computerized gait analysis before and after the program. Paired t tests were performed on kinematic data for each joint. Results: Significant improvements (P ≤ .008) and large effect sizes (ESs) for sagittal plane hip positions at initial contact and toe-off we...
Cozzi B, Pellegrini M, Droghi A.The structure and histochemical properties of neuromelanin in the Substantia nigra of the horse were studied by light and electron microscopy. Morphological, histochemical and cytochemical evidences showed the presence of a melanin component in some pigment granules, even if a large quantity of granules displayed only the properties of lipofuscins. Pigment formation in the neurons of the Substantia nigra of the horse may take place through the tyrosine-tyrosinase enzymatic pathway, as shown by positive Dopa-reaction. The results obtained were discussed in reference to the possible use of melan...
Gomes FA, Jansen AM, Machado RZ, Jesus Pena HF, Fumagalli MJ, Silva A, Alves BF, Roque ALR, Moraes Figueiredo LT.Arboviruses and protozoans can cause neurologic disorders in horses. In Brazilian Amazon, several horses presenting signs compatible with disorders caused by these infectious agents have been observed. To contribute to the knowledge of this epidemiological picture, we sought to construct a serological diagnostic panel for neurotrophic infectious agents in local horses. A total of 213 blood samples from horses were collected from 29 farms in three municipalities. Samples were evaluated and considered positive when they met the following criteria: titers ≥ 1:80 with the indirect fluorescent an...
Camino E, Schmid S, Weber F, Pozo P, de Juan L, König M, Cruz-Lopez F.Tick-borne encephalitis virus (TBEV) and louping-ill virus (LIV) are two closely related zoonotic flaviviruses leading to neurological diseases and belonging to the tick-borne encephalitis (TBE) serocomplex. Both viruses are transmitted by the same ixodid tick vector, Ixodes ricinus. Due to global warming affecting vector biology and pathogen transmission, the viruses pose an emerging threat for public health in Europe and Asia. These flaviviruses share some hosts, like sheep, goats and humans, although the main hosts for LIV and TBEV are sheep and small rodents, respectively. Whereas LIV has ...
Clayton HM, Bialski DE, Lanovaz JL, Mullineaux DR.To assess the reliability of the center-of-pressure (COP) values obtained from a force platform for analysis of postural sway in horses. Methods: Six 2-year-old horses that were free from lameness and neurologic disease. Methods: Horses stood stationary with all 4 hooves on a force platform; COP data were collected at 1,000 Hz and 3-dimensional kinematics collected at 60 Hz for 10 seconds. Five trials were recorded at each of 3 time periods (15-minute intervals) or at 1 time period on 3 separate days. Mean values for each set of 5 trials and actual, normalized, and relative COP variables were ...
Zimmermann W, Dürrwald R, Ludwig H.Borna disease virus in naturally infected horses, a donkey and sheep was detected for the first time by amplification of viral RNA using PCR. In contrast to a control group of healthy horses, brain tissue was positive by this assay in all animals with neurological symptoms. The use of a second round of PCR with nested primers following Southern hybridization confirmed the specificity and increased the sensitivity of the test. Comparison with conventional methods recommends this technique for monitoring of BDV infections at a molecular level.
Moore BR, Holbrook TC, Stefanacci JD, Reed SM, Tate LP, Menard MC.The cervical spines of 6 horses with cervical stenotic myelopathy (CSM) were examined using myelography and contrast-enhanced computed tomography (CECT). Histopathology of the spinal cord of these horses identified 10 neurologically significant compressive lesions. Myelography and CECT were both able to demonstrate all 10 spinal cord compressive lesions, but myelography falsely identified 2 sites and CECT falsely identified 1 site as compressive lesions of the spinal cord which were not supported by histopathology. Additional qualitative information was obtained by CECT regarding the source, s...
Gennari SM, Pena HF, Lindsay DS, Lopes MG, Soares HS, Cabral AD, Vitaliano SN, Amaku M.Sarcocystis neurona and Neospora hughesi are coccidian protozoa that can cause neurological illness in horses in America. In this study we report seroprevalence of Neospora spp. andS. neurona in sera of 333 donkeys from the northeastern region of Brazil. Antibodies to Neospora spp. were detected in 2% (7 donkeys) of 333 sera tested by the indirect fluorescent antibody test (IFAT) with a cut-off dilution of 1:40. Antibodies to S. neurona were found in 3% (10 donkeys) of the samples tested by IFAT (cut-off ≥50) and 21% (69 donkeys) by the direct agglutination test (SAT ≥50). The SAT and IFAT...
Daly JM, Whitwell KE, Miller J, Dowd G, Cardwell JM, Smith KC.Equine influenza is usually a transient and self-limiting disease. However, during an outbreak of equine influenza in the UK in 2003 there were reports of unusually severe clinical signs among unvaccinated animals. Two influenza-infected horses developed neurological signs, and one was subjected to euthanasia. Post-mortem examination of the brain revealed viral-type non-suppurative encephalitis, and influenza virus antigen was demonstrated by immunolabelling of sections of nasal mucosa. A syndrome known as influenza-associated encephalopathy has been described in man. Although not proved, the ...
Blythe LL.Otitis media/interna in the equine most commonly is a chronic, insidious infection with the unique sequella of temporohyoid osteoarthropathy in some horses. Head shaking may be the only clinical sign of the early stages of this disease. The arthritic condition often leads to fusion of the temporohyoid joint with resultant stress fractures of the petrous temporal bone. When this occurs, the horse presents as an acute neurologic case with clinical signs of vestibular and facial nerve dysfunction. Diagnosis, treatment, and prognosis are discussed. Recognition of this syndrome is important because...
Edwards LA, Donnelly CG, Reed SM, Valberg S, Chigerwe M, Johnson AL, Finno CJ.Currently, there is little information regarding the concentrations of phosphorylated neurofilament heavy protein (pNfH) in the serum and cerebrospinal fluid (CSF) of horses with neurodegenerative diseases. Specifically, pNfH concentrations have not yet been evaluated in horses with equine neuroaxonal dystrophy/equine degenerative myeloencephalopathy (eNAD/EDM). Objective: To determine pNfH concentrations using a commercial enzyme-linked immunosorbent assay (ELISA) in serum and CSF from control horses and horses with eNAD/EDM, cervical vertebral compressive myelopathy (CVCM) and Shivers. Metho...
Delcambre GH, Liu J, Streit WJ, Shaw GPJ, Vallario K, Herrington J, Wenzlow N, Barr KL, Long MT.West Nile virus (WNV), a mosquito borne member of the Flaviviridae, is one of the most commonly diagnosed agents of viral encephalitis in horses and people worldwide. Objective: A cassette of markers for formalin-fixed paraffin-embedded tissue and an archive of tissues from experimental infections in the horse were used to investigate the equine neuroimmune response to WNV meningoencephalomyelitis to phenotype the early response to WNV infection in the horse. Methods: Quantitative analysis using archived tissue from experimentally infected horses. Methods: The thalamus and hindbrain from 2 gro...
Moore BR, Reed SM, Robertson JT.Seventy-three horses with cervical stenotic myelopathy underwent cervical vertebral interbody fusion (n = 63) or dorsal laminectomy (n = 10). Neurologic function improved in 77% of horses, and 46% of horses achieved athletic function (racing, race training, or pleasure riding) after cervical vertebral interbody fusion for static and dynamic spinal cord compressive lesions. Neurologic status improved in 4 of 10 horses after dorsal decompression for static compressive spinal cord lesions. The duration of clinical signs prior to surgical intervention was shorter for horses that achieved athletic ...
Solbrig MV, Koob GF.Borna Disease Virus (BDV) is a neurotropic RNA virus that is worldwide in distribution, causing movement and behavior disorders in a wide range of animal species. BDV has also been reported to be associated with neuropsychiatric diseases of humans by serologic study and by recovery of nucleic acid or virus from blood or brain. Natural infections of horses and sheep produce encephalitis with erratic excited behaviors, hyperkinetic movement or gait abnormalities; naturally infected cats have ataxic "staggering disease." Experimentally infected primates develop hyperactivity, aggression, disinhib...
Steiss JE, Naylor JM.A three year old Quarter Horse stallion was presented with a one year history of episodes of generalized muscle tremors and stiffness, and spasm of the muscles of facial expression, lasting 10-15 minutes. Between attacks, the horse was either normal or had a localized muscle tremor in the flank region. Episodes appeared unrelated to exercise. The major abnormal findings included 1) a rise in plasma potassium from a resting level of 4.4 to 7.9 mmol/L during an attack and 2) electromyographic findings of generalized increased insertion activity and myotonic discharges. The horse was treated with...
Bach FS, Bodo G, Kuemmerle JM, Bienert-Zeit A, Hainisch EK, Simhofer H.To report meningoencephalitis as a complication after paranasal sinus surgery in 5 horses. Methods: Case series. Methods: Adult horses (n = 5). Methods: Medical records (2005-2010) of 5 horses that developed neurologic signs after sinus surgery were reviewed to identify potential risk factors, cause(s), or common pathways for infection. Results: Underlying diseases were primary (n = 1) and secondary sinusitis (4) because of apical dental infection (1), sinus cyst (2), or masses in the ethmoturbinate region (2). Horses were treated by conventional surgical approaches and aftercare inclu...
Tukov FF, Rimoldi JM, Matthews JC.Repin, a major constituent in extracts of the plant Centaurea repens is thought to be the active principal responsible for the development of equine nigropallidal encephalomalacia (ENE), a fatal Parkinson-like neurodegenerative disorder in horses. Although the exact mechanism by which ingestion of this weed causes ENE is uncertain, a limited body of experimental evidence suggests a critical role for the glutathione redox system. In the present study, the mechanism of repin neurotoxicity was examined in PC12 cells with a focus on determining the role of glutathione (GSH) in repin-induced mitoch...
Pecoraro HL, Felippe MJB, Miller AD, Divers TJ, Simpson KW, Guyer KM, Duhamel GE.Common variable immunodeficiency (CVID) is a rare condition in adult horses characterized by hypogammaglobulinemia and increased susceptibility to parasitic and bacterial infections, including recurrent respiratory diseases, septicemia, and meningitis. Lyme disease is often included as a differential diagnosis in CVID horses with signs of meningitis; however, the Borrelia burgdorferi organism has not been demonstrated previously within central nervous system tissues of CVID horses with neurologic disease, to our knowledge. We report herein a case of neuroborreliosis in a CVID horse, confirmed ...
Bryan LK, Hamer SA, Shaw S, Curtis-Robles R, Auckland LD, Hodo CL, Chaffin K, Rech RR.A 10-year-old Quarter Horse gelding presented to the Texas A&M University Veterinary Teaching Hospital with a six month-history of ataxia and lameness in the hind limbs. The horse was treated presumptively for equine protozoal myeloencephalitis (EPM) based on clinical signs but was ultimately euthanized after its condition worsened. Gross lesions were limited to a small area of reddening in the gray matter of the thoracic spinal cord. Histologically, trypanosome amastigotes morphologically similar to Trypanosoma cruzi, the agent of Chagas disease in humans and dogs, were sporadically detec...
Van Eeden C, Zaayman D, Venter M.Recently Shuni virus (SHUV) has been identified in clinical cases of neurological disease in horses in South Africa. Being that it was one of the less recognized orthobunyaviruses, with limited clinical descriptions of disease dating back to the 1960s and 1970s, SHUV-specific assays were never developed. In this study, the development of a nested real-time PCR assay is described for the detection of SHUV by means of melt-curve analysis using fluorescence resonance energy transfer (FRET) probe technology. The assay was validated against previously positive clinical specimens and a dilution seri...
Fehér OE, Fehérvári P, Tolnai CH, Forgách P, Malik P, Jerzsele Á, Wagenhoffer Z, Szenci O, Korbacska-Kutasi O.West Nile virus (WNV) is an emerging pathogen in Hungary, causing severe outbreaks in equines and humans since 2007. The aim of our study was to provide a comprehensive report on the clinical signs of West Nile neuroinvasive disease (WNND) in horses in Hungary. Clinical details of 124 confirmed equine WNND cases were collected between 2007 and 2019. Data about the seasonal and geographical presentation, demographic data, clinical signs, treatment protocols, and disease progression were evaluated. Starting from an initial case originating from the area of possible virus introduction by migrator...
