Topic:Neurological Diseases
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.
Investigating the Risk of Equine Motor Neuron Disease in a Brazilian Stable and Successful Intervention. We carried out an investigation to identify the factors that predispose to the risk of equine motor neuron disease (EMND) and evaluated the long-term impact of an intervention. Data on several biomarkers, including antioxidants (α-tocopherols, β-carotenes, glutathione peroxidase (GSHPx)), and superoxide dismutase (SOD1), neurofilaments, and other putative risk factors hypothesized to associate with the likelihood of EMND were collected. The data were analyzed for their significance of association with the condition. The EMND outbreak started in 1991 and continued until 1998. A total of 69 EM...
Three-Dimensional Kinematic Motion Analysis of Shivers in Horses: A Pilot Study. Our aim was to assess three-dimensional kinematic motion analysis as an objective diagnostic tool for the characterization of the movement disorder of Shivers in horses. Kinematic parameters were measured in three horses with Shivers and were compared with a control group of four normal horses. Multiple parameter differences were found in the horses with Shivers at the walk, during backing, and when asked to pick up their hindlimbs. Most significant changes were a wider hindlimb stance of 0.39 ± 0.15 m and increased abduction angle of 48.7 ± 7.52° and hoof elevation (0.77 ± 0.08 m left a...
Equine Herpesvirus 1 Bridles T Lymphocytes To Reach Its Target Organs. Equine herpesvirus 1 (EHV1) replicates in the respiratory epithelium and disseminates through the body via a cell-associated viremia in leukocytes, despite the presence of neutralizing antibodies. "Hijacked" leukocytes, previously identified as monocytic cells and T lymphocytes, transmit EHV1 to endothelial cells of the endometrium or central nervous system, causing reproductive (abortigenic variants) or neurological (neurological variants) disorders. In the present study, we questioned the potential route of EHV1 infection of T lymphocytes and how EHV1 misuses T lymphocytes as a vehicle to re...
Polyradiculoneuropathy in dourine-affected horses. Dourine is an equine protozoan disease caused by Trypanosoma equiperdum. Dourine-afflicted animals die after developing neurological clinical signs, such as unilateral paresis. The disease has been a problem for many years; however, the pathogenesis regarding the neurological clinical signs of dourine has been unclear. In the present study, we conducted a histopathological examination in order to investigate the mechanisms by which dourine-afflicted horses develop the accompanying neurological clinical signs. Four dourine-afflicted horses in Mongolia were evaluated. An apparently healthy horse...
An atypical presentation of multi-systemic B-cell lymphoma in a horse. This report describes an unusual presentation of multicentric B-cell lymphoma with central and peripheral nerve involvement in a horse that was presented with acute onset, severe, multiple limb lameness, and muscle atrophy. This case highlights the importance of including neoplasia in the differential list in horses presenting for severe limb lameness associated with muscle atrophy, muscle fasciculations, and weakness. Présentation atypique d’un lymphome à cellules B multisystémique chez un cheval. Ce rapport décrit la présentation inhabituelle d’un lymphome à cellules B multicentriq...
Histopathologic Findings Following Experimental Equine Herpesvirus 1 Infection of Horses. Histopathological differences in horses infected with equine herpesvirus type 1 (EHV-1) of differing neuropathogenic potential [wild-type (Ab4), polymerase mutant (Ab4 N752), EHV-1/4 gD mutant (Ab4 gD4)] were evaluated to examine the impact of viral factors on clinical disease, tissue tropism and pathology. Three of 8 Ab4 infected horses developed Equine Herpesvirus Myeloencephalopathy (EHM) requiring euthanasia of 2 horses on day 9 post-infection. None of the other horses showed neurologic signs and all remaining animals were sacrificed 10 weeks post-infection. EHM horses had lymphohistiocyti...
Asymmetric recurrent laryngeal nerve conduction velocities and dorsal cricoarytenoid muscle electromyographic characteristics in clinically normal horses. The dorsal cricoarytenoid (DCA) muscles, are a fundamental component of the athletic horse's respiratory system: as the sole abductors of the airways, they maintain the size of the rima glottis which is essential for enabling maximal air intake during intense exercise. Dysfunction of the DCA muscle leads to arytenoid collapse during exercise, resulting in poor performance. An electrodiagnostic study including electromyography of the dorsal cricoarytenoid muscles and conduction velocity testing of the innervating recurrent laryngeal nerves (RLn) was conducted in horses with normal laryngeal fu...
Congenital hydrocephalus in a Belgian draft horse associated with a nonsense mutation in B3GALNT2. Congenital hydrocephalus has been reported for a number of horse breeds, and for Friesian horses this condition has been associated with a nonsense mutation of B3GALNT2. We report the first case of congenital hydrocephalus associated with the said mutation in a Belgian draft horse. Genetic testing and consideration of the testing results in breeding programs are warranted. Hydrocéphalie congénitale chez un cheval de trait Belge associée à une mutation non-sens de B3GALNT2. L’hydrocéphalie congénitale a été signalée pour plusieurs races de chevaux et, pour les chevaux Frisons, cette ...
Can levamisole upregulate the equine cell-mediated macrophage (M1) dendritic cell (DC1) T-helper 1 (CD4 Th1) T-cytotoxic (CD8) immune response in vitro? Equine protozoal myeloencephalitis (EPM) is a common and devastating neurologic disease of horses in the United States. Because some EPM-affected horses have decreased immune responses, immunomodulators such as levamisole have been proposed as supplemental treatments. However, little is known about levamisole's effects or its mechanism of action in horses. Objective: Levamisole in combination with another mitogen will stimulate a macrophage 1 (M1), dendritic cell 1 (DC1), T-helper 1 (CD4 Th1), and T-cytotoxic (CD8) immune response in equine peripheral blood mononuclear cells (PBMCs) in vitro a...
First description of a fatal equine infection with Halicephalobus gingivalis in Portugal. Relevance for public health. Halicephalobus gingivalis is a small saprophytic rhabditid nematode, represented only by females with a typical rhabditoid oesophagus and one egg in the uterus, capable of infecting vertebrates. This opportunistic parasite present in the soil, manure and decaying humus, is thought to penetrate through previous injuries to the mouth, eyes and skin of horses and migrate to various organs. The brain is one such organ, where the females lay their eggs, leading to malacia and causing a sudden onset of neurological signs, such as anorexia, ataxia, urinary incontinence, blindness, decreased menace an...
Neuroborreliosis in a horse with common variable immunodeficiency. 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 ...
Trigeminal-mediated headshaking in horses: prevalence, impact, and management strategies. Trigeminal-mediated headshaking is a little-understood neuropathic facial pain condition of the horse. The condition may affect around 1% of the equine population to a degree of severity sufficient to require veterinary attention. As a pain condition, this represents a significant welfare issue. Horses are usually more severely affected at exercise which can leave them unable to perform, or even dangerous to ride and handle. With little known about the condition and variable response to treatments, severely affected horses are often euthanized. This review article considers the literature on t...
Hippotherapy in Rehabilitation Care for Children With Neurological Impairments and Developmental Delays: A Case Series. This report assesses functional mobility in children with neurological impairments and documented gross motor delays, before and after receiving either hippotherapy or standard outpatient physical therapy (PT). This is a case-series report using data previously collected for a discontinued randomized controlled trial, in which participants received hippotherapy or standard outpatient clinic PT for a 12-week treatment period. Results demonstrated both subjective and objective functional mobility improvements after treatment in participants receiving hippotherapy and standard outpatient PT, as d...
Viral Enrichment Methods Affect the Detection but Not Sequence Variation of West Nile Virus in Equine Brain Tissue. West Nile virus (WNV), a small, positive sense, single stranded RNA virus continues to encroach into new locales with emergence of new viral variants. Neurological disease in the equine can be moderate to severe in the face of low to undetectable virus loads. Physical methods of virus enrichment may increase sensitivity of virus detection and enhance analysis of viral diversity, especially for deep sequencing studies. However, the use of these techniques is limited mainly to non-neural tissues. We investigated the hypothesis that elimination of equine brain RNA enhances viral detection without...
Genome-wide association study of equine herpesvirus type 1-induced myeloencephalopathy identifies a significant single nucleotide polymorphism in a platelet-related gene. Equine herpesvirus type 1 (EHV-1)-induced myeloencephalopathy (EHM) is a neurologic disease of horses that represents one outcome of infection. The neurologic form of disease occurs in a subset of infected horses when virus-induced endothelial cell damage triggers vasculitis and subsequent ischemic insult to the central nervous system. EHM causes considerable animal suffering and economic loss for the horse industry. Virus polymorphisms have been previously associated with disease outcome but cannot fully explain why only some horses develop EHM. This study investigated the role of host geneti...
Neuromyotonia in a horse. This article describes the clinical and electromyographic findings of neuromyotonia in a 19-month-old male crossbred Quarter Horse that presented with stiffness and muscle asymmetry in the hind limbs as well as sacrococcygeal, paravertebral, and gluteal myokymia. An electromyographic study showed spontaneous continuous muscle fiber activity with high-frequency discharges, fibrillations, positive sharp waves, fasciculation potentials, and complex repetitive discharges. Histological examination of the gluteal muscle showed a mixed neurogenic and myopathic pattern. The findings are consistent wit...
Surveillance of animal diseases through implementation of a Bayesian spatio-temporal model: A simulation example with neurological syndromes in horses and West Nile Virus. A potentially sensitive way to detect disease outbreaks is syndromic surveillance, i.e. monitoring the number of syndromes reported in the population of interest, comparing it to the baseline rate, and drawing conclusions about outbreaks using statistical methods. A decision maker may use the results to take disease control actions or to initiate enhanced epidemiological investigations. In addition to the total count of syndromes there are often additional pieces of information to consider when assessing the probability of an outbreak. This includes clustering of syndromes in space and time as...
The prevalence of temporal bone fractures is high in horses with severe temporohyoid osteoarthropathy. Temporohyoid osteoarthropathy is a well-recognized cause of equine neurologic disease. Temporal bone fractures associated with temporohyoid osteoarthropathy have been recognized with CT, however, little information is available regarding these fractures. The aims of this retrospective analytical study were to assess the prevalence of these fractures and to describe the specific configurations and associated imaging and clinical features. Fracture of the temporal bone was identified with CT in 16 of 39 included horses. All fractures were unilateral, minimally displaced and extended through the ...
Melarsomine hydrochloride (Cymelarsan®) fails to cure horses with Trypanosoma equiperdum OVI parasites in their cerebrospinal fluid. The aim of this study was to evaluate the ability of melarsomine hydrochloride (Cymelarsan) to cure horses suffering from a nervous form of dourine, a sexually-transmitted disease caused by Trypanosoma equiperdum. The recently described experimental model for assessing drug efficacy against horse trypanosomosis allowed us to obtain eight horses (Welsh pony mares) infected by T. equiperdum with parasites in their cerebrospinal fluid. The Cymelarsan treatment evaluated consisted of the daily administration of 0.5 mg/kg of Cymelarsan over 7 days. Two control horses remained untreated, three hor...
West Nile virus associated with equid encephalitis in Brazil, 2018. Mosquito-borne arboviruses are a major public health concern worldwide and are responsible for emerging and re-emerging diseases. Taken together, the arboviruses have a strong impact on public health and are the most common causes of equine encephalitis. In-depth diagnostic investigation of equine viral encephalitis is of utmost importance for the epidemiological surveillance and control of this disease. Regarding neurological disorders in equids, in April-May 2018, at least 12 cases of equid mortality with acute neurological signs were reported in six farms from Espirito Santo state, Brazil. ...
Extradural spinal hydatid cyst causing hindlimb ataxia in a horse. This case report describes a 13-year-old cob-cross gelding presented for evaluation of recent onset hindlimb ataxia. The gelding had undergone general anaesthesia and tenoscopy of the right hindlimb digital flexor tendon sheath at a nearby clinic three months earlier and had appeared normal at routine post-operative assessments until the sudden onset of neurological deficits. Spinal trauma was suspected initially but radiography and scintigraphy were unremarkable. Due to the severity and progressive nature of the clinical signs the -gelding was subjected to euthanasia. Post mortem examinations...
Nerve Stimulator-guided Injection of Autologous Stem Cells Near the Equine Left Recurrent Laryngeal Nerve. Recurrent laryngeal neuropathy (RLN) commonly affects horses and is characterized by abnormal respiratory sounds and exercise intolerance. The recurrent laryngeal nerve shows lesions of demyelination. The benefit of applying stem cells to demyelinated nerves has been demonstrated in various animal models. The aim of the study was to test the feasibility and safety of a peri-neuronal injection of autologous muscle-derived mesenchymal stem cells to the left recurrent laryngeal nerve in healthy horses by using an electrical nerve stimulator. Muscle-derived stems cell are obtained from five health...
Magnetic motor evoked potentials of cervical muscles in horses. When surgical treatment of cervical vertebral malformation is considered, precise localization of compression sites is essential, but remains challenging. Magnetic motor evoked potentials (mMEP) from paravertebral muscles are useful in localizing spinal cord lesions, but no information about cervical muscle mMEP in horses is available yet. Therefore, the aim of this study was to determine the possibility, normal values, inter- and intra-observer agreement and factors that have an effect on cervical mMEP in healthy horses. Methods: Transcranial magnetic stimulation was performed on 50 normal ho...
Utility of C-reactive protein and serum amyloid A in the diagnosis of equine protozoal myeloencephalitis. Accurate antemortem EPM diagnosis requires evidence of intrathecal antibody production. Some advocate the use of acute phase proteins in addition to serology, which alone results in substantial false positives. Objective: The purpose of this study was to determine if serum C-reactive protein (CRP) or serum amyloid A (SAA) concentrations were elevated in cases of equine protozoal myeloencephalitis (EPM) compared to other neurological diseases. Methods: 25 clinical cases of equine neurological disease: EPM (10), cervical vertebral stenotic myelopathy (CVSM) (10), neuroborreliosis (2), equine mot...
In silico identification of immunodominant B-cell and T-cell epitopes of non-structural proteins of Usutu Virus. Usutu Virus (USUV; flavivirus) is a re-emerging pathogen invading the territories of European countries, Asia, and Africa. It is a mosquito-borne zoonotic virus with a bi-directional transmission route from animal to human and vice versa, and causes neurological disorders such as meningoencephalitis in bats, Homo sapiens, birds and horses. Due to limited availability of information about USUV and its deleterious effects on neural cells causing neurologic impairments, it becomes imperative to study this virus in detail to equip ourselves with a solution beforehand. The current study aims to ide...
Cervical stabilization with polyaxial pedicle screw and rod construct in horses: A proof of concept study. To evaluate safety and efficacy of a novel technique for cervical stabilization. Methods: In vivo experimental. Methods: Four normal adult quarterhorse crossbreed horses (2-4 years of age, > 250 kg). Methods: One mid-cervical spinal unit (C3-C4) was distracted with a porous metal interbody fusion device (IFD) and stabilized with a polyaxial pedicle screw and rod construct. Neurologic examinations were performed preoperatively and postoperatively. Radiographs of the fusion site and adjoining vertebrae were obtained preoperatively and monthly. Horses were euthanized at 8 months and spin...
Equine degenerative myeloencephalopathy: prevalence, impact, and management. Equine neuroaxonal dystrophy/equine degenerative myeloencephalopathy is an inherited neurodegenerative disorder affecting many horse breeds. Clinical signs include a symmetric ataxia and an abnormal stance at rest, similar to cervical vertebral compressive myelopathy, equine protozoal myeloencephalitis, and equine herpesvirus 1 myeloencephalopathy. This review will provide an update on the disease prevalence, management, impact, and ongoing research.
Detection and genotyping of equid herpesvirus 1 in Uruguay. Infection with equid alphaherpesvirus 1 (EHV-1) causes respiratory disease, abortion and neurological disorders in horses. Molecular epidemiology studies have demonstrated that a single nucleotide polymorphism (A2254/G2254) in the genome region of open reading frame 30 which results in an amino acid variation (N752/D752) of the EHV-1 DNA polymerase, is significantly associated with the neuropathogenic potential of naturally occurring strains. In recent years, an increase in the number of cases of equine neurological disease caused by neuropathogenic variants of EHV-1 has been observed in numer...
Metaphyeal and Diaphyseal Dysplasia of the Third Cervical Vertebra Secondary to Physeal Necrosis in a Quarter Horse Foal. Ischaemia-induced physeal injury has not been described previously in the horse. A 1-month-old Quarter horse foal was submitted for necropsy examination due to an acute onset of ataxia followed by a 4-week history of progressive decline. Focal narrowing of the spinal canal due to ventral compression by the rotation of the cranial aspect of the third cervical vertebra (C3) was observed. The metaphysis and diaphysis of C3 were markedly shortened and white-tan in colour. Microscopically, there was complete loss of the dorsal compact bone of C3 and replacement of 80% of the physis that runs parall...