Search

Background: Discriminating the underlying cause of gait abnormalities can be challenging in a clinical setting, especially in the presence of bilateral disease. Pressure-sensitive walkways (PSWs) have been utilized to characterize the gait of dogs with various neurologic or orthopaedic conditions. The potential use of the PSW includes the discrimination of conditions that can be similar in clinical presentation, such as bilateral hindlimb lameness and hindlimb ataxia. The primary aim of this study was to describe the spatial, temporal, and kinetic gait parameters of dogs with hindlimb ataxia or bilateral hindlimb lameness and compare them to those of normal dogs. Forty-six dogs were prospectively recruited. The normal group included 20 dogs with normal neurologic and orthopaedic exams. The orthopaedic group included 15 dogs with bilateral hindlimb orthopaedic diseases with weight-bearing hindlimb lameness and normal neurologic exams. The neurologic group included 11 dogs with ambulatory paraparesis and normal orthopaedic exams. Each dog was walked across the PSW, and at least 3 valid trials were collected. The stride time, stance time, swing time, stride length, gait velocity, peak vertical force (PVF), vertical impulse (VI), and limb symmetry were recorded. The mean values of all parameters from the valid trials were calculated and used for data analysis. The outcomes were compared among all groups., Results: Compared with the normal group, the orthopaedic group had a significantly greater percent body weight distribution (%BWD) and vertical impulse distribution (VID) in the forelimbs. When comparing the spatiotemporal parameters, the neurologic group showed an increase in forelimb stance time compared to that of the normal group. Compared with that in the normal group, the stride velocity in the forelimbs in the orthopaedic group was greater. There were no significant differences in the kinetic parameters between the neurologic group and the normal group, nor in stride time or stride length among the groups., Conclusion: The gait parameters obtained by PSW demonstrated that the orthopaedic and neurologic groups may have different compensatory mechanisms for their gait deficiencies. These parameters can potentially be used to construct a predictive model to evaluate PSW as a diagnostic tool in future studies., (© 2024. The Author(s).)

The Asiatic lion ( Panthera leo persica ) is an endangered species with a slowly increasing captive and wild population. Several zoos from within the European Association of Zoos and Aquaria Ex Situ Program reported Asiatic lions with neurological signs such as (progressive) ataxia, and stargazing. The aim of this study was to evaluate the frequency (prevalence and incidence) and etiology of these clinical signs within the captive Asiatic lion population. The medical history of 74 Asiatic lions (36 healthy and 38 affected) was retrieved and reviewed for blood tests (biochemical, hematological, and retinol), diagnostic imaging (MRI and CT scans) and postmortem examinations. The data of the affected lions was compared with those of healthy lions. Between 2002 and 2020, the prevalence of ataxia ranged from 0.6% in 2004 to 13.0% in 2020. The incidence of ataxia was variable per year between 2002 and 2020 and ranged between 0 and 40%. Besides ataxia, stiffness and lameness were the most described signs in this study. Blood results showed lower total protein, ALT and creatinine, and higher phosphate in lions with neurological signs. Moreover, neurologically affected lions showed a significant lower blood retinol than the control lions (0.59-0.81 µmol/L). The most important finding in diagnostic imaging and necropsy included caudal fossa hyperostosis and cerebellar herniation. These abnormalities are similar as found in African lions ( Panthera leo ) with calvarial hyperostosis syndrome associated with vitamin A deficiency. Leucomyelopathy, syringomyelia (in one case combined with cerebellar herniation) and incidental mineralization of the dura mater were also described. A possible congenital/hereditary component should not be excluded.

Bovine familial convulsions and ataxia (BFCA) is considered an autosomal dominant syndrome with incomplete penetrance. Nine Angus calves from the same herd were diagnosed with BFCA within days of birth. Necropsy revealed cerebellar and spinal cord lesions associated with the condition. Parentage testing confirmed that all affected calves had a common sire. The sire was then bred to 36 cows across two herds using artificial insemination, producing an additional 14 affected calves. The objective of this investigation was to identify hypothesized dominant genetic variation underlying the condition. Whole-genome sequencing was performed on the sire, six affected and seven unaffected paternal half-sibling calves and combined with data from 135 unrelated controls. The sire and five of the six affected calves were heterozygous for a nonsense variant (Chr7 g.12367906C>T, c.5073C>T, p.Arg1681*) in CACNA1A. The other affected calves (N = 8) were heterozygous for the variant but it was absent in the other unaffected calves (N = 7) and parents of the sire. This variant was also absent in sequence data from over 6500 other cattle obtained via public repositories and collaborator projects. The variant in CACNA1A is expressed in the cerebellum of the ataxic calves as detected in the transcriptome and was not differentially expressed compared with controls. The CACNA1A protein is part of a highly expressed cerebellar calcium voltage gated channel. The nonsense variant is proposed to cause haploinsufficiency, preventing proper transmission of neuronal signals through the channel and resulting in BFCA., (© 2024 The Authors. Animal Genetics published by John Wiley & Sons Ltd on behalf of Stichting International Foundation for Animal Genetics.)

Background: Equine herpesvirus myeloencephalopathy (EHM) has severe impact on the sport horse population., Objective: Study the influence of EHM on the likelihood of affected horses to return to their previous performance and investigate the association of clinical variables with prognosis., Animals: Twenty-six horses positive for equine herpesvirus type 1 (EHV-1) were admitted to a veterinary teaching hospital (VTH) during a natural EHM outbreak at an international jumping event., Methods: Data collected from the VTH, the International Equestrian Federation, and surveys completed by the riders and horse owners were retrospectively analyzed., Results: Horses affected by EHM had 68% chance of returning to exercise, and 52.9% were able to achieve their preoutbreak performance level. Horses with an ataxia grade at admission ≥4/5 had an increased fatality rate (P < .05) and 10% chance of reaching their preoutbreak performance level. None of the horses with both vascular and urinary complications returned to their previous performance level. Finally, horses vaccinated against EHV-1 and those with urinary complications had a 71.4% and 43.7% fatality rate, respectively., Conclusions and Clinical Importance: Horses affected by EHM were able to return to their previous performance levels, but certain clinical variables were negatively associated with postoutbreak performance. Ataxia grade upon admission and the development of systemic signs of vasculitis and urinary complications were potential poor prognostic indicators in sport horses. Variables linked to fatality included prior vaccination against EHV-1, ataxia grade upon admission, and the development of urinary complications., (© 2024 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals LLC on behalf of American College of Veterinary Internal Medicine.)

Background: Eight-hydroxy-2'-deoxyguanosine (8-OHdG), a biomarker of oxidative damage evaluated in human neurodegenerative disease, has potential to correlate with postmortem diagnosis of neuroaxonal dystrophy/degenerative myeloencephalopathy (NAD/DM) in horses., Hypothesis: We hypothesized that 8-OHdG will be higher in CSF and serum from NAD/DM horses compared with horses with other neurologic diseases (CVSM, EPM) and a control group of neurologically normal horses. We also hypothesized that 8-OHdG will be higher in CSF compared with serum from NAD/DM horses., Animals: Fifty client-owned horses with postmortem diagnoses: 20 NAD/DM, 10 CVSM, 10 EPM, and 10 control horses. Serum and CSF samples were obtained between November 2010 and March 2022., Methods: Case-control study using biobanked samples was performed and commercial competitive ELISA kit (Highly Sensitive 8-OHdG Check ELISA) utilized. Concentration of 8-OHdG was quantitated in both CSF and serum and compared between groups., Results: No correlation was established between the measures of 8-OHdG in serum and CSF and group. CSF median [8-OHdG] for NAD/DM was 169.9 pg/mL (IQR 25-75 : 67.18-210.6), CVSM 157.1 pg/mL (IQR 25-75 : 132.1-229.1), EPM 131.4 pg/mL (IQR 25-75 : 102.1-193.2), and control 149.8 pg/mL (IQR 25-75 : 113.3-196.4). Serum median [8-OHdG] for NAD/DM was 130 pg/mL (IQR 25-75 : 51.73-157.2), CVSM 125.8 pg/mL (IQR 25-75 : 62.8-170.8), EPM 120.6 pg/mL (IQR 25-75 : 87.23-229.7), and control 157.6 pg/mL (IQR 25-75 : 97.15-245.6). Poisson regression analysis showed no difference established once confounding variables were considered., Conclusions: Eight-OHdG did not aid in antemortem diagnosis of NAD/DM in this cohort of horses. At the time of diagnosis horses with NAD/DM do not have ongoing oxidative stress., (© 2024 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals LLC on behalf of American College of Veterinary Internal Medicine.)

Electroejaculation (EE) represents the main technique for semen collection from domestic and wild animals independently of libido. However, the technique is associated with intense involuntary muscle contractions, vocalization, ataxia and lying down, caused by the electric stimulation of the nerves in the caudal epigastric region. These clinical manifestations represent important indicators of discomfort. In this context, the objective of this study was to evaluate two protocols of local anaesthetic blockade and two anatomical access for pharmacological desensitization of the caudal epigastric innervation as alternatives to promote comfort and reduce stress associated with EE in rams. For the study, four clinically healthy Dorper rams were selected. All animals were subjected to a design consisting of five semen collection treatments (n = 3 collections per treatment): T1-control, conventional EE without local anaesthetic blockade; T2, EE with ventral blockade (VB) of epigastric innervation using lidocaine hydrochloride 2%; T3, EE with VB of epigastric innervation using a combination of lidocaine hydrochloride 2% and fentanyl citrate; T4, EE with blockade of epigastric innervation through the perineal access using lidocaine hydrochloride 2%; T5, EE with blockade of epigastric innervation through the perineal access using a combination of lidocaine hydrochloride and fentanyl citrate. Seminal samples resulting from EE were subjectively evaluated for sperm motility and concentration, vigour and volume. Additionally, blood serum samples were collected for quantification of cortisol and creatine kinase (CK) enzyme. Assessments of stress and discomfort were conducted by measuring blood pressure, heart rate (HR) and respiratory rate (RR), as well as observing involuntary muscle contractions, ataxia and animal vocalization. No variations in blood pressure, sperm motility, vigour, CK, and cortisol were observed among the treatments. Individual variations were observed for the occurrence of vocalization (p = .0066), but there were no differences between the groups. Anaesthetic blockades conducted using the combination of lidocaine and fentanyl resulted in a lower incidence of ataxia during EE (p < .0001). It is concluded that the combination of fentanyl citrate and lidocaine hydrochloride results in less discomfort for animals undergoing EE, regardless of the anatomical access used for local anaesthetic blockades., (© 2024 Wiley-VCH GmbH. Published by John Wiley & Sons Ltd.)

Background: Adult horses with proprioceptive ataxia and behavior changes that have histologic lesions consistent with neurodegenerative disease have been increasingly recognized., Hypothesis/objectives: Describe the history, clinical findings and histopathologic features of horses presented to a referral institution with neuroaxonal degeneration., Animals: One hundred horses with a necropsy diagnosis of neuroaxonal degeneration compatible with neuroaxonal dystrophy/degenerative myeloencephalopathy (eNAD/EDM)., Methods: Retrospective study of horses presented to the University of Pennsylvania, New Bolton Center, between 2017 and 2021 with a necropsy diagnosis of eNAD/EDM., Results: Affected horses had a median age of 8 years (range, 1-22), and the majority were Warmbloods (72). Sixty-eight horses had behavioral changes, and all 100 had proprioceptive ataxia (median grade, 2/5). Fifty-seven horses had abnormal findings on cervical vertebral radiographs, and 14 had myelographic findings consistent with compressive myelopathy. No antemortem diagnostic test results were consistently associated with necropsy diagnosis of neurodegenerative disease. All 100 horses had degenerative lesions characteristic of eNAD in the brainstem gray matter, and 24 had concurrent degenerative features of EDM in the spinal cord white matter., Conclusions and Clinical Importance: Clinical and histopathologic findings in this large group of horses with neurodegenerative disease were most consistent with eNAD/EDM, but with a different signalment and clinical presentation from earlier descriptions. The increasing occurrence of neurodegenerative disease in horses and the safety risk posed emphasize the importance of focused research in affected horses., (© 2023 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals LLC on behalf of American College of Veterinary Internal Medicine.)

Background: Equine neuroaxonal dystrophy/equine degenerative myeloencephalopathy (eNAD/EDM) is an inherited neurodegenerative disorder associated with vitamin E deficiency. In humans, polymorphisms in genes involved in vitamin E uptake and distribution determines individual vitamin E requirements., Hypothesis/objectives: Genetic polymorphisms in genes involved in vitamin E metabolism would be associated with an increased risk of eNAD/EDM in Quarter Horses (QHs)., Animals: Whole-genome sequencing: eNAD/EDM affected (n = 9, postmortem [PM]-confirmed) and control (n = 32) QHs., Validation: eNAD/EDM affected (n = 39, 23-PM confirmed) and control (n = 68, 7-PM confirmed) QHs. Allele frequency (AF): Publicly available data from 504 horses across 47 breeds., Methods: Retrospective, case control study. Whole-genome sequencing was performed and genetic variants identified within 28 vitamin E candidate genes. These variants were subsequently genotyped in the validation cohort., Results: Thirty-nine confirmed variants in 15 vitamin E candidate genes were significantly associated with eNAD/EDM (P < .01). In the validation cohort, 2 intronic CD36 variants (chr4:726485 and chr4:731082) were significantly associated with eNAD/EDM in clinical (P = 2.78 × 10 -4 and P = 4 × 10 -4 , respectively) and PM-confirmed cases (P = 6.32 × 10 -6 and 1.04 × 10 -5 , respectively). Despite the significant association, variant AFs were low in the postmortem-confirmed eNAD/EDM cases (0.22-0.26). In publicly available equine genomes, AFs ranged from 0.06 to 0.1., Conclusions and Clinical Importance: Many PM-confirmed cases of eNAD/EDM were wild-type for the 2 intronic CD36 SNPs, suggesting either a false positive association or genetic heterogeneity of eNAD/EDM within the QH breed., (© 2023 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals LLC on behalf of American College of Veterinary Internal Medicine.)

Background: Dystonia is a common component of the movement disorder paroxysmal dyskinesia (PD) in dogs. However, the incidence of dystonic head tremor (DHT) in these dogs has not previously been evaluated., Methods: The medical records of dogs presenting with PD between 2021 and 2023 were retrospectively reviewed, and those with available video footage and the presence of a head tremor were selected for further analysis., Results: Seventeen of the 39 (43.6%) dogs diagnosed with PD that had video footage available manifested DHT. Poodle or Poodle-cross was the most commonly affected breed (7/17). DHTs were described as fine irregular head tremors accompanied by cervical dystonia (17/17), truncal (11/17) or head (10/17) sway, shifting limb (10/17) or single limb (6/17) dystonia, freezing (8/17), ataxia (6/17), ptyalism (5/17), falling (5/17), kyphosis (4/17) and prayer posture (4/17). Neurological examination and advanced imaging, when available, were within normal limits., Limitations: The limitations of the study include its retrospective nature, the lack of video recordings for all PD patients and the lack of electrophysiological evaluation of tremors and electroencephalography., Conclusions: DHT exists in dogs with PD; it has characteristic features, and it should be considered in differential diagnoses for dogs with head tremors., (© 2023 The Authors. Veterinary Record published by John Wiley & Sons Ltd on behalf of British Veterinary Association.)

Background: KCNJ10 and CAPN1 variants cause "spinocerebellar" ataxia in dogs, but their association with generalized myokymia and neuromyotonia remains unclear., Objective: To investigate the association between KCNJ10 and CAPN1 and myokymia or neuromyotonia, with or without concurrent spinocerebellar ataxia., Animals: Thirty-three client-owned dogs with spinocerebellar ataxia, myokymia neuromytonia, or a combination of these signs., Methods: Genetic analysis of a cohort of dogs clinically diagnosed with spinocerebellar ataxia, myokymia or neuromyotonia. KCNJ10 c.627C>G and CAPN1 c.344G>A variants and the coding sequence of KCNA1, KCNA2, KCNA6, KCNJ10 and HINT1 were sequenced using DNA extracted from blood samples., Results: Twenty-four Jack Russell terriers, 1 Jack Russell terrier cross, 1 Dachshund and 1 mixed breed with spinocerebellar ataxia were biallelic (homozygous) for the KCNJ10 c.627C>G variant. Twenty-one of those dogs had myokymia, neuromyotonia, or both. One Parson Russell terrier with spinocerebellar ataxia alone was biallelic for the CAPN1 c.344G>A variant. Neither variant was found in 1 Jack Russell terrier with ataxia alone, nor in 3 Jack Russell terriers and 1 Yorkshire terrier with myokymia and neuromyotonia alone. No other causal variants were found in the coding sequence of the investigated candidate genes in these latter 5 dogs., Conclusion: The KCNJ10 c.627C>G variant, or rarely the CAPN1 c.344G>A variant, was confirmed to be the causal variant of spinocerebellar ataxia. We also report the presence of the KCNJ10 c.627C>G variant in the Dachshund breed. In dogs with myokymia and neuromyotonia alone the reported gene variants were not found. Other genetic or immune-mediated causes should be investigated to explain the clinical signs of these cases., (© 2023 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals LLC on behalf of American College of Veterinary Internal Medicine.)

Background: Cervical vertebral compressive myelopathy (CVCM) and equine neuroaxonal dystrophy/degenerative myeloencephalopathy (eNAD/EDM) are leading causes of spinal ataxia in horses. The conditions can be difficult to differentiate, and there is currently no diagnostic modality that offers a definitive antemortem diagnosis., Objective: Evaluate novel proteomic techniques and machine learning algorithms to predict biomarkers that can aid in the antemortem diagnosis of noninfectious spinal ataxia in horses., Animals: Banked serum and cerebrospinal fluid (CSF) samples from necropsy-confirmed adult eNAD/EDM (n = 47) and CVCM (n = 25) horses and neurologically normal adult horses (n = 45)., Methods: . A subset of serum and CSF samples from eNAD/EDM (n = 5) and normal (n = 5) horses was used to evaluate the proximity extension assay (PEA). All samples were assayed by PEA for 368 neurologically relevant proteins. Data were analyzed using machine learning algorithms to define potential diagnostic biomarkers., Results: Of the 368 proteins, 84 were detected in CSF and 146 in serum. Eighteen of 84 proteins in CSF and 30/146 in serum were differentially abundant among the 3 groups, after correction for multiple testing. Modeling indicated that a 2-protein test using CSF had the highest accuracy for discriminating among all 3 groups. Cerebrospinal fluid R-spondin 1 (RSPO1) and neurofilament-light (NEFL), in parallel, predicted normal horses with an accuracy of 87.18%, CVCM with 84.62%, and eNAD/EDM with 73.5%., Main Limitations: Cross-species platform. Uneven sample size., Conclusions and Clinical Importance: Proximity extension assay technology allows for rapid screening of equine biologic matrices for potential protein biomarkers. Machine learning analysis allows for unbiased selection of highly accurate biomarkers from high-dimensional data., (© 2023 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals LLC on behalf of American College of Veterinary Internal Medicine.)

Physiotherapeutic exercises aimed at stimulating motor control, flexibility, and stability are regularly employed in human physical therapy programs. Specifically, the use of such exercises has been shown to reduce both pain and reinjury. Pursuant to the equine patient, several core strengthening exercises and their role in activating deep epaxial musculature to subsequently improve postural motor control and alter thoracolumbar kinematics have been investigated. Both baited and passive exercises offer opportunities to facilitate stretching during dynamic phases and strengthening during static phases of exercise. Blanket recommendations regarding prescription of exercises is not advised, individual patient prescription should be considered in context of handler safety, specific rehabilitation goals, and patient ability to effectively complete the exercise., Competing Interests: Disclosure The author has nothing to disclose., (Published by Elsevier Inc.)

Background: Cerebellar abiotrophy (CA) is an uncommon hereditary neurodegenerative disorder affecting the cerebellar Purkinje cells. Equine CA has been reported in several breeds, but a genetic etiology has only been confirmed in the Arabian breed, where CA is caused by an autosomal recessive mutation., Case Presentation: Clinical and histological findings consistent with CA are reported in an 8.5-month-old Icelandic filly. The filly showed a perceived sudden onset of marked head tremor, incoordination, ataxia, lack of menace response and a broad-based stance. Cerebrospinal fluid, hematological and biochemical findings were all within the normal range, ruling out several differential diagnoses. Post mortem histopathological examination revealed Purkinje cell degeneration accompanied by astrogliosis. Assessment of the filly's pedigree revealed that its parents shared a common ancestor., Conclusions: To the authors' knowledge, this is the first report of CA in the Icelandic breed. The identification of a common parental ancestor makes autosomal recessive inheritance of CA in this filly possible, but this would need to be confirmed by further studies. Veterinarians and breeders working with Icelandic horses should be aware of this condition and report suspected cases in order to support genetic investigation., (© 2022. The Author(s).)

An 8-y-old Labrador Retriever dog had mild ataxia of the hindlimbs 4 mo after lumbosacral dorsal laminectomy for intervertebral disk disease. Ataxia of the hindlimbs gradually worsened over the next 6 y. On autopsy, gross lesions were not recognized in the spinal cord. Histopathology revealed an intradural extraparenchymal cholesterol granuloma in the cauda equina associated with remnant nerve roots. Nerves associated with the cholesterol granuloma had axonal degeneration, myelin vacuolation, and edema. In those foci, macrophages were increased in number between nerve fibers. Immunohistochemistry for neurofilament protein and Luxol fast blue staining highlighted the presence of remnant axons and myelin sheaths within the granuloma. Inflammatory cell infiltrates in the granuloma were mainly macrophages and CD3- or CD20-immunopositive T or B lymphocytes, respectively. We conclude that the cholesterol granuloma likely formed subsequent to degenerative neuropathy in the cauda equina.

Supplements containing Cannabidiol (CBD) are available for horses, however, few studies have been published on their effects on behavior and health parameters. The purpose of this study was to determine if a daily oral supplement containing CBD would cause sedation, ataxia or alterations in other health parameters during administration for 56 days. Twenty clinically healthy adult Thoroughbred horses were housed in stalls. Before treatment was initiated, a complete physical examination, complete blood count (CBC) and biochemical panel were evaluated. In addition, horses were examined for sedation and ataxia using standard scoring systems. Horses were randomly divided into two treatment groups, treated (supplement pellets containing CBD as Hemp Extract, 150 mg) or control (supplement pellets without CBD). Horses were treated daily and sedation and ataxia scores were assigned by two masked observers once weekly for 56 days. Horses were monitored daily for clinical signs or adverse events and body weights were recorded weekly. A CBC and biochemical panel were repeated on days 28 and 56, two hours after administration of the supplement. The supplement was readily consumed by the horses and no adverse effects were seen over the treatment period. Sedation and ataxia scores ranged from zero to two for all horses during the weekly examinations and there was no statistical difference between treatment groups. There were no treatment effects on blood values, including indicators of anemia and blood proteins, liver enzymes, kidney values, electrolytes or calcium. Body weight significantly increased in all horses, by Day 56 compared to Day zero but no treatment by day effect was noted. The CBD supplement (150 mg) was readily consumed and safe and did not result in changes in mentation, gait, or other health parameters, and no adverse clinical signs were observed during 56 days of oral administration., (Copyright © 2022. Published by Elsevier Inc.)

Background: Since 2013, the number of requests for diagnosis for horses based on neurological symptoms has increased rapidly in South Korea. The affected horses have commonly exhibited symptoms of acute seasonal hindlimb ataxia. A previous study from 2015-2016 identified Setaria digitata as the causative agent., Objectives: This study is an epidemiological investigation to find out risk factors related to the rapid increase in hindlimb ataxia of horses due to aberrant parasites in South Korea., Methods: An epidemiological investigation was conducted on 155 cohabiting horses in 41 horse ranches where the disease occurred. The surrounding environment was investigated at the disease-causing horse ranches (n = 41) and 20, randomly selected, non-infected ranches., Results: Hindlimb ataxia was confirmed in nine cohabiting horses; this was presumed to be caused by ectopic parasitism. Environments that mosquitoes inhabit, such as paddy fields within 2 km and less than 0.5 km from a river, had the greatest association with disease occurrence., Conclusions: Most horse ranches in South Korea are situated in favorable environments for mosquitoes. Moreover, the number of mosquitoes in the country has increased since 2013 due to climate change. Additional research is required; however, these data show that it is necessary to establish guidelines for the use of anthelmintic agents based on local factors in South Korea and disinfection of the environment to prevent disease outbreaks., Competing Interests: The authors declare no conflicts of interest., (© 2022 The Korean Society of Veterinary Science.)

Depending on the localization of the lesion, spinal cord ataxia is the most common type of ataxia in horses. Most prevalent diagnoses include cervical vertebral stenotic myelopathy (CVSM), equine protozoal myeloencephalitis (EPM), trauma and equine degenerative myeloencephalopathy (EDM). Other causes of ataxia and weakness are associated with infectious causes, trauma and neoplasia. A neurologic examination is indispensable to identify the type of ataxia. In addition, clinical neurophysiology offers tools to locate functional abnormalities in the central and peripheral nervous system. Clinical EMG assessment looks at the lower motoneuron function (LMN) and is used to differentiate between neuropathy in peripheral nerves, which belong to LMNs and myopathy. As LMNs reside in the spinal cord, it is possible to grossly localize lesions in the myelum by muscle examination. Transcranial (tc) stimulation techniques are gaining importance in all areas of medicine to assess the motor function of the spinal cord along the motor tracts to the LMNs. Applications in diagnostics, intraoperative neurophysiological monitoring (IONM), and evaluation of effects of treatment are still evolving in human medicine and offer new challenges in equine medicine. Tc stimulation techniques comprise transcranial magnetic stimulation (TMS) and transcranial electrical stimulation (TES). TMS was first applied in horses in 1996 by Mayhew and colleagues and followed by TES. The methods are exchangeable for clinical diagnostic assessment but show a few differences. An outline is given on the principles, current clinical diagnostic applications and challenging possibilities of muscle evoked potentials (MEP) from transcranial stimulation in horses., (Copyright © 2022 The Author(s). Published by Elsevier Inc. All rights reserved.)

Background: Polymyxin B (PolyB) is used to treat endotoxemia in horses; neurologic and nephrogenic adverse effects occur in humans., Objectives: To describe PolyB adverse effects in horses., Animals: Five healthy horses (ataxia 0/5), 1 horse with cervical osteoarthritis (ataxia 1/5)., Methods: Prospective blinded randomized cross-over trial; 3-weeks wash out. Horses received PolyB (PolyB 6000 IU/kg IV, 7 doses q12h, n = 6) and PolyB/gentamicin (PolyB 6000 IU/kg IV, q12h 7 doses; gentamicin 10 mg/kg IV q24h 4 doses n = 4, or q12-24 h 5 doses because of an additional erroneous dose, n = 2). Daily neurological examinations were video recorded, and ataxia graded by 3 observers. Urine status, urinary GGT/creatinine ratio, plasma creatinine, and urea were assessed every other day, EMG daily. Mixed model analysis was used to evaluate factors associated with ataxia grade and [PolyB]., Results: Median ataxia score increased from 0/5 (range 0-2/5) to 2/5 (range 1-3/5) during administration and declined to 0.5/5 (range 0-2/5) after cessation. Gentamicin co-administration (P < .01, effect size: .8), number of PolyB doses (P < .001, effect size: .6), and time since last PolyB dose (P < .001, effect size: .5) had a significant effect on ataxia grades, while horse, day, [Genta], [PolyB], and [PolyB] CSF did not. Gentamicin co-administration and [Genta] C peak had no effect on median [PolyB] C peak (4.67 and 4.89 μg/ml for PolyB and PolyB/gentamicin, respectively). Urinary GGT/creatinine ratio was elevated in 3/6 horses receiving PolyB/gentamicin. The EMG remained unchanged., Conclusions and Clinical Importance: PolyB caused transient ataxia, worsening with cumulative PolyB doses and gentamicin co-administration. Nephrotoxicity of PolyB was only evident when gentamicin was co-administered., (© 2022 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals LLC on behalf of American College of Veterinary Internal Medicine.)

The present study aimed to compare the sedative and analgesic effects of caudal epidural administration of lidocaine alone or in combination with four different α 2 -adrenergic agonists in Mediterranean miniature donkeys. A total of ten clinically healthy (five males and five females) Mediterranean miniature donkeys with an age of 5 ± 1 years, a weight of 100 ± 2 kg and a height at the withers of 0.8 ± 0.06 m (mean ± standard deviation) were used in experimental, crossover (Latin square), randomized, and blinded study. Animals were assigned to five treatment groups including lidocaine alone (0.22 mg kg -1 ), or associated with one among xylazine (0.17 mg kg -1 ), detomidine (30 μg kg -1 ), medetomidine (15 μg kg -1 ), dexmedetomidine (5 μg kg -1 ) with a minimum washout period of 8 days between treatments. The degree of sedation was investigated using a simple descriptive scale of 0-3. Sedation scores were compared at each time using nonparametric (Kruskal-Wallis and Mann-Whitney U) tests. Analgesia was assessed by pinprick test. Sedation was greater in lidocaine and/or α 2 -adrenergic agonist groups than in lidocaine group at 45-75 minutes after drug administration (P < .05). There were no significant differences among groups in time to onset of analgesia and ataxia and also in number of animals with complete perineal analgesia and ataxia. Duration of analgesia and ataxia were longer in lidocaine and/or α 2 -adrenergic agonist groups than in lidocaine (P < .05). There were no significant differences among lidocaine and/or α 2 -adrenergic agonist groups in sedation score and duration of analgesia and ataxia. No significant differences were observed in heart and respiratory rate and also rectal temperature at any time points between groups and within groups. Caudal epidural administration of α 2 - adrenergic agonists associated with lidocaine resulted in sedative effects on Mediterranean miniature donkeys, while lidocaine alone did not induce sedation. These drugs associations should be considered when superior analgesia is advocated., (Copyright © 2022. Published by Elsevier Inc.)

Objective: To assess the outcome and safety of surgically placed artificial urethral sphincters in male dogs with urethral sphincter mechanism incompetence., Materials and Methods: We included dogs with urethral sphincter mechanism incompetence treated by placing an artificial urethral sphincter from January 1, 2010 to December 31, 2017. The continence score (scale 1 to 5, with 5 indicating complete continence) was evaluated before and after implantation. Follow-up information was obtained from the institution's medical records (short-term up to 12 months) and questionnaires were completed by telephone (long-term ≥12 months) for evaluation., Results: Medical therapy was unsuccessful in 18 dogs and unknown in one dog before the artificial urethral sphincter placement. Short-term continence improved in 16 of the 19 (84%) dogs. Four patients were lost to follow-up. Nine of 15 (60%) dogs showed long-term continence improvement, eight of 15 (53%) remained completely continent. The median follow-up was 1785 (range 2 to 3234) days. The complication rate was 56% (9/16). Minor complications, including haematoma, stranguria/temporary dyssynergia and mild inflammation at the port, were reported in four of 16 (25%) dogs. Five of 16 (31%) experienced major complications, including stranguria/mechanical urethral obstruction, persistent dyssynergia, fistula at the port and port rotation., Clinical Significance: Artificial urethral sphincter placement is a valid option for treating incontinent male dogs that show an insufficient response or become refractory to medical or other prior surgical management. A high-complication rate is associated with this procedure., (© 2022 British Small Animal Veterinary Association.)

The pharmacokinetics and pharmacodynamics of midazolam were studied in eight 1-to-3-year-old healthy gelded donkeys. Blood samples were obtained. Heart rate, respiratory rate, rectal temperature, sedation/excitement, ataxia, and response to tactile and auditory stimuli were recorded at baseline until 48 hours after intravenous (IV) midazolam (0.1 mg/kg) administration. Plasma midazolam and 1-hydroxymidazolam were measured using reversed-phase high-performance liquid chromatography. Pharmacokinetic variables were calculated using non-compartmental analysis. Physiologic data were analyzed using a mixed-effects model followed by Dunnett's test and behavioral data were analyzed using a Friedman test then a Dunn's test; P < 0.05 was considered significant. Midazolam was detectable for up to 60 minutes post-treatment in 7 donkeys. The median total body clearance, volume of distribution at steady state, elimination half-life, and area under concentration-time profile were 1210 mL/kg/h, 359 mL/kg, 0.27 hours, and 82.7 h × ng/mL, respectively. 1-hydroxymidazolam was detected (29 to 105 ng/mL) between 5 to 15 minutes post-treatment in 4 donkeys. Compared to baseline, rectal temperature and ataxia increased from 90 to 720 minutes ( P ≤ 0.038) and 3 to 15 minutes ( P ≤ 0.024) post-treatment, respectively. No other parameters showed statistically significant differences. Healthy donkeys cleared midazolam rapidly from plasma after IV administration. Transient ataxia and recumbency without sedation were observed., (Copyright and/or publishing rights held by the Canadian Veterinary Medical Association.)

An episodic nervous system disorder triggered by strenuous exercise, termed border collie collapse (BCC), exists in border collies and related breeds. The genetic basis of BCC is unknown but is believed to be a complex genetic disorder. Our goal was to estimate the heritability (h 2 SNP ) of BCC, define its underlying genetic architecture, and identify associated genomic loci using dense whole-genome single-nucleotide polymorphism (SNP) genotyping data. Genotype data were obtained for ~440,000 SNPs from 343 border collies (168 BCC cases and 175 controls). h 2 SNP was calculated to be 49-61% depending on the estimated BCC prevalence. A total of 2407 SNPs across the genome accounted for nearly all the h2 SNP of BCC, with an estimated 2003 SNPs of small effect, 349 SNPs of moderate effect, and 56 SNPs of large effect. Genome-wide association analyses identified significantly associated loci on chromosomes 1, 6, 11, 20, and 28, which accounted for ~5% of the total BCC h 2 SNP . We conclude that BCC is a moderately- to highly-heritable complex polygenetic disease resulting from contributions from hundreds to thousands of genetic variants with variable effect sizes. Understanding how much the BCC phenotype is determined by genetics and whether major gene mutations are likely to exist inform veterinarians and working/stock dog communities of the true nature of this condition.

Objective: To quantify the degree of dural compression and assess the association between site and direction of compression and articular process (AP) size and degree of dural compression with CT myelography., Animals: 26 client-oriented horses with ataxia., Procedures: Spinal cord-to-dura and AP-to-cross-sectional area of the C6 body ratios (APBRs) were calculated for each noncompressive site and site that had > 50% compression of the subarachnoid space. Site of maximum compression had the largest spinal cord-to-dura ratio. Fisher exact test and linear regression analyses were used to assess the association between site and direction of compression and mean or maximum APBR and spinal cord-todura ratio, respectively., Results: Mean ± SD spinal cord-to-dura ratio was 0.31 ± 0.044 (range, 0.20 to 0.41) for noncompressive sites and 0.44 ± 0.078 (0.29 to 0.60) for sites of maximum compression. Sites of maximum compression were intervertebral and extra-dural, most frequently at C6 through 7 (n = 10), followed by C3 through 4 (6). Thirteen horses had dorsolateral and lateral compression at the AP joints, secondary to AP (n = 7) or soft tissue proliferation (6). Site significantly affected direction of compression, and directions of compression from occiput through C4 were primarily ventral and lateral, whereas from C6 through T1 were primarily dorsal and dorsolateral. No linear relationship was identified between mean or maximum APBR and spinal cord-to-dura ratio., Conclusions and Clinical Relevance: CT myelography may be useful for examination of horses with suspected cervical compressive myelopathy. Degree of compression can be assessed quantitatively, and site of compression significantly affected direction of compression.

Background: Diseases of the central nervous system are a well-recognized cause of morbidity and mortality in equine. Collection and analysis of cerebrospinal fluid (CSF) give information about the type and stage of degenerative and inflammatory diseases in central nervous system (CNS). The present research aimed to assess the clinical complications of CSF collections and to establish range values of cytological and biochemical parameters of CSF in adult healthy donkeys (Equus asinus). The CSF samples were collected from fifty healthy donkeys at the lumbosacral (LS) and atlanto-occipital (AO) sites., Results: Hypothermia, tachycardia, ataxia and recumbency may develop post-puncture. Erythrocytes were noticed in 35 of 50 CSF samples. Total nucleated cell counts ranged from 0 to 6 cells/μL, and lymphocytes predominated the cells (61%). The concentration of glucose (1.2 to 5.3 mmol/L) was lower than that of serum (P < 0.05). The CSF sodium concentration (123 to 160 mmol/L) was approximately like that of serum, but potassium (1.5-3 mmol/L) was lower than that of serum (P < 0.01). Urea concentrations (1.1-2.9 mmol/L) were markedly lower than serum (P < 0.001). Concentrations of CSF total proteins, and albumin ranged from 0.1 to 0.6 g/dL, and from 0.002 to 0.013 g/dL, respectively. The albumin quotient ranged from 0.06 to 0.56., Conclusions: Transient hypothermia, tachycardia, ataxia and recumbency may develop as clinical complications of CSF puncture procedures. The collection site has no impact on the constituents in CSF. Furthermore, this study presented the range values for normal cytological and biochemical constituents of CSF in donkeys (Equus asinus) that can provide a basis in comparison when evaluating CSF from donkeys with neurologic diseases., (© 2021. The Author(s).)

An 8-year-old Warmblood gelding presented with a history of progressive ataxia for 6 weeks. Intra- and intervertebral ratios measured from lateral radiographs of the cervical spine were within normal limits. Computed tomographic myelography of the cervical spine revealed focal compression of the dorsal and the ventral contrast column as well as a ventral displacement of the spinal cord within the spinal canal due to a bulging of soft tissue attenuating material in the dorsal half of the intervertebral junction of C6 and C7. Post-mortem histopathological examination confirmed chondroid metaplasia of the ligamentum flavum at C6-C7., (© 2021 The Authors. Veterinary Radiology & Ultrasound published by Wiley Periodicals LLC on behalf of American College of Veterinary Radiology.)

Objective: To determine the feasibility of umbilical cord-derived mesenchymal stem cell (UC-MSC) transplantation into the cervical spinal cord of horses by using fluoroscopy with or without endoscopic guidance and to evaluate the neurological signs and tissue reaction after injection., Study Design: Experimental study., Animals: Eight healthy adult horses with no clinical signs of neurological disease., Methods: After cervical ventral interbody fusion (CVIF), ten million fluorescently labeled allogeneic UC-MSC were injected into the spinal cord under endoscopic and fluoroscopic guidance (n = 5) or fluoroscopic guidance only (n = 3). Postoperative neurological examinations were performed, and horses were humanely killed 48 hours (n = 4) or 14 days (n = 4) postoperatively. Spinal tissues were examined after gross dissection and with bright field and fluorescent microscopy., Results: Needle endoscopy of the cervical canal by ventral approach was associated with intraoperative spinal cord puncture (2/5) and postoperative ataxia (3/5). No intraoperative complications occurred, and one (1/3) horse developed ataxia with cell transplantation under fluoroscopy alone. Umbilical cord-derived MSC were associated with small vessels and detected up to 14 days in the spinal cord. Demyelination was observed in six of eight cases., Conclusion: Fluoroscopically guided intramedullary UC-MSC transplantation during CVIF avoids spinal cord trauma and decreases risk of ataxia from endoscopy. Umbilical cord-derived MSC persist in the spinal cord for up to 14 days. Cell injection promotes angiogenesis and induces demyelination of the spinal tissue., Clinical Significance: Umbilical cord-derived MSC transplantation into the spinal cord during CVIF without endoscopy is recommended for future evaluation of cell therapy in horses affected by cervical vertebral compressive myelopathy., (© 2021 The American College of Veterinary Surgeons.)

Objective: To determine period prevalences of postmortem diagnoses for spinal cord or vertebral column lesions as underlying causes of ataxia (spinal ataxia) in horses., Animals: 2,861 client-owned horses (316 with ataxia [ataxic group] and 2,545 without ataxia [control group])., Procedures: The medical records database of the University of California-Davis Veterinary Medical Teaching Hospital was searched to identify horses necropsied between January 1, 2005, and December 31, 2017. Results were compared between the ataxic and control groups and between various groups of horses in the ataxic group. Period prevalences were determined for the most common causes of ataxia., Results: 2,861 horses underwent full necropsy, and the period prevalences for the most common definitive diagnoses for ataxia were 2.7% (77/2,861) for cervical vertebral compressive myelopathy (CVCM), 1.3% (38/2,861) for equine neuroaxonal dystrophy or equine degenerative myeloencephalopathy (eNAD-EDM), and 0.9% (25/2,861) for trauma; the period prevalence of ataxia of unknown origin was 2.0% (56/2,861). Horses in the ataxic group (vs the control group) were more likely to have been warmblood horses (OR, 2.70) and less likely to have been Arabian horses (OR, 0.53). In the ataxic group, horses < 5 (vs ≥ 5) years of age had greater odds of CVCM (OR, 2.82) or eNAD-EDM (OR, 6.17) versus trauma or ataxia of unknown origin. Horses in the ataxic group with CVCM were more likely Thoroughbreds (OR, 2.54), whereas horses with eNAD-EDM were more likely American Quarter Horses (OR, 2.95) and less likely Thoroughbreds (OR, 0.11)., Conclusions and Clinical Relevance: Results indicated that breed distributions differed for horses with CVCM versus eNAD-EDM; therefore, breed should be considered in the clinical evaluation of spinal ataxia in horses.

This study was performed to examine and clarify the cause of hindlimb ataxia and neuropathy seen in the South Korean horse population. Fifty horses diagnosed with hindlimb ataxia and neuropathy were referred for this study. Neurological examination was performed on 47 horses while necropsy was performed in all 50 animals. The occurrence of neurological diseases increased rapidly in the summer and 47 out of 50 horses were referred after the end of July. The incidence of neurological diseases started from the southern part of Korea in July and proceeded northward in August and September. Although there was no correlation with age, Thoroughbred and Warmblood horses showed a higher incidence rate than Halla and Jeju horses. The incidence rate was 5 times higher in geldings than in mares and stallions. Of the 20 cases, 16 were diagnosed with eosinophilic meningoencephalomyelitis in 2015. The most common lesions observed in 2016 were parasitic meningoencephalomyelitis (10 cases, 33%) and eosinophilic meningomyelitis (7 cases, 23%). Histopathological analysis of the brain and spinal cord revealed nematodes of approximately 100-200 µm in diameter, microcavitation and infiltrates of eosinophils, and brown pigmented macrophage infiltrates. The nematodes were identified as Setaria digitata via DNA sequencing, performed subsequent to polymerase chain reaction using DNA isolated from formalin-fixed paraffin-embedded tissue sections of the spinal cord. These results show that aberrant migration of Setaria digitata larva in the brain and spinal cord was a major cause for neurological signs in horses.

Background: Shaking puppy syndrome is commonly attributed to abnormal myelination of the central nervous system., Hypothesis/objectives: To report the long-term clinical course and the imaging characteristics of hypomyelinating leukodystrophy in German Shepherd dogs., Animals and Methods: Three related litters with 11 affected dogs., Results: The 11 affected dogs experienced coarse, side-to-side tremors of the head and trunk, which interfered with normal goal-oriented movements and disappeared at rest. Signs were noticed shortly after birth. Nine dogs were euthanized, 3 dogs underwent pathological examination, and 2 littermates were raised by their breeder. Tremors improved gradually until 6 to 7 months of age. Adult dogs walked with severe residual pelvic limb ataxia. One dog developed epilepsy with tonic-clonic seizures at 15 months of age. Conventional magnetic resonance imaging (MRI) disclosed homogenous hyperintense signal of the entire subcortical white matter in 3 affected 7-week-old dogs and a hypointense signal in a presumably unaffected littermate. Subcortical white matter appeared isointense to gray matter at 15 and 27 weeks of age on repeated MRI. Abnormal white matter signal with failure to display normal gray-white matter contrast persisted into adulthood. Cerebellar arbor vitae was not visible at any time point. Clinical signs, MRI findings, and pathological examinations were indicative of a hypomyelinating leukodystrophy. All parents of the affected litters shared a common ancestor and relatedness of the puppies suggested an autosomal recessive mode of inheritance., Conclusion: We describe a novel hypomyelinating leukodystrophy in German Shepherd dogs with a suspected inherited origin., (© 2021 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals LLC. on behalf of the American College of Veterinary Internal Medicine.)

Background: Abnormalities of the ventral lamina of the sixth cervical vertebra (AVL-C6) are thought to exert abnormal stress on the articular process joints (APJs) of the cervicothoracic junction. The aim of the study was to investigate the association between AVL-C6 and radiographic findings in the caudal cervical area and between clinical signs of neck pain and ataxia and radiographic findings., Methods: Medical records of horses subjected to cervical radiography were reviewed. Horses were classified into those with neck pain (group C), those with ataxia (group A) and healthy horses (group H). Presence of AVL-C6 and increased size, dysplasia, remodelling, fragmentation and osteochondral fragment at the APJs (C5-T1) were recorded. Univariable logistic regression analysis was performed to identify the associations between explanatory and dependent variables. Variables with P<0.2 were included in the multivariable analysis., Results: One hundred and sixteen horses were included (44 in group C, 29 in group A, 66 in group H); 24 of 116 horses had radiographic AVL-C6. Age, AVL-C6 and overall/C6-C7 increase in size remained in the final models., Conclusions: The presence of AVL-C6 and moderate/severe increase in size of the caudal cervical APJs increase the odds of showing neck pain and, if severe, ataxia., Competing Interests: Competing interests: None declared., (© British Veterinary Association 2020. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: This case report describes the clinical signs of a calf with focal diplomyelia at the level of the fourth lumbar vertebra. Magnetic resonance imaging (MRI) images and histological findings of the affected spinal cord are included in this case report. This case differs from previously reported cases in terms of localization and minimal extent of the congenital anomaly, clinical symptoms and findings during further examinations., Case Presentation: The calf was presented to the Farm Animal Health clinic, Faculty of Veterinary Medicine, Utrecht University, with an abnormal, stiff, 'bunny-hop' gait of the pelvic limbs. Prominent clinical findings included general proprioceptive ataxia with paraparesis, pathological spinal reflexes of the pelvic limbs and pollakiuria. MRI revealed a focal dilated central canal, and mid-sagittal T2 hyperintense band in the dorsal part of the spinal cord at the level of the third to fourth lumbar vertebra. By means of histology, the calf was diagnosed with focal diplomyelia at the level of the fourth lumbar vertebra, a rare congenital malformation of the spinal cord. The calf tested positive for Schmallenberg virus antibodies, however this is not considered to be part of the pathogenesis of the diplomyelia., Conclusions: This case report adds value to future clinical practice, as it provides a clear description of focal diplomyelia as a previously unreported lesion and details its diagnosis using advanced imaging and histology. This type of lesion should be included in the differential diagnoses when a calf is presented with a general proprioceptive ataxia of the hind limbs. In particular, a 'bunny-hop' gait of the pelvic limbs is thought to be a specific clinical symptom of diplomyelia. This case report is of clinical and scientific importance as it demonstrates the possibility of a focal microscopic diplomyelia, which would not be evident by gross examination alone, as a cause of hind-limb ataxia. The aetiology of diplomyelia in calves remains unclear.

Lysosomal storage diseases are inherited and acquired disorders characterized by dysfunctional lysosomes. Intracytoplasmic accumulation of undegraded substrates leads to impaired cellular function and death. Several plant species are toxic to livestock because of the presence of indolizidine alkaloids, including swainsonine, which cause a storage disease. Swainsonine-induced nervous disease (i.e., locoism) of sheep and cattle is well recognized in several parts of the world, particularly in the western United States and in parts of Australia. Spontaneous intoxication by Astragalus garbancillo var. garbancillo was suspected in a group of 70 llamas ( Lama glama ) in Jujuy Province, northwestern Argentina. The animals grazed an area dominated by stands of A. garbancillo var. garbancillo . Clinical signs were staggering, ataxia, hypermetria, and progressive weight loss. The clinical course in individual animals was ~50 d. The main microscopic changes were Purkinje cell degeneration, necrosis, and loss, associated with intracytoplasmic vacuolation, meganeurite formation, and Wallerian degeneration. Specific positive labeling for ubiquitin was observed in axonal spheroids. Composite leaf and stem samples of A. garbancillo var. garbancillo analyzed by high-performance liquid chromatography contained 0.03% swainsonine. Based on the microscopic lesions, clinical history, and plant analysis, a diagnosis was made of storage disease caused by consumption of swainsonine-containing A. garbancillo var. garbancillo .

A 2-y-old Brahman bull was presented with progressive hindlimb ataxia and paraparesis that led to recumbency. Postmortem examination revealed scattered pinpoint, red-brown foci within the brainstem and gray matter of the spinal cord, and a larger lesion within the spinal cord at the level of T13. Histology of the section of T13 contained cross-sections of nematodes consistent with Parelaphostrongylus tenuis . Evidence of inflammation was present in other affected areas of the spinal cord and brain. DNA extraction and nested PCR were performed, which demonstrated 98% identity and 100% coverage to both P. tenuis and P. andersoni . Our case highlights the utility of DNA sequencing in parasite identification.

The objective of this study was to determine if the genotype of equine herpesvirus-1 (EHV-1) impacted clinical disease and outcome of horses with laboratory confirmed equine herpesvirus myeloencephalopathy (EHM). Medical records from 65 horses diagnosed with EHM from 2011 to 2019 were reviewed for signalment, presence and severity of clinical signs (lethargy, fever, ataxia, urinary incontinence) and outcome. Horses were further grouped based on the EHV-1 genotype into neuropathic (D 752 ) or non-neuropathic (N 752 ) EHV-1 infection. Between the two EHV-1 genotype groups, age and sex distributions were similar, although breed distribution was different (Quarter Horses and Saddlebreds were overrepresented and Warmbloods were underrepresented in the EHV-1 D 752 group compared to the EHV-1 N 752 group; P = 0.009). Lethargy, fever, ataxia and outcome were not significantly different between the two EHV-1 genotype groups (P > 0.05). However, urinary incontinence was significantly more frequently reported in horses infected with the D 752 genotype of EHV-1 (P=0.04). Contrary to previous studies, the present study showed no difference in frequency of genotype (D 752 or N 752 ) among 65 horses with EHM and, with the exception of urinary incontinence, no difference in clinical disease or outcome related to the EHV-1 genotype., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Aims : To assess the use of potassium bromide (KBr) as a therapeutic intervention for perennial ryegrass toxicosis (PRGT) in lambs fed ryegrass seed containing lolitrem B. Methods : Male lambs aged 10-12 months (n = 43) were assigned to receive ryegrass seed containing lolitrem B, at a dose of 0.16 mg/kg/day (Groups 2, 3 and 4), or lucerne chaff and molasses (Groups 1 and 5). Lambs in Groups 2 and 3 were observed for clinical signs and gait changes until defined signs of PGRT were observed, when they were transferred, with lambs in Group 1, to the Testing phase of the trial. Lambs in Group 3 were then treated with a single oral dose of 300 mg/kg bromide. Lambs in Groups 4 and 5 received KBr daily from the start of the trial (540 mg/kg bromide over 3 days then 20 mg/kg daily) and were transferred to the Testing phase after 18 days. Clinical examination and gait assessment, and surface electromyography of the triceps muscle, measuring root-mean-square (RMS) voltages, were carried out on Days 0, 1 and 2 of the Testing phase followed by necropsy, histopathology, measurement of concentrations of bromide in serum and CSF and faecal cortisol metabolites (FCM). Results : In Group 3 lambs, mean composite gait scores decreased between Testing phase Day 0 and Days 1 and 2 (p < 0.001), but increased in lambs in Group 2 between Day 0 and Day 2 (p = 0.015). Scores for lambs in Group 3 on Day 2 were lower than for lambs in Group 2 (p < 0.001). Mean RMS voltages on Day 2 were higher in lambs in Group 2 than Group 3 (p = 0.045). Mean concentrations of bromide in serum were >800 µg/mL in lambs in Groups 3 and 4 on Day 2. Concentrations of FCM were higher in lambs from Group 2 than in Groups 1 or 5, but were similar in Groups 2, 3 and 4. Histopathological findings in the cerebellum of lambs from Groups 2, 3 and 4 were similar, showing pyknosis of neurons within the granular layer of the cerebellum and Purkinje neuron proximal axonal spheroid formation. Conclusions and clinical relevance : A single oral dose of 300 mg/kg bromide in lambs with neurological signs of PRGT resulted in reduced composite gait scores and reduced RMS voltages, indicating a significant improvement in clinical signs of ataxia, movement disorder and muscle tremor associated with the neurotoxic effects of lolitrem B.

Background: Transcranial magnetic stimulation (TMS) and recording of magnetic motor evoked potentials (MMEP) can detect neurological dysfunction in horses but cutoff values based on confirmed spinal cord dysfunction are lacking., Objectives: To determine latency time cutoff for neurological dysfunction., Animals: Five control horses and 17 horses with proprioceptive ataxia., Methods: Case-control study with receiver operating characteristic curve analysis, based on diagnostic imaging, TMS, and histopathological findings. Horses were included if all 3 examinations were performed., Results: Diagnostic imaging and histopathology did not show abnormalities in the control group but confirmed spinal cord compression in 14 of 17 ataxic horses. In the remaining 3 horses, histopathological lesions were mild to severe, but diagnostic imaging did not confirm spinal cord compression. In control horses, latency time values of thoracic and pelvic limbs were significantly lower than in ataxic horses (20 ± 1 vs 34 ± 16 milliseconds, P = .05; and 39 ± 1 vs 78 ± 26 milliseconds, P = .004). Optimal cutoff values to detect spinal cord dysfunction were 22 milliseconds (sensitivity [95% CI interval], 88% [73%-100%]; specificity, 100% [100%-100%]) in thoracic and 40 milliseconds (sensitivity, 94% [83%-100%]; specificity, 100% [100%-100%]) in pelvic limbs. To detect spinal cord dysfunction caused by compression, the optimal cutoff for thoracic limbs remained 22 milliseconds, while it increased to 43 milliseconds in pelvic limbs (sensitivity, 100% [100%-100%]; specificity, 100% [100%-100%] for thoracic and pelvic limbs)., Conclusions and Clinical Importance: Magnetic motor evoked potential analysis using these cutoff values is a promising diagnostic tool for spinal cord dysfunction diagnosis in horses., (© 2019 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals, Inc. on behalf of the American College of Veterinary Internal Medicine.)

Background: Cervical vertebral stenotic myelopathy (CVSM) remains one of the most important abnormalities of the cervical spine resulting in neurological deficits in horses. The aim of the following study was to compare the results of the clinical and neurological examination, the results of myelography and the post mortem anatomical and histological appearance of the spinal cord and cervical vertebrae in a horse with CVSM., Case Presentation: The following study describes a clinical case of an eight-month-old stallion with ataxia. Plain cervical radiographs indicated narrowing of the spinal canal. Conservative therapy using NSAIDs did not result in any improvement in the gait of the horse. Due to economic constraints, surgical intervention was excluded. The owner chose to humanely euthanise the horse. Immediately after euthanasia, post mortem myelography was performed, and measurements of the myelographic dye column were taken. They revealed a 67% DMC reduction and a 64% DD reduction at the C3/C4 level. Afterwards, an anatomical dissection was performed. The cervical vertebrae and vertebral canal were macroscopically inspected and measured and indicated a 44% narrowing of the canal at the C3/C4 level. The spinal cord was removed and underwent histological evaluation after staining. Microscopic lesions were visible at the level of the compression and included axonal degeneration with partial or complete loss of myelin in the white matter of the lateral and dorsal funiculi as well as the formation of dysfunctional so-called "spongy structures". An increase in the number of microglial cells and collagen was also observed. The formation of glial scars was excluded. Immunohistochemical studies revealed a negative transmembrane glycoprotein CD68(-) - monocyte response and a negative tumor necrosis alpha TNFα (-) reaction., Conclusions: CVSM may be difficult to diagnose, even for experienced veterinary surgeons. Currently, an ex vivo histopathologic examination of the spinal cord is thought to be the gold standard in the diagnosis of CVSM. Our histological examination revealed no CVSM-specific glial scar formation and a CD68(-) negative and TNF-α negative reaction, which have not been previously reported. Histological lesions in CVSM may vary depending show inter-individual variability and on the treatment, which further hinders ex-vivo diagnostics.

Background: One of the remaining questions in treating dogs with internal hydrocephalus is the association between the decrease of ventricular volume and re-expansion of cerebral parenchyma with clinical improvement., Hypothesis: A decrease in ventricular volume and re-expansion of brain tissue occur after ventriculoperitoneal shunting (VPS). Clinical improvement defined by resolution of ≥1 clinical signs is associated with decreased size of cerebral ventricles and that the extent of change in ventricular size is associated with clinical improvement., Animals: Forty-five client-owned dogs with newly diagnosed communicating internal hydrocephalus., Methods: Ventricular volume, brain volume, and clinical status of dogs that underwent VPS were measured before and 3 months after surgery. Multiple logistic regression analysis was performed to assess the influence of decrease in ventricular size in addition to the covariates "age of the animal" and "duration of clinical signs before surgery" on improvement of clinical signs., Results: Decreased volume of cerebral ventricles was associated with resolution of ≥1 preoperative clinical sign (P < .003). The covariates "age of the animal" and "duration of clinical signs" were not associated with improvement of clinical signs. The percentage decrease in ventricular size was associated with resolution of ataxia (P = .008) and obtundation (P = .011)., Conclusion and Clinical Importance: The decrease in ventricular volume and increase in brain parenchyma after VPS are associated with improvement in clinical signs., (© 2019 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals, Inc. on behalf of the American College of Veterinary Internal Medicine.)