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Bruce Mcgorum - One of the best experts on this subject based on the ideXlab platform.
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managing the chronic Grass Sickness case
UK-Vet Equine, 2018Co-Authors: Scott Pirie, Bruce McgorumAbstract:The acute and subacute forms of equine Grass Sickness (EGS) are invariably fatal. In comparison, approximately 45–55% of cases with the chronic form of EGS recover with intensive nursing care. Prior to, and throughout the period of nursing, the clinician can be faced with difficult decision making dilemmas, including the identification of suitable candidates for treatment, the selection of an applicable treatment plan and the establishment of appropriate criteria to inform the decision for continued treatment or euthanasia. This article will cover the various aspects of nursing care and will also address some of the difficult clinical decisions, the outcomes of which have a major impact both on the case and the owner.
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equine Grass Sickness an update
UK-Vet Equine, 2018Co-Authors: Scott Pirie, Bruce McgorumAbstract:Equine Grass Sickness (EGS), a pasture-associated multi-system neuropathy of horses, continues to present a diagnostic, therapeutic, prognostic and prophylactic challenge to clinicians. The associated high mortality rate, and the potentially devastating implications for both horse owners and premises managers, combine to make EGS an extremely emotive disease. This has resulted in almost continuous research activity throughout the years, principally aimed at identifying a causal agent, but also focused on improving diagnostic accuracy, treatment success and the effectiveness of preventative strategies. This article briefly reviews the established facts regarding EGS derived from decades of research, and highlights recent research that has aetiological, diagnostic and prognostic relevance.
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histological assessment of β amyloid precursor protein immunolabelled rectal biopsies aids diagnosis of equine Grass Sickness
Equine Veterinary Journal, 2018Co-Authors: R. C. Jago, R. S. Pirie, Elspeth Milne, Ian Handel, T S Mair, Sandra Scholes, Gemma Pearson, F Coyle, Bruce McgorumAbstract:SummaryBackground An accurate, minimally invasive, ante mortem, diagnostic test for equine Grass Sickness (EGS) is currently lacking. While histological examination of haematoxylin-eosin stained rectal biopsies for chromatolytic neurons is insensitive as a diagnostic test for EGS, we hypothesised that the diagnostic accuracy could be improved by immunolabelling for β-amyloid precursor protein (β-APP) which has increased expression in cranial cervical ganglia (CCG) neuronal perikarya in EGS. Objectives To develop a grading scheme for assessing the distribution and intensity of β-APP immunoreactivity within individual rectal submucosal neurons and subsequently determine the diagnostic value of the distribution of different grades of neurons for EGS diagnosis. Study design Retrospective case-control diagnostic accuracy study. Methods Initially a standardised grading scheme was developed and β-APP immunoreactivity in individual neuronal perikarya and axons was compared in sections of CCG and ileum from EGS and control horses. The grading scheme was further refined before being blindly applied to submucosal neurons in rectal biopsies derived from 21 EGS and 23 control horses. Results β-APP immunoreactivity was increased in neuronal perikarya and axons in sections of CCG, ileum and rectum from EGS horses compared with controls. For rectal biopsies, a mean immunoreactivity grade exceeding 1.1 was 100% specific and sensitive for EGS, and the presence of at least one neuron with diffuse labelling of the entire cytoplasm (grade 3) was 95% sensitive and 100% specific for EGS. Main limitations While the diagnostic criteria facilitated discrimination of the EGS and control biopsies evaluated in this study, further prospective validation using a larger sample set is required. Conclusions Histological assessment of β-APP immunolabelled rectal biopsies is more sensitive than conventional histological examination for EGS diagnosis. Further validation is required before this technique can be advocated for clinical decision making. This article is protected by copyright. All rights reserved.
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neurodegeneration in equine Grass Sickness is not attributable to niacin deficiency
Equine Veterinary Journal, 2017Co-Authors: Bruce Mcgorum, R. S. Pirie, R. C. Jago, John Keen, Eugenio Cillangarcia, Richard Reardon, P Y Saffu, N J MillerAbstract:SummaryBackground The aetiology of equine Grass Sickness (EGS) is currently unknown. We hypothesised that acute deficiency of niacin (vitamin B3), which has a key role in neural homeostasis, may contribute to neurodegeneration in EGS. Niacin deficiency could potentially result from ingestion of niacin antagonists produced by pasture mycotoxigenic fungi. Objectives To compare the niacin status of EGS and control grazing horses. A secondary objective was to compare blood concentrations of vitamins B1, B2 and B6 in EGS and control grazing horses to determine if the status of these vitamins was altered in EGS. Study design Case-control study. Methods Indices of niacin status, namely the erythrocyte nicotinamide adenine dinucleotide:nicotinamide adenine dinucleotide phosphate ratio (NAD:NADP ratio) and erythrocyte concentrations of NAD and NADP, were compared in blood collected from EGS and healthy control grazing horses. Blood concentrations of vitamins B1, B2 and B6 were also compared. Results There was no significant inter-group difference in the NAD:NADP ratio, the main index of functional niacin status (control median 2.1, interquartile range 1.8-2.6; EGS 2.1, 1.9-2.6). EGS horses had significantly higher (median value increased by 25%) concentrations of NADP. There were no inter-group differences in blood concentrations of vitamins B1, B2 and B6. Main limitations Interpretation of data was limited by lack of previously defined equine reference ranges for many of the analytes. Sample size was low. Conclusions Niacin deficiency does not contribute to EGS neurodegeneration. This article is protected by copyright. All rights reserved.
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bodyweight change aids prediction of survival in chronic equine Grass Sickness
Equine Veterinary Journal, 2016Co-Authors: R. C. Jago, R. S. Pirie, Caroline Hahn, Ian Handel, John Keen, Bryony Waggett, Bruce McgorumAbstract:SummaryReasons for performing study Objective criteria for predicting survival of chronic Grass Sickness cases are currently lacking. Objectives To determine whether the rate and/or magnitude of bodyweight change during hospitalisation of chronic Grass Sickness cases can provide an objective predictor of survival to discharge from hospital. Clinicians’ recorded indication(s) for euthanasia were also reviewed. Study design Single centre retrospective observational study. Methods Case records of all horses admitted for management of chronic Grass Sickness to The Dick Vet Equine Hospital between 1998 and 2013 were analysed. Case background, survival to hospital discharge, indication(s) for euthanasia, disease duration at admission and bodyweight changes during the hospitalisation period were analysed, and data for survivors and nonsurvivors compared. Percentage weight change was calculated for 7 day intervals up to 28 days (0–7, 7–14, 14–21, 21–28 days) and for entire periods from the first weight recorded (0–7, 0–14, 0–21, 0–28 days). These results were used to estimate survival probability conditional on weight change. Results The study sample comprised 213 horses, with 114 survivors (53.5%) and 99 (46.5%) nonsurvivors. Compared with nonsurvivors, survivors had significantly lower median maximum bodyweight loss as a percentage of first weight (survivors 5.9%, interquartile range 1.8–13.5; nonsurvivors 12.7%, 6.4–17.3). Throughout all time periods analysed, survivors had significantly lower median bodyweight loss than nonsurvivors, but no specific time period was more predictive of survival. Highest percentages of total bodyweight loss for individual horses were comparable for survivors (36%) and nonsurvivors (37%). Survival prediction curves reporting percentage survival rates for all time periods analysed provided data to aid prediction of chronic Grass Sickness survival. Conclusions Overall, nonsurvivors had greater bodyweight loss than survivors. Rapidity and magnitude of bodyweight loss were equally predictive of outcome. Percentage survival prediction curves provide objective data to aid discussion of prognosis, but greater predictive specificity with associated sensitivity is required for clinical decision making in individual cases.
Elspeth Milne - One of the best experts on this subject based on the ideXlab platform.
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histological assessment of β amyloid precursor protein immunolabelled rectal biopsies aids diagnosis of equine Grass Sickness
Equine Veterinary Journal, 2018Co-Authors: R. C. Jago, R. S. Pirie, Elspeth Milne, Ian Handel, T S Mair, Sandra Scholes, Gemma Pearson, F Coyle, Bruce McgorumAbstract:SummaryBackground An accurate, minimally invasive, ante mortem, diagnostic test for equine Grass Sickness (EGS) is currently lacking. While histological examination of haematoxylin-eosin stained rectal biopsies for chromatolytic neurons is insensitive as a diagnostic test for EGS, we hypothesised that the diagnostic accuracy could be improved by immunolabelling for β-amyloid precursor protein (β-APP) which has increased expression in cranial cervical ganglia (CCG) neuronal perikarya in EGS. Objectives To develop a grading scheme for assessing the distribution and intensity of β-APP immunoreactivity within individual rectal submucosal neurons and subsequently determine the diagnostic value of the distribution of different grades of neurons for EGS diagnosis. Study design Retrospective case-control diagnostic accuracy study. Methods Initially a standardised grading scheme was developed and β-APP immunoreactivity in individual neuronal perikarya and axons was compared in sections of CCG and ileum from EGS and control horses. The grading scheme was further refined before being blindly applied to submucosal neurons in rectal biopsies derived from 21 EGS and 23 control horses. Results β-APP immunoreactivity was increased in neuronal perikarya and axons in sections of CCG, ileum and rectum from EGS horses compared with controls. For rectal biopsies, a mean immunoreactivity grade exceeding 1.1 was 100% specific and sensitive for EGS, and the presence of at least one neuron with diffuse labelling of the entire cytoplasm (grade 3) was 95% sensitive and 100% specific for EGS. Main limitations While the diagnostic criteria facilitated discrimination of the EGS and control biopsies evaluated in this study, further prospective validation using a larger sample set is required. Conclusions Histological assessment of β-APP immunolabelled rectal biopsies is more sensitive than conventional histological examination for EGS diagnosis. Further validation is required before this technique can be advocated for clinical decision making. This article is protected by copyright. All rights reserved.
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evaluation of synaptophysin as an immunohistochemical marker for equine Grass Sickness
Journal of Comparative Pathology, 2010Co-Authors: Bryony Waggett, R. S. Pirie, Bruce Mcgorum, U Wernery, Darren J Shaw, Neil Macintyre, Elspeth MilneAbstract:It has been proposed that synaptophysin, an abundant integral membrane protein of synaptic vesicles, is an immunohistochemical marker for degenerating neurons in equine Grass Sickness (GS). In the present study, a statistically generated decision tree based on assessment of synaptophysin-immunolabelled ileal sections facilitated correct differentiation of all 20 cases of GS and 24 cases of non-GS disease (comprising eight horses with colic, six with neuroparalytic botulism and 10 controls). This technique also facilitated correct diagnosis of GS in all three cases that had been erroneously classified as having non-GS disease based on conventional interpretation of haematoxylin and eosin-stained cryostat sections of ileal surgical biopsies. Further prospective studies involving larger numbers of horses are required to fully validate this decision tree. In contrast to GS, botulism did not alter ileal neuron density or synaptophysin labelling, indicating that different mechanisms cause neuronal damage and/or dysfunction in GS and botulism.
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evaluation of formalin fixed ileum as the optimum method to diagnose equine dysautonomia Grass Sickness in simulated intestinal biopsies
Journal of Veterinary Diagnostic Investigation, 2010Co-Authors: Elspeth Milne, Scott Pirie, B.c. Mcgorum, Darren J ShawAbstract:Equine dysautonomia, or Grass Sickness, is a frequently fatal disease of unknown etiology, manifested as poor gastrointestinal motility and colic as a result of degenerative changes in the autonomic nervous system. Examination of ileal biopsies collected at laparotomy is currently the best antemortem diagnostic method to distinguish equine dysautonomia from colic cases, which can present with similar signs, but their value has not been previously critically evaluated. Using simulated biopsies collected postmortem from 23 cases of equine dysautonomia and 11 of colic, the sensitivity and specificity of 1-cm long, formalin- fixed ileal biopsies was 100% for the diagnosis of equine dysautonomia. There was therefore no advantag et o using larger biopsies or examining jejunum either in addition to or instead of ileal biopsies. Furthermore, although cryostat sections of ileum, 1-cm long, had a sensitivity of 100%, the specificity was only 73%, meaning that 27% of cases would have been misclassified, resulting in unnecessary euthanasia. Increasing the size of the cryostat or examining jejunum in addition to ileum cryostat sections did not significantly improve the specificity. Results of the current study indicate that in diagnostic practice, 1-cm long, formalin-fixed biopsies are likely to be the most suitable for accurate diagnosis, despite the slower turnaround time compared with cryostat sections.
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evaluation of urinalysis as an aid in the diagnosis of equine Grass Sickness
Veterinary Record, 2002Co-Authors: C Fintl, Elspeth Milne, Bruce McgorumAbstract:To determine whether urinalysis can aid the diagnosis of equine Grass Sickness, samples of urine from 15 horses with acute Grass Sickness, eight horses with subacute Grass Sickness, 17 co-grazing horses and 17 stabled control horses were analysed. The samples from all of the horses with Grass Sickness had a significantly higher specific gravity, higher protein and creatinine concentrations and a significantly lower pH; the samples from the horses with acute Grass Sickness also had significantly higher glucose concentrations. These differences may support a diagnosis of Grass Sickness but they are not pathognomonic for the disease.
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liver and biliary system pathology in equine dysautonomia Grass Sickness
Journal of Veterinary Medicine Series A-physiology Pathology Clinical Medicine, 2001Co-Authors: J Marrs, Elspeth Milne, J Small, H A JohnAbstract:Hepatocellular and hepatobiliary damage was assessed in equine acute, subacute and chronic Grass Sickness cases (AGS, SAGS, CGS). Histopathological analysis showed that even in some early AGS cases enlarged hepatocytes, hepatocyte vacuolation indicative of lipid accumulation (steatosis), intrahepatocyte, canalicular and periportal deposition of pigments, frequent leucocyte infiltration and cholangitis occurred. Analysis of serum indicated significantly increased levels of unconjugated bilirubin in all groups and conjugated bilirubin in AGS and SAGS groups, increased levels of bile acids in some individuals from each group and significantly increased levels of glutamate dehydrogenase (GLDH) in AGS and SAGS cases. Conjugated bilirubin was significantly elevated in urine of AGS and SAGS cases. The evidence suggests that abnormal liver function involving moderate hepatocellular pathology in conjunction with steatosis and cholestasis may contribute to the pathogenesis of GS.
D L Doxey - One of the best experts on this subject based on the ideXlab platform.
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a case control study of Grass Sickness equine dysautonomia in the united kingdom
Veterinary Journal, 1998Co-Authors: James L N Wood, Elspeth Milne, D L DoxeyAbstract:Summary A case-control study was performed to investigate the epidemiology of Grass Sickness in the United Kingdom from 1992 to 1995. Data were collected by means of postal questionnaire when cases of Grass Sickness were identified. Sets of three questionnaires were posted to owners of, or veterinary surgeons attending, cases of Grass Sickness, with a request to provide information on the case, on one healthy animal on the same premises as the case and on another healthy animal on other premises. Controls were matched to cases by date of onset. After univariate analyses, the probability of Grass Sickness in horses was modelled using conditional logistic regression techniques. Young animals were found to be at increased nick of Grass Sickness and females were less likely to becomeaffected, as were animals that had a history of contact with previous cases of the disease. The probability of Grass Sickness was higher in animals that were on premises where Grass Sickness had previously occurred, particularly if this was recent. Animals were at particular risk of disease if they changed fields within the previous 2 weeks; the risk thereafter reduced with time. The disease had a seasonal pattern, with a peak from April to June. More than 95% of cases had access to grazing, and 66% occurred after 2 week periods of predominantly dry weather.
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long term prospects for horses with Grass Sickness dysautonomia
Veterinary Record, 1998Co-Authors: D L Doxey, Elspeth Milne, J Ellison, P J S CurryAbstract:Responses to questionnaires were received from 31 owners of horses or ponies treated for chronic Grass Sickness (dysautonomia). Contrary to previous opinions the respondents indicated that the majority of the animals were capable of strenuous work, had regained the weight they had lost and, apart from a few residual problems such as difficulty in coping with dry fibrous food, had returned to a normal life. They had recovered slowly and had involved the owners in considerable extra work, but all the owners indicated that they considered the effort to have been worthwhile.
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an evaluation of the use of cisapride in horses with chronic Grass Sickness equine dysautonomia
British Veterinary Journal, 1996Co-Authors: Elspeth Milne, D L Doxey, M P Woodman, D Cuddeford, R A PearsonAbstract:Summary A clinical trial was carried out to determine the effect of cisapride on rateof passage of digesta and clinical parameters in horses with chronic Grass Sickness. Sixteen horses were given intramuscular cisapride (0.1 mg kg −1 three times daily) (group I), and 15 received oral cisapride (0.8 mg kg −1 three times daily) (group O). A liquid-phase marker (cobalt-EDTA) and a solid-phase marker (polystyrene pellets) were given by stomach tube at the beginning of each of three consecutive 7 day periods, i.e., before, during and after cisapride therapy. Seven horses in each group completed the rate of passage trial; the remainder provided clinical data only. The rate of passage was found to be significantly faster after cisapride therapy than before. Comparison with data from 20 normal animals showed a trend towards normal rates of passage after therapy. In cases that died during the trial, the caecum and large colon were the main sites of pellet retention. Dry matter intake was significantly higher after therapy than before in group O and dry matter output was higher after treatment than before in both groups. Gut auscultation score increased in both groups in the periods during and after cisapride administration but heart rate was unaffected. Diarrhoea and colic occurred in each group but its occurrence was not associated with cisapride therapy. The results suggest that by increasing gut motility, cisapride is of benefit in the management of selected cases of chronic Grass Sickness.
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patterns of feeding and behaviour in horses recovering from dysautonomia Grass Sickness
Veterinary Record, 1995Co-Authors: D L Doxey, Elspeth Milne, S Tothill, Z DavisAbstract:Three horses suffering from Grass Sickness were treated successfully but showed clinical signs which varied in severity and duration. They were all characterised by marked and often erratic changes in behaviour and appetite.
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evidence that the agent of equine Grass Sickness may reach neurons by retrograde axonal transport
Veterinary Record, 1994Co-Authors: I R Griffiths, D L Doxey, S Smith, K Whitwell, S LoveAbstract:Sera from acute and chronic cases of natural Grass Sickness or normal horses were injected into the parotid salivary gland of ponies. This gland receives its sympathetic innervation from the ipsilateral cranial cervical ganglion. None of the ponies showed any local or systemic signs of illness. After one week the cranial cervical ganglia, stellate and coeliaco-mesenteric ganglia were removed for histological study. Pathological changes were found only in the cranial cervical ganglion ipsilateral to a parotid salivary gland which had received an injection of Grass Sickness serum. Four out of five batches of test sera from cases of acute natural Grass Sickness were associated with chromatolytic changes in neurons; the remaining batch of serum produced no abnormalities. The most severe chromatolytic changes were induced by two samples obtained from horses whose signs of Grass Sickness had been present for less than 12 hours. A serum sample from a chronic case of Grass Sickness of three weeks duration did not produce chromatolysis but was associated with a moderately severe inflammatory infiltrate and neuronophagia in the ipsilateral cranial cervical ganglion. One batch of serum was size fractionated to separate components with molecular weights above or below 30 kDa. Only the fraction containing components above 30 kDa induced chromatolytic changes.
R. S. Pirie - One of the best experts on this subject based on the ideXlab platform.
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histological assessment of β amyloid precursor protein immunolabelled rectal biopsies aids diagnosis of equine Grass Sickness
Equine Veterinary Journal, 2018Co-Authors: R. C. Jago, R. S. Pirie, Elspeth Milne, Ian Handel, T S Mair, Sandra Scholes, Gemma Pearson, F Coyle, Bruce McgorumAbstract:SummaryBackground An accurate, minimally invasive, ante mortem, diagnostic test for equine Grass Sickness (EGS) is currently lacking. While histological examination of haematoxylin-eosin stained rectal biopsies for chromatolytic neurons is insensitive as a diagnostic test for EGS, we hypothesised that the diagnostic accuracy could be improved by immunolabelling for β-amyloid precursor protein (β-APP) which has increased expression in cranial cervical ganglia (CCG) neuronal perikarya in EGS. Objectives To develop a grading scheme for assessing the distribution and intensity of β-APP immunoreactivity within individual rectal submucosal neurons and subsequently determine the diagnostic value of the distribution of different grades of neurons for EGS diagnosis. Study design Retrospective case-control diagnostic accuracy study. Methods Initially a standardised grading scheme was developed and β-APP immunoreactivity in individual neuronal perikarya and axons was compared in sections of CCG and ileum from EGS and control horses. The grading scheme was further refined before being blindly applied to submucosal neurons in rectal biopsies derived from 21 EGS and 23 control horses. Results β-APP immunoreactivity was increased in neuronal perikarya and axons in sections of CCG, ileum and rectum from EGS horses compared with controls. For rectal biopsies, a mean immunoreactivity grade exceeding 1.1 was 100% specific and sensitive for EGS, and the presence of at least one neuron with diffuse labelling of the entire cytoplasm (grade 3) was 95% sensitive and 100% specific for EGS. Main limitations While the diagnostic criteria facilitated discrimination of the EGS and control biopsies evaluated in this study, further prospective validation using a larger sample set is required. Conclusions Histological assessment of β-APP immunolabelled rectal biopsies is more sensitive than conventional histological examination for EGS diagnosis. Further validation is required before this technique can be advocated for clinical decision making. This article is protected by copyright. All rights reserved.
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neurodegeneration in equine Grass Sickness is not attributable to niacin deficiency
Equine Veterinary Journal, 2017Co-Authors: Bruce Mcgorum, R. S. Pirie, R. C. Jago, John Keen, Eugenio Cillangarcia, Richard Reardon, P Y Saffu, N J MillerAbstract:SummaryBackground The aetiology of equine Grass Sickness (EGS) is currently unknown. We hypothesised that acute deficiency of niacin (vitamin B3), which has a key role in neural homeostasis, may contribute to neurodegeneration in EGS. Niacin deficiency could potentially result from ingestion of niacin antagonists produced by pasture mycotoxigenic fungi. Objectives To compare the niacin status of EGS and control grazing horses. A secondary objective was to compare blood concentrations of vitamins B1, B2 and B6 in EGS and control grazing horses to determine if the status of these vitamins was altered in EGS. Study design Case-control study. Methods Indices of niacin status, namely the erythrocyte nicotinamide adenine dinucleotide:nicotinamide adenine dinucleotide phosphate ratio (NAD:NADP ratio) and erythrocyte concentrations of NAD and NADP, were compared in blood collected from EGS and healthy control grazing horses. Blood concentrations of vitamins B1, B2 and B6 were also compared. Results There was no significant inter-group difference in the NAD:NADP ratio, the main index of functional niacin status (control median 2.1, interquartile range 1.8-2.6; EGS 2.1, 1.9-2.6). EGS horses had significantly higher (median value increased by 25%) concentrations of NADP. There were no inter-group differences in blood concentrations of vitamins B1, B2 and B6. Main limitations Interpretation of data was limited by lack of previously defined equine reference ranges for many of the analytes. Sample size was low. Conclusions Niacin deficiency does not contribute to EGS neurodegeneration. This article is protected by copyright. All rights reserved.
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bodyweight change aids prediction of survival in chronic equine Grass Sickness
Equine Veterinary Journal, 2016Co-Authors: R. C. Jago, R. S. Pirie, Caroline Hahn, Ian Handel, John Keen, Bryony Waggett, Bruce McgorumAbstract:SummaryReasons for performing study Objective criteria for predicting survival of chronic Grass Sickness cases are currently lacking. Objectives To determine whether the rate and/or magnitude of bodyweight change during hospitalisation of chronic Grass Sickness cases can provide an objective predictor of survival to discharge from hospital. Clinicians’ recorded indication(s) for euthanasia were also reviewed. Study design Single centre retrospective observational study. Methods Case records of all horses admitted for management of chronic Grass Sickness to The Dick Vet Equine Hospital between 1998 and 2013 were analysed. Case background, survival to hospital discharge, indication(s) for euthanasia, disease duration at admission and bodyweight changes during the hospitalisation period were analysed, and data for survivors and nonsurvivors compared. Percentage weight change was calculated for 7 day intervals up to 28 days (0–7, 7–14, 14–21, 21–28 days) and for entire periods from the first weight recorded (0–7, 0–14, 0–21, 0–28 days). These results were used to estimate survival probability conditional on weight change. Results The study sample comprised 213 horses, with 114 survivors (53.5%) and 99 (46.5%) nonsurvivors. Compared with nonsurvivors, survivors had significantly lower median maximum bodyweight loss as a percentage of first weight (survivors 5.9%, interquartile range 1.8–13.5; nonsurvivors 12.7%, 6.4–17.3). Throughout all time periods analysed, survivors had significantly lower median bodyweight loss than nonsurvivors, but no specific time period was more predictive of survival. Highest percentages of total bodyweight loss for individual horses were comparable for survivors (36%) and nonsurvivors (37%). Survival prediction curves reporting percentage survival rates for all time periods analysed provided data to aid prediction of chronic Grass Sickness survival. Conclusions Overall, nonsurvivors had greater bodyweight loss than survivors. Rapidity and magnitude of bodyweight loss were equally predictive of outcome. Percentage survival prediction curves provide objective data to aid discussion of prognosis, but greater predictive specificity with associated sensitivity is required for clinical decision making in individual cases.
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neuronal chromatolysis in the subgemmal plexus of gustatory papillae in horses with Grass Sickness
Equine Veterinary Journal, 2016Co-Authors: Bruce Mcgorum, R. S. Pirie, Darren J Shaw, Neil MacintyreAbstract:REASONS FOR PERFORMING STUDY: Diagnosis of equine Grass Sickness (EGS) can be challenging. We hypothesised that subgemmal plexus neurons are chromatolytic in EGS. If correct, histopathological examination of gustatory papillae biopsies could aid premortem diagnosis of EGS, and EGS could represent a spontaneous model of subgemmal neuronal chromatolysis to facilitate study of the pathology of structures involved in taste. OBJECTIVE: To compare subgemmal plexi and gustatory papillae in EGS and control horses. STUDY DESIGN: Observational study. METHODS: Conventional histology and immunohistochemistry were used to compare subgemmal plexi and gustatory papillae in post mortem samples from 10 EGS and 13 control horses. RESULTS: Chromatolytic neurons were present in all 57 EGS sections which had identifiable neurons, and in only one of 57 control sections. Blinded examination of all haematoxylin-eosin stained sections from each horse for chromatolysis facilitated accurate differentiation of EGS and control horses, with a sensitivity of 100% (95% confidence interval 93.7-100) and specificity of 98.2% (90.6-100) for diagnosing EGS; however, the presence of chromatolytic neurons in one control section indicated that multiple sections per horse must be analysed to achieve diagnostic accuracy. Equine Grass Sickness was not associated with alterations in taste bud density or morphology, proportion of taste buds with neurofilament immunopositive intragemmal axons or proportion of taste buds containing cells undergoing apoptosis, suggesting taste buds had adequate neurotrophic support at the time of sampling. Horses with EGS had no detectable alteration in lingual gland morphology, but had increased proportions of apoptotic lingual serous gland cells. CONCLUSIONS: While identification of chromatolytic subgemmal neurons in post mortem samples correctly differentiated EGS and control horses, further study is required to evaluate this technique for premortem EGS diagnosis. Equine Grass Sickness represents a spontaneous model of subgemmal neuronal chromatolysis that facilitates study of the pathology of structures involved in taste.
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Equine Grass Sickness
Equine Veterinary Journal, 2014Co-Authors: R. S. Pirie, R. C. Jago, N. P.h. HudsonAbstract:Equine Grass Sickness (EGS; equine dysautonomia) is a polyneuronopathy affecting both the central and the peripheral nervous systems of horses. As the name implies, EGS almost exclusively affects grazing horses, resulting in the development of a characteristic array of clinical signs, most of which can be attributed to neuronal degeneration in the autonomic and enteric nervous systems. Varying disease severities occur, largely determined by the extent of neuronal degeneration in the myenteric and submucous plexuses of the enteric nervous system. Extensive neuronal degeneration, as seen in acute and subacute forms of EGS, results in intestinal dysmotility, the severity of which is incompatible with survival. In comparison, a proportion of chronic forms of EGS, characterised by less severe neuronal degeneration, will survive. Despite extensive research efforts since EGS was first reported over 100 years ago, the precise aetiology remains elusive. This article reviews much of the scientific literature on EGS, covering epidemiology, pathology, diagnosis, treatment and aetiological hypotheses.
C E Wylie - One of the best experts on this subject based on the ideXlab platform.
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Equine Grass Sickness in Scotland: A Case-Control Study of Environmental Geochemical Risk Factors
Equine Veterinary Journal, 2014Co-Authors: C E Wylie, Fiona M. Fordyce, Allan Lilly, D.j. Shaw, B.c. McgorumAbstract:\ud \ud Epidemiological investigations suggest that soil macro- and micro-nutrients may be a trigger for the occurrence of equine Grass Sickness (EGS). However, there is limited information regarding relationships between exposure to geochemical elements and the occurrence of EGS.\ud \ud \ud Objectives\ud \ud \ud To determine whether the geographical distribution of EGS cases referred to the Royal (Dick) School of Veterinary Studies was associated with the presence or absence of particular geochemical elements in the environment.\u
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equine Grass Sickness in scotland a case control study of signalment and meteorology related risk factors
Equine Veterinary Journal, 2014Co-Authors: C E Wylie, Darren J Shaw, Fiona M. Fordyce, Allan Lilly, Bruce McgorumAbstract:Reasons for performing study: Equine Grass Sickness (EGS) remains a frequently fatal disease of equids in Britain. Since previous investigations of signalment- and meteorology-related risk factors for EGS have yielded some conflicting data, further investigation is warranted. Objectives: To identify signalment- and meteorology-related risk factors for EGS in Scotland. Study design: Retrospective time-matched case–control study. Methods: This study was undertaken using data for 455 EGS cases and 910 time-matched controls that were referred to the Royal (Dick) School of Veterinary Studies, and average UK Meteorological Office weather station meteorological values from the month of admission of the animal, from the 3, 6 and 12 months prior to admission, and for the entire 1990–2006 period. Results and conclusion: Signalment-related risk factors associated with an increased risk of EGS were native Scottish pure breeds compared with crossbreeds (odds ratio [OR] = 3.56, 95% confidence interval [CI] 2.43–5.43) and animals living on premises located further north within the study region (OR = 1.08, 95% CI 1.06–1.10). There was a decreased risk of EGS in animals aged 11–20 years compared with animals 2–10 years (OR = 0.32, 95% CI 0.22–0.45), non-native Scottish pure breeds compared with crossbreeds (OR = 0.71, 95% CI 0.54–0.94), and stallions compared with mares (OR = 0.43, 95% CI 0.22–0.86). Meteorology-related risk factors associated with an increased risk of EGS were (if Ordnance Survey northing is excluded) more sun hours (OR>1.43) and more frost days (OR>1.13), while there was a decreased risk of EGS with higher average maximum temperature (OR<0.83). Potential relevance: The signalment-related risk factors will help owners identify high-risk animals, thereby allowing them to prioritise management strategies. The identification of meteorological risk factors may assist studies on the aetiology of EGS.
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a nationwide surveillance scheme for equine Grass Sickness in great britain results for the period 2000 2009
Equine Veterinary Journal, 2011Co-Authors: C E Wylie, Bruce Mcgorum, C J Proudman, J R NewtonAbstract:Reasons for performing study: Equine Grass Sickness (EGS) remains a frequently fatal disease of equids in Great Britain (GB). The first nationwide surveillance scheme for EGS was developed to obtain information on the occurrence of EGS and to help facilitate future proposed intervention studies, such as vaccine trials. Objectives: To collect both retrospective and prospective data on cases of EGS occurring in GB since 2000 and to assess potential risk factors for categories of EGS and survival after chronic EGS. Methods: Prospective data were collected using a nationwide surveillance scheme for EGS that was developed and initiated in 2007. Data were collected by means of postal and online questionnaires documenting both retrospective premises-level and prospective case-level information. Data on outcomes of EGS category and survival after chronic Grass Sickness (CGS) were analysed using univariable logistic regression. Results: Descriptive data for 1410 EGS cases occurring in GB in the decade between the beginning of 2000 and the end of 2009 are presented. Univariable logistic regression analyses identified that CGS cases in Scotland were significantly more likely to survive than those occurring elsewhere in GB. There was no relationship between case details and the category of EGS or the outcome among CGS cases. Conclusions: EGS affected equids throughout England, Scotland and Wales. Although an overall average of 141 cases were reported to the nationwide surveillance scheme annually, this number of cases was not consistent between years. Around 50% of CGS cases survived, although regional differences in survival rates existed, probably due to variation in expertise of care and/or disease severity. Potential relevance: This study provides information on the spatiotemporal occurrence of EGS in GB during the last decade. Data from the nationwide surveillance scheme can be used in developing protocols for future intervention studies such as Clostridium botulinum vaccine trials. © 2011 EVJ Ltd.
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equine Grass Sickness epidemiology diagnosis and global distribution
Veterinary Clinics of North America-equine Practice, 2009Co-Authors: C E Wylie, C J ProudmanAbstract:: Equine Grass Sickness (EGS) is recognized as a debilitating and predominantly fatal neurodegenerative disease affecting grazing equids. The gastrointestinal tract is the most severely affected body system, resulting in the main clinical signs of colic (acute Grass Sickness), weight loss, or dysphagia (chronic Grass Sickness). EGS predominantly occurs within Great Britain, although it is also recognized in regions of mainland Europe, and mainly affects young horses with access to pasture in the springtime. There is strong evidence of an association between EGS and the type C toxins produced by the bacterium Clostridium botulinum. This article covers the clinical aspects, epidemiology, and global distribution of EGS, along with comparisons with botulism and developments in disease prevention.
