Equine Dysautonomia

McGorum, Bruce; Pirie, R. S.

doi:10.1016/j.cveq.2017.11.010

Cited by 13 publications

(20 citation statements)

References 61 publications

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“…Three different syndromes can be recognized on the basis of the clinical signs, that are severe in the acute form, moderate in the subacute form, and mild in the chronic form [ 3 ].…”

Section: Introductionmentioning

confidence: 99%

Equine grass sickness in italy: a case series study

Laus

Jacopo²,

Teresa

et al. 2021

BMC Vet Res

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Background Equine grass sickness (EGS) has been reported in several European and extra-European countries. Despite this, no scientific paper about clinical cases of EGS in Italy has been published. EGS is a disease affecting almost exclusively horses kept on pasture, characterized by clinical signs related to lesions in autonomic nervous system (ANS), particularly in the enteric nervous system (ENS). According to clinical presentation, acute, subacute and chornic syndromes can be observed, with various sympthoms including dullness, anorexia, dysphagia, drooling of saliva, tachycardia, ptosis, patchy sweating and muscle fasciculations. In horses affected by acute forms, mild to moderate abdominal pain and large volumes of nasogastric reflux can be observed. The etiology is still speculative and many hypothesis have been proposed to explain the pathogenesis. Case presentation The present study describes four cases of EGS (one subacute and three chronic forms) occurred in Central Italy during early spring. In all the cases included in the study, the prognosis was poor and the horses were euthanized. The diagnosis was confirmed by histological examination of ANS or ENS. In two cases, in vivo diagnosis was obtained by histological examination of enteric bioptic samples collected during laparoscopy. Conclusions EGS in Italy could be underdiagnosed and incidence understimated. Greater awareness should be applied in Italy for the inclusion of EGS in differential diagnosis for horses presenting clinical signs of abdominal pain associated or not with gastric reflux and muscular fasciculation. All the cases in this study concerned horses kept in the same pasture, confirming a possible premise-linked and management-linked factors on the ethiopathogenesis of EGS. The age of horses ranged from 2 to 6 years, that is consistent with the risk factor age for EGS (from 2 to 7 years of age). Previous suspected EGS diagnosis in the same livestock and recent cool dry weather were considered additional potential risk factors.

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“…Three different syndromes can be recognized on the basis of the clinical signs, that are severe in the acute form, moderate in the subacute form, and mild in the chronic form [ 3 ].…”

Section: Introductionmentioning

confidence: 99%

Equine grass sickness in italy: a case series study

Laus

Jacopo²,

Teresa

et al. 2021

BMC Vet Res

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“…Equine dysautonomia (also known as equine grass sickness, EGS) is a life-threatening disease of unknown aetiology, affecting horses. Approximately 80% of the affected animals die within days after the recognition of the first clinical signs; the mortality is reported as 100% in the acute and subacute forms and 50% in the chronic form (McGorum and Pirie, 2018). This polyneuropathy affects both the central and the peripheral nervous system and leads to severe clinical signs, due to gross and microscopic pathological alterations in the ganglions and neurocytes localised primarily in the gastrointestinal tract.…”

Section: Introductionmentioning

confidence: 99%

“…This polyneuropathy affects both the central and the peripheral nervous system and leads to severe clinical signs, due to gross and microscopic pathological alterations in the ganglions and neurocytes localised primarily in the gastrointestinal tract. Since its first recognition in 1909 (Tocher et al, 1923), multiple cases have been reported around the world (McGorum and Pirie, 2018;Piccinelli et al, 2019).…”

Section: Introductionmentioning

confidence: 99%

“…), management (grazing, movement, stress, anthelmintic use, supplementary feeding, etc.) and climatic factors (cool, dry weather, frosts, increased number of hours of sunshine, maximum temperature, snowing) have been described (Doxey et al, 1991a(Doxey et al, , 1991bWood et al, 1998;McCarthy et al, 2004;Newton et al, 2004;Edwards et al, 2010;Wylie et al, 2014Wylie et al, , 2016McGorum and Pirie, 2018). The prevalence rate of the disease differs by country, but EGS can cause high morbidity (10-25%) and high mortality (50-100%) rates within a single herd, resulting in significant economic losses.…”

Section: Introductionmentioning

confidence: 99%

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Family aggregation analysis shows a possible heritable background of equine grass sickness (dysautonomia) in a Hungarian stud population

Vincze

Varga

Kutasi

et al. 2020

AVet

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Equine grass sickness (also known as dysautonomia) is a life-threatening polyneuropathic disease affecting horses with approx. 80% mortality. Since its first description over a century ago, several factors, such as the phenotype, intestinal microbiome, environment, management and climate, have been supposed to be associated with the increased risk of dysautonomia. In this retrospective study, we examined the possible involvement of genetic factors. Medical and pedigree datasets regarding 1,233 horses with 49 affected animals born during a 23-year period were used in the analysis. Among the descendants of some stallions, the proportion of animals diagnosed with dysautonomia was unexpectedly high. Among males, the odds of dysautonomia were found to be higher, albeit not significantly, than among females. Significant familial clustering (genealogical index of familiality, P = 0.001) was observed among the affected animals. Further subgroups were identified with significant (P < 0.001) aggregation among close relatives using kinship-based methods. Our analysis, along with the slightly higher disease frequency in males, suggests that dysautonomia may have a genetic causal factor with an X-linked recessive inheritance pattern. This is the first study providing ancestry data and suggesting a heritable component in the likely multifactorial aetiology of the disease.

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“…Clinical signs and severity of the disease are largely defined by degeneration of neurons in the enteric nervous system. The disease almost exclusively appears in grazing horses and, although many agents are being discussed, the causative factor remains to be found [2]. Furthermore, intestinal volvulus and strangulation create ischemia of affected intestine and once necessary perfusion is surgically re-established, intestinal damage is often exacerbated.…”

Section: Introductionmentioning

confidence: 99%

Establishment of a model for equine small intestinal disease: effects of extracorporeal blood perfusion of equine ileum on metabolic variables and histological morphology – an experimental ex vivo study

et al. 2019

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BackgroundIn horses a number of small intestinal diseases is potentially life threatening. Among them are Equine Grass Sickness (EGS), which is characterised by enteric neurodegeneration of unknown aetiology, as well as reperfusion injury of ischaemic intestine (I/R), and post-operative ileus (POI), common after colic surgery. The perfusion of isolated organs is successfully used to minimize animal testing for the study of pathophysiology in other scenarios. However, extracorporeal perfusion of equine ileum sourced from horses slaughtered for meat production has not yet been described. Therefore the present study evaluated the potential of such a model for the investigation of small intestinal diseases in an ex vivo and cost-efficient system avoiding experiments in live animals.ResultNine ileum specimens were sourced from horses aged 1–10 years after routine slaughter at a commercial abattoir. Ileum perfusion with oxygenated autologous blood and plasma was successfully performed for 4 h in a warm isotonic bath (37.0–37.5 °C). Ileum specimens had good motility and overall pink to red mucosa throughout the experiment; blood parameters indicated good tissue vitality: 82 ± 34 mmHg mean arterial partial pressure of oxygen (pO2) compared to 50 ± 17 mmHg mean venous pO2, 48 ± 10 mmHg mean arterial partial pressure of carbon dioxide (pCO2) compared to 66 ± 7 mmHg venous pCO2 and 9.8 ± 2.8 mmol/L mean arterial lactate compared to 11.6 ± 2.7 mmol/L venous lactate. There was a mild increase in ileum mass reaching 105 ± 7.5% of the pre-perfusion mass after 4 hours. Histology of haematoxylin and eosin stained biopsy samples taken at the end of perfusion showed on average 99% (±1%) histologically normal neurons in the submucosal plexus and 76.1% (±23.9%) histologically normal neurons in the myenteric plexus and were not significantly different to control biopsies.ConclusionExtracorporeal, normothermic perfusion of equine ileum over 4 h using autologous oxygenated blood/plasma perfusate showed potential as experimental model to test whether haematogenous or intestinal exposure to neurotoxins suspected in the pathogenesis of EGS can induce neuronal damage typical for EGS. Also, this model may allow investigations into the effect of pharmaceuticals on I/R injury, as well as into the pathogenesis of equine POI.

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Equine Dysautonomia

Cited by 13 publications

References 61 publications

Equine grass sickness in italy: a case series study

Equine grass sickness in italy: a case series study

Family aggregation analysis shows a possible heritable background of equine grass sickness (dysautonomia) in a Hungarian stud population

Establishment of a model for equine small intestinal disease: effects of extracorporeal blood perfusion of equine ileum on metabolic variables and histological morphology – an experimental ex vivo study

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