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Vincze B, Varga M, Kutasi O, Zenke P, Szenci O, Baska F, Bartels A, Spisák S, Cseh S, Solymosi N. Family aggregation analysis shows a possible heritable background of equine grass sickness (dysautonomia) in a Hungarian stud population. Acta Vet Hung 2020; 68:263-268. [PMID: 33128520 DOI: 10.1556/004.2020.00038] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Accepted: 05/08/2020] [Indexed: 11/19/2022]
Abstract
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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Affiliation(s)
- Boglárka Vincze
- 1Department of Obstetrics and Food Animal Medicine Clinic, University of Veterinary Medicine, István u. 2, H-1078 Budapest, Hungary
| | - Márta Varga
- 2Department of Animal Breeding, Nutrition and Laboratory Animal Science, Laboratory of Genetics, University of Veterinary Medicine, Budapest, Hungary
| | - Orsolya Kutasi
- 2Department of Animal Breeding, Nutrition and Laboratory Animal Science, Laboratory of Genetics, University of Veterinary Medicine, Budapest, Hungary
| | - Petra Zenke
- 2Department of Animal Breeding, Nutrition and Laboratory Animal Science, Laboratory of Genetics, University of Veterinary Medicine, Budapest, Hungary
| | - Ottó Szenci
- 1Department of Obstetrics and Food Animal Medicine Clinic, University of Veterinary Medicine, István u. 2, H-1078 Budapest, Hungary
| | - Ferenc Baska
- 3Department and Clinic of Zoo and Wildlife Medicine, University of Veterinary Medicine, Budapest, Hungary
| | - Alan Bartels
- 4Department of Medical Oncology, Dana-Farber Cancer Institute, Harvard University, Boston, MA, USA
| | - Sándor Spisák
- 4Department of Medical Oncology, Dana-Farber Cancer Institute, Harvard University, Boston, MA, USA
| | - Sándor Cseh
- 1Department of Obstetrics and Food Animal Medicine Clinic, University of Veterinary Medicine, István u. 2, H-1078 Budapest, Hungary
| | - Norbert Solymosi
- 5Centre for Bioinformatics, University of Veterinary Medicine, Budapest, Hungary
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Pirie RS, Jago RC, Hudson NPH. Equine grass sickness. Equine Vet J 2014; 46:545-53. [PMID: 24580639 DOI: 10.1111/evj.12254] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2013] [Accepted: 02/18/2014] [Indexed: 11/30/2022]
Abstract
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.
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Affiliation(s)
- R S Pirie
- Royal (Dick) School of Veterinary Studies and Roslin Institute, University of Edinburgh, Easter Bush Veterinary Campus, Midlothian, UK
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Wylie CE, Shaw DJ, Fordyce FM, Lilly A, McGorum BC. Equine grass sickness in Scotland: A case-control study of signalment- and meteorology-related risk factors. Equine Vet J 2013; 46:64-71. [DOI: 10.1111/evj.12077] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2011] [Accepted: 02/22/2013] [Indexed: 11/29/2022]
Affiliation(s)
- C. E. Wylie
- Royal (Dick) School of Veterinary Studies & Roslin Institute; Easter Bush Veterinary Centre; University of Edinburgh; UK
| | - D. J. Shaw
- Royal (Dick) School of Veterinary Studies & Roslin Institute; Easter Bush Veterinary Centre; University of Edinburgh; UK
| | | | - A. Lilly
- James Hutton Institute; Aberdeen UK
| | - B. C. McGorum
- Royal (Dick) School of Veterinary Studies & Roslin Institute; Easter Bush Veterinary Centre; University of Edinburgh; UK
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Shotton HR, Lincoln J, McGorum BC. Effects of equine grass sickness on sympathetic neurons in prevertebral and paravertebral ganglia. J Comp Pathol 2011; 145:35-44. [PMID: 21457994 DOI: 10.1016/j.jcpa.2010.11.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2010] [Revised: 07/13/2010] [Accepted: 11/06/2010] [Indexed: 12/24/2022]
Abstract
Acute equine grass sickness (EGS) is a fatal disease of horses that is thought to be due to ingestion of a neurotoxic agent causing extensive damage to autonomic neurons. The aim of this study was to compare the effects of EGS on neurons in two sympathetic ganglia, the paravertebral cranial cervical ganglion (CCG) and the prevertebral coeliac/cranial mesenteric ganglion (CG/CMG). Specimens from horses with EGS and controls were obtained post mortem and processed using single and double immunofluorescence labelling for PGP 9.5 and HuC/HuD (pan-neuronal markers), TUNEL and caspase 3 (markers for apoptosis), vasoactive intestinal polypeptide (VIP) and galanin (markers of the cell body response to injury following axotomy or exposure to sympathetic neurotoxins) and tyrosine hydroxylase (TH, marker for noradrenaline synthesis). In control horses, all neurons contained PGP 9.5 and HuC/HuD. There was a significant loss of PGP 9.5 and HuC/HuD expression in samples from horses with EGS that occurred to a greater extent in the CG/CMG than the CCG. The number of caspase 3-positive neurons increased significantly in both ganglia, but TUNEL staining of sympathetic neurons was only significantly increased in the CG/CMG in EGS. No VIP was observed in any ganglia; however, there was a significant increase in galanin-positive neurons in both ganglia in EGS. In the CCG, there was a significant shift towards increased fluorescence intensity for TH, possibly indicating an initial accumulation of TH within the cell body. In contrast, TH fluorescence intensity was significantly reduced in the CG/CMG in EGS correlating with the greater loss of neurons. These results demonstrate that EGS can induce a cell body response that is similar to the response of sympathetic neurons to a chemical neurotoxin. EGS also causes loss of sympathetic neurons, some of which occurs via apoptosis. Changes were more marked in the CG/CMG than the CCG indicating that the prevertebral ganglia were affected earlier than the paravertebral ganglia in the pathological process and had undergone greater neurodegeneration.
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Affiliation(s)
- H R Shotton
- Department of Cell and Developmental Biology, University College London, Gower Street, London WC1E 6BT, UK
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Newton J, Wylie C, Proudman C, McGorum B, Poxton I. Equine grass sickness: Are we any nearer to answers on cause and prevention after a century of research? Equine Vet J 2010; 42:477-81. [DOI: 10.1111/j.2042-3306.2010.00155.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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