Chromatolysis and Axonal Dystrophy in the Autonomic Nervous System in Grass Sickness of Equidae

Abstract

Chromatolysis and axonal dystrophy in the autonomic nervous system in grass sickness of equidaeLight and electron microscopic examinations of autonomic ganglia from cases of grass sickness have been carried out. The main alterations are pyknosis, cytoplasmic vacuolation originating from granular endoplasmic reticulum, and axonal dystrophy. The cell body changes bear some resemblance to chromatolysis. OBEL A-L. (1955) Studies on grass disease. The morphological picture with special reference to the vegetative nervous system. Journal of Comparative Pathology 65, 334-346 of horses with and without grass sickness. British Veterinary Journal 130, 265-270 analysis. Journal of Comparative Neurology 132, 18S212 and dystrophic axons.

Are the Equine Motor Neuron Disease (EMND) and the Grass Sickness of the horse different manifestations of the same underlying disease?

“…Die histologischen Veränderungen im Rtckenmark bei 7 von 10 Grass Sickness-Fällen unterstreichen die Berechtigung unserer Arbeitshypothese, vor allem der Nervenzellnekrose wegen, die in den Ventralhörnern festgestellt worden ist, und die den in den Arbeiten von Obel (1955), von Gilmour (1975) Doxey et al (1992) und auch andere Autoren haben übrigens die Grass Sickness als ,,equine dysautonomia" bezeichnet, in Anlehnung an die,,feline dysautonomia" (Key-Gaskell-Syndrom), die histologisch ähnlich aussieht (Guscetti et. al.…”

“…Aus England und Brasilien berichtet man ebenfalls von EMND (Hahn and Mayhew 1993;Mayhew 1994;Proudman et al 1993), doch steht bei diesen Fallen eine histopathologische Sicherung der Diagnose noch aus. Die Graskrankheit oder Grass-Sickness (GS) dagegen ist seit langem bekannt; ihre eingehende Charakterisierung verdanken wir Obel (1955) und später vor allem Gilmour und seiner Gruppe (Gilmour 1973aund b, Gilmour and Jolly 1974, Gilmour 1975, Gilmour and Mould 1977.Sie ist möglicherweise identisch mit dem ,,Mal seco" Südamerikas (Anonym 1993;Uzal er al. 1992).…”

Neurodegenerative Disorders

“…[96][97][98] There is chromatolysis, nuclear eccentricity, nuclear degenerative changes, cell death and neuronophagia, cytoplasmic vacuolation, and spheroid formation. 99 Lesions are most evident in prevertebral (celiacomesenteric, cranial mesenteric, caudal mesenteric) and paravertebral (stellate, cranial cervical, caudal cervical, thoracic sympathetic chain) ganglia of the autonomic nervous system and enteric neurons (myenteric and submucous plexuses). 85 Lesions are also found in autonomic and somatic cranial nerve nuclei (particularly those of cranial nerves III, V, VI, and V and X) and in the intermediolateral and ventral horns of the spinal cord grey matter.…”

Prospects for vaccination against equine grass sickness

“…Clinical signs of grass sickness are characterised as acute, subacute or chronic according to the duration and severity of signs (Doxey et al 1991) and are attributable to histologically evident disruption of the autonomic nervous system, particularly of the gastrointestinal tract (Obel 1955;Brownlee 1959;Mahaffey 1959;Barlow 1969;Gilmour 1973aGilmour , 1975Scholes et al 1993a;Doxey et al 2000;John et al 2001). Clinical presentation of EGS is typically characterised by signs of mild colic, increased heart rate, muscle tremors, patchy sweating, difficulty in swallowing, alimentary stasis, abdominal distension, oesophageal ulceration, ptosis, rhinitis sicca, weight loss and, occasionally, sudden death (Tocher et al 1923;Tocher 1924;Greig 1942;Doxey et al 1991;Milne 1996).…”