Changes

====Aetiology====

====Aetiology====

EPM results from infection of the CNS by the apicomplexan parasite ''Sarcocystis neurona'' or, less frequently, its close relative ''Neospora hughesi'' (Mayhew and others 1976, Marsh and others 1996, Dubey and others 2001a).(EPM6, Wobeser 2009).  These protozoans develop within neurons (Furr) causing immediate or inflammatory-mediated neuronal damage (Vetstream).  The organisms migrate randomly through the brain and spinal cord causing asymmetrical lesions of the grey and white matter and thus multifocal lower and upper motor neuron deficits.<ref name="Pasq">Pasquini, C, Pasquini, S, Woods, P (2005) '''Guide to Equine Clinics Volume 1: Equine Medicine''', third edition, SUDZ Publishing, 245-250.</ref>

EPM results from infection of the CNS by the apicomplexan parasite ''Sarcocystis neurona'' or, less frequently, its close relative ''Neospora hughesi''.<ref>Dubey, J.P, Lindsay, D.S, Saville, W.J, Reed, S.M, Granstrom, D.E, Speer, C.A (2001)A review of ''Sarcocystis neurona'' and equine protozoal myeloencephalitis (EPM). ''Vet Parasitol'', 95:89-131. In: Pusterla, N, Wilson, W.D, Conrad, P.A, Barr, B.C, Ferraro, G.L, Daft, B.M, Leutenegger, C.M (2006) Cytokine gene signatures in neural tissue of horses with equine protozoal myeloencephalitis or equine herpes type 1 myeloencephalopathy. ''The Vet Record'', Sep 9:''Papers & Articles''.</ref><ref>Wobeser, B.K, Godson, D.L, Rejmanek, D, Dowling, P (2009) Equine protozoal myeloencephalitis caused by ''Neospora hughesi'' in an adult horse in Saskatchewan. ''Can Vet J'', 50(8):851-3.</ref> These protozoans develop within neurons<ref name="Furr">Furr, M (2010) ''Equine protozoal myeloencephalitis'' in:</ref>  causing immediate or inflammatory-mediated neuronal damage (Vetstream).  The organisms migrate randomly through the brain and spinal cord causing asymmetrical lesions of the grey and white matter and thus multifocal lower and upper motor neuron deficits.<ref name="Pasq">Pasquini, C, Pasquini, S, Woods, P (2005) '''Guide to Equine Clinics Volume 1: Equine Medicine''', third edition, SUDZ Publishing, 245-250.</ref>

====Signalment====

====Signalment====