Doença do neurônio motor dos equinos

Abstract

This thesis is made up of a literature review on Nervous System Diseases in Equines in Brazil and a paper submitted to the Journal of Veterinary Diagnostic Investigation entitled Motor Neuron Disease in Young and Adult Equines. The first paper is a review of nervous system diseases in horses in Brazil. This review describes the epidemiology, clinical signs, pathology, diagnosis and ways of controlling the following diseases: rabies, eastern and western equine encephalomyelitis, equine herpesvirus-1 myeloencephalopathy, tetanus, equine protozoal myeloencephalitis caused by Sarcocystis neurona, trypanosomiasis caused by Trypanosoma evansi, cerebral nematodiasis caused by Halicephalobus gingivalis, leukoencephalomalacia caused by moldy corn, hepatic encephalopathy caused by the ingestion of Senecio spp. and Crotalaria spp, poisoning by Trema micanthra, Bambusa vulgaris, Indigofera lespedezioides, Equisetum spp. and Hypochaeris radicata, Amitraz poisoning, equine motor neuron disease and cervical stenotic myelopathy. The second describes an outbreak of neurological disease observed on a farm with 400 horses. The animals were divided into 2 groups. Group I, made up of Mangalarga Marchador donor mares and stallions, kept under adequate management and health conditions; Group II, made up of mixed-breed recipient mares and Mangalarga Marchador foals born to these mares, grazing on degraded pastures and receiving only low quality hay. Only the horses in Group II showed neuropathy during the dry season. Foals and adult mares showed clinical signs such as apathy, incoordination, lameness and, in more serious cases, permanent decubitus and death. Laboratory findings included low serum concentrations of vitamin E (α-tocopherol) and elevated creatine kinase activities. Histological lesions included neuronal and axonal degeneration. Following the diagnosis of equine motor neuron disease (EMND), all affected animals received vitamin E treatment for 5 days and fully recovered. This is the first time that EMND has been reported in animals under 3 years of age. In addition, the clinical course of the disease was shorter than previously described, as it is usually a chronic and slowly progressive disease.