ABSTRACT:The first case of post anaesthetic myelopathy in a horse is described. A two year old 530 kg Shire stallion underwent surgical removal of a granuloma in the ventral sternal region under general inhalation anaesthesia in dorsal recumbency. Total duration of the operation was 85 min. The anaesthesia was uneventful except for profuse sweating and arterial hypertension observed during the whole period. During recovery the horse was not able to stand, and flaccid paralysis of hind limbs, absence of reaction to an induced pain stimulus on the hind limbs and no patellar or anal reflex was recorded; in addition, tail tonus was weak. Panniculus reflex was absent distally from the 17 th intercostal space. Head, neck and front limb movement was not affected. The horse did not respond to treatment by intravenous administration of dexamethasone, hypertonic or isotonic saline. The status deteriorated and the horse was euthanised 4 h after the end of anaesthesia. The main pathological findings were haemorrhage, oedema and malacia of L5-L6 spinal cord segments and cauda equina. Histological examination of the spinal cord revealed haemorrhage and areas of necrosis predominantly in the grey matter of L5 and L6 segments. Impairment of spinal cord perfusion due to haemodynamic changes associated with dorsal recumbency and general anaesthesia is presumed. Predisposition factors could include young age, dorsal recumbency and high weight.

Ludvíková E., L. Pavlata, M. Vyskoãil, P. Jahn: Selenium Status of Horses in the Czech Republic. Acta Vet. Brno 2005, 74: 369-375.The aim of this study was to determine the relation between selenium concentration and activity of glutathione peroxidase (GSH-Px, EC 1.11.19) in whole blood of horses, reference ranges for the activity of GSH-Px and to evaluate the selenium status of horses in the Czech Republic. Blood samples were collected from 159 horses from 35 different farms and processed using the AAS and photometric methods to determine concentrations of selenium and the GSH-Px activity, respectively. Data on both parameters were processed using correlation and regression analysis in order to obtain reference values of GSH-Px for the indirect evaluation of the selenium status of horses. The results were also used to evaluate the occurrence of selenium deficiency in the horses examined. A highly significant linear relation was found between both variables. It can be expressed using the Spearman's coefficient of rank correlation (r s = 0.873; p < 0.01) and the regression equation (y = 3.621x -28.698; p < 0.01, r = 0.842). The value of 75 µg·l -1 of selenium in whole blood is considered as a threshold of selenium deficiency in horses. According to our results, the corresponding level of the activity of GSH-Px useful in the diagnostics is 200 µkat·l -1 . Using these criteria, there was a high prevalence of selenium deficiency in the collection of horses examined amounting to 47% and 48% when evaluating the selenium status by the selenium concentration and the activity of GSH-Px, respectively. It can be concluded that there is a high correlation of the activity of GSH-Px and selenium concentration in whole blood of horses and that reference values of the activity of GSH-Px useful in the diagnostics of selenium deficiency in horses in the Czech Republic were determined. The occurrence of selenium deficiency in horses is a topical problem in the Czech Republic.

A serological survey for West Nile virus (WNV) infection involved 395 horses from 43 administrative districts of the Czech Republic (163 animals) and 29 districts of Slovakia (232 animals), sampled between 2008 and 2011. Using a plaque-reduction neutralization microtest, antibodies to WNV were not detected in any horse from the Czech Republic, whereas 19 nonvaccinated horses from Slovakia had specific antibodies to WNV (no cross-reactions were observed with tick-borne encephalitis and Usutu flaviviruses in those animals). The seropositivity rate of nonvaccinated horses in Slovakia was 8.3% (95% confidence interval [CI] 4.7-11.9%), and autochthonous local infection with WNV occurred at least in 11, i.e., 4.8% (95% CI 2.0-7.6%) of the animals. All seropositive horses lived in six lowland districts of southern Slovakia; overall, 15.1% (95% CI 8.8-21.4%) of 126 nonvaccinated horses were seropositive in those districts, situated relatively closely to the border with Hungary, i.e., the country where WNV disease cases have been reported in birds, horses and humans since 2003.

Three cases of nutritional myodegeneration caused by selenium deficiency in adult horses are described. Difficulty in eating and drinking was a common clinical sign in all horses. Blood biochemistry revealed a marked elevation of muscle enzymes and low glutathione peroxidase activity or low selenium concentration in whole blood in all cases. The treatment with sodium selenite and vitamin E was instituted in all horses. Two of them were euthanized because of continuing muscle injuries, one patient was cured. The post-mortem examination of euthanized horses revealed pale muscles that were distributed with bilateral symmetry on hind and thoracic limbs, diaphragm, tongue, masticatory and intercostal muscles and the myocardium. Histopathology revealed the areas of degeneration and necrosis. Large groups of regenerating fibres and pronounced lymphoplasmocytic reaction among the groups of intact fibres were also present. The clinical outcome of the disease is probably influenced by timely diagnosis and treatment.

The occurrence of sleep disorder in three half sibling Lipizzaner is described. Sleepiness, swaying, stumbling, carpal joints buckling and falling down onto the carpal joints had been present since early foal age in all of them. Clinical signs had gradually reduced since the age of 2 years in cases 1 and 3. Sleepiness was induced by going out from the stable in adulthood. A physostigmine test was performed in all three affected horses and produced positive results in cases 1 and 3. The result of the test in case 2 was unclear due to the almost continuous sleepiness of the foal. Hypocretin-1 concentration in the cerebrospinal fluid was established using a standardised radioimmunoassay in case 1 (317.85 pg/mL), case 2 (303.43 pg/mL) and five adult control horses (275.2 AE 47.9[SD] pg/mL) and was considered as normal in all horses. The sire of the affected horses has had 19 other registered offspring who did not show clinical signs of sleep disorder and also dams of all three cases produced healthy foals. Based on the demographic and clinical data together with the responses to the physostigmine challenges, the diagnosis of familial equine narcolepsy was made.