Prevalence of respiratory pathogens in nasal swabs from horses with acute respiratory disease in Belgium

Contagious respiratory infections are an important cause of respiratory disease in horses, resulting in impaired pulmonary function, poor performance and sometimes severe illness. Although bacterial infections are often suspected to be involved, viruses are frequently overlooked and are an underestimated cause of respiratory disease outbreaks in horses. In this study, nasal swabs of 103 horses with acute symptoms of respiratory disease were analyzed for the presence of 13 different respiratory pathogens. Gamma herpesviruses were the most commonly detected, with 60% of the samples being positive, followed by streptococcus equi subsp. zooepidemicus infection (30%). Rhinovirus B, streptococcus equi subsp. equi, adenovirus 1 and EHV-4 were more rarely detected. Further research is necessary to correctly interpret the importance of gamma herpesviruses in horses, for example by screening a healthy control population. National surveillance of respiratory viruses in horses by PCR analysis on nasal swabs might be a useful, early warning system for viral epidemics

Plasma exchange as a treatment for hyperbilirubinemia in 2 foals with neonatal isoerythrolysis

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Atypische myopathie bij het paard

Atypical myopathy (AM) is a frequently fatal pasture myopathy that emerges in Europe. Outbreaks are of an acute and unexpected nature and practitioners and owners should be prepared to handle the critically ill patients of this disease. Different hypotheses concerning the etiology and pathogenesis have been described. In this review, the most important hypotheses are summarized, and treatment plans and preventive measures are suggested. At this moment, maple seeds are thought to be the cause of AM. These seeds contain a toxin, hypoglycin A, which may lead to multiple acyl-CoA dehydrogenase deficiency (MADD). Treatment is often limited to supportive care. Since treatment is often unsuccessful, the main emphasis is currently still on prevention

Measurement variability of right atrial and ventricular monophasic action potential and refractory period measurements in the standing non-sedated horse

Background: In human and veterinary medicine, monophasic action potential (MAP) analysis and determination of local refractory periods by contact electrode technique gives valuable information about local cardiac electrophysiological properties. It is used to investigate dysrhythmias and the impact of drugs on the myocardium. Precise measurement of total MAP duration is difficult, therefore the MAP duration is usually determined at a repolarization level of 90% (APD90). Until now, no studies are published about the feasibility of this technique in the standing non-sedated horse. In 6 healthy Warmblood horses, on two different days, an 8F quadripolar contact catheter was passed through a jugular introducer sheath and placed under ultrasound guidance at the level of the intervenous tubercle or right atrial free wall (RA), and in the right ventricular apex (RV) to record the MAP. The MAP amplitude and APD90 were measured at a resting sinus rhythm (heart rate of 30-42 bpm) and at pacing cycle lengths (PCL) of 1000 and 600 ms. The effective refractory period (ERP) was determined at PCL of 1000 and 600 ms. Results: The overall mean (+/- SD) APD90 (rest), APD90 (1000) and APD90 (600) were 263 +/- 39 ms, 262 +/- 41 ms, 236 +/- 47 ms for the RA and 467 +/- 23 ms, 412 +/- 38 ms, 322 +/- 29 ms for the RV. The mean ERP1000 and ERP600 were 273 +/- 24 ms and 256 +/- 22 ms for the RA and 386 +/- 40 ms and 293 +/- 30 ms for the RV. The measurement variability for the amplitude, APD90 and ERP measurements in the RA ranged between 36 and 44, 9-22 and 7-8%, respectively. The measurement variability for the amplitude, APD90 and ERP measurements in the RV ranged between 49 and 66, 6-7 and 10-12%, respectively. Conclusions: RA and RV MAP duration and ERP can be obtained by a contact electrode in standing non-sedated horses. The measurement variability varies with catheter location

Een ongewoon geval van leptospirose: acute dyspnee en icterus bij een twee maanden oud veulen

A two-month-old warmblood foal was presented with complaints of acute respiratory distress and lethargy. Both clinical examination and blood tests revealed icterus, dyspnea and kidney failure. The foal was euthanized and necropsy and histological examination showed extensive kidney damage, liver damage and alveolar hemorrhage. The diagnosis of leptospirosis was confirmed by immunofluorescense. Unlike in human cases of leptospirosis, respiratory symptoms caused by alveolar hemorrhage in horses are not often associated with leptospirosis. This case shows that the frequency of respiratory complications caused by alveolar hemorrhage after leptospira infection might be underestimated. It is important to consider leptospirosis in the differential diagnosis of dyspnea in the foal

Can heart rate variability parameters derived by a heart rate monitor differentiate between atrial fibrillation and sinus rhythm?

Background: Heart rate variability (HRV) parameters, and especially RMSSD (root mean squared successive differences in RR interval), could distinguish atrial fibrillation (AF) from sinus rhythm(SR) in horses, as was demonstrated in a previous study. If heart rate monitors (HRM) automatically calculating RMSSD could also distinguish AF from SR, they would be useful for the monitoring of AF recurrence. The objective of the study was to assess whether RMSSD values obtained from a HRM can differentiate AF from SR in horses. Furthermore, the impact of artifact correction algorithms, integrated in the analyses software for HRV analyses was evaluated. Fourteen horses presented for AF treatment were simultaneously equipped with a HRM and an electrocardiogram (ECG). A two-minute recording at rest, walk and trot, before and after cardioversion, was obtained. RR intervals used were those determined automatically by the HRM and by the equine ECG analysis software, and those obtained after manual correction of QRS detection within the ECG software. RMSSD was calculated by the HRM software and by dedicated HRV software, using six different artifact filters. Statistical analysis was performed using the Wilcoxon signed-rank test and receiver operating curves. Results: The HRM, which applies a low level filter, produced high area under the curve (AUC) (>0.9) and cut off values with high sensitivity and specificity. Similar results were obtained for the ECG, when low level artifact filtering was applied. When no artifact correction was used during trotting, an important decrease in AUC (0.75) occurred. Conclusion: In horses treated for AF, HRMs with automatic RMSSD calculations distinguish between AF and SR. Such devices might be a useful aid to monitor for AF recurrence in horses

Pheochromocytoma in a horse with polymorphic ventricular tachycardia

A twenty-four-year-old mare, which had been examined seven years earlier for mitral valve regurgitation and mild left sided cardiomegaly, was presented with tachycardia, profuse sweating and muscle fasciculations. Blood examination revealed an increased packed cell volume, meta-bolic acidosis, hypocalcemia, hyperglycemia and increased cardiac troponin I concentration. ECG revealed ventricular premature beats and monomorphic ventricular tachycardia followed by polymorphic ventricular tachycardia with R-on-T phenomenon. The horse was treated immediately with hypertonic solution followed by isotonic solution and calcium, but the general condition deteriorated within forty-five minutes after arrival. The horse was euthanized due to poor prognosis. On necropsy, a pheochromocytoma of the left adrenal gland was found. Although this horse had undergone a cardiovascular examination seven and one year prior to the onset of the clinical signs, no indications for a neoplastic process or symptoms of a pheochromocytoma were found at that time. Early diagnosis of pheochromocytoma is based on catecholamine mediated cardiovascular effects, blood examination, blood pressure measurement, rectal palpation and rectal ultrasound of the adrenal gland. Based on a retrospective analysis of echocardiographic images and measurements, no predisposing factors were found. In this article, the importance of including pheochromocytoma as a differential diagnosis is highlighted, especially in older horses with acute polymorphic ventricular tachycardia, sweating, muscle tremors and signs of acute abdominal pain