Characterization of an outbreak of equine coronavirus infection in adult horses in Switzerland.

INTRODUCTION: Outbreaks of equine coronavirus (ECoV) infections have been described in different parts of the world including Europe. The aim of this report was to describe clinical signs, diagnostic work-up and outcome of the first documented outbreak of ECoV in Switzerland in order to raise the awareness for the disease and its various clinical presentations. The outbreak occurred on a farm with 26 horses. Of these, seven horses developed clinical disease ranging from mild signs such as fever and anorexia to severe signs of acute colitis. One horse died due to severe endotoxemia and circulatory shock secondary to severe acute necrotizing enteritis and colitis. Out of the 26 horses, five horses tested positive for ECoV, including two ponies without any clinical signs of infection. The low number of positive cases should nevertheless be interpreted with caution as testing was only performed on one occasion, over a month after the onset of clinical signs in the first suspected case. This report highlights the importance of diagnostic testing and early implementation of biosecurity measures on a farm with an ECoV outbreak. It should furthermore raise the awareness for unspecific and mild clinical signs such as fever and anorexia in affected animals that are potentially able to spread the disease.

INTRODUCTION: Des foyers d'infection à coronavirus équin (ECoV) ont été décrits dans différentes parties du monde, y compris en Europe. L'objectif de ce rapport est de décrire les signes cliniques, le diagnostic et les conséquences du premier foyer d'ECoV documenté en Suisse, afin de sensibiliser le public à cette maladie et à ses différents aspects cliniques. L'épidémie s'est produite dans une écurie comptant 26 chevaux. Parmi ceux-ci, sept chevaux ont développé une forme clinique allant de signes légers tels que la fièvre et l'anorexie à des signes sévères de colite aiguë. Un cheval est mort en raison d'une endotoxémie sévère et d>un choc circulatoire secondaire à une entérite nécrosante aiguë sévère et à une colite. Sur les 26 chevaux, cinq ont été testés positifs à l>ECoV, dont deux poneys sans aucun signe clinique d'infection. Le faible nombre de cas positifs doit néanmoins être interprété avec prudence car les tests n'ont été effectués qu'à une seule occasion, plus d'un mois après l'apparition des signes cliniques chez le premier cas suspect. Ce rapport souligne l'importance des tests de diagnostic et de la mise en œuvre rapide de mesures de biosécurité dans une exploitation où un foyer d'ECoV est détecté. Il devrait en outre sensibiliser à la présence de signes cliniques peu spécifiques et bénins tels que la fièvre et l'anorexie chez les animaux atteints qui sont potentiellement capables de propager la maladie.

Assessment of anti-Müllerian hormone in mares' transitional period and in relation to fertility in elderly mares.

Anti-Müllerian Hormone (AMH) has been linked to reproductive tract abnormalities in mares and stallions. This study aimed at evaluating AMH as a biomarker for two reproductive conditions in mares. In the first part of this study, plasma AMH was evaluated as an early indicator of the onset of cyclicity in mares in the transitional period from the anovulatory phase during winter anoestrus to the cyclic phase during the breeding season. Ten mares between 8 and 17 years old were included in the experiment which lasted from mid-February until the end of April. Ovarian activity was monitored with ultrasonography three times per week, the detection of a corpus haemorrhagicum/luteum was documented and antral follicle counts (AFC) were recorded. Blood samples were collected weekly by jugular venipuncture during the whole study period to compare AMH concentrations before and after the first ovulation of the year. The second objective was to evaluate if plasma AMH concentrations in middle-aged mares are linked to fertility and could serve as a prognostic marker in that age group. A total of 41 privately-owned clinically sound mares aged between 12 and 21 years of various breeds were inseminated with fresh or frozen semen. Mares were scanned between day 14 and 20 and the "early pregnancy rate" included only positive pregnancy examinations after the first observed cycle in the season of each mare. Potential associations between the early pregnancy rate in the first cycle and the explanatory factors AMH concentrations, age, status of the mare, stud, development of post-breeding endometritis, number of inseminations and semen type were analysed using logistic regression models. In the first part of the study, correlation between AMH and AFC for the whole study period (P = 0.0002, ρ = 0.55) as well as prior to (P = 0.008, ρ = 0.58) and after the first ovulation (P = 0.0007, ρ = 0.69) were observed. However, AMH concentrations before and after the first ovulation of the year were not statistically different. The second part of the study revealed no association between early pregnancy rate and AMH concentrations or any of the other mentioned factors. In conclusion, this study showed no evidence of a difference between AMH concentrations before and after the first ovulation of the year thus not supporting the use of AMH as a biomarker to predict the onset of cyclicity in mares. We could furthermore not show a relationship between plasma AMH concentrations and early pregnancy rates in this cohort of animals.

Pre-analytical stability of sorbitol dehydrogenase in equine heparinized plasma.

Sorbitol dehydrogenase (SDH) activity is one of the most sensitive and specific markers for hepatocellular injury in horses, but its reported lability makes it impractical for use in many clinical settings. To date, stability of SDH in equine samples has only been evaluated in a limited number of studies in serum samples of horses with activities within reference intervals. The objective of the study was to determine pre-analytical stability of equine SDH activity in heparinized plasma stored at different temperatures for up to 72 h. Twenty client-owned horses admitted to a veterinary teaching hospital for any reason were included in the study. Blood samples collected in lithium-heparin tubes were immediately centrifuged and SDH activity was analyzed within 1 h of collection (T0). Aliquots of plasma were stored at room temperature, 4 °C and -20 °C and SDH activity was re-analyzed after 4 h (T4), 24 h (T24) and 72 h (T72). A significant difference from values measured at T0 was found for samples stored at room temperature (P = 0.022) and -20 °C (P < 0.001), but not at 4 °C. The activity of SDH was within ±20% of that measured at T0 for all samples under all temperature conditions stored for 4 h, and for all samples stored at 4 °C for 24 h. Bland-Altman plots revealed narrow limits of agreement at T4 for all storage temperatures and at T24 for samples stored at 4 °C. The mean absolute percentage error and 95th percentile of the absolute percentage error were lower for samples stored at 4 °C than those stored at room temperature or -20 °C. The activity of SDH has adequate stability for 4 h regardless of storage temperature and 24 h if stored at 4 °C across a wide range of values. Knowledge of the pre-analytical stability of SDH may permit its broader use in assessing hepatic disorders in horses.

Age over 25 years, but not plasma adrenocorticotropic hormone con-cen-tration above the seasonally adjusted reference range is predictive for radio-graphically assessed changes of chronic laminitis in elderly horses.

INTRODUCTION: Endocrinopathic laminitis occurs as a consequence of hormonal derangements like pituitary pars intermedia dysfunction (PPID). The objective of the present study was to assess the occurrence of radiographic changes associated with chronic laminitis in elderly, clinically sound horses. Fifty-one horses were included in the study. Horses were assigned to different age groups, in groups according to their BCS and CNS as well as to groups with different ACTH concentrations in order to assess their risk of chronic laminitis (reported as odds ratios (OR) and confidence intervals (CI)). Horses assigned to an older age group (26-32 years) were significantly more likely to have radiographically assessed changes of chronic laminitis than horses in a younger age group (15-25 years) (OR 3.33; CI 1.05-10.59). The other variables (body condition score, cresty neck score, ACTH concentration) were not associated with an increased risk of having laminitic changes in these horses.

INTRODUCTION: La fourbure endocrinopathique survient à la suite de troubles hormonaux tels que le dysfonctionnement de la pars intermedia de l'hypophyse (DPIH). L'objectif de la présente étude était d'évaluer les changements radiographiques associés à la fourbure subclinique chez les chevaux âgés cliniquement sains. Cinquante et un chevaux ont été inclus dans l'étude. Les chevaux ont été assignés à différents groupes d'âge, en groupes en fonction de leur Body Condition Score (BCS) et de leur Cresty Neck Score (CNS) ainsi que des groupes avec différentes concentrations d'ACTH afin d'évaluer leur risque de fourbure chronique (rapportés sous forme de rapports de cotes (Odds-Ratio, OR) et d'intervalles de confiance (IC)). Les chevaux faisant partie d'un groupe d'âge plus avancé (26 à 32 ans) étaient significativement plus susceptibles de présenter des signes radiographiques de fourbure chronique que les chevaux d'un groupe d'âge plus jeune (15 à 25 ans) (OR 3,33; IC 1,05­10,59). Les autres variables (BCS, CNS, concentration d'ACTH) n'étaient pas associées à un risque accru de modifications de type fourbure chez ces chevaux.

Antimicrobial susceptibility patterns of blood culture isolates from foals in Switzerland.

INTRODUCTION: We report blood culture results of 43 foals admitted to an equine hospital for medical or surgical disorders and determine minimal inhibitory concentrations (MIC) of different antibiotics. Eleven foals had a positive blood culture result despite prior administration of antibiotics in 10 of these animals. MIC values above EUCAST and/or CLSI breakpoints were identified in coagulase-negative staphylococci, methicillin-resistant Staphylococcus aureus (MRSA) and Enterococcus faecium. Gram-negative isolates were less frequently identified and did not appear to exhibit increased MIC values. This study shows that bloodstream infections in foals in Switzerland are caused by diverse bacteria including Gram-positive bacteria which exhibit resistance to several classes of antibiotics.

INTRODUCTION: Nous rapportons les résultats d'hémoculture de 43 poulains admis dans un hôpital équin pour des affections médicales ou chirurgicales et déterminons les concentrations minimales inhibitrices (CMI) de différents antibiotiques. Le résultat de l'hémoculture a été positif pour onze poulains malgré l'administration préalable d'antibiotiques à 10 de ces animaux. Des valeurs de CMI supérieures aux seuils EUCAST et/ou CLSI ont été identifiées chez des staphylocoques coagulase négative, chez Staphylococcus aureus résistant à la méthicilline (MRSA) et chez Enterococcus faecium. Les isolats Gram négatifs étaient moins fréquemment identifiés et ne semblaient pas présenter de valeurs de CMI augmentées. Cette étude montre que les infections sanguines des poulains en Suisse sont causées par diverses bactéries, notamment des bactéries Gram positif, qui résistent à plusieurs classes d'antibiotiques.

Kinematic discrimination of ataxia in horses is facilitated by blindfolding.

BACKGROUND: Agreement among experienced clinicians is poor when assessing the presence and severity of ataxia, especially when signs are mild. Consequently, objective gait measurements might be beneficial for assessment of horses with neurological diseases. OBJECTIVES: To assess diagnostic criteria using motion capture to measure variability in spatial gait-characteristics and swing duration derived from ataxic and non-ataxic horses, and to assess if variability increases with blindfolding. STUDY DESIGN: Cross-sectional. METHODS: A total of 21 horses underwent measurements in a gait laboratory and live neurological grading by multiple raters. In the gait laboratory, the horses were made to walk across a runway surrounded by a 12-camera motion capture system with a sample frequency of 240 Hz. They were made to walk normally and with a blindfold in at least three trials each. Displacements of reflective markers on head, fetlock, hoof, fourth lumbar vertebra, tuber coxae and sacrum derived from three to four consecutive strides were processed and descriptive statistics, receiver operator characteristics (ROC) to determine the diagnostic sensitivity, specificity and area under the curve (AUC), and correlation between median ataxia grade and gait parameters were determined. RESULTS: For horses with a median ataxia grade ≥2, coefficient of variation for the location of maximum vertical displacement of pelvic and thoracic distal limbs generated good diagnostic yield. The hoofs of the thoracic limbs yielded an AUC of 0.81 with 64% sensitivity and 90% specificity. Blindfolding exacerbated the variation for ataxic horses compared to non-ataxic horses with the hoof marker having an AUC of 0.89 with 82% sensitivity and 90% specificity. MAIN LIMITATIONS: The low number of consecutive strides per horse obtained with motion capture could decrease diagnostic utility. CONCLUSIONS: Motion capture can objectively aid the assessment of horses with ataxia. Furthermore, blindfolding increases variation in distal pelvic limb kinematics making it a useful clinical tool.

Validation of a Point-of-Care Quantitative Equine IgG Turbidimetric Immunoassay and Comparison of IgG Concentrations Measured with Radial Immunodiffusion and a Point-of-Care IgG ELISA.

BACKGROUND: Point-of-care (POC) diagnostic tests with good sensitivity and specificity are needed for diagnosing failure of transfer of passive immunity (FTPI) in foals. Turbidimetric immunoassays (TIA) have these characteristics and provide quantitative results. A commercially available TIA-based POC test (POC-TIA) has not been validated in horses. OBJECTIVE: To validate a POC-TIA and compare results of POC-TIA, a POC-ELISA, and radial immunodiffusion (RID). ANIMALS: Heparinized blood samples (n = 127) from 48 hospitalized foals (<12 hour to 48 days). METHODS: Prospective validation study. IgG concentrations were measured using RID (gold standard), POC-TIA, and POC-ELISA. Agreement between assays was assessed using Bland-Altman analysis. Sensitivity and specificity were calculated using ROC curves. Inter- and intra-assay coefficients of variation (CVs) and linearity were evaluated for POC-TIA. RESULTS: The mean bias (95% limits of agreement) between RID and POC-TIA was -4 (-185 to 176), 27 (-201 to 255), and 308 (-377 to 993) mg/dL for samples with IgG concentrations of <400, 400-800, and >800 mg/dL, respectively. Sensitivity and specificity at optimal cutoff were 94 and 100% for the POC-TIA and 94 and 100% for the POC-ELISA to detect IgG <400 mg/dL, and 85 and 87% (POC-TIA) and 69 and 79% (POC-ELISA) to detect IgG ≤800 mg/dL. Intra- and interassay CVs for POC-TIA ranged between 1.6-3.8 and 11.9-18.8%, respectively. Linearity of the dilution series was preserved (R2 > 0.96). CONCLUSIONS AND CLINICAL IMPORTANCE: The POC-TIA provided unambiguous results and had sufficient sensitivity, specificity, accuracy, and precision to be used as an alternative to other POC tests to assess FTPI in foals.

A comparison between the equine and bovine hypothalamus-pituitary-adrenocortical axis.

In this review, we address the function of the hypothalamus-pituitary-adrenocortical (HPA) axis with special emphasis on the comparison between the bovine and equine species. The pars intermedia of the pituitary gland is particularly well developed in horses and cattle. However, its function is not well appreciated in cattle yet. The Wulzen's cone of the adenohypophysis is a special feature of ruminants. Total basal cortisol concentration is much higher in horses than that in cows with similar free cortisol fractions. Corticotropin-releasing factor (CRF) concentrations in equine pituitary venous blood are lower compared with other species, whereas plasma ACTH concentrations in cows are higher than those in horses. A CRF challenge test induced a more pronounced cortisol response in horses compared with cattle, whereas regarding ACTH challenge testing, the opposite seems true. Based on data from literature, the bovine species is characterized by relatively high basal blood CRF and ACTH and low cortisol and glucose concentrations. Obviously, further lowering of blood cortisol in cattle is easily prevented by the high sensitivity to ACTH, and as a consequence, subsequent increased gluconeogenesis prevents imminent hypoglycemia. Hypoglycemia is less likely in horses given their high muscle glycogen content and their relatively high cortisol concentration. When assessing HPA axis reactivity, response patterns to exogenous ACTH or CRH might be used as a reliable indicator of animal welfare status in cows and horses, respectively, although it is emphasized that considerable caution should be exercised in using measures of HPA activity solely to assess animal welfare.

The physiological consequences of crib-biting in horses in response to an ACTH challenge test.

Stereotypies are repetitive and relatively invariant patterns of behavior, which are observed in a wide range of species in captivity. Stereotypic behavior occurs when environmental demands produce a physiological response that, if sustained for an extended period, exceeds the natural physiological regulatory capacity of the organism, particularly in situations that include unpredictability and uncontrollability. One hypothesis is that stereotypic behavior functions to cope with stressful environments, but the existing evidence is contradictory. To address the coping hypothesis of stereotypies, we triggered physiological reactions in 22 horses affected by stereotypic behavior (crib-biters) and 21 non-crib-biters (controls), using an ACTH challenge test. Following administration of an ACTH injection, we measured saliva cortisol every 30 min and heart rate (HR) continuously for a period of 3h. We did not find any differences in HR or HR variability between the two groups, but crib-biters (Group CB) had significantly higher cortisol responses than controls (Group C; mean ± SD: CB, 5.84 ± 2.62 ng/ml, C, 4.76 ± 3.04 ng/ml). Moreover, crib-biters that did not perform the stereotypic behavior during the 3-hour test period (Group B) had significantly higher cortisol levels than controls, which was not the case of crib-biters showing stereotypic behavior (Group A) (B, 6.44 ± 2.38 ng/ml A, 5.58 ± 2.69 ng/ml). Our results suggest that crib-biting is a coping strategy that helps stereotypic individuals to reduce cortisol levels caused by stressful situations. We conclude that preventing stereotypic horses from crib-biting could be an inappropriate strategy to control this abnormal behavior, as it prevents individuals from coping with situations that they perceive as stressful.

Transcutaneous treatment with vetdrop(®) sustains the adjacent cartilage in a microfracturing joint defect model in sheep.

The significance of the adjacent cartilage in cartilage defect healing is not yet completely understood. Furthermore, it is unknown if the adjacent cartilage can somehow be influenced into responding after cartilage damage. The present study was undertaken to investigate whether the adjacent cartilage can be better sustained after microfracturing in a cartilage defect model in the stifle joint of sheep using a transcutaneous treatment concept (Vetdrop(®)). Carprofen and chito-oligosaccharids were added either as single components or as a mixture to a vehicle suspension consisting of a herbal carrier oil in a water-in-oil phase. This mixture was administered onto the skin with the aid of a specific applicator during 6 weeks in 28 sheep, allocated into 6 different groups, that underwent microfracturing surgery either on the left or the right medial femoral condyle. Two groups served as control and were either treated intravenously or sham treated with oxygen only. Sheep were sacrificed and their medial condyle histologically evaluated qualitatively and semi-quantitatively according to 4 different scoring systems (Mankin, ICRS, Little and O'Driscoll). The adjacent cartilage of animals of group 4 treated transcutaneously with vehicle, chito-oligosaccharids and carprofen had better histological scores compared to all the other groups (Mankin 3.3±0.8, ICRS 15.7±0.7, Little 9.0±1.4). Complete defect filling was absent from the transcutaneous treatment groups. The experiment suggests that the adjacent cartilage is susceptible to treatment and that the combination of vehicle, chitooligosaccharids and carprofen may sustain the adjacent cartilage during the recovery period.