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ZusammenfassungDer Begriff Remodeling beschreibt den Prozess, der zu Veränderungen in Struktur und Aufbau im Vergleich zu gesundem Gewebe führt. Zumindest beim schweren equinen Asthma kommt es hauptsächlich, aber nicht ausschließlich, infolge der neutrophilen Entzündung zu einer Hypertrophie der glatten Bronchial- und arteriellen Gefäßmuskulatur sowie zu einer Fibrosierung der luftführenden Wege, aber auch des pulmonalen Interstitiums. Zur milden bis moderaten Form des equinen Asthmas ist bislang deutlich weniger bekannt. Lange wurde davon ausgegangen, dass das Remodeling irreversibel ist. Während dies für die glatte Bronchialmuskulatur weitgehend bis >heute gilt, gibt es beim Remodeling der extrazellulären Matrix der Lamina propria der Atemwege neue Erkenntnisse. Sowohl eine langfristige Remission durch konsequente Haltungsoptimierung als auch Glukokortikoide können den Kollagengehalt hier annähernd normalisieren. Das Remodeling der arteriellen Gefäßmuskulatur ist durch langfristige Haltungsoptimierung über mindestens 12 Monate und Bronchodilatatoren, nicht aber alleinig durch inhalative Glukokortikoide ebenfalls reversibel. Obwohl noch nicht abschließend geklärt, könnte die mit guter Prognose oft ausheilende milde bis moderate Form des equinen Asthmas eine Vorläuferform der schweren Form sein, bei der auch in der Phase der Remission Einschränkungen der Lungenfunktion nachweisbar sind, selbst wenn keine offensichtlichen klinischen Symptome vorliegen. Somit sind die frühzeitige Diagnosestellung des equinen Asthmas und ein früher Therapiebeginn entscheidend, damit zu Beginn der Behandlung möglichst wenige irreversible Veränderungen vorliegen. Der konsequenten Haltungsoptimierung kommt therapeutisch die größte Bedeutung zu, daneben sollten Glukokortikoide und Bronchodilatatoren eingesetzt werden.

Background There is contradictory evidence on the potential benefits of tongue ties on upper airway function and their efficacy in inhibiting intermittent dorsal displacement of the soft palate (DDSP) in racehorses. Objectives To test the hypothesis that tongue ties increase the pharyngeal diameter and decrease the occurrence of dynamic airway obstruction in racehorses. Study design Prospective, crossover blinded clinical study. Methods Data of 22 Thoroughbred and 8 Standardbred racehorses examined using overground endoscopy under full-intensity exercise on training racetracks with and without fixation of the tongue by use of tongue ties were analysed. Equivalent exercise intensity was ensured by measuring heart rate (bpm), speed (GPS) and venous lactate. Pharyngeal diameter was expressed as pharyngeal-epiglottis (PE) ratios and laryngeal abduction accordingly as laryngeal-median-ratios. Data were analysed using multivariable repeated-measurements ANOVA. Results The PE ratio increased significantly from 1.11 ± 0.19 to 1.28 ± 0.30 in all horses between rest and full-intensity exercise (p < 0.01). Multi-variable analysis revealed that this effect decreased significantly by the application of tongue ties (1.15 ± 0.27, p < 0.01). Tongue ties did not influence maximum laryngeal width (p = 0.09) and area (p = 0.2) significantly. DDSP was found in 4 of 30 examinations with tongue tie and in 1 of 30 examinations without tongue tie. Main limitations The study population was not randomly chosen and was heterogeneous. Few horses had a respiratory noise and the prevalence of upper respiratory tract disorders was too low for statistical comparison of the rate of DDSP with and without tongue ties. Conclusions A positive effect of tongue ties on pharyngeal or laryngeal diameters was not found in this study. Therefore, the results of this study do not support the use of tongue ties to enhance upper airway function., Hintergrund Zu potenziellen Vorteilen von Zungenbändern auf die Funktion der oberen Atemwege und deren Wirksamkeit zur Unterbindung von „DDSP“ (Dorsal displacement of the soft palate) bei Rennpferden gibt es im Widerspruch stehend publizierte Evidenz. Ziel der Studie Überprüfung der Hypothese, dass Zungenbänder den Pharyngealdurchmesser vergrößern und das Auftreten von dynamischen Atemwegsobstruktionen bei Rennpferden verringert. Studiendesign Klinische, prospektive Crossover-Blindstudie. Methodik Analysiert wurden Daten von 22 Vollblutpferden und acht Standardbred Trabrennpferden, untersucht mithilfe Dynamischer Atemwegs-Endoskopie unter Vollbelastung auf Trainingsrennbahnen mit und ohne Fixation der Zunge durch ein Zungenband. Eine gleichwertige Belastungsintensität wurde mithilfe von Messungen der Herzfrequenz (bpm), Geschwindigkeit (GPS) und venöser Laktatwerte sichergestellt. Pharyngealdurchmesser wurden als Pharyngeal-Epiglottis (PE) Verhältnis und laryngeale Abduktion, folglich Laryngeal-Median-Verhältnis, dargestellt. Daten wurden mithilfe multivariabler ANOVA mit wiederholten Messungen analysiert. Ergebnisse Das PE Verhältnis erhöhte sich signifikant von 1.11 ± 0.19 auf 1.28 ± 0.3 bei allen Pferden zwischen Ruhe und Vollbelastung (p

Asthma is a chronic inflammatory disorder of the lower respiratory tract and naturally occurs in humans and animals including horses. The annotation of an asthma microscopy whole slide image (WSI) is an extremely labour-intensive task due to the hundreds of thousands of cells per WSI. To overcome the limitation of annotating WSI incompletely, we developed a training pipeline which can train a deep learning-based object detection model with partially annotated WSIs and compensate class imbalances on the fly. With this approach we can freely sample from annotated WSIs areas and are not restricted to fully annotated extracted sub-images of the WSI as with classical approaches. We evaluated our pipeline in a cross-validation setup with a fxed training set using a dataset of six equine WSIs of which four are partially annotated and used for training, and two fully annotated WSI are used for validation and testing. Our WSI-based training approach outperformed classical sub-image-based training methods by up to 15% mAP and yielded human-like performance when compared to the annotations of ten trained pathologists.

Clinical examination, bronchoalveolar lavage fluid (BALF) cytology, acute- phase protein, and pulmonary hemostasis and fibrinolysis marker (fibrinogen, serum amyloid A [SAA], and D-dimer) results were compared between control and respiratory disease-affected horses. Using a clinical scoring system, horses (n = 58) were classified as respiratory disease-free (Controls, n = 15) or with recurrent airway obstruction (RAO; n = 18), inflammatory airway disease (n = 14) or chronic interstitial pneumopathy (n = 11). There were no significant differences in fibrinogen concentrations among groups, but there was a trend toward a lower value in controls (median 0.0024 g/L) than in horses with chronic pneumopathies (median 0.0052 g/L), in particular, those with RAO (median 0.0062 g/L). Fibrinogen concentration was positively correlated with percentage of neutrophils in BALF (rs = 0.377, p = 0.004). SAA concentrations were low; 65.5% of samples were below the detection limit. D-dimer concentrations were also low and quantifiable concentrations were only obtained after ultrafiltration and only in RAO (median 0.1 mg/L). In conclusion, there was limited evidence of increased coagulatory activity in chronic pneumopathies, apart from RAO. It is uncertain whether fibrinogen and D-dimer concentrations increased due to their role as acute-phase proteins or as a misbalance of coagulation and fibrinolysis.

Procalcitonin (PCT), a precursor protein of the hormone calcitonin, is a sensitive inflammatory marker useful in diagnosis of exacerbation of asthma and chronic obstructive pulmonary disease. In this study, PCT was evaluated as a potential biomarker for the success of budesonide inhalation therapy in equine recurrent airway obstruction (RAO). Twelve horses suffering from RAO were included in a prospective clinical study. Clinical examinations, exercise test, blood gas analysis, endoscopy, bronchoalveolar lavage fluid cytology, and thoracic radiography were performed before and after therapy and results included in a scoring system. Inhalative therapy using budesonide at a dosage of 1,500μg twice daily was performed over 10days. Equine-specific enzyme-linked immunosorbent assays were used to evaluate concentrations of PCT as well as interleukins-1ß and 6 in bronchoalveolar lavage fluid. A significant reduction in clinical score, in particular in dyspnea, amount, and viscosity of tracheal secretion, was found after 10days of inhalation (P = .005). For PCT, no difference was found before and after therapy. The median PCT concentration increased insignificantly from 13.85 (6.8–42.09) ng/mL to 16.47 (2.04–151.01) ng/mL after therapy (P = .158). In conclusion, PCT does not seem to be a useful marker to monitor treatment success of glucocorticoid inhalation in RAO.

Recently, a syndrome called “equine idiopathic hemorrhagic cystitis” was described and clinical features compared with bladder neoplasia. In this case report, we describe a case of hemorrhagic cystitis with a favorable outcome in a high-performance dressage horse, in which exercise intensity might be the etiologic factor for the development of bladder-wall hyperplasia and hematuria. A 14-year-old Warmblood gelding was presented with a history of hematuria of 2-day duration. The high-level dressage horse had performed on the previous 3 weekends and was trained at least three times a week at performance intensity level. Sonographically, the dorsal bladder wall was about 1.5 cm thick and the different layers of the bladder wall could not be differentiated. Endoscopy revealed that the bladder was highly edematous and showed diffuse submucosal bleeding. Histopathological differential diagnoses were severe reactive hyperplasia or a low-grade transitional cell carcinoma. Four months later, bladder wall thickness had decreased to 1.0 cm and the different layers of the bladder wall were easily visible sonographically. Endoscopy showed a normal bladder mucosa. On histopathology, hyperplasia of the epithelium was significantly decreased. A diet low in calcium was recommended after the checkup, and the owners started working the horse very lightly for 2 days a week. Over the following 2 months, hematuria had not recurred. In conclusion, it seems likely that hemorrhagic cystitis in this horse was exercise-associated, but as repeated provocation by high exercise intensity was not performed in this case, this remains an assumption.

Objectives. Inhalation of immunostimulatory bacterial DNA segments (cytosine-phosphate-guanosine-oligodeoxynucleotides, CpG-ODN) normalizes clinical and cytologic parameters in severe equine asthma. We hypothesized that CpG-ODN inhalation also reduces the misbalance of elastinolytic activity in asthmatic horses.Methods. Twenty asthmatic horses diagnosed by clinical examinations using a scoring system were included. All horses inhaled CpG-ODNs for 14 days in 2-day intervals. Matrix metalloproteinase (MMP-2/-9) and tissue inhibitors of metalloproteinase (TIMP-1/-2) concentrations were measured in tracheal aspirates using equine sandwich ELISAs before and 2 and 6 weeks after CpG-ODN inhalation.Results. MMP and TIMP concentrations correlated with the results of clinical scoring in all stages of equine asthma. Inhalation therapy led to significant reductions in clinical scores. MMP-2, MMP-9, and TIMP-2 concentrations were significantly reduced immediately, and all MMP and TIMP concentrations 6 weeks after therapy.Discussion. In equine asthma, overexpression of MMPs contributes to pathological tissue destruction, while TIMPs counteract MMPs with overexpression leading to fibrosis formation. The results of this study show that CpG-ODN inhalation may be an effective therapy to address a misbalance in equine asthma.Conclusions. Misbalance of elastinolytic activity seems to improve by CpG-ODN inhalation for at least 6 weeks posttherapy, which may reduce the remodeling of the extracellular matrix. Further studies should evaluate this effect in comparison to glucocorticoid inhalation therapy.Significance. CpG-ODN inhalation may be an effective therapy in the prevention of pulmonary fibrosis formation in equine asthma.

BACKGROUND During bronchoalveolar lavage fluid (BALF) sample preparation in horses, several technical aspects can affect sample variability. To date, the effects of different fixatives on prepared equine BALF films have been insufficiently investigated. OBJECTIVES This study aimed to determine the effect of various on-slide fixation methods on cell quality, including spray fixation of wet films, and acetone and methanol fixation of air-dried samples in comparison with unfixed, air-dried films. METHODS Cytocentrifuged BALF samples from 5 horses were fixed in a wet state using a commercially available fixation spray. They were also fixed with acetone or methanol after air-drying using standard protocols or were air-dried with no fixation. After different postfixation storage durations and temperatures, the samples were stained with May-Grunwald Giemsa or immunocytochemistry stains. Subsequently, differential cell counts (DCCs) were performed, cell areas were measured, and cell morphologies and immunocytochemical staining intensities were assessed semiquantitatively. RESULTS Optimal cell morphology results were achieved with the wet-spray fixation method. Acetone and methanol fixation, especially when performed at -20°C, caused reduced cell morphology quality, thereby significantly altering DCCs. For storage of unstained samples for 1 week at room temperature, no significant changes in cell morphology were observed for either fixation method. Wet-spray fixation resulted in enhanced preservation of macrophage, granulocyte, and mast cell sizes compared with air-drying techniques. Immunocytochemical staining of unfixed and acetone-fixed samples was the most intense. CONCLUSIONS Wet-spray fixation resulted in the best preservation of cellular morphology and less cell shrinkage compared with unfixed specimens and is, therefore, recommended for BALF cytology.

OBJECTIVE To evaluate the influence of respiratory tract disease (ie, recurrent airway obstruction [RAO]) and mode of inhalation on detectability of inhaled budesonide in equine plasma and urine samples. ANIMALS 16 horses (8 healthy control horses and 8 horses affected by RAO, as determined by results of clinical examination, blood gas analysis, bronchoscopy, and cytologic examination of bronchoalveolar lavage fluid). PROCEDURES 4 horses of each group inhaled budesonide (3 μg/kg) twice daily for 10 days while at rest, and the remaining 4 horses of each group inhaled budesonide during lunging exercise. Plasma and urine samples were obtained 4 to 96 hours after inhalation and evaluated for budesonide and, in urine samples, the metabolites 6β-hydroxybudesonide and 16α-hydroxyprednisolone. RESULTS Detected concentrations of budesonide were significantly higher at all time points for RAO-affected horses, compared with concentrations for the control horses. All samples of RAO-affected horses contained budesonide concentrations above the limit of detection at 96 hours after inhalation, whereas this was found for only 2 control horses. Detected concentrations of budesonide were higher, but not significantly so, at all time points in horses that inhaled budesonide during exercise, compared with concentrations for inhalation at rest. CONCLUSIONS AND CLINICAL RELEVANCE Results of this study indicated that the time interval between inhalation of a glucocorticoid and participation in sporting events should be increased when inhalation treatment is administered during exercise to horses affected by respiratory tract disease.

Summary In this study, 59 Warmblood horses were examined endoscopically at rest, during overground endoscopy and by laryngeal ultrasonography to evaluate the validity of ultrasonography as an additional diagnostic tool for left recurrent laryngeal neuropathy in Warmblood horses. Left laryngeal function during endoscopy at rest and overground exercise was scored by 3 blinded examiners. A new semiquantitative subjective-descriptive score was used for evaluation of ultrasonographic images. Sensitivity and specificity as well as positive and negative predictive values of ultrasonographic images for longitudinal and transverse planes were calculated in reference to endoscopic scoring results. Laryngeal ultrasonography with semiquantitative grading proved to be a very sensitive and specific technique for evaluation of recurrent laryngeal neuropathy in Warmblood horses.

Objective To determine outcome after transendoscopic laser fenestration of the median septum and removal of the salpingopharyngeal fold of the guttural pouch on nasopharyngeal obstruction caused by poll flexion in Warmblood horses. Study Design Clinical study. Animals Horses (n = 9). Methods Nine horses with a history of performance insufficiency and respiratory noise during poll flexion were examined. On endoscopy, an often asymmetric dorsoventral obstruction of the nasopharynx occurred during poll flexion. Left lateral radiographs were taken in neutral, extended, and flexed head positions showed that mean nasopharyngeal diameter during poll flexion was significantly smaller than in healthy horses. Transendoscopic laser fenestration of the median septum between the guttural pouches was fenestrated and on the worst affected side, resection of the salpingopharyngeal fold was performed for correction. Three days after surgery a follow-up examination including an exercise test, endoscopy, and radiology was performed in 7 horses. Results Mean ± SD nasopharyngeal diameter based on radiographic measurements had increased significantly by 64% from 1.67 ± 0.49 to 2.58 ± 0.61 cm (P = .01) and the respiratory noise was reduced or eliminated in 7 horses. Six months after surgery, a beneficial long-term effect on performance was confirmed by an owner interview in 8 horses. Conclusions Transendoscopic laser surgery offers a promising low-risk treatment option for horses suffering from nasopharyngeal obstruction caused by poll flexion.

Background Overexpression of matrix-metalloproteinases (MMPs) has been shown to lead to tissue damage in equine recurrent airway obstruction (RAO), as a misbalance with their natural inhibitors, the tissue inhibitors of metalloproteinases (TIMPs), occurs. This favors irreversible pulmonary fibrosis formation. Increased levels of MMPs, TIMPs or altered ratios between them can be used as biomarkers of respiratory disease. We hypothesized that levels of MMPs, TIMPs and their ratios correlate with improvement in clinical findings and bronchoalveolar lavage fluid (BALF) cytology after 10 days of inhalative glucocorticoid therapy and environmental dust reduction (EDR) and may be used to monitor treatment success. Ten horses with a history of RAO participated in a prospective clinical study. Clinical and cytological scoring was performed before and after inhalative therapy using budesonide (1500 μg BID over 10 days) and EDR (bedding of wood shavings and wet hay as roughage). Gelatin zymography was performed for qualitative and semi-quantitative evaluation of MMP-2 and MMP-9 in BALF supernatant, while fluorimetry was used to evaluate MMP-8 activity. Additionally, specific equine ELISA assays were used for quantitative assessment of MMP-2, MMP-9, TIMP-1 and TIMP-2. Results A significant reduction in the total and several single parameters of the clinical score were found after 10 days of inhalative therapy and EDR. The concentrations of MMP-2, MMP-9, TIMP-1 and TIMP-2 (ELISA) as well as their activities (MMP-2 and MMP-9 zymography and MMP-8 fluorimetry) were significantly decreased after therapy. Significant improvements in MMP-8/TIMP-1 and MMP-8/TIMP-2 ratios were also found, differences between other ratios before and after therapy were insignificant. Conclusions Metalloproteinases and their inhibitors, in particular MMP-9 and TIMP-2, are valuable markers for clinical improvement in RAO.

Background: Procalcitonin (PCT), a precursor protein of the hormone calcitonin, is a sensitive inflammatory marker in human medicine, which is primarily used for diagnosis of bacterial sepsis, but is also useful in diagnosis of exacerbation of asthma and COPD. In this study, PCT was evaluated as a potential biomarker for different chronic pneumopathies in the horse using an equine specific ELISA in comparison to established clinical markers and different interleukins. Sixty-four horses were classified as free of respiratory disease, recurrent airway obstruction (RAO), inflammatory airway disease (IAD) or chronic interstitial pneumopathy (CIP) using a scoring system. PCT concentrations were measured in plasma (n = 17) and in the cell-free supernatant of bronchoalveolar lavage (n = 64). PCT concentrations were correlated to interleukins IL-1ß and IL-6 in BALF, clinical findings and BALF cytology. Results: The median PCT concentrations in plasma were increased in respiratory disease (174.46 ng/ml, n = 7) compared to controls (13.94 ng/ml, n = 10, P = 0.05) and correlated to PCT in BALF supernatant (rs = 0.48). Compared to controls (5.49 ng/ml, n = 15), median PCT concentrations in BALF supernatant correlated to the overall clinical score (rs = 0.32, P = 0.007) and were significantly increased in RAO (13.40 ng/ml, n = 21) and IAD (16.89 ng/ml, n = 16), while no differences were found for CIP (12.02 ng/ml, n = 12). No significant increases were found for IL-1 and IL-6 between controls and respiratory disease in general as well as different disease groups. Conclusions: Although some correlations were found between PCT in plasma, BALF supernatant and clinical scores, PCT in BALF does not seem to be a superior marker compared to established clinical markers. PCT in plasma seems to be more promising and a greater number of samples should be evaluated in further studies.

Dynamic nasopharyngeal collapse with upper airway obstruction is an important cause of exercise intolerance in performance horses. Its underlying pathophysiology is not fully understood. We hypothesize that head position affects pharyngeal diameter, and thus head position may be a contributing factor to nasopharyngeal obstruction. Fifteen adult healthy horses were subjected to endoscopy and radiography at rest. The pharyngeal diameter was measured at nine different head and neck positions. The effect of sedation and breathing cycle on the pharyngeal diameter was determined, and the relationship between the head angle and the pharyngeal diameter was analyzed. There was a significant influence of head and neck position on pharyngeal diameter, with head position having the major effect (P < 0.001); neck position was less important, but still significant (P < 0.05). The smallest pharyngeal diameter was found at the dorsal, flexed position, which is a clinically important head position in dressage horses. The largest pharyngeal diameter was found at the extended midway position. At each head level, the pharyngeal diameter decreased with flexing the head and it increased with extending the head. The head angle was not associated with pharyngeal diameter, and neither sedation status nor breathing cycle significantly affected pharyngeal diameter. A decrease in pharyngeal diameter will limit the airflow through the upper respiratory tract, and it may result in turbulence with subsequent dynamic collapse. Head and neck position should therefore be considered a possible contributing factor in horses with suspected nasopharyngeal dysfunction.

Equine inflammatory airway disease (IAD) and recurrent airway obstruction (RAO) represent a spectrum of chronic inflammatory disease of the airways in horses resembling human asthma in many aspects. Therefore, both are now described as severity grades of equine asthma. Increasing evidence in horses and humans suggests that local pulmonary inflammation is influenced by systemic inflammatory processes and the other way around. Inflammation, coagulation, and fibrinolysis as well as extracellular remodeling show close interactions. Cytology of bronchoalveolar lavage fluid and tracheal wash is commonly used to evaluate the severity of local inflammation in the lung. Other mediators of inflammation, like interleukins involved in the chemotaxis of neutrophils, have been studied. Chronic obstructive pneumopathies lead to remodeling of bronchial walls and lung parenchyma, ultimately causing fibrosis. Matrix metalloproteinases (MMPs) are discussed as the most important proteolytic enzymes during remodeling in human medicine and increasing evidence exists for the horse as well. A systemic involvement has been shown for severe equine asthma by increased acute phase proteins like serum amyloid A and haptoglobin in peripheral blood during exacerbation. Studies focusing on these and further possible inflammatory markers for chronic respiratory disease in the horse are discussed in this review of the literature.

Enterobacteriaceae such as Escherichia coli are common commensals as well as opportunistic and obligate pathogens. They cause a broad spectrum of infectious diseases in various hosts, including hospital-associated infections. In recent years, the rise of extended spectrum beta-lactamase (ESBL)-producing E. coli in companion animals (dogs, cats and horses) has been striking. However, reports on nosocomial infections are mostly anecdotic. Here we report on the suspected nosocomial spread of both ESBL-producing and non-ESBL-producing multi-drug resistant E. coli isolates in three equine patients within an equine clinic. Unlike easy-to-clean hospitalization opportunities available for small animal settings like boxes and cages made of ceramic floor tiles or stainless steel, clinical settings for horses are challenging environments for infection control programs due to unavoidable extraneous material including at least hay and materials used for horse bedding. The development of practice-orientated recommendations is needed to improve the possibilities for infection control to prevent nosocomial infections with multi-drug resistant and other transmissible pathogens in equine clinical settings.

With the rising importance of nosocomial infections in equine hospitals, increased efforts with regard to biosecurity and infection control are necessary. This even more since nosocomial infections are often associated with multi-drug resistant pathogens. Consequently, the implementation of targeted prevention programs is essential. Since nosocomial infections are usually multifactorial events, realization of only a single measure is rarely effective to overcome nosocomial spread in clinical practice. Equine patients may be colonized at admission with multi-drug resistant pathogens such as methicillin resistant Staphylococcus aureus (MRSA) and/or extended spectrum beta lactamase-producing (ESBL-) Enterobacteriaceae. Regardless of their individual resistance properties, these bacteria are common and usually unnoticed colonizers of either the nasopharynx or the intestinal tract. Also viral diseases caused by equine herpesvirus 1 (EHV-1) and EHV-4 may reach a clinic by patients which are latently infected or in the incubation period. To prevent nosocomal outbreaks, achieve an interruption in the infection chain and to eradicate infectious agents from the hospital environment, a professional hospital management is necessary. This should be adapted to both the wide range of pathogens causing nosocomial infections and the individual needs of equine patients. Amongst others, this approach includes a risk classification of equine patients at admission and information/enlightenment of the animal owners at discharge. An efficient management of inpatients, a targeted hygiene management and clear responsibilities with respect to biosecurity together with a surveillance of nosocomial infections form the cornerstone of infection control in equine hospitals.

Pathogens frequently associated with multi-drug resistant (MDR) phenotypes, including extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae (ESBL-E) and Acinetobacter baumannii isolated from horses admitted to horse clinics, pose a risk for animal patients and personnel in horse clinics. To estimate current rates of colonization, a total of 341 equine patients were screened for carriage of zoonotic indicator pathogens at hospital admission. Horses showing clinical signs associated with colic (n = 233) or open wounds (n = 108) were selected for microbiological examination of nostril swabs, faecal samples and wound swabs taken from the open wound group. The results showed alarming carriage rates of Gram-negative MDR pathogens in equine patients: 10.7% (34 of 318) of validated faecal specimens were positive for ESBL-E (94%: ESBL-producing Escherichia coli), with recorded rates of 10.5% for the colic and 11% for the open wound group. 92.7% of the ESBL-producing E. coli were phenotypically resistant to three or more classes of antimicrobials. A. baumannii was rarely detected (0.9%), and all faecal samples investigated were negative for Salmonella, both directly and after two enrichment steps. Screening results for the equine nostril swabs showed detection rates for ESBL-E of 3.4% among colic patients and 0.9% in the open wound group, with an average rate of 2.6% (9/340) for both indications. For all 41 ESBL-producing E. coli isolated, a broad heterogeneity was revealed using pulsed-field gel electrophoresis (PFGE) patterns and whole genome sequencing (WGS) -analysis. However, a predominance of sequence type complex (STC)10 and STC1250 was observed, including several novel STs. The most common genes associated with ESBL-production were identified as blaCTX-M-1 (31/41; 75.6%) and blaSHV-12 (24.4%). The results of this study reveal a disturbingly large fraction of multi-drug resistant and ESBL-producing E. coli among equine patients, posing a clear threat to established hygiene management systems and work-place safety of veterinary staff in horse clinics.

Bronchoalveolar lavage (BAL) and thoracic radiography are routinely performed diagnostic procedures. We hypothesized that BAL increases the interstitial opacity of caudoventral and caudodorsal thoracic radiographs. Fifty-three horses, including 8 clinic owned and 45 from a referral hospital population, were classified as healthy controls (n = 12), severe equine asthma (recurrent airway obstruction, n = 12) or mild-to-moderate equine asthma (inflammatory airway disease, n = 21) based on the results of a clinical scoring system. Eight were excluded due to different diagnoses and poor image quality. Four randomized thoracic radiographs of each horse were scored by two blinded observers, who were also asked to identify the image as obtained before or after a BAL procedure. In severe equine asthma, the chance (adjusted odds) of misinterpretation of the correct imaging time was approximately 5 times higher than in controls (odds ratio [OR] = 5.373, p = 0.028). The chance of misinterpretation was approximately 4 times lower in caudodorsal images than in caudoventral projections (OR = 0.241, p = 0.004). Identification of the correct imaging time was highly correlated with an increase in interstitial opacity (OR = 9.976, p < 0.0001). In conclusion, we recommend performing BAL after thoracic radiography to avoid possible misinterpretation.

In human medicine, procalcitonin (PCT) is a very common and well-established biomarker for sepsis. Even though sepsis is also a leading cause of death in foals and adult horses, up to now, no data about the role of equine PCT in septic horses has been available. Based on monoclonal antibodies targeted against human PCT, we report here the development of a sandwich ELISA for the quantification of equine PCT in equine plasma samples. The ELISA was characterized for intra- and interassay variance and a working range from 25 to 1,000 ng mL(-1) was defined as within this range; both intra- and interassay variances were below 15 %. The target recovery ranged between 73 and 106 %. The ELISA was used to determine the equine PCT concentration in 24 healthy and 5 septic horses to show the potential for clinical evaluation of equine PCT. Significantly different (P = 0.0006) mean equine PCT concentrations were found for the healthy control group and the sepsis group (47 and 8,450 ng mL(-1)).

This review summarizes similarities and differences between the metabolic syndromes in humans and equines, concerning the anatomy, symptoms, and pathophysiological mechanisms. In particular, it discusses the structure and distribution of adipose tissue and its specific metabolic pathways. Furthermore, this article provides insights and focuses on issues concerning laminitis in horses and cardiovascular diseases in humans, as well as their overlap.

Background Various head and neck positions in sport horses are significant as they can interfere with upper airway flow mechanics during exercise. Until now, research has focused on subjectively described head and neck positions. The objective of this study was to develop an objective, reproducible method for quantifying head and neck positions accurately. Results Determining the angle between the ridge of the nose and the horizontal plane (ground angle) together with the angle between the ridge of nose and the line connecting the neck and the withers (withers angle) has provided values that allow precise identification of three preselected head and neck positions for performing sport horses. The pharyngeal diameter, determined on lateral radiographs of 35 horses, differed significantly between the established flexed position and the remaining two head and neck positions (extended and neutral). There was a significant correlation between the pharyngeal diameter and the ground angle (Spearman’s rank correlation coefficient −0.769, p

Dynamic nasopharyngeal collapse with upper airway obstruction is an important cause of exercise intolerance in performance horses. Its underlying pathophysiology is not fully understood. We hypothesize that head position affects pharyngeal diameter, and thus head position may be a contributing factor to nasopharyngeal obstruction. Fifteen adult healthy horses were subjected to endoscopy and radiography at rest. The pharyngeal diameter was measured at nine different head and neck positions. The effect of sedation and breathing cycle on the pharyngeal diameter was determined, and the relationship between the head angle and the pharyngeal diameter was analyzed. There was a significant influence of head and neck position on pharyngeal diameter, with head position having the major effect (P0.001); neck position was less important, but still significant (P0.05). The smallest pharyngeal diameter was found at the dorsal, flexed position, which is a clinically important head position in dressage horses. The largest pharyngeal diameter was found at the extended midway position. At each head level, the pharyngeal diameter decreased with flexing the head and it increased with extending the head. The head angle was not associated with pharyngeal diameter, and neither sedation status nor breathing cycle significantly affected pharyngeal diameter. A decrease in pharyngeal diameter will limit the airflow through the upper respiratory tract, and it may result in turbulence with subsequent dynamic collapse. Head and neck position should therefore be considered a possible contributing factor in horses with suspected nasopharyngeal dysfunction.

Equine precision cut lung slices (PCLS) were used to evaluate the ability of several pharmacologic compounds, parasympatholytics atropine, ipratropium, tiotropium and phosphodiesterase (PDE) 4-inhibitor cilomilast, to inhibit methacholine (MCh) induced bronchial constriction. The study war performed using vital lung samples from 20 horses, harvested immediately after euthanasia and lung examination.Tissue samples from the cranial, caudal and accessory lobe were taken for histological examination. Viability in PCLS of 250 +/- 20 microm was confirmed by observation of cilia movement and bronchial contraction in response to the addition of increasing concentrations of MCh (10(-8) to 10(-4) mol/l). Washing in pure RPMI-medium resulted in bronchial reopening. After incubation (20 minutes in an RPMI-solution containing cilomilast (10(-5) mol/l), atropine, ipratropium or tiotropium (10(-7) mol/l) each group (randomized, placebo controlled) was treated with MCh again. After reopening the unaffected viability of the PCLS was confirmed by the addition of MCh. EC50 values were calculated from bronchial cross-sections for each contraction. EC50 values significantly increased after atropine, ipratropium and tiotropium addition. No difference was found for cilomilast and in control slices. Statistical analysis showed a large interindividual, but a small intraindivual variability. No correlation was found between the clinical examination, histological findings and PCLS' responsiveness. We were able to confirm Vietmeier's (2007) values for the responsiveness of equine PCLS to MCh and to proof the effect of several new bronchodilatators using a new technique that allows the assessment of several substances in the same horse.

Background Glucocorticoids have been proven to be effective in the therapy of recurrent airway obstruction (RAO) in horses via systemic as well as local (inhalative) administration. Elective analysis of the effects of this drug on bronchoconstriction in viable lung tissue offers an insight into the mechanism of action of the inflammatory cascade occurring during RAO which is still unclear. The mechanism of action of steroids in treatment of RAO is thought to be induced through classical genomic pathways. We aimed at electively studying the effects of the glucocorticoid beclomethasone dipropionate on equine precision-cut lung slices (PCLS). PCLS were used to analyze ex-vivo effects of beclomethasone on inhibiting bronchoconstriction in the horse. The inhibiting effect was measured through instillation of a known mediator of inflammation and bronchoconstriction, leukotriene C4. For this, the accessory lobes of 13 horses subjected to euthanasia for reasons unrelated to the respiratory apparatus were used to obtain viable lung slices. Results After 30 minutes of PCLS incubation, beclomethasone showed to significantly inhibit the contraction of the bronchioles after instillation with leukotriene C4. The EC50 values of the two contraction curves (LTC4 with and without BDP) differed significantly from each other (p = 0.002). The possibility of a non-genomic rapid mechanism of action seems likely since transcriptional activities require a longer lag period. Conclusions In human neuroendocrinology, high levels of glucocorticoids have been proven to function via a non-genomic mechanism of membrane receptors. The concentration of beclomethasone used on the lung slices in our study can be considered as high. This allows speculation about similar rapid non-genomic mechanisms of high-dosage inhaled glucocorticoids in the lower airways of horses. However, further assessment on a molecular basis is needed to confirm this.