Effects of soaked hay on lung function and airway inflammation in horses with severe asthma.

BACKGROUND: Reducing inhaled dust particles improves lung function in horses with severe asthma. Soaked hay is commonly used by owners, but its efficacy in improving lung function and inflammation has not been documented. OBJECTIVES: To measure the effects of soaked hay and alfalfa pellets in horses with severe asthma. ANIMALS: Ten adult horses with severe asthma from a research colony. METHODS: Prospective controlled trial. Horses in clinical exacerbation were housed indoors and allocated to be fed either soaked hay (n = 5) or alfalfa pellets (n = 5) for 6 weeks. Soaked hay was immersed for 45 minutes and dried out hay was discarded between meals. Pulmonary function and clinical scores were measured before and after 2, 4, and 6 weeks. Tracheal mucus scores and bronchoalveolar lavages were performed before and after 6 weeks. Lung function was analyzed with a linear mixed model using log-transformed data. RESULTS: Lung resistance decreased from (median (range)) 2.47 (1.54-3.95) to 1.59 (0.52-2.10) cmH2 O/L/s in the pellets group and from 1.89 (1.2-3.54) to 0.61 (0.42-2.08) cmH2 O/L/s in the soaked hay group over the 6-week period for an average difference of 1.06 cmH2 O/L/s for pellets (95% confidence interval [95% CI]: 0.09-2.04, P = .03, not significant after correction) and 1.31 cmH2 O/L/s for soaked hay (95% CI: -0.23 to 2.85, P < .001, significant). CONCLUSION AND CLINICAL IMPORTANCE: Soaked hay can control airway obstruction in horses with severe asthma. The strict protocol for soaking and discarding dried-out hay in this study could however be considered too great of an inconvenience by owners.

Lower airway ultrasonographic, endoscopic, and cytological changes in horses undergoing inhalation anesthesia with controlled ventilation for minor elective surgeries.

Effects of general anesthesia with controlled ventilation on the respiratory system have had limited evaluation in horses. A prospective observational study was performed with eleven client-owned horses undergoing elective surgery. Physical examination, auscultation with a rebreathing bag, complete blood cell count, lung ultrasound imaging, tracheal endoscopy imaging and transendoscopic tracheal wash were conducted before and 24 hours after anesthesia. Lung ultrasound imaging was also repeated just after recovery. A significant increase in blood neutrophil count between pre- and post-anesthesia (P=0.004) was observed. There was an increase in ultrasonographic score of the lungs at recovery (left P=0.007, right P=0.017). The score of the dependent lung was higher than the independent lung at recovery time (P=0.026) but no difference was observed 24 hours after anesthesia. The tracheal mucus score was higher after anesthesia (P=0.001); severe local inflammation was present in several horses at the site of endotracheal tube cuff. Neutrophil count was significantly higher on tracheal wash fluid cytology after anesthesia (P=0.016), without any significant changes on bacterial load. Increased tracheal mucus score and neutrophil count in tracheal wash samples were observed after general anesthesia in healthy horses without clinical evidence of pneumonia (fever, cough). Tracheal inflammation secondary to endotracheal intubation and cuff inflation was, therefore, suspected. Elective surgery without complications can induce inflammation of the trachea and changes in ultrasound images of the lungs in healthy horses and should be considered when evaluating respiratory system after a general anesthesia.

Minimally invasive removal of obstructive ureteral stones by intracorporeal lithotripsy in horses: 3 patients.

Three client-owned horses diagnosed with obstructive ureteral stones were referred and treated in a minimally invasive manner by retrograde ureteroscopy in conjunction with electrohydraulic lithotripsy (EHL) or laser Holmium:YAG lithotripsy (HYL). For all 3 horses, additional tests revealed variable degrees of azotemia and ureteral obstruction. Ultrasound examination (2 horses) revealed a loss of cortico-medullary distinction consistent with a chronic nephropathy. Ultrasound-guided biopsy of the right kidney in 1 horse revealed moderate glomerulosclerosis and lymphoplasmacytic nephritis. A standing anesthesia with a coccygeal epidural was done for each horse. A perineal urethrotomy was performed in 2 horses before the urethrocystoscopy. One horse was treated with Holmium:YAG laser lithotripsy and 2 others were treated using a electrohydraulic lithotripsy probe. Each procedure was successful. The ureteroscopy was successfully performed and visualization was excellent. Fragmentation of stones seemed easier with the electrohydraulic lithotripsy probe. No complications, pain, or signs of discomfort after the procedure were noticed. All 3 horses were discharged from the hospital. Key clinical message: Obstructive ureteral stones in horses can be successfully treated in a minimally invasive manner by retrograde ureteroscopy accompanied by lithotripsy. This technique is safe, not painful and did not require general anesthesia. Electrohydraulic lithotripsy appeared superior for stone fragmentation.

Exérèse minimalement invasive de calculs urétéraux obstructifs par lithotritie intracorporelle chez le cheval : trois patients. Trois chevaux appartenant à des clients diagnostiqués avec des calculs urétéraux obstructifs ont été référés et traités de manière peu invasive par urétéroscopie rétrograde en conjonction avec une lithotripsie électrohydraulique (EHL) ou une lithotripsie au laser Holmium:YAG (HYL). Pour les trois chevaux, des tests supplémentaires ont révélé des degrés variables d'azotémie et d'obstruction urétérale. L'échographie (deux chevaux) a révélé une perte de distinction cortico-médullaire compatible avec une néphropathie chronique. La biopsie échoguidée du rein droit chez un cheval a révélé une glomérulosclérose modérée et une néphrite lymphoplasmocytaire. Une anesthésie debout avec une péridurale coccygienne était effectuée pour chaque cheval. Une urétrotomie périnéale a été réalisée chez deux chevaux avant l'urétrocystoscopie. Un cheval a été traité par lithotripsie au laser Holmium:YAG et deux autres ont été traités à l'aide d'une sonde de lithotripsie électrohydraulique. Chaque procédure a réussi. L'urétéroscopie a été réalisée avec succès et la visualisation était excellente. La fragmentation des calculs semblait plus facile avec la sonde de lithotripsie électrohydraulique. Aucune complication, douleur ou signe d'inconfort après la procédure n'a été remarqué. Les trois chevaux ont obtenu leur congé de l'hôpital.Message clinique clé :Les calculs urétéraux obstructifs chez les chevaux peuvent être traités avec succès de manière peu invasive par urétéroscopie rétrograde accompagnée de lithotripsie. Cette technique est sûre, non douloureuse et ne nécessite pas d'anesthésie générale. La lithotritie électrohydraulique est apparue supérieure pour la fragmentation des calculs.(Traduit par Dr Serge Messier).

Characterization of fungal exposure and dectin-1 expression in healthy horses and horses with severe asthma.

OBJECTIVE: To quantify dectin-1 expression in bronchoalveolar lavage fluid (BALF), create polyclonal antibodies against equine dectin-1 and localize it in tissues, and quantify fungal exposure in pastured and stabled asthmatic and nonasthmatic horses. SAMPLES: BALF samples from 6 controls and 6 horses with severe asthma. Stored lung and nasal wash samples. PROCEDURES: Dectin-1 expression was quantified by quantitative PCR (qPCR). Purified peptide from equine dectin-1 was used to generate polyclonal antibodies and was confirmed with immunological testing. Fungal exposure was quantified in BALF samples by counting fungal-like intracellular particles in phagocytic cells, by qPCR quantification of the "universal" 18S rRNA fungal gene, and by quantifying 36 specific fungi in equine and dust samples using qPCR assays. RESULTS: Equine dectin-1 was localized in tissues and cells, and functional isoforms were upregulated significantly in BALF after stabling. Pastured horses from both groups had low levels of fungi in BALF, and there was a significant increase in some specific fungi, most notably for Eurotium amstelodami, Wallemia sebi, and Aspergillus niger after stabling. However, stabled asthmatic horses had fewer phagocytized particles, less 18S rRNA signal, and fewer specific fungi compared to nonasthmatic horses. CLINICAL RELEVANCE: Stabling increases exposure to fungi, but asthmatic horses had fewer fungi reaching their lower airways, presumably resulting from congestion and narrowing of the airways. Exposure to fungi could contribute to airway inflammation by increasing dectin-1 functional isoforms, and exposure to indoor molds should be avoided.

Tracheal microbial populations in horses with moderate asthma.

BACKGROUND: There are limited data on potential dysbiosis of the airway microbiota in horses with asthma. HYPOTHESIS/OBJECTIVES: We hypothesized that the respiratory microbiota of horses with moderate asthma is altered. Our objectives were (a) to quantify tracheal bacterial populations using culture and qPCR, (2) to compare aerobic culture and qPCR, and (c) to correlate bacterial populations with bronchoalveolar lavage fluid (BALF) cytology. ANIMALS: Eighteen horses with moderate asthma from a hospital population and 10 controls. METHODS: Prospective case-control study. Aerobic culture was performed on tracheal aspirates, and streptococci, Pasteurella multocida, Chlamydophila spp., Mycoplasma spp., as well as 16S (bacterial) and 18S (fungal) rRNA subunits were quantified by qPCR. RESULTS: Potential pathogens such as Streptococcus spp., Actinobacillus spp., and Pasteurellaceae were isolated from 8, 5, and 6 horses with asthma and 3, 0, and 2 controls, respectively. There was a positive correlation between Streptococcus spp. DNA and 16S rRNA gene (r ≥ 0.7, P ≤ 0.02 in both groups), but the overall bacterial load (16S) was lower in asthma (1.5 ± 1.3 versus 2.5 ± 0.8 × 104 copy/µL, P < 0.05). There was no association between microbial populations and clinical signs, tracheal mucus or BALF inflammation. CONCLUSIONS AND CLINICAL IMPORTANCE: This study does not support that bacterial overgrowth is a common feature of chronic moderate asthma in horses. Lower bacterial load could suggest dysbiosis of the lower airways, either as a consequence of chronic inflammation or previous treatments, or as a perpetuating factor of inflammation.