Heaves, an asthma‐like disease of horses

BackgroundMultiple hypersensitivities (MHS) have been described in humans, cats, and dogs, but not horses.HypothesesHorses suffering from recurrent airway obstruction (RAO), insect bite hypersensitivity (IBH), or urticaria (URT) will have an increased risk of also being affected by another one of these hypersensitivities. This predisposition for MHS also will be associated with decreased shedding of strongylid eggs in feces and with a single nucleotide polymorphism (SNP BIEC2‐224511), previously shown to be associated with RAO.AnimalsThe first population (P1) included 119 randomly sampled horses representative of the Swiss sporthorse population; the replication population (P2) included 210 RAO‐affected Warmblood horses and 264 RAO‐unaffected controls. All horses were Warmbloods, 14 years or older.MethodsAssociations between disease phenotypes (RAO, IBH, URT, MHS) fecal egg counts, the SNP BIEC2‐224511 as well as management and environmental factors were investigated.ResultsIn P1, RAO‐affected horses had a 13.1 times higher odds ratio (OR) of also suffering from IBH (P = .004). In P2, the respective OR was 7.4 (P = .002) and IBH‐affected horses also showed a 7.1 times increased OR of concomitantly suffering from URT (P < .001). IBH, URT, and MHS phenotypes were significantly associated with the absence of nematode eggs in the feces.Conclusions and Clinical ImportanceThis is the first report of MHS in horses. Specifically, an increased risk for IBH should be expected in RAO‐affected horses.

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confidence: 99%

Multiple Hypersensitivities Including Recurrent Airway Obstruction, Insect Bite Hypersensitivity, and Urticaria in 2 Warmblood Horse Populations

Kehrli

Jandova

Fey

et al. 2014

“…The replication population was a random sample from the register of the Swiss Equestrian Federation 17. Feeding of hay during the whole study period was an inclusion criterion, as hay feeding is the most important environmental factor in the development of RAO 4, 10, 11. Age (In the half‐sibling group (F1 and F2 combined), the overall age range was 6–15 years, while the overall age range of the replication group was 5–24 years.…”

Section: Methodsmentioning

confidence: 99%

“…RAO, in contrast, affects middle‐aged to older horses and provokes more severe respiratory signs. A strong genetic basis was shown for RAO7, 8, 9 and hay feeding is the most important environmental factor for its development4, 10, 11 and exacerbation 12, 13…”

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confidence: 99%

Evaluation of Coughing and Nasal Discharge as Early Indicators for An Increased Risk to Develop Equine Recurrent Airway Obstruction (RAO)

Bosshard

Gerber

2014

BackgroundIt is often assumed that horses with mild respiratory clinical signs, such as mucous nasal discharge and occasional coughing, have an increased risk of developing recurrent airway obstruction (RAO).HypothesisCompared to horses without any clinical signs of respiratory disease, those with occasional coughing, mucous nasal discharge, or both have an increased risk of developing signs of RAO (frequent coughing, increased breathing effort, exercise intolerance, or a combination of these) as characterized by the Horse Owner Assessed Respiratory Signs Index (HOARSI 1–4).AnimalsTwo half‐sibling families descending from 2 RAO‐affected stallions (n = 65 and n = 47) and an independent replication population of unrelated horses (n = 88).MethodsIn a retrospective cohort study, standardized information on occurrence and frequency of coughing, mucous nasal discharge, poor performance, and abnormal breathing effort—and these factors combined in the HOARSI—as well as management factors were collected at intervals of 1.3–5 years.ResultsCompared to horses without clinical signs of respiratory disease (half‐siblings 7%; unrelated horses 3%), those with mild respiratory signs developed clinical signs of RAO more frequently: half‐siblings with mucous nasal discharge 35% (P < .001, OR: 7.0, sensitivity: 62%, specificity: 81%), with mucous nasal discharge and occasional coughing 43% (P < .001, OR: 9.9, sensitivity: 55%, specificity: 89%); unrelated horses with occasional coughing: 25% (P = .006, OR = 9.7, sensitivity: 75%, specificity: 76%).Conclusions and Clinical importanceOccasional coughing and mucous nasal discharge might represent an increased risk of developing RAO.

“…Airway remodeling1, 2, 3 leads to the thickening of the bronchial wall, contributing to airflow obstruction in heaves. Hyperplasia and hypertrophy of airway myocytes and fibrosis of the lamina propria are mainly involved in this process 2.…”

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confidence: 99%

“…Hyperplasia and hypertrophy of airway myocytes and fibrosis of the lamina propria are mainly involved in this process 2. However, angiogenesis develops concurrently with inflammation and remodeling in human with asthma,4 increasing bronchial wall thickness, and therefore could be present in horses with heaves given the similarities between these conditions 1. If present, targeting new blood vessel formation could represent a possible strategy to control inflammation and remodeling in heaves.…”

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confidence: 99%

Endoscopic Evaluation of Angiogenesis in the Large Airways of Horses with Heaves Using Narrow Band Imaging

Herteman

Bullone

Lavoie

2016

BackgroundHeaves is a severe debilitating condition of horses, characterized by lower airway inflammation and permanent structural changes of the bronchial wall. Chronic inflammation promotes the formation of new vessels, a phenomenon known as angiogenesis. Narrow band imaging (NBI) endoscopy is a noninvasive technique that enhances the visualization of submucosal vessels, and commonly is employed for the study of angiogenesis in human patients.ObjectivesUsing NBI, we aimed to determine whether or not the central airways of horses with heaves undergo angiogenesis.AnimalsHorses with heaves during exacerbation of the disease (n = 5) and healthy controls (n = 6).MethodsA library of NBI images was established from previously recorded videoendoscopies. Images were acquired by an operator blinded to horse ID. Images were obtained from 3 sites: 130 from the trachea (14 ± 9.3 [mean ± SD] images per horse with heaves and 10 ± 5.4 from controls; P = .45), 58 from the carina (5.4 ± 3.2 from horses with heaves and 5.2 ± 2.8 fromn controls; P > .99) and 167 from the intermediate bronchi (17.8 ± 6.7 from horses with heaves and 13 ± 5.6 from controls; P = .17). Using dedicated stereology software (NewCAST, Visiopharm; Denmark), the volume density of superficial and deep vessels was calculated blindly by point counting at each site for all horses.ResultsIn the trachea, the volume density of superficial vessels was increased in horses with heaves compared to controls (P = .02). No difference was found between groups for the volume density of both superficial and deep vessels at the carina or intermediate bronchi.Conclusion and Clinical Relevance NBI imaging of the airways was easily performed in standing sedated horses.