Topic:Asthma
Equine asthma, also known as equine recurrent airway obstruction (RAO) or heaves, is a chronic respiratory condition affecting horses. It is characterized by airway inflammation, mucus production, and bronchoconstriction, leading to clinical signs such as coughing, nasal discharge, and labored breathing. The condition is often exacerbated by environmental factors such as dust, mold, and pollen, which can trigger an immune response in susceptible horses. Equine asthma is managed through environmental modifications, medical treatments, and sometimes dietary adjustments to alleviate symptoms and improve respiratory function. This page compiles peer-reviewed research studies and scholarly articles that explore the pathophysiology, diagnosis, and management strategies of equine asthma.
Increased pulmonary production of immunoreactive 15-hydroxyeicosatetraenoic acid in an animal model of asthma. Airway obstruction and hyperreactivity are characteristics of human asthma and of "heaves," a naturally occurring respiratory disorder of horses and ponies. We measured pulmonary function and plasma immunoreactive 15-hydroxyeicosatetraenoic acid (i15-HETE) concentrations in simultaneously collected carotid artery and right ventricle blood samples in five affected ponies and their age- and gender-matched control ponies. Measurements and sampling were performed before (Period A), during (Period B), and following recovery from (Period C) acute airway obstruction precipitated by housing ponies in ...
[An outbreak of allergy to horses in children. A review of 56 recent cases]. Over the past 11 years, signs of allergy were observed in 56 children and adolescents in contact with horses. The cases consisted of 35 boys and 21 girls, 35 of them were under 10 years of age. The main clinical signs were ocular symptoms (36), asthma (30) and rhinopharyngitis (24). All the children had very positive cutaneous prick tests and specific IgE (class 3 and 4: 62%) and were polysensitized. In several children, the first manifestation occurred at the time of the first known contact with a horse or pony. No further contact was usually the only therapeutic solution. In disabled childre...
The genetic basis of equine allergic diseases. 1. Chronic hypersensitivity bronchitis. The genetic influence on chronic hypersensitivity bronchitis (CB) was investigated in families at two studs and among half-siblings of three affected and three non-affected sires at several farms. The family members at the two studs were born and raised under the same conditions, whereas the half-siblings were kept individually under very different conditions and were exposed to various environmental factors. The diagnosis was based on long-term observations and multiple clinical examinations at each of the two studs. In the half-sibling group, the diagnosis was based on the individual history...
Histamine inhalation challenge in normal horses and in horses with small airway disease. A histamine inhalation challenge (HIC) procedure was developed to assess hyperreactive states in horses. Following clinical evaluation, percutaneous lung biopsies were performed on nine light breed mares aged 6 to 15 years. Five horses, with normal small airways, were classified as group A and four subjects with small airway disease (SAD) lesions formed group B. Pulmonary mechanics parameters were monitored following an aerosol of 0.9% saline and every 5 min for up to 30 min after HIC with 0.5% w/v of histamine diphosphate, administered through a face mask for 2.5 min. Tidal volume (VT) and ai...
Observations on heaves. An asthma-like syndrome in the horse. 1964. Observations in six horses with heaves established a clear relationship between attacks of heaves and the feeding of hay. Severe acute attacks were accompanied by striking changes in the eosinophil count and the sedimentation rate. The variation in the severity of heaves in relation to the feeding and withholding of hay is accounted for by assuming that attacks result from a transient, obstructive lesion in the bronchial tree or lung caused by hypersensitivity to some component of hay. The observations strongly suggest that heaves is a respiratory allergic disease in the horse. The relation of...
Plasma theophylline concentration and lung function in ponies with recurrent obstructive lung disease. Six ponies with recurrent obstructive lung disease were studied during two separate 60 min periods while receiving constant equal volume infusions of either aminophylline or sterile water. Dynamic lung compliance, pulmonary resistance, respiratory rate, tidal volume, blood gas tensions and heart rate were measured. Plasma samples were obtained for determination of theophylline concentrations before, and at 10 min intervals during, the infusion period. Excitability was assessed subjectively at these same time periods. The plasma theophylline concentrations in ponies were well predicted by a pre...
[Allergic rhinitis in the horse: first case]. The responsibility of the artificial environment in the development of respiratory allergy in horses is well known as the most important factor for the development of asthma, chronic dry cough and pulmonary emphysema. One case of allergy to the natural environment could be observed. One allergic rhinitis with asthma could be explored. Pathology, cause, tests and specific immuno-therapy are presented.
The role of cyclooxygenase products in the acute airway obstruction and airway hyperreactivity of ponies with heaves. Airway obstruction and hyperreactivity are characteristics of human asthma and of "heaves," a naturally occurring respiratory disorder of horses and ponies. To document the role of cyclooxygenase products of arachidonic acid metabolism in the pathogenesis of heaves, we measured plasma and bronchoalveolar lavage (BAL) fluid concentrations of metabolites of thromboxane (TX)A2 and prostaglandins (PG) I2 and D2 in five affected ponies and their age- and gender-matched controls prior to and during acute airway obstruction precipitated by housing the ponies in a barn and exposing them to hay dust. P...
Comparison of respiratory secretion cytology and pulmonary histology in horses. Equine respiratory secretions (RS) collected before (33 horses) and after (76 horses) slaughter were evaluated cytologically and grouped according to the histological diagnosis of the lungs from which they were obtained. The histological categories included normal lungs (control; 17 horses), chronic small airway disease with mild (23 horses), moderate (13 horses) and severe lesions (25 horses), interstitial pneumonia (13 horses), pulmonary eosinophilic infiltration (13 horses) and pulmonary haemorrhage (5 horses). On a group basis there were significantly more neutrophils in RS of horses with ...
Beta-adrenergic blockade in ponies with recurrent obstructive pulmonary disease. Ponies with recurrent airway obstruction have hyperresponsive airways during acute disease exacerbations but not during clinical remission. We examined the effect of beta-adrenergic blockade with propranolol on airway responsiveness to aerosol histamine in six ponies with recurrent airway obstruction and six age- and gender-matched controls. Measurements were made with principal ponies in clinical remission (period A) and during an acute period of airway obstruction (period B). beta-Adrenergic blockade did not change airway responsiveness, dynamic compliance (Cdyn), or pulmonary resistance (RL...
Chronic small airway disease in the horse: immunohistochemical evaluation of lungs with mild, moderate and severe lesions. The peroxidase anti-peroxidase technique was used to demonstrate free and intracellular immunoglobulin (Ig) within the lungs of 23 horses with chronic small airway disease. Histologically, all the horses had chronic bronchiolitis; however, the lesions varied in degree from mild in eight horses, to moderate in nine horses and severe in six horses. Lungs from three horses which had no gross or histopathological lesions were used as controls. In comparison with control horses, horses with mild chronic bronchiolitis had increased numbers of Ig A-containing and non-immunoglobulin staining cells aro...
Drug therapy of respiratory disorders. The emphasis of this article is on the clinical application of drugs in therapy for treatment of disorders of the lower respiratory tract. Medications discussed include those used to enhance clearance of secretions and those employed to prevent and/or alleviate bronchoconstriction. Antimicrobial agents and respiratory stimulants are briefly mentioned.
[Examination and treatment of respiratory tract diseases in the horse in clinical practice]. In spite of regular vaccinations against equine influenza we are still observing a high rate of patients with respiratory problems in the equine practice. In our practice in Munich Riem, into which a horse clinic has been integrated, 4000 horses have been treated in 1985 alone. 874 of these showed some form of respiratory disease (= 22%). All of the 4000 horses have only been treated curatively, i.e. preventive forms of treatment such as vaccinations, deworming and examinations for insurance companies and prior to selling have not been taken into account. From 1983 until today in our clinic 25...
Airway responses to aerosolized methacholine and citric acid in ponies with recurrent airway obstruction (heaves). We measured lung function and airway reactivity in response to methacholine and citric acid administered by aerosol in 2 groups of ponies (principal and control). Principal ponies had a history of heaves, a disease characterized by recurrent airway obstruction. Control ponies had no history of respiratory disease. Both principal and control ponies were paired (principal and control), and measurements were made when principal ponies were in clinical remission (Period A), following barn exposure when principal ponies had acute airway obstruction (Period B), and 1 and 2 wk after they were returne...
Intravenous histamine administration in ponies with recurrent airway obstruction (heaves). Pulmonary function and airway reactivity to IV histamine were measured in a group of ponies with a history of recurrent airway obstruction (heaves) and their age-, weight-, and gender-matched controls. Ponies were studied during a period of clinical remission (period A), after exposure to a barn environment (period B), and twice during a 2-week recovery phase (periods C and D). At periods A, C, and D, PaO2, dynamic compliance (Cdyn), pulmonary resistance, tidal volume, respiratory frequency, and the log dose of histamine required to reduce Cdyn to 65% of base-line value (log ED65Cdyn) of princ...
Airway reactivity in ponies with recurrent airway obstruction (heaves). We measured lung function and airway reactivity to histamine administered by aerosol in two groups of ponies. Principal ponies had a history of heaves, a disease characterized by recurrent airway obstruction when ponies are housed in a barn and fed hay; control ponies had no history of airway obstruction. Ponies were paired (principal and control) and measurements were made when principal ponies were at pasture and in clinical remission (period A), following barn housing when principal ponies had acute airway obstruction (period B), and after a further 1 and 2 wk at pasture (periods C and D). ...
Chronic obstructive pulmonary disease in the horse. 1: Nature of the disease. The aetiology, pathophysiological changes, pathology and clinical signs of the disease as presently understood are discussed. The condition appears to be a hypersensitivity of the respiratory system in some horses to poor quality hay and straw. Micropolyspora faeni is the chief agent identified in the northern part of the United Kingdom. In other locations, the chief agent is probably different. The principal changes are spasm of the airways and bronchiolitis of the small airways. Onset may be acute or insidious. The chief clinical signs are well known but the disease process is reversible if ...
Ovalbumin-induced lung disease in the pony: role of vagal mechanisms. In awake sensitized ponies, we studied the effect of aerosol ovalbumin challenge on ventilation, pulmonary mechanics, lung volume, and gas exchange before and after vagal blockade. We also challenged the left lung and measured respiratory rate (f) and right and left respiratory system resistance (RrsR, RrsL) before and after both left and bilateral vagal section. Bilateral ovalbumin aerosol challenge increased f, minute ventilation (VE), total respiratory system resistance (Rrs), and minimal volume, decreased dynamic compliance, total lung capacity, and arterial oxygen tension, and was without...
Criteria for development of animal models of diseases of the respiratory system: the comparative approach in respiratory disease model development. Advances in the understanding of human respiratory disease can come from careful clinical studies of the diseases as they occur in man, but such studies are naturally limited in terms of experimental manipulation. In the last 2 decades, an increasingly complex plethora of experimental respiratory disease models has been developed and utilized by investigators, but relatively less attention has been paid to the naturally occurring pulmonary diseases of animals as potential models. This paper is aimed at presenting selected examples of spontaneous pulmonary disease in animals that may serve as e...
Effects of trimetaquinol on equine pulmonary vascular and airway smooth muscle. Trimetaquinol [TMQ: 1-(3’,4‘,5’-trimethoxybenzyl)6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline hydrochloride] a potential p-sympathomimetic bronchodilator (Iwasawa & Kiyomoto 1967), has been shown to be an effective tracheal smooth muscle relaxant in guineapigs (Iwasawa & Kiyomoto 1967; Brittain 1972; Brittain et a1 1970, 1976) and an inhibitor of experimental bronchospasm in guinea-pigs and cats (Brittain et a1 1970; Brittain 1972). In addition, clinical studies with TMQ indicated that the drug was an effective bronchodilator in mild to moderate asthma (Yamamura & Kishimoto 1968). It may...
Pharmacological studies on the pulmonary vein of the horse. I. Effects of selected spasmogens. Horses suffer from a respiratory condition, similar to human allergic asthma, that is characterized by severe dyspnea, wheezing, coughing, and mucus production. Mediator substances released during the allergic reaction may contract airways and pulmonary vasculature. Nothing is known of the effects of autacoids and other vasoactive substances on equine pulmonary vessels. Therefore, spiral strips of equine pulmonary vein were prepared in vitro and the effects of histamine (H), 5-hydroxytryptamine (5HT), bradykinin (BK), carbachol (Carb), and phenylephrine (phen) were studied. The order of contra...