Respiratory disease in horses encompasses a range of conditions affecting the respiratory system, including the upper and lower airways. These diseases can result from various etiologies such as infectious agents, environmental factors, or genetic predispositions. Common respiratory conditions in horses include equine asthma, equine influenza, and strangles. Clinical signs often associated with respiratory disease in horses include coughing, nasal discharge, and labored breathing. Diagnostic approaches may involve endoscopy, imaging, and laboratory tests to assess the function and health of the respiratory tract. This page compiles peer-reviewed research studies and scholarly articles that explore the pathophysiology, diagnosis, and management of respiratory diseases in equine populations.
Duvivier DH, Bayly WM, Votion D, Vandenput S, Art T, Farnir F, Lekeux P.The present study evaluated ventilatory, cardiovascular and metabolic parameters during recovery from strenuous exercise in horses suffering from a crisis of chronic obstructive pulmonary disease (COPD) and to determine whether ipratropium dry powder inhalation (DPI) before exercise has an effect on these parameters. When 6 saddle horses, affected with COPD, developed airway obstruction, they inhaled placebo and ipratropium (2400 microg/horse), the order being randomly chosen. Pulmonary function tests were then recorded 15 min after inhalation. Following these tests, the horses underwent a str...
Gilroy BJ, Lofstedt J, Pack L, McBurney SR.Sinus cysts are epithelium-lined, fluid-filled cavities that can occur in the paranasal sinuses of horses. Extensive damage to the permanent tooth buds was a significant feature in this case. The sequellae of these abnormalities, although not apparent at the time of presentation, remain an important consideration for prognosis.
Scarratt WK, Crisman MV.Tumors of the equine respiratory tract occur infrequently. An accurate diagnosis of neoplasia of the respiratory tract is critical because the prognosis is usually grave. The clinical signs and diagnostic procedures are discussed for tumors of the nasal and paranasal sinuses, nasopharynx/larynx, guttural pouch and thorax including lung, pleura, and thymus.
Taylor PM.The study was designed to contribute to identification of the stimulus to adrenocortical activity during halothane anaesthesia in equidae. Two groups of six ponies were premedicated with acepromazine before induction of anaesthesia with thiopentone and maintenance for 120 min with halothane in oxygen. In group H Haemaccel modified gelatine plasma replacer was infused (48+/-13 mL/kg) to maintain mean arterial blood pressure (MABP) close to preanaesthetic values. In group DH, blood pressure was maintained close to preanaesthetic levels with a lower dose of Haemaccel (10 mL/kg) combined with an i...
Kimbell-Dunn M, Bradshaw L, Slater T, Erkinjuntti-Pekkanen R, Fishwick D, Pearce N.To examine the prevalence of symptoms of asthma and allergy in different farming groups in New Zealand. Methods: A postal questionnaire was sent to a random sample of 2,500 farmers throughout New Zealand. Results: The response rate was 77% (1,706 of 2,203 eligibles). The 12-month period prevalence of current asthma was 11.8% overall, compared with 15% in the general population. Asthma prevalence was higher for horse breeders/groomers (16.5%), pig farmers (18.2%), poultry farmers (17.4%), and those working with oats (17.4%). Asthma was also significantly elevated among those working with cleani...
Venugopalan CS, Beadle RE, Seahorn TL, Holmes EP.The response of parenchymal strips from guinea-pig lungs to tracheobronchial lavage fluid (TBLF) collected from 8 normal horses and from 8 affected with summer pasture-associated obstructive pulmonary disease (SPAOPD) was determined. TBLF was collected during the summer (July) and winter (February) seasons. The serum/TBLF urea nitrogen ratio was used to standardize the mediator concentration in the TBLF. Four strips were used from each guinea-pig. The first strip did not receive any antagonist and served as the control. The second, third and fourth strips received antagonists of PGE2, LTD4 and...
Savage CJ, Traub-Dargatz JL, Mumford EL.A survey designed to obtain information on the indications, contraindications, complications, and methodology of percutaneous lung biopsy in the horse was sent to large animal diplomates of the American College of Veterinary Internal Medicine. Sixty-five of 190 diplomates returned the survey (response rate: 34%) and 59 of these 65 respondents (91%) indicated that they worked with horses. Forty-four diplomates had performed a percutaneous lung biopsy in 1 or more horses (i.e. 75% of those diplomates working with horses and 68% of total respondents). Clinical and radiologic diagnoses that prompt...
Csellner H, Walker C, Love DN, Whalley JM.An equine herpesvirus 1 (EHV-1) mutant was constructed by inserting a lacZ expression cassette into the intergenic region upstream of gene 62 (glycoprotein L; gL) and downstream of gene 63 (a homologue of the herpes simplex virus transcriptional activator ICP0). The recombinant lacZ62/63-EHV-1 had similar growth kinetics in cell culture to those of the parental wild type (wt) virus, with indistinguishable cytopathic effects and plaque morphology. Reverse transcriptase PCR confirmed that the lacZ insertion did not interfere with transcription of gL and immunoblot analysis indicated there was no...
Franchini M, Gilli U, Akens MK, Fellenberg RV, Bracher V.Chronic obstructive pulmonary disease (COPD) is defined as a chronic obstructive inflammatory disease affecting the small airways associated with hay dust exposure (Lowell, F.C., 1964. Observation on heaves. An asthma like syndrome in the horse, J. Allergy 35, 322-330). The disease corresponds histopathologically to a chronic bronchiolitis (Gerber, H., 1973. Chronic pulmonary disease in the horse, Equine Vet. J. 5, 26-33; Winder, N.C., Grünig, G., Hermann, M., Howald, B., von Fellenberg, R., 1989. Comparison of respiratory secretion cytology and pulmonary histology in horses, J. Vet. Med., A3...
Gross DK, Hinchcliff KW, French PS, Goclan SA, Lahmers KK, Lauderdale M, Ellis JA, Haines DM, Slemons RD, Morley PS.The purpose of this experiment was to determine if exercising horses, infected with influenza virus, exacerbates the severity of clinical disease. Eight horses were trained on a treadmill for 42 days and then challenged with aerosolised influenza A/equine/Kentucky/91 (H3N8). Following challenge, 4 horses (exercise group) continued training for 28 days, while the other 4 horses (nonexercise group) were confined to their stalls. All horses developed clinical signs within 36 h of challenge (fever, coughing, and mucopurulent nasal discharge) and clinical scores were greater in the exercise group. ...
Gilkerson JR, Love DN, Drummer HE, Studdert MJ, Whalley JM.To investigate the seroprevalence of equine herpesvirus 1 in foals around weaning and after weaning on two large Thoroughbred farms using a type-specific enzyme-linked immunosorbent assay to determine exposure to infection. Methods: A longitudinal population study in groups of Thoroughbred weanling foals. Methods: Two hundred weanling Thoroughbred foals from a population of about 380 foals were enrolled on two adjacent stud farms in the Hunter Valley of New South Wales. Foals on both farms were weaned from February to May 1995 into randomly selected groups of 10 to 15 foals. Farms were selecte...
Butt TD, MacDonald DG, Crawford WH, Dechant JE.A 14-month-old filly with chronic pharyngitis was diagnosed with incomplete esophageal constriction and megaesophagus due to a persistent right aortic arch. This report is unusual because clinical signs of respiratory dysfunction secondary to chronic regurgitation occurred prior to the recognition of dysphagia.
Törneke K, Ingvast Larsson C, Appelgren LE.Beta2-adrenoceptor agonists are used as bronchodilators in both humans and horses. Of these drugs, clenbuterol is the one most frequently used when treating chronic obstructive pulmonary disease in the horse, while salbutamol and terbutaline are used in the treatment of human asthma. Little is known of the properties of the latter two drugs in equine medicine. We have compared salbutamol and terbutaline with clenbuterol in relation to their ability to relax muscle strips from equine tracheal muscle, precontracted with 40 nM carbachol, in tissue chambers. The affinities of these drugs to the be...
Ohnesorge B, Deegen E.From 1995 to 1997 11 racehorses, one Hanoverian and one Pony were presented to the clinic with a sudden appearing, very loudly gurgling expiratory respiratory noise. Considering the preliminary report and the clinical and endoscopical findings, as exercise induced dorsal displacement of the soft palate (DDSP) was found to be the cause of the respiratory noise. The 13 horses were treated in general anaesthesia by transendoscopic coagulation of the caudal margin of the soft palate with a Neodym-YAG-Laser. This surgical intervention had to be repeated on four horses with unchanged signs. Eight of...
Ward CL, Wood JL, Houghton SB, Mumford JA, Chanter N.Seventy-three bacterial isolates from 65 horses with and without evidence of lower airway disease were identified to assess whether the association with disease was accounted for by a small or large number of species. Just over half (50.5 per cent were Actinobacillus equuli, 17.8 per cent were A suis-like, 11 per cent were Pasteurella pneumotropica, 8.2 per cent were A lignieresii, 6.8 per cent were P haemolytica and 5.5 per cent were P mairii. These results suggest that a range of Actinobacillus and Pasteurella species can be isolated from the lower airways of horses, with many of the isolate...
Szöke MO, Blais D, Cuvelliez SG, Lavoie JP.To evaluate the cardiovascular and respiratory effects of buprenorphine administered intravenously in clinically normal horses and horses with chronic obstructive pulmonary disease (COPD). Methods: 5 clinically normal horses and 5 horses with COPD that were in partial clinical remission (period A) or were having an acute attack of airway obstruction (period B). Methods: Pulmonary function testing, arterial blood gas analysis, and arterial blood pressure measurements were performed before and after a single intravenous bolus of buprenorphine (3 microg/kg of body weight). Respiratory rate (f), t...
McGorum BC, Ellison J, Cullen RT.The concentrations of total and respirable airborne endotoxin in the breathing zone of a pony in 3 different management systems, on 8 occasions, are reported. Airborne endotoxin concentrations in all 3 systems were lower than those reported for many other agricultural environments. However, total airborne endotoxin concentrations in many of the conventional stables exceeded those which can induce pulmonary inflammation and bronchial hyper-responsiveness in normal human subjects, and exceeded those which can induce bronchoconstriction in humans with pre-existing pulmonary inflammation. Therefor...
Borchers K, Wolfinger U, Ludwig H, Thein P, Baxi S, Field HJ, Slater JD.Two 18-month-old naturally reared ponies were used to investigate the pathogenicity of EHV-2. After dexamethasone treatment, pony 1 was inoculated intranasally with EHV-2 strain T16, which has been isolated from a foal with keratoconjunctivitis superficialis and pony 2 was similarly inoculated with strain LK4 which was originally isolated from a horse with upper respiratory tract disease. Following virus inoculation, pyrexia was not detected in either pony but both developed conjunctivitis, lymphadenopathy, and coughing. EHV-2 was detected in nasal mucus samples up to day 12 post infection (p....
Rush BR, Flaminio MJ, Matson CJ, Hakala JE, Shuman W.To determine cytologic changes in horses with recurrent airway obstruction (heaves) after administration of aerosolized beclomethasone dipropionate and dexamethasone parenterally. Methods: 6 horses with inducible and reversible heaves. Methods: Episodes of heaves were induced by exposure to moldy hay and straw for 7 days. Horses were assigned to treatment groups (aerosolized beclomethasone, parenterally administered dexamethasone, aerosolized propellant), and pulmonary inflammation was evaluated by serial cytologic examination of bronchoalveolar lavage (BAL) fluid samples obtained on days 0, 7...
Rush BR, Raub ES, Rhoads WS, Flaminio MJ, Matson CJ, Hakala JE, Gillespie JR.To determine changes in clinical signs of disease and response to pulmonary function testing in horses with recurrent airway obstruction (heaves) after aerosol and parenteral administration of beclomethasone dipropionate and dexamethasone, respectively. Methods: 6 horses with inducible and reversible heaves. Methods: Episodes of heaves were induced by exposure (challenge) to moldy hay and straw for 7 days. Horses were assigned to treatment groups (aerosolized beclomethasone dipropionate, parenterally administered dexamethasone, aerosolized propellant [control]), and respiratory frequency and s...
Rush BR, Worster AA, Flaminio MJ, Matson CJ, Hakala JE.To determine alteration in adrenocortical function in horses with recurrent airway obstruction (heaves) after aerosol and parenteral administration of beclomethasone dipropionate and dexamethasone, respectively. Methods: 6 horses with inducible and reversible heaves. Methods: Episodes of heaves were induced by exposure to moldy hay and straw for 7 days (natural challenge). Horses then underwent treatment (aerosolized beclomethasone, parenterally administered dexamethasone, and aerosolized propellant) for 7 days. Horses remained in the mold-contaminated environment for 7 days after discontinuat...
Mumford EL, Traub-Dargatz JL, Salman MD, Collins JK, Getzy DM, Carman J.To develop a system to monitor and detect acute infections of the upper respiratory tract (i.e., nares, nasopharynx, and pharynx) in horses and to assess the association among specific viral infections, risk factors, and clinical signs of disease. Methods: Prospective study. Methods: 151 horses with clinical signs of acute infectious upper respiratory tract disease (IURD) from 56 premises in Colorado. Methods: Health management data, blood samples, and nasal or nasopharyngeal swab samples were obtained for 151 horses with clinical signs of acute IURD. Of these horses, 112 had an additional blo...
Marr KA, Lees P, Page CP, Cunningham FM.Leukotrienes have been shown to mimic many of the pathophysiological processes in allergic airway disease. In this study the bronchoconstrictor effect of inhaled LTD4, and radiolabelled neutrophil accumulation in response to inhalation of LTB4, have been examined in the horse. In separate studies, solutions of LTD4 and LTB4 were administered to the airways of normal animals by nebulisation. LTD4, but not LTB4, caused a dose-dependent increase in pleural pressure which was maximal at three to four minutes and had returned to baseline by 15 to 20 minutes. On a molar basis LTD4 was 305 to 970 tim...
Marr KA, Lees P, Page CP, Cunningham FM.The leukotrienes (LT) LTD4 and LTB4 have been shown to cause bronchoconstriction and neutrophil accumulation, respectively, in horse lungs. Such changes are characteristic of the equine allergic respiratory disease, chronic obstructive pulmonary disease (COPD). To further investigate the role of these putative mediators in the pathogenesis of equine COPD the effect of a 5-lipoxygenase inhibitor, fenleuton, on antigen-induced changes in horses with this condition has been examined. Six horses with COPD underwent a series of four antigen challenges, one month apart, with placebo pre-treatment on...
Raulo SM, Maisi P.To determine whether gelatinolytic activity in tracheal epithelial lining fluid (TELF), blood neutrophils, and blood lymphocytes from horses was metalloprotease activity, and to compare, for healthy horses and horses with chronic obstructive pulmonary disease, gelatinolytic activity in neutrophils, lymphocytes, and serum with activity in TELF. Methods: 7 horses with chronic obstructive pulmonary disease (COPD) and 4 healthy control horses. Methods: Neutrophils and lymphocytes were obtained by means of Percoll separation. Zymography was used to detect gelatinolytic activity; EDTA inhibition and...
Flaminio MJ, Rush BR, Shuman W.Inactivated Propionibacterium acnes is a biologic response modifier for treatment of non-specific respiratory disease in horses. The objectives of this investigation were to determine alterations in phagocytic activity, phenotypic expression of lymphocyte subpopulations and lymphokine-activated killing cell response in healthy young horses. Samples were collected on day 0, 7 and 14 of the investigation. Blood samples were obtained via jugular venipuncture and pulmonary leukocytes were recovered via bronchoalveolar lavage (BAL). Commercially available P. acnes (Eqstim) was administered intraven...
Takai S, Vigo G, Ikushima H, Higuchi T, Hagiwara S, Hashikura S, Sasaki Y, Tsubaki S, Anzai T, Kamada M.Polymerase chain reaction (PCR)-based assays were developed to detect virulent Rhodococcus equi in transtracheal aspirate samples from sick foals showing respiratory signs. An oligonucleotide primer pair from the sequence of the virulence-associated 15- to 17-kDa antigen gene of the virulence plasmid in virulent R. equi was used to amplify a 564 bp region by PCR, and the result was confirmed by Southern blot hybridization. No positive reaction was seen in DNA from 13 different microorganisms typically found in the respiratory tract. In tracheal aspirates seeded with virulent R. equi, a visible...
Pellegrini A, Kalkinc M, Hermann M, Grünig B, Winder C, Von Fellenberg R.Equinins are a closely related group of proteins found in equine neutrophil granules. They demonstrate proteinase inhibiting activity restricted to microbial proteinase K and subtilisin, and they also possess antibacterial and antiviral properties. Antiproteinase K activity was measured in tracheobronchial secretions (TBS) of horses with mild (n = 15), moderate (n = 30) and severe (n = 16) chronic pulmonary disease, to determine its usefulness as an indicator of severity of disease and to measure neutrophil content. Determination of proteinase K inhibiting activity was based on a colorimetric ...
Knubben JM, Gygax L, Auer J, Fürst A, Staᆲher M.Through a written questionnaire, which was sent to a representatively distributed and randomly selected sample of Swiss horse owners, data of 2912 horses and ponies were acquired to extrapolate prevalence data of health disorders. General questions about the horse and associated factors of housing and use, as well as questions about the current health status and the occurrence of diseases and injuries had been asked. 718 horses (24.7% of the sample) had been examined by a veterinarian within the 12 months prior to the survey. Orthopaedic and traumatic disorders (41.5%) had the largest proporti...
Sharma A, Thompson MS, Schnabel LV, Mete A, Hackett R.We describe the use of computed tomography (CT) in a 6-year-old mare with upper airway obstruction due to an abnormally thick nasal septum. Upon CT imaging, multifocal, expansile cyst-like lesions were detected in the nasal septum. The histopathologic diagnosis was chronic dissecting chondritis. Resection of the abnormal nasal septum resulted in resolution of the clinical signs.
Smith KC.Respiratory disease is an important cause of wastage in the Thoroughbred industry and is a cause of welfare problems in all types of horse. This review concerns developments in our understanding of equine respiratory disease since 1998 and illustrates how strategic funding from the Horserace Betting Levy Board has contributed to this understanding.
Roberts MC, Seawright AA, Ng JC, Norman PD.Chronic mercuric chloride intoxication in an aged horse given 0.8 mg Hg/kg/day for 14 weeks was manifest by signs of progressive respiratory difficulty and renal disease. The effects were not self-limiting after mercury was withdrawn, and the animal was destroyed six weeks later. Renal function changes included heavy glycosuria, modest proteinuria, phosphaturia, reduced urine osmolality, gradually increasing urine production, reduced glomerular filtration rate, and terminally, azotemia. The condition bore similarities to the Fanconi syndrome in man. Urinary gamma-glutamyl transpeptidase, alkal...
Kemper T, Spier S, Barratt-Boyes SM, Hoffman R.Five horses were admitted for treatment of smoke-inhalation injuries sustained in a barn fire. Three of the horses were mildly affected, with high respiratory rates (24 to 36 breaths/min) and normal to low arterial oxygen tensions (77.0 to 94.1 mm of Hg), and responded well to administration of diuretics, bronchodilators, corticosteroids, and antibiotics. The 2 remaining horses were severely affected. Both were in respiratory distress, with markedly low arterial oxygen tensions (50.4 and 57.1 mm of Hg) and cyanosis. These 2 horses required fluid resuscitation in addition to the treatments give...
Zendri F, Isgren CM, Sinovich M, Richards-Rios P, Hopkins KL, Russell K, Groves N, Litt D, Fry NK, Timofte D. () may cause diphtheria in humans and can be carried by a wide range of animal species including dairy cows and, more recently, dogs and cats that have been increasingly involved in zoonotic trasmission. We isolated and characterized, by WGS, a toxigenic strain from a diseased horse in the United Kingdom showing clinical signs of respiratory diphtheria comparable to those seen in people. Our results indicate a role for horses as reservoirs for zoonotic .
Shawley RV, Mandsager RE.Positive-pressure ventilation is used to provide improved ventilatory support during anesthesia in the horse. Because of the horse's size and the physiologic changes it undergoes during anesthesia, however, the use of positive-pressure ventilation does not always provide the improvement seen in smaller species. Careful attention to respiratory rate, inspiratory pressure, and I:E ratio minimizes the negative aspect of IPPV on the cardiovascular system. The goal of future ventilatory techniques will be to improve oxygenation without cardiovascular compromise and to do so at a reasonable cost to ...
Long JR, Mitchell L.Aspergillosis, caused by species of Aspergillus, is primarily a respiratory infection but may
occasionally be generalized (1). This genus is
distributed widely in nature and almost any
substrate supplying organic matter and moisture will support growth of the fungus. It grows
especially well on damp hay, straw and grain
that has heated during storage. Aspergillus
fumigatus is responsible for the majority of
cases of aspergillosis in animals and birds.
This organism causes acute respiratory infection
when susceptible animals are exposed to heavy
concentrations of airbqrne conidia. Alt...