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.
Raulo SM, Sorsa TA, Kiili MT, Maisi PS.To determine collagenase activity and evaluate matrix metalloproteinase (MMP)-8 and MMP-13 in horses with chronic obstructive pulmonary disease (COPD). Methods: 12 horses with COPD and 12 healthy control horses. Methods: Collagenase activity was determined by use of an assay for degradation of type-I collagen. Western immunoblot analysis was used to identify interstitial collagenases MMP-8 and MMP-13 in tracheal epithelial lining fluid (TELF). Immunocytochemistry and in situ hybridization were used to determine cellular expression of these 2 collagenases in cells in bronchoalveolar lavage flui...
Henrikson SL, Rush BR.To determine the onset, magnitude, and duration of bronchodilation after administration of aerosolized salmeterol xinafoate in horses with recurrent airway obstruction. Methods: Randomized controlled study Methods: 6 horses with recurrent airway obstruction. Procedure Horses received aerosolized salmeterol (210 microg) or no treatment, using a crossover design. Salmeterol was administered, using a mask designed for aerosol delivery in horses. Subjective rating of airway obstruction (RAO), maximal change in pleural pressure (deltaPplmax), and pulmonary resistance (RL) were determined at baselin...
Hauser B, Wehrend A, Bostedt H, Failing K.Analysis of blood gases in equine neonatology is regarded as a diagnostic tool to study the neonatal adaptation period. Aim of this study therefore was to compare the diagnostic value of venous blood gas parameters to arterial parameters in newborn foals with pulmonary disorders. Venous as well as arterial blood samples were taken from 24 foals (1 to 6 days old) and the partial pressure of oxygen (pO2), partial pressure of carbon dioxide (pCO2), pH, and oxygen parturition (S-O2) of these samples were investigated. In addition, the alveolar (A) to arterial (a) gradients (A-aDO2) were calculated...
Makrai L, Fodor L, Csivincsik A, Varga J, Senoner Z, Szabó B.The cultural, morphological, biochemical, serological characteristics and antibiotic susceptibility of 25 Rhodococcus equi strains isolated from lungs and lung abscesses of pneumonic foals and 5 R. equi strains isolated from immuno-compromised human patients were examined. All R. equi strains showed common cultural, morphological and biochemical characteristics both with conventional tests and on the basis of their enzyme profile. The R. equi strains examined were resistant to penicillins with the exception of ampicillin, to sulphamethazine and several strains also to sulphamethoxazole-trimeth...
Horowitz ML, Cohen ND, Takai S, Becu T, Chaffin MK, Chu KK, Magdesian KG, Martens RJ.The distributions of the incubation periods for infectious and neoplastic diseases originating from point-source exposures, and for genetic diseases, follow a lognormal distribution (Sartwell's model). Conversely, incubation periods in propagated outbreaks and diseases with strong environmental components do not follow a lognormal distribution. In this study Sartwell's model was applied to the age at onset and age at death of foals with Rhodococcus equi pneumonia. The age at onset of clinical signs and age at death were compiled for 107 foals that had been diagnosed with R. equi pneumonia at b...
Luna SP, Taylor PM.Halothane depresses cardiorespiratory function and activates the pituitary-adrenal axis, increasing beta endorphin. In horses, beta endorphin may enhance the anaesthetic-associated cardiorespiratory depression and mortality risk. The authors studied endogenous opioid effects on cardiorespiratory function and pituitary-adrenal activity in halothane-anaesthetised ponies by investigating opioid antagonism by naloxone. Six ponies were anaesthetised three times (crossover design). Anaesthesia was induced with thiopentone and maintained with 1.2 per cent halothane for 2 hours. Immediately after indu...
Holcombe SJ, Jackson C, Gerber V, Jefcoat A, Berney C, Eberhardt S, Robinson NE.We examined the effect of stabling on upper and lower airway inflammation in 14 yearling Arabian horses that had been at pasture since birth. Horses were divided into 2 groups of 7. One group was stabled for 3 months and the other remained at pasture. The groups were then switched over for another 3 months. The nasopharynx, guttural pouches and trachea were examined endoscopically and bronchoalveolar lavage performed every month. An upper airway inflammation score was devised based on the magnitude of pharyngeal lymphoid hyperplasia and guttural pouch inflammation. During stabling this score r...
Christley RM, Hodgson DR, Rose RJ, Wood JL, Reids SW, Whitear KG, Hodgson JL.In order to investigate the role of infectious agents in the aetiology of lower respiratory tract disease in Thoroughbred racehorses, a matched case-control study was conducted. Cases were identified by the presence of coughing, and were compared to a control population matched on time of sample collection and location within the same training establishment. Tracheal wash samples were collected from 100 cases and 148 controls. Case horses were more likely than controls to have endoscopic and cytological evidence of airway inflammation. There was no significant association between serological e...
Pirie RS, Dixon PM, Collie DD, McGorum BC.To investigate whether inhaled endotoxin contributes to airway inflammation and dysfunction in stabled horses, control (n = 6) and asymptomatic heaves (previously termed chronic obstructive pulmonary disease)-susceptible (n = 7) horses were given inhalation challenges with 20, 200 and 2,000 microg of soluble Salmonella typhimurium Ra60 lipopolysaccharide (LPS). LPS inhalation induced a dose-dependent neutrophilic airway inflammatory response in both groups. Inhalation with 2,000 microg of LPS also induced detectable lung dysfunction in the heaves group. LPS inhalation did not alter clinical sc...
Cornelisse CJ, Holcombe SJ, Derksen FJ, Berney C, Jackson CA.To determine the effect of a tongue-tie on upper airway mechanics in exercising horses. Methods: 5 Standardbreds. Methods: Peak inspiratory and expiratory tracheal and pharyngeal pressures and airflow were measured while horses exercised on a treadmill with and without a tongue-tie. Respiratory rate was also measured. Horses ran at speeds that corresponded to 50 (HR50), 75, 90 (HR90), and 100% of maximal heart rate. The tongue-tie was applied by pulling the tongue forward out of the mouth as far as possible and tying it at the level of the base of the frenulum to the mandible with an elastic g...
Beard WL, Holcombe SJ, Hinchcliff KW.To determine the effect of a tongue-tie on upper airway mechanics in clinically normal horses exercising on a treadmill following sternothyrohyoid myectomy. Methods: 6 Standardbreds. Methods: Upper airway mechanics were measured with horses exercising on a treadmill at 5, 8, and 10 m/s 4 weeks after a sternothyrohyoid myectomy was performed. Pharyngeal and tracheal inspiratory and expiratory pressures were measured by use of transnasal pharyngeal and tracheal catheters connected to differential pressure transducers. Horses were fitted with a facemask and airflow was measured by use of a pneumo...
Couëtil LL, Rosenthal FS, DeNicola DB, Chilcoat CD.To evaluate the association among clinical signs, results of cytologic evaluation of bronchoalveolar lavage (BAL) fluid, and measures of pulmonary function in horses with inflammatory respiratory disease. Methods: 9 healthy horses, 5 horses with inflammatory airway disease (IAD), and 9 horses with chronic obstructive pulmonary disease (COPD). Methods: Clinical examination, lung function tests, and BAL were performed on each horse. Results: Standard lung mechanics of horses with exacerbated COPD differed significantly from those of healthy horses; however, there were few differences among horse...
Herholz C, Straub R, Moens Y, Busato A.The shape of the volumetric capnogram is modified by airway obstruction, and the evaluation of this deformation could allow an indirect measurement of bronchial patency. The study included 35 horses; five horses without evidence of pulmonary disease (group I) and 30 horses suffering from different degrees of chronic obstructive pulmonary disease (COPD) (groups II-IV). Data of recorded CO2 and volume curves were off-line plotted and statistically analysed using regression analysis. Analyses were performed separately for fractions 25-95% (VTE25-95), 25-50% (VTE25-50) and 50-95% (VTE50-95) of exp...
Raulo SM, Sorsa T, Tervahartiala T, Pirilä E, Maisi P.Gelatinolytic activity was analysed to study whether elevated activity previously found at the tracheal level of the respiratory tract of horses with chronic obstructive pulmonary disease (COPD) could also be found at the lower part of the respiratory tract. Furthermore, presence and significance of the gelatinolytic matrix metalloproteinases (MMPs) MMP-2 and MMP-9 in respiratory secretions of healthy and COPD horses were determined. Elevated gelatinolytic matrix metalloproteinases were detected in bronchoalveolar and tracheobronchial secretions from COPD horses. The main pathologically elevat...
Dart AJ, Dowling BA, Hodgson DR, Rose RJ.To evaluate high-speed treadmill videoendoscopy as a diagnostic technique and document the abnormalities found in Australian horses referred for poor performance associated with abnormal upper respiratory tract noise but where a definitive diagnosis could not be made at rest. Methods: A retrospective clinical study using client-owned horses. Methods: The clinical records and videorecordings of all horses referred to the University of Sydney for poor performance associated with abnormal upper respiratory tract noise during a 13-month period were examined. Only horses with a normal physical exam...
Herholz C, Straub R, Busato A.Ultrasound-spirometry and capnography and the evaluation of corresponding 'single-breath diagrams for CO2' (SBD-CO2) is a relatively new, non-invasive method for assessing pulmonary function in horses. The relative variation and the reliability of observations within measurement sessions were calculated for expiratory tidal volume, for expired CO2 volume (%) and for the phase II and phase III slopes of the SBD-CO2 in horses without pulmonary disease and in horses suffering from differing degrees of chronic obstructive pulmonary disease. The coefficient of variation of expiratory tidal volume r...
Christley RM, Hodgson DR, Rose RJ, Hodgson JL, Wood JL, Reid SW.A matched case-control study was made of 100 thoroughbred horses which were coughing and 148 control horses which were free of clinical signs of respiratory tract disease. The variables identified by multivariable conditional logistic regression as being significantly associated with coughing included age (the risk decreased with age), the stage of training (horses in early training were at greatest risk), the time since the last race (horses that had never raced were at greatest risk) and the time since they were last transported (horses transported more than 14 days previously were more like...
Blikslager AT, Tate LP, Tudor R.To document the use and clinical outcome of transendoscopic laser techniques for treatment of rostral displacement of the palatopharyngeal arch (RDPA) in horses. Background: Rostral displacement of the palatopharyngeal arch is a rare cause of upper respiratory noise and exercise intolerance in horses, and may be associated with abnormal laryngeal anatomy. There are few reports of successful treatment of this condition, and no reports of the treatment of RDPA using laser techniques. Methods: The diagnosis of RDPA was based on the presence of palatal tissue covering the dorsal aspect of the aryt...
Pietra M, Guglielmini C, Forni M, Cinotti S.The viscosity of the mucus, its DNA concentration and the size range of the DNA were determined on tracheobronchial samples from 11 horses with lower airway diseases before and after incubation with recombinant human deoxyribonuclease (rhDNase). The horses were divided into two groups on the basis of the cytology of the samples: group A (five horses) with more than 60 per cent neutrophils and group B (six horses) with fewer than 50 per cent neutrophils. The mean mucus viscosity and DNA concentration in the preincubation samples were significantly higher in group A than in group B, and there wa...
Harkins JD, Robinson NE, Woods WE, Lehner AF, Smith MD, Gates RS, Fisher M, Tobin T.Clenbuterol, a beta2 agonist/antagonist, is the only bronchodilator approved by the US Food and Drug Administration for use in horses. The Association of Racing Commissioners International classifies clenbuterol as a class 3 agent, and, as such, its identification in post-race samples may lead to sanctions. Anecdotal reports suggest that clenbuterol may have been administered by intratracheal (IT) injection to obtain beneficial effects and avoid post-race detection. The objectives of this study were (1) to measure the pharmacological efficacy of IT dose of clenbuterol and (2) to determine the ...
Franchini M, Gill U, von Fellenberg R, Bracher VD.To analyze effects of hay dust exposure on interleukin-8 (IL-8) concentration, percentage of neutrophils, and neutrophil chemotactic activity in bronchoalveolar lavage fluid (BALF) of horses with chronic obstructive pulmonary disease (COPD). Methods: 16 healthy horses and 29 horses with COPD. Methods: IL-8 concentration, percentage of neutrophils, and neutrophil chemotactic activity in BALF were measured. Values were analyzed with respect to hay dust exposure. These variables were also measured in 5 asymptomatic horses with COPD after the induction of clinical signs by changing feed from silag...
Hashikura S, Higuchi T, Taharaguchi S, Orita Y, Nanao Y, Takai S.The reliability of preparing bacteriological cultures from nasotracheal aspirates of foals routinely in order to diagnose R. equi pneumonia in foals was studied by isolating Rhodococcus equi from specimens obtained from 96 foals by nasotracheal aspiration with a silicon catheter. Results were compared with specimens obtained from 21 foals by transtracheal aspiration (percutaneous tracheal puncture). These 117 foals showed clinical signs of respiratory tract infection at sampling. R. equi was isolated from 14 of 21 (66.7%) specimens by transtracheal aspiration and from 59 of 96 (61.4%) specimen...
Vivrette SL, Sellon DC, Gibbons DS.Diagnosis of pneumonia caused by Rhodococcus equi can be made more rapidly by use of a polymerase chain reaction (PCR) assay than by use of conventional bacteriologic culture techniques. Use of a PCR assay aids in the differentiation between virulent and avirulent strains of R equi, and the assay may be used to identify R equi in feces and soil of breeding farms.
Barclay AJ, Paton DJ.Hendra has been recognized in Australia as a new zoonotic disease of horses since 1994/5 and subsequent work has shown that the viral agent is endemic in certain species of fruit bat. The Hendra virus is the type species of a new genus within the sub-family Paramyxovirinae, which also contains another newly identified zoonotic bat virus, namely Nipah. It is assumed that contact with bats has led to the Hendra virus being transferred to horses on each of the three separate incidents that have been reported in the last five years. No evidence has been found for widespread subclinical infection o...
Rickards KJ, Page CP, Lees P, Cunningham FM.Neutrophils are recruited to the lungs of horses with chronic obstructive pulmonary disease (COPD) and exhibit increased activity after antigen challenge. Phosphodiesterase type4 (PDE4) inhibitors have been shown to attenuate human neutrophil activation. The aim of this study was to establish the PDE isoenzyme profile of equine neutrophils using isoenzyme selective inhibitors to determine if these compounds should be evaluated in horses with COPD. Total cAMP and cGMP dependent PDE activity was no different in neutrophils from normal (156.2+/-7.1 and 6.8+/-0.6 pmol/min/mg for cAMP and cGMP, res...
Richards AJ, Kelly DF, Knottenbelt DC, Cheeseman MT, Dixon JB.This report summarises clinical and pathological observations on Fell pony foals with a range of signs that included ill thrift, anaemia, respiratory infection, glossal hyperkeratosis and diarrhoea. Some of the foals had normochromic, normocytic anaemia and some had low levels of plasma proteins, including immunoglobulin G. Antibiotic and supportive treatment was ineffective and all affected foals died or were killed on humane grounds. Postmortem examination of 12 foals and tissues from 2 other foals revealed a range of lesions that included glossal hyperkeratosis, typhlocolitis, intestinal cr...
Laan TT, Bull S, Pirie RS, Fink-Gremmels J.Cyclic AMP elevating agents have been shown to exhibit anti-inflammatory properties in addition to functions such as bronchodilation. The aim of this study was to investigate this dual action of clenbuterol (CB; Ventipulmin) on horses affected with recurrent airway obstruction (RAO). Seven RAO susceptible horses received inhalation challenges with aerosolised lipopolysaccharide (LPS), hay dust suspension (HDS) and Aspergillus fumigatus antigen (AF) with and without prior treatment with intravenous CB. Data showed that CB exerted significant beneficial effects on lung function, total cell count...
Hance SR, Robertson JT.A 5-year-old Thoroughbred gelding was examined because of a small axillary wound sustained 5 days earlier and had resulted in extensive subcutaneous emphysema. Three days after admission, the horse's respiratory rate had increased to 72 breaths/min, and the horse appeared anxious and distressed. Thoracic radiography revealed pneumomediastinum and severe bilateral pneumothorax. Tube thoracostomy was performed on both hemithoraxes. The drains were connected to one-way suction valves and suction devices to decompress the thorax. A nasopharyngeal catheter was inserted, and oxygen insufflation was ...
Dixon PM, Railton DI, McGorum BC, Tothill S.One-hundred and forty-seven of 270 (54.4%) horses suffering from pulmonary disorders were given at least one re-examination including, clinical, bronchoscopic, pulmonary function and cytological examinations after treatment and a further 83 of these horses (30.7%) had their clinical progress assessed by verbal or written reports. These examinations and progress reports showed high levels of partial or total recovery for most pulmonary disease categories, including chronic obstructive pulmonary disease, infectious, S. zooepidemicus and undifferentiated pulmonary disease and lungworm infection g...
Ben Hamouda S, Vargas A, Boivin R, Miglino MA, da Palma RK, Lavoie JP.Severe asthma is associated with an increased airway smooth muscle (ASM) mass and altered composition of the extracellular matrix (ECM). Studies have indicated that ECM-ASM cell interactions contribute to this remodeling and its limited reversibility with current therapy. Three-dimensional matrices allow the study of complex cellular responses to different stimuli in an almost natural environment. Our goal was to obtain acellular bronchial matrices and then develop a recellularization protocol with ASM cells. We studied equine bronchi as horses spontaneously develop a human asthma-like disease...
Pirie RS, McGorum BC, Owen C, Carr O, Oakley H, McLachlan G.Despite frequent use of metered dose inhalers (MDIs) and spacers in equine practice, limited information exists on the efficiency of aerosol delivery using such devices. We determined the particle size distribution within an MDI-generated salbutamol aerosol delivered via an equine spacer using 'best practice' delivery technique and assessed the effect of variations in MDI use technique (shaking prior to each actuation, rapid repetitive actuations, and MDI angulation) on aerosol delivery efficiency. Under optimal conditions, only 53(±18) μg salbutamol per 100 μg actuation was delivered bey...
Daniels S, Hepworth J, Moore-Colyer M.Respirable dust in conserved forages can pose problems with equid respiratory health, thus soaking (W) and high temperature steaming (HTS) are employed to reduce the levels in hay. The aim of this study was to characterize the viable bacterial community profile of four hays from two different locations in UK following pre-feeding wetting regimens. Hypothesis: (1) Viable microbial community profile of hays will not differ between different pre-feeding regimens. (2) Hay type and location will not influence microbial community profile. Replicates of each of the four hays were subjected to dry (D)...
Millares-Ramirez EM, Lavoie JP.Severe asthma in horses is characterized by structural changes that thicken the lower airway wall, a change that is only partially reversible by current treatments. Increased vascularization contributes to the thickening of the bronchial wall in humans with asthma and is considered a potential new therapeutic target. Objective: To determine the presence of angiogenesis in the bronchi of severely asthmatic horses, and if present, to evaluate its reversibility by treatment with corticosteroids. Methods: Study 1: Bronchial samples from asthmatic horses in exacerbation (7), in remission (7), and a...
Alaql FA, Alhafufi AN, Kasem S, Alhammad YMO, Albaqshi H, Alyousaf A, Alsubaie FM, Alghamdi AN, Abdel-Moneim AS, Alharbi SA.Equine influenza is a major cause of respiratory infections in horses and can spread rapidly despite the availability of commercial vaccines. This study aimed to screen the incidence of equine influenza virus (EIV) and molecularly characterize the haemagglutinin and neuraminidase from positive EIV field samples collected from Saudi Arabia. Six-hundred twenty-one horses from 57 horse barns were screened for the presence of the clinical signs, suggestive for equine influenza, from different parts of Saudi Arabia. Nasopharyngeal swabs were collected from each horse showing respiratory distress. S...
Pourali Dogaheh S, Boivin R, Lavoie JP.Severe equine asthma is characterized by airway hyperresponsiveness, neutrophilic inflammation and structural alterations of the lower airways. In asthmatic horses with neutrophilic inflammation, there is insensitivity to corticosteroids characterized by the persistence of neutrophils within the airways with therapy. We hypothesized that hypoxia or oxidative stress in the microenvironment of the lung contributes to this insensitivity of neutrophils to corticosteroids in asthmatic horses. Blood neutrophils isolated from horses with severe asthma (N = 8) and from healthy controls (N = 8)...
Johnson JE, Beech J, Saik JE.A 6.5-year-old horse with a history of exercise-induced pulmonary hemorrhage was admitted because of acute onset of epistaxis, dyspnea, high respiratory rate, pale mucous membranes, and dark feces. There was no clinical or laboratory evidence of a bleeding disorder, and the horse's anemia was considered to be secondary to pulmonary hemorrhage. The cause of the hemorrhage was not found on thoracic sonograms or from cytologic examination of transtracheal aspirates. Despite supportive care, the horse's health deteriorated, and it was euthanatized. Necropsy revealed blood in the thoracic and perit...
Awan AR, Baxi M, Field HJ.The most important consequence of equine herpesvirus-1 (EHV-1) infection is abortion. The object of the present study was to characteristic further a murine EHV-1 abortion model and to make comparisons with the natural host with particular reference to the stage of gestation during which the infection occurs. BALB/c mice at different stages of pregnancy were infected intranasally with EHV-1 (strain AB4); they suffered respiratory distress, weight loss, and other constitutional signs of infection. When the virus was inoculated in the late second or early third week of gestation dead or dying fe...
Ross MW, Gentile DG, Evans LE.Transoral axial division was performed, using endoscopic guidance, in 20 horses with epiglottic entrapment. Mean age of affected horses was 3 years (range, 2 to 5 years), and there were 18 Standardbreds and 2 Thoroughbreds. Standardbreds and female horses were significantly overrepresented when compared with a reference population. Upper respiratory noise prompted endoscopic examination before surgery in 16 horses, but noise was not heard in 4 horses. Ten horses had entrapment by thin tissue without ulceration, 6 horses had entrapment by thin tissue with small, partial-thickness ulceration, 3 ...
Hoffman AM, Viel L, Juniper E, Prescott JF.Respiratory tract infections are prevalent in foals, yet the frequency with which the distal airways are affected in clinical episodes of respiratory tract disease has not been evaluated to our knowledge. The objective of the study was to determine the incidence of distal respiratory tract infection (DRTI) in foals on a sample of Thoroughbred breeding farms (n = 10) in Ontario. In a pilot study, clinical criteria commonly used to select foals for antimicrobial treatment (detection of abnormal lung sounds, plus nasal discharge, cough, fever, tachypnea, and/or lethargy) were found to segregate f...
Varegg MS, Kløverød KM, Austnes MK, Siwinska N, Slowikowska M, Zak A, Niedzwiedz A.Bronchoalveolar lavage (BAL) is a method for the recovery of respiratory secretion from the lower airways. Objective: To investigate if the administration of a single dose of a bronchodilatator in horses with a suspected or confirmed severe equine asthma could improve recovery of bronchoalveolar lavage fluid (BALF). Methods: Twenty-eight horses with severe equine asthma. Methods: Horses were divided into 2 groups: group "treated" was given salbutamol before endoscopic examination and BALF collection, whereas group "not treated" was not given. BAL was performed with BAL-catheter by instilling 3...
Floriano D, Watkins AR, Hopster K.To evaluate the efficacy of 2 different oxygen delivery strategies-intranasal and tracheal insufflation-on the inspired fraction of oxygen (FIO2) in standing horses and to determine the time needed for arterial oxygen partial pressure (PaO2) equilibration. Methods: 6 healthy adult horses. Methods: In this blinded, randomized crossover design study, horses were randomly assigned to receive oxygen via nasal cannula (group N) or transcutaneous tracheal catheter (group T). After placement of venous and arterial catheters, FIO2 was measured through a catheter placed into the distal portion of the t...
Goulden BE, Anderson LJ.Some clinical features of laryngeal hemiplegia in 127 horses are described. Possible aetiologic factors were found in only 11% of affected animals. The onset of clinical signs was either sudden or insidious. The majority of cases were presented because of an abnormal respiratory noise made at exercise. Other clinical signs, particularly those usually attributed to laryngopalatal dislocation, were observed in a substantial proportion of affected animals. In all cases surveyed the left arytenoid was affected, although in 3 animals a bilateral laryngeal dysfunction was noted. Thirty of 65 animals...
Tydén E, Olsén L, Tallkvist J, Tjälve H, Larsson P.Gene and protein expression as well as catalytic activity of cytochrome P450 (CYP) 3A were studied in the nasal olfactory and respiratory mucosa and the tracheal mucosa of the horse. We also examined the activity of NADPH cytochrome P450 reductase (NADPH P450 reductase), the amount of cytochrome b(5) and the total CYP content in these tissues. Comparative values for the above were obtained using liver as a control. The CYP3A related catalytic activity in the tissues of the upper airways was considerably higher than in the liver. The CYP3A gene and protein expression, on the other hand, was hig...
Pisch C, Wensch-Dorendorf M, Schwarzenbolz U, Henle T, Greef JM, Zeyner A.Steaming hay is increasingly used to treat low-quality forage because it was proven to reduce inhalable allergens such as mould spores, bacteria, and airborne dust particles. Preliminary results have shown a substantial loss of precaecal (pc) digestibility (D) of crude protein (CP) and amino acids (AA). For this purpose, six different batches of hay from central Germany were divided into four subsamples, and each one was individually steamed. Native hay and four replicates of each steamed subsample were analysed for CP, AA, neutral detergent insoluble crude protein (NDICP), neutral detergent s...
Frippiat T, Dams L, Wielick C, Delguste C, Ludwig-Begall LF, Art T, Thiry E.Viruses can be involved in respiratory disorders in horses, with limited therapeutic options. Citrate-complexed silver nanoparticles (C-AgNP) have shown bactericidal properties after in vitro nebulization. The aim of the present study was to assess the virucidal activity of C-AgNP after in vitro instillation or nebulization on equine herpesvirus-1 (EHV-1) and murine norovirus (MNV), the latter used as surrogate for small non-enveloped viruses. Both viruses were instilled or nebulized with C-AgNP of increasing concentrations, and titres were determined via TCID50 method. We demonstrated efficie...
Laan TT, Bull S, van Nieuwstadt RA, Fink-Gremmels J.Beta-agonists have been shown to display anti-inflammatory properties in several experimental models. The aim of this study was to investigate the anti-inflammatory properties of clenbuterol (CB), administered either intravenously or by aerosol, in comparison with fluticasone propionate (FP) in recurrent airway obstruction (RAO)-susceptible horses. Eight horses, of which five were known to be susceptible to RAO, underwent an inhalation challenge with Aspergillus fumigatus (AF) antigen and were treated with CB intravenously, CB by aerosol, or FP by aerosol. Twenty-four hours after the challenge...
Lapointe JM, Vrins A, Lavoie JP.Bronchoalveolar lavages (BAL) were performed for 6 healthy horses and 8 horses with lower airway diseases (LAD). Total cell and differential counts were performed before and after centrifugation and resuspension of the BAL cells in a small volume of fluid; there was no difference in the total cell counts, but mast cell percentages were significantly (P < 0.05) lower, after centrifugation, in the LAD group. The two specimen preparation techniques compared were cytocentrifugation and centrifugation on microscope glass covers. For both groups of horses, lymphocyte percentages were significantl...
Lindberg A, Robinson NE, Näsman-Glaser B, Jensen-Waern M, Lindgren JA.To determine the ex vivo leukotriene (LT) biosynthesis in peripheral blood neutrophils (PBNs) and inflammatory cells in bronchoalveolar lavage fluid (BALF) obtained from horses affected with recurrent airway obstruction (RAO). Methods: 6 RAO-affected and 6 control horses. Methods: Before and 6, 24, and 48 hours after stabling, disease severity was determined subjectively by clinical and mucus scores and measurement of the maximal change in pleural pressure (deltaPpl(max)); PBNs were isolated and BALF samples were examined cytologically. The PBN and BALF cells were activated with a calcium iono...
Duvivier DH, Votion D, Vandenput S, Lekeux P.Inhalation therapy plays an increasing role in the management of equine respiratory disorders. This alternative to systematic treatment permits a high concentration of medication to act locally while minimizing side effects and residues. In human medicine, literature in this field is prolific and continuously renewed, whereas in veterinary medicine, applications of aerosol therapy are less extensive. This review considers the principles of action of the different types of devices used for inhalation, i.e., nebulization, metered-dose inhalation and dry powder inhalation, describes the technical...
Scott JS, Garon H, Broadstone RV, Derksen FJ, Robinson NE.We examined the response of five ponies with recurrent airway obstruction (principals) and five age- and gender-matched controls to the aerosol alpha-adrenergic agonist phenylephrine after blockade with propranolol and atropine. Measurements were made with principal ponies in clinical remission (period A) and during acute airway obstruction (period B). The blockade had no effect on base-line pulmonary mechanics in control ponies during periods A and B or in the principal ponies during period A. However, in the principal ponies during period B, blockade increased dynamic compliance (Cdyn) and d...
Berry CR, O'Brien TR, Madigan JE, Hager DA.Clinical records and thoracic radiographs of 19 horses with a confirmed pathologic diagnosis of silicosis were reviewed. These horses had histories of varying degrees of chronic weight loss, exercise intolerance, and respiratory distress. At the time of presentation, two horses were asymptomatic. Ten horses were geldings and nine were female. The mean age of the 19 horses was 10.7 +/- 5.5 years. Fourteen horses were identified as being from the Monterey-Carmel Peninsula of midcoastal California. An abnormal, structured interstitial pulmonary pattern was identified on thoracic radiographs in ea...
Hackett ES, Traub-Dargatz JL, Knowles JE, Tarr SF, Dargatz DA.Arterial blood gas analysis is widely accepted as a diagnostic tool to assess respiratory function in neonates. To the authors' knowledge, there are no published reports of arterial blood gas parameters in normal neonatal foals at altitude. Objective: To provide information on arterial blood gas parameters of normal foals born at 1500 m elevation (Fort Collins, Colorado) in the first 48 h post partum. Objective: Foals born at 1500 m will have lower PaO2 and PaCO2 than foals born at sea level due to low inspired oxygen and compensatory hyperventilation occurring at altitude. Methods: Sixteen fo...
McClure S, Sibert G, Hallberg J, Bade D.The efficacy and safety of sustained release ceftiofur administered twice, 4 days apart, for treatment of horses with naturally acquired Streptococcus equi subsp. zooepidemicus (Strep. zoo.) pneumonia was evaluated in a multicenter, placebo-controlled, double-blinded, randomized clinical trial. The study included 373 horses (278 treated and 95 placebos) with naturally acquired pneumonia. Inclusion in the statistical analyses for treatment efficacy for Strep. zoo. required recovery of ≥10(4) CFU/mL of Strep. zoo. on the primary isolation plate which resulted in 201 cases (145 treated and 56 p...
Frippiat T, Paindaveine C, Duprez JN, Delguste C, Mainil J, Art T.Antimicrobial resistance is increasing in both human and veterinary medicine. Bacteria can be part of the etiology of respiratory disorders in horses. Bactericidal activity of silver has been largely described and silver is currently used in veterinary therapeutic applications such as wound dressings. The aim of this study was to assess the in vitro bactericidal effects of nebulized silver nanoparticles (AgNP) on 2 common equine respiratory bacteria, Streptococcus equi subsp. zooepidemicus and Actinobacillus equuli subsp. equuli. Firstly, antimicrobial susceptibility of AgNP was determined ove...
Velineni S, Breathnach CC, Timoney JF.Streptococcus zooepidemicus (Sz) is a tonsillar commensal of healthy horses but with potential to opportunistically invade the lower respiratory tract. Sz is genetically variable and recombinogenic based on analysis of gene sequences including szp, szm and MLST data. Although a variety of serovars of the protective SzP are commonly harbored in the tonsils of the same horse, lower respiratory infections usually involve a single clone. Nevertheless, isolation of specific clones from epizootics of respiratory disease has been recently reported in horses and dogs in N. America, Europe and Asia. In...
Sherman J, Mitchell WR, Martin SW, Thorsen J, Ingram DG.The outbreaks of upper respiratory tract infections in horses at Standardbred racetracks were investigated over a three year period. The most serious epidemics of respiratory disease occurred in the winter and spring seasons. Both influenza viruses and equine herpesvirus 1 were shown to be present in the horse population. The herpesvirus was associated with respiratory disease particularly in the winter but the equine influenza viruses apparently were responsible for the major epidemics of respiratory disease at these tracks. Younger horses, two or three years of age, were particularly suscept...
