The trachea, commonly referred to as the windpipe, is a vital component of the equine respiratory system. It functions as a conduit for air passage between the larynx and the bronchi, facilitating respiration in horses. Structurally, the equine trachea is composed of a series of cartilaginous rings that maintain its shape and provide necessary support, preventing collapse during inhalation and exhalation. The inner lining of the trachea is lined with ciliated epithelium and mucus-producing cells, which help trap and expel particulates and pathogens, contributing to respiratory health. This page gathers peer-reviewed research studies and scholarly articles that explore the anatomy, physiology, and clinical implications of tracheal health and diseases in horses.
Calero IM, McKenzie EC, Johns JL.This report describes the diagnosis and successful management of a yearling filly with Coombs-positive anemia, thrombocytopenia, and fungal pneumonia. Diagnostic procedures, including thoracic ultrasonography and radiography, respiratory pathogen PCR testing, and evaluation of tracheal wash and bronchoalveolar lavage samples established multi-pathogen lower respiratory tract infection including a fungal agent. Orally administered voriconazole was a key component of treatment in this case to successfully eliminate fungal infection, alongside therapies for managing hematologic disease. This case...
Vermedal H, Hellings IR, Fretheim-Kelly ZL, Fintl C, Olsen HMB, Strand E.Exercise-related upper respiratory tract (URT) disorders are common in racehorses. Objective assessment of URT mechanics is essential to quantify degrees of obstruction caused by URT disorders identified upon dynamic endoscopy. Objective: To establish reference values for inspiratory and expiratory tracheal pressures (cmHO) during high-speed treadmill endoscopy in harness racehorses with clinically normal URTs. Methods: Prospective observational study. Methods: Tracheal pressures were measured in harness racehorses (Standardbreds and Norwegian-Swedish coldblooded trotters) in which no URT abno...
Mellish M, Burns J, Elce Y, Stull JW.Donkeys (Equus asinus) in East Africa are recognised as working with poorly designed harnesses and carts. The donkey cart used in regions of Africa, specifically Meru County, Kenya, appears to place the cart's weight solely on the donkey's mid-cervical region. The ventral area of the neck is vulnerable to external pressure on the trachea, which is superficially located. Objective: To compare the presence and severity of endoscopic abnormalities in the upper airway and trachea of Meru County working cart donkeys compared to pack donkeys. To determine associations between endoscopic and physical...
Parente A, Geburek F, Kästner S, Iversen C, Hopster K.Orotracheal intubation is commonly performed for inhalation anaesthesia in horses to ensure safe and reliable administration of volatile anaesthetics and to secure the airways. In human and equine medicine, the occurrence of intubation-associated complications has been described, which can range from mild mucosal irritation to severe necrosis. However, there are only sparse descriptions of mucosal alterations and the course of healing after elective surgery in horses. Objective: To investigate the prevalence and severity of tracheal lesions following endotracheal intubation associated with gen...
Barbazanges P, Couroucé A, Le Digarcher G, Cardwell JM, Schmitt E, Toquet MP, Lemonnier LC, Richard EA.Fungi are ubiquitous in horses' environment. Their contribution to the pathophysiology of severe asthma (SA) is acknowledged, while controversies remain for mild-moderate asthma (MA). Objective: We hypothesised that fungi are a risk factor for asthma. Our objective was to compare different combinations of analytical methods (cytology, culture) and sampling sites (tracheal wash (TW), bronchoalveolar lavage fluid (BALF)) in relation to clinical status (control, MA, SA). Methods: Prospective cross-sectional study. Methods: The study population included asymptomatic racing horses in the field and ...
Holley L, Creasey HN, Bedenice D, Reed S, Romualdo da Silva DR, Trautwein V, Mazan M, Widmer G.Glucocorticosteroids remain the most common pharmaceutical approach for the treatment of equine asthma but can be associated with significant side effects, including respiratory microbiome alterations. The goal of the study was to assess the impact of 2% lidocaine nebulization, a projected alternative treatment of equine asthma, on the healthy equine respiratory microbiota. A prospective, randomized, controlled, blinded, 2-way crossover study was performed, to assess the effect of 1 mg/kg 2% lidocaine (7 treatments over 4 days) on the equine respiratory microbiota compared to control horses (s...
Bishop RC, Nobrega AD, Mersich I, Wilkins PA.To describe indications for and demonstrate the technique to perform a transtracheal aspirate in horses. Transtracheal aspirate is indicated to collect samples for cytology and bacteriologic culture in cases of suspected pneumonia or other lower respiratory tract disease. Methods: 1 healthy university-owned horse was used for demonstration purposes. Images of clinical case samples from the University of Illinois Veterinary Teaching Hospital are shown. Methods: The horse is restrained and sedated with detomidine or xylazine to facilitate restraint and butorphanol to minimize coughing. The ventr...
Bozzola C, Sala G, Schinardi L, Stancari G, Stucchi L, Ferrucci F, Zucca E.Exercise-Induced Pulmonary Hemorrhage (EIPH) is a common pulmonary disease among racehorses, diagnosed by the detection of blood in the trachea after strenuous exercise or the presence of hemosiderophages in the bronchoalveolar lavage fluid (BALF). Although the latter is considered the most sensitive method to diagnose EIPH, it is perceived as a less practical and more invasive procedure compared to tracheal wash (TW) collection among racehorse trainers. The present retrospective study aimed to verify the agreement between Tracheal wash and BALF cytology in assessing EIPH in racehorses. For th...
Takahashi Y, Niwa H, Ebisuda Y, Mukai K, Yoshida T, Raidal S, Padalino B, Ohmura H.Protection of horse welfare during transport is crucial. The aim of this study was to determine the effect of head and neck restraint on behavior and airway bacteria. Unassigned: In a randomized crossover study, six healthy Thoroughbreds were transported by road for 22 h in an individual bay with tight head restraint (50 cm short-rope) or loose head restraint (95 cm long-rope). Behavioral parameters relating to head position, eating, and stress were monitored during transportation. Tracheal wash samples were obtained 6 days before and immediately after transport for bacterial culture a...
Lopes MAF, Hollenbach E, Schliewert EC, Murphy MA, Corrêa F.A mare was admitted for progressive swelling of the neck, lethargy and anorexia. Radiography revealed perilaryngeal, peritracheal, and periesophageal emphysema. Endoscopy revealed pharyngeal and tracheal roof collapse, and a small laceration on the trachea. Treatment with antimicrobials, fluids, and flunixin was initiated. To prevent exacerbation of the emphysema, temporary tracheostomy was performed. Clipping for the tracheostomy revealed a hoofprint mark on the ventral neck. Subsequent endoscopies revealed laceration of the esophagus and guttural pouch septum communicating with the visceral ...
Dély S, Gerber V, Peters LM, Sage SE.The presence of fungi in tracheal wash (TW) of horses was recently linked to mild-moderate equine asthma, indicating a possible causal role; however, increased numbers of fungi may also stem from asthma-related alteration of tracheal mucus clearance or from environmental exposure. Our objective was to elucidate the association between the presence of fungi in TW and asthma status while controlling for relevant confounders. We conducted a retrospective case-control study involving 73 horses, including 34 controls and 39 asthmatic cases. Each asthmatic horse was matched with a control from the s...
Shawaf T.Exercise-induced pulmonary hemorrhage (EIPH) is one of the most commonly diagnosed disorders in racehorses. Many EIPH risk factors such as breed, age, high or low environmental temperature, and distance of the race have been studied in racehorses. Unassigned: The aim of this study was to study the relationship between EIPH and the presence of jugular vein thrombose in racehorses. Unassigned: Forty-eight thoroughbred racehorses randomly selected from animals with exercise intolerance due to respiratory disorders were enrolled in the present study. Clinical and tracheobronchoscopy examinations w...
Tavanaeimanesh H, Alinia Z, Sadeghian Chaleshtori S, Moosavian H, Mohebi Z, Daneshi M.During transportation many horses develop post-transportation infection, which can be life-threatening and end their sport career. Preventing mucus accumulation and inflammation during transportation is vital, emphasizing the need for effective strategies to enhance overall horse health welfare. Objective: Assess the impact of N-acetylcysteine (NAC) on mucus accumulation and inflammation in horses subjected to 18 hours of head confinement. Methods: Six healthy crossbred horses, 5.3 ± 2.1 years of age and weighing 387 ± 30 kg. Methods: Prospective placebo-controlled cross-over d...
Laclaire AL, Manguin E, Tanquerel L.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-anesthesi...
Hansen S, Otten ND, Nissen SD, Carstensen H, Hopster-Iversen C, Fjeldborg J, Staun SH, Fenner M, Hesselkilde EM, Buhl R.Atrial fibrillation (AF) has been proposed as a risk factor for exercise-induced pulmonary haemorrhage (EIPH) due to increased pressure in the left atrium. Objective: To evaluate if AF was associated with EIPH following a standardised exercise test (SET) to fatigue. Methods: Two-arm controlled experiment. Methods: Ten untrained Standardbred mares mean (standard deviation [SD]) age 6 (2) years performed a SET on the treadmill in sinus rhythm (SR) (SET1) and 25-44 days after induction of self-sustained AF (SET2). AF was induced by tachypacing using a pacing device. Endoscopy, including trachea...
Burns JJ, MacMillan KM, John E.Respiratory disease is common in the horse population and is often associated with poor performance in equine athletes. Despite their outstanding strength and aerobic capacity, little regard is given to draft horses and the respiratory disorders they may encounter when performing athletic activity. For this reason, the objectives of this study were: (1) to determine the prevalence of exercise-induced pulmonary hemorrhage (EIPH), tracheal mucus (TM) and recurrent laryngeal hemiplegia (RLH) in a population of competitive draft pulling horses, and (2) to determine if there was an association betw...
Cartilage injury defects in animals and humans result in the development of osteoarthritis and the progression of joint deterioration. Cell isolation from equine hyaline cartilage and evaluation of their ability to repair equine joint cartilage injuries establish a new experimental protocol for an alternative approach to osteochondral lesions treatment. Chondrocytes (CCs), isolated from the autologous cartilage of the trachea, grown in the laboratory, and subsequently arthroscopically implanted into the lesion site, were used to regenerate a chondral lesion of the carpal joint of a horse. Biop...
Gordon D, Clark-Price S, Keating S, Schaeffer DJ, Lascola KM.This study evaluated the effects of various flow rates and fractions of oxygen on arterial blood gas parameters and on the fraction of inspired oxygen (FO) delivered to the distal trachea. Oxygen was administered to 6 healthy, conscious, standing, adult horses via single nasal cannula positioned within the nasopharynx. Three flow rates (5, 15, 30 L/min) and fractions of oxygen (21, 50, 100%) were delivered for 15 minutes, each in a randomized order. FO was measured at the level of the nares and distal trachea. Adverse reactions were not observed with any flow rate. FO (nares and trachea) and P...
Bond S, McMullen C, Timsit E, Léguillette R.The lower respiratory tract microbiota of the horse is different in states of health and disease, but the bacterial and fungal composition of the healthy respiratory tract of the horse has not been studied in detail. Objective: The respiratory tract environment contains distinct niche microbiotas, which decrease in species richness at more distal sampling locations. Objective: Characterize the bacterial and fungal microbiotas along the upper and lower respiratory tract of the horse. Methods: Healthy Argentinian Thoroughbred horses (n = 11) from the same client-owned herd. Methods: Prospectiv...
Vinardell T, David F, Galezowski AM, Ali M, Qasim M, Massie SL, McCrae P, Filho S, Leguillette R.Swimming is used for rehabilitation of musculoskeletal injuries and for conditioning to improve equine fitness. However, there are anecdotal reports that suggest that tethered swimming can induce epistaxis, likely secondary to exercise-induced pulmonary hemorrhage (EIPH). The objective of this observational, prospective study was to investigate if EIPH occurs during intensive free-swimming training sessions (5 × 70m) using 15 endurance horses. On tracheo-bronchoscopic evaluations following swimming, low grade mucus scores were observed, but no tracheal blood was observed. Bronchoalveolar la...
Cascardo B, Bernardes C, de Souza GN, Silva KM, Pires NR, de Alencar NX, Lessa DAB.Lower airway cytology has been proposed as a complementary diagnostic method to confirm the presence and quantifying the severity of exercise-induced pulmonary hemorrhage (EIPH). Bronchoalveolar lavage is usually preferred over tracheal wash (TW), yet the need for sedation imposes as a limitation for active sport horses in addition to be a highly invasive technique. This study aims to evaluate the diagnostic value of TW with Total Hemosiderin Score (THS) for monitoring EIPH in active Thoroughbred racehorses. A sampling of 47 randomly selected Thoroughbreds were endoscopically examined for EIPH...
Wilkens HL, Neudeck S, Kästner SBR.The present study aimed to investigate the effect of endotracheal intubation on nasal and tracheal endogenous NO concentrations, gas exchange and oxygenation in horses undergoing general anaesthesia. In many species a major part of physiological nitric oxide (NO) production takes place in the nasopharynx. Inhaled NO acts as a pulmonary vasodilator and regulates lung perfusion and endotracheal intubation bypasses the nasopharynx. Six horses were randomly assigned to either the "intubated" (INT) or the "non-intubated" (nINT) treatment group. Horses were premedicated with dexmedetomidine (5 μg...
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...
Takai S, Yoda A, Sasaki Y, Kakuda T, Suzuki Y, Oikawa M.Tracheal washing fluid was collected from 170 foals at 28 and 35 d old from February to July in a foaling season on horse-breeding farms with sporadic rhodococcosis in Japan and was investigated by quantitative culture. The history of the 170 foals followed up for the next few months. The proportion of R. equi-positive foals at 28 and 35 d old was significantly increased according to the birth month. Furthermore, the mean number of R. equi in the tracheal washing fluid of each month group increased according to their birth month with the rise in outside temperature. During the follow-up observ...
Lo Feudo CM, Stucchi L, Stancari G, Alberti E, Conturba B, Zucca E, Ferrucci F.Exercise-induced pulmonary hemorrhage (EIPH) is a condition affecting up to 95% of racehorses, diagnosed by detecting blood in the trachea after exercise and/or the presence of hemosiderophages in the bronchoalveolar lavage fluid (BALf). Although EIPH is commonly associated with poor performance, scientific evidence is scarce. The athletic capacity of racehorses can be quantified through some parameters obtained during an incremental treadmill test; in particular, the speed at a heart rate of 200 bpm (V200), and the speed (VLa4) and the heart rate (HRLa4) at which the blood lactate concentrati...
Mönki J, Saastamoinen M, Karikoski N, Norring M, Rajamäki M, Mykkänen A.The effects of bedding material on air quality are important amongst horses worldwide. Respiratory diseases, especially equine asthma, are highly prevalent with air hygiene playing a major role on the pathophysiology of these diseases. The objective of our study was to investigate the effects of four bedding materials on the respiratory signs, tracheal mucus score, and tracheal wash (TW) and bronchoalveolar lavage fluid (BALF) cytology in healthy adult horses. The study design was a prospective controlled cross-over study, and the subjects were healthy adult riding school horses ( = 32) from a...
Ferreira TH, Allen M, De Gasperi D, Buhr KA, Morello SL.To assess the effects of two sizes of silicone endotracheal tubes with internal diameter 26 mm (ETT) and 30 mm (ETT) inflated to minimum occlusive volume on tracheal and laryngeal mucosa of adult horses anesthetized for 2 hours with isoflurane. Methods: Prospective, randomized, blinded, crossover experimental study. Methods: A total of eight healthy adult mares. Methods: Upper airway endoscopy and ultrasound measurements of internal tracheal diameter were performed the day before anesthesia. Horses were anesthetized and orotracheally intubated with ETT or ETT. Ease of intubation was scored. Th...
McGilvray TA, Cardwell JM.Exercise induced pulmonary haemorrhage (EIPH) is an important condition of horses performing high intensity exercise, with reported prevalence among racehorses of up to 95%, based on the detection of blood on tracheobronchoscopy. Previously identified risk factors include age, sex, season, race type, years spent in racing and lower airway inflammation. Objective: To estimate the prevalence of EIPH in British National Hunt racehorses as indicated by two outcome measures: presence of tracheal blood on tracheobronchoscopy, and presence of moderate-large (significant) proportions of haemosideropha...
Mönki J, Saastamoinen M, Karikoski N, Rajamäki M, Raekallio M, Junnila J, Särkijärvi S, Norring M, Valros A, Oranen Ben Fatma S, Mykkänen A.Bedding materials affect stable air hygiene, and thus the development and exacerbation of equine asthma. There is limited knowledge concerning the effects of different types of bedding material on equine lower airway inflammation. The objective of our study was to investigate the effects of bedding materials on respiratory signs, tracheal mucus score, and lower airway cytology in healthy adult horses. The study design was a prospective controlled study, and the subjects were healthy adult riding school horses (n = 32) from a single stable. Wood shavings were compared to peat, which was used as...
Gerber V, Straub R, Marti E, Hauptman J, Herholz C, King M, Imhof A, Tahon L, Robinson NE.Endoscopic scoring of airway mucus quantity and quality has not been critically assessed. Objective: To evaluate mucus scores for 1) observer- and horse-related variance and 2) association with inflammation, mucus viscoelasticity and measured volume. Methods: Variance of scoring within and between observers and over time within horses were determined for airway mucus accumulation, apparent viscosity, localisation and colour, and correlations of mucus accumulation scores with neutrophil ratios in secretions. The relationship of accumulation score to measured volumes of 'artificial mucus' was in...
Gonzalez G, Marshall JF, Morrell J, Robb D, McCauley JW, Perez DR, Parrish CR, Murcia PR.Influenza A viruses (IAVs) can jump species barriers and occasionally cause epidemics, epizootics, pandemics, and panzootics. Characterizing the infection dynamics at the target tissues of natural hosts is central to understanding the mechanisms that control host range, tropism, and virulence. Canine influenza virus (CIV; H3N8) originated after the transfer of an equine influenza virus (EIV) into dogs. Thus, comparing CIV and EIV isolates provides an opportunity to study the determinants of influenza virus emergence. Here we characterize the replication of canine, equine, and human IAVs in the...
Holcombe SJ, Robinson NE, Derksen FJ, Bertold B, Genovese R, Miller R, de Feiter Rupp H, Carr EA, Eberhart SW, Boruta D, Kaneene JB.Accumulations of mucus within the trachea are often found during endoscopic examinations of the airways of poorly performing racehorses, but the clinical importance of this finding is unknown. Objective: To determine the effect of tracheal mucus, pharyngeal lymphoid hyperplasia (PLH) and cytological indices of tracheal aspirate on racing performance in Thoroughbred horses assessed by race place and whether the horse was raced. Methods: Endoscopic examination of the nasopharynx, larynx and trachea was performed, and a tracheal aspirate obtained monthly at Thistledown racetrack from April to Dec...
Wada R, Kamada M, Anzai T, Nakanishi A, Kanemaru T, Takai S, Tsubaki S.Twelve foals, between 27 and 83 days old, were infected with 2 strains of Rhodococcus equi by intratracheal administration. Ten of the 12 foals were inoculated with 10(4)-10(10) colony forming units (cfu) of ATCC 33701 strain. The other 2 foals were inoculated with 10(9) cfu of a plasmid-cured derivative of the ATCC 33701 strain (ATCC 33701P-). All of the 10 foals challenged with the ATCC 33701 strain showed clinical signs of pulmonary disease within 5-13 days, such as gross lesions associated with acute bronchopneumonia and microscopic lesions associated with granulomatous pneumonia. The two ...
Robinson NE, Karmaus W, Holcombe SJ, Carr EA, Derksen FJ.Although subclinical airway inflammation is thought to be common in horses, there is little information on its prevalence and none on risk factors. Objective: To determine the prevalence and risk factors for an increased number of inflammatory cells and for mucus accumulation in the trachea of pleasure horses. Methods: Horses (n = 266) in stables (n = 21) in Michigan were examined endoscopically, once in winter and once in summer 2004. Visible tracheal mucoid secretions were graded 0-5 and inflammatory cell numbers counted in a tracheal lavage sample. Information collected about each horse inc...
Allen KJ, Tremaine WH, Franklin SH.Inflammatory airway disease (IAD) is thought to be an important cause of poor performance in young Thoroughbred racehorses. However, little study has been made of IAD in older National Hunt (NH) horses. Objective: To determine the prevalence of IAD in NH racehorses referred for investigation of poor athletic performance and identify some of the risk factors that may be associated with IAD in this group of horses. Methods: Tracheal mucus was graded, and tracheal wash (TW) and bronchoalveolar lavage (BAL) performed after treadmill exercise in 91 NH horses referred to the University of Bristol. C...
Couetil LL, Thompson CA.Indications for bronchoalveolar lavage, tracheal wash, and thoracocentesis for the diagnosis of respiratory diseases are discussed. Each technique is described in detail and illustrated by videos. Sample handling, preparation and evaluation are reviewed. The advantages and limitations of bronchoalveolar lavage and tracheal wash procedures as well as a critical comparison between the 2 techniques for equine asthma diagnosis are presented. Finally, validated cut-off values for equine asthma diagnosis are reviewed.
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...
Derksen FJ, Brown CM, Sonea I, Darien BJ, Robinson NE.Comparisons were made between transtracheal aspirate (TTA) and bronchoalveolar lavage (BAL) cytology obtained from 50 horses with chronic lung disease and from 10 control horses. There was no significant correlation between the TTA cytology and the BAL cytology, suggesting that the cell population in the trachea is not representative of the cell population in the lower airways. In control horses the range of differential cell counts obtained from TTA fluid was remarkably large, whereas the variability in cell populations observed in BAL fluid was smaller. In the principal horses the total and ...
Koblinger K, Nicol J, McDonald K, Wasko A, Logie N, Weiss M, Léguillette R.Comprehensive endoscopic scoring of the upper and lower airways for inflammation has not been critically assessed among a large population of horses. The relationship between upper and lower airways described in humans by the "one airway, one disease" concept might also apply to horses. Objective: To evaluate if an association exists between endoscopic inflammatory scores and mucus scores of upper and lower airways and to investigate if endoscopic findings correlate with the lower airway inflammation measured by bronchoalveolar lavage (BAL) cytology. Methods: Prospective field study. Pharyngit...
Pascoe JR, Ferraro GL, Cannon JH, Arthur RM, Wheat JD.Of 235 Thoroughbred racehorses examined with a flexible fiberoptic endoscope within 2 hours of racing to determine the frequency of exercise-induced pulmonary hemorrhage (EIPH), 103 (43.8%) had various degrees of hemorrhage in the tracheal lumen. Two of these horses (0.8%) subsequently had blood flow from the nostrils. Blood seemed to originate from the lung. Statistical analysis of frequency data for 191 horses which finished in 1st, 2nd, and 3rd places did not show any relationship between EIPH and horse's age, sex, or finishing position. However, a trend toward an increased frequency of EIP...
Reznik GK.The anatomical characteristics of the upper respiratory tract of various experimental animals and man are described. There are a number of differences and similarities macroscopically and microscopically between the species. Perhaps one of the most obvious examples of anatomical differences is in the structure of the turbinates. Some of the differences could affect deposition and clearance of particles in the nasal cavities. Effects of compounds in the nasal cavity, larynx, and trachea can differ depending on the cellular composition of the mucosa.
Hinchcliff KW, Jackson MA, Brown JA, Dredge AF, O'Callaghan PA, McCaffrey JP, Morley PS, Slocombe RE, Clarke AF.To determine the interobserver variability of assessment of exercise-induced pulmonary hemorrhage (EIPH) during tracheobronchoscopic examination in horses. Methods: 747 Thoroughbred racehorses. Procedures-850 tracheobronchoscopic examinations were performed within 2 hours of racing for the horses. Examinations were recorded on videotape, and EIPH and its severity were assessed independently by 3 veterinarians. Concordance was determined by calculation of the Cohen weighted kappa statistic and tabulation of scores assigned by each observer. Results: Weighted kappa statistics ranged from 0.75 to...
Millerick-May ML, Karmaus W, Derksen FJ, Berthold B, Holcombe SJ, Robinson NE.Accumulations of tracheal mucus assessed by endoscopic examination are associated with poor performance in racehorses. The air quality in horses' stalls may contribute to this visible tracheal mucus. Objective: To determine whether the concentration and number of airborne particulates in stalls are associated with visible accumulations of tracheal mucus and with the number of inflammatory cells in tracheal aspirates. Methods: We studied 107 racehorses from 3 stables, in 3 different months, and measured airborne particulate matter 3 times daily in each of the stalls. On each monthly visit, hors...
Im Hof V, Gehr P, Gerber V, Lee MM, Schürch S.We measured the surface tension in the trachea of the non-anaesthetised horse from the spreading behaviour of fluid drops, using videotracheoscopy. To do this, we placed small oil drops onto the tracheal wall with a thin Teflon tubing inserted into a videocolonoscope used in humans. Either 5 ml of saline (control) or 5 ml of bovine lipid extract surfactant (BLES) at 4 mg/ml were administered. Tracheal surface tension was 31.9 +/- 0.54 mN/m (Mean +/- SEM, n = 30) in the control experiments and 24.5 +/- 0.51 mN/m (Mean +/- SEM, n = 21) in the entire trachea after the administration of BLES. Thes...
Chand N, Eyre P.Histamine, 2-methylhistamine (a specific H1-agonist), 5-HT, PGF2alpha, SRS-A, bradykinin (BK) and carbachol contract bronchial and tracheal smooth muscles of the horse. Isoprenaline, PGE1, E2, dimaprit and 4-methylhistamine (last two = specific H2-agonists) relaxed airways which were partially contracted to carbachol. Mepyramine (a specific H1-antagonist) selectively antagonized contractions to histamine. In the presence of mepyramine, histamine caused relaxation of airways partially contracted to carbachol. Metiamide and burimamide (specific H2-antagonists) specifically antagonized or reverse...
Fortier G, van Erck E, Fortier C, Richard E, Pottier D, Pronost S, Miszczak F, Thiry E, Lekeux P.The objectives of this study were to estimate the prevalence and the potential role of equine herpesviruses (EHVs) detection in both bronchoalveolar lavage (BAL) and tracheal wash (TW). The population included a control group (CTL; 37 TW and 25 BAL) and a pathological group (PAT; 259 TW and 387 BAL), including horses either suffering from respiratory diseases including syndrome of tracheal inflammation, inflammatory airway disease, recurrent airway obstruction, or submitted to respiratory investigation because of exercise intolerance or poor performance. Each respiratory liquid was submitted t...
The Journal of physiologyFebruary 16, 2000
Volume 523 Pt 1, Issue Pt 1 131-138 doi: 10.1111/j.1469-7793.2000.t01-3-00131.x
Wang YX, Kotlikoff MI.1. The signalling pathway underlying histamine activation of non-selective cation channels was investigated in single equine tracheal myocytes. Application of histamine (100 microM) activated the transient calcium-activated chloride current (ICl(Ca)) and sustained, low amplitude non-selective cation current (ICat). The H1 receptor antagonist pyrilamine (10 microM) blocked activation of ICl(Ca) and ICat. Simultaneous application of histamine (100 microM) and caffeine (8 mM) during H1 receptor blockade activated ICl(Ca), but not ICat. Neither the H2 receptor antagonist cimetidine (20 microM) nor...
The Journal of physiologyApril 15, 1996
Volume 492 ( Pt 2), Issue Pt 2 347-358 doi: 10.1113/jphysiol.1996.sp021313
Fleischmann BK, Wang YX, Pring M, Kotlikoff MI.1. The relationship between voltage-dependent calcium channel current (I(Ca)) and cytosolic free calcium concentration ([Ca2+]i) was studied in fura-2 AM-loaded equine tracheal myocytes at 35 degrees C and 1.8 mM Ca2+ using the nystatin patch clamp method. The average cytosolic calcium buffering constant was 77 +/- 3 (n = 14), and the endogenous calcium buffering constant component is likely to be between 15 and 50. 2. I(Ca) did not evoke significant calcium-induced calcium release (CICR) since (i)[Ca2+]i scaled with the integrated I(Ca) over the full voltage range of evoked calcium currents, ...
Bazzano M, Laghi L, Zhu C, Magi GE, Serri E, Spaterna A, Tesei B, Laus F.The present work characterized the metabolomic profile of tracheal wash (TW) and exhaled breath condensate (EBC) in healthy horses and horses with respiratory disease. Six asthma-affected horses (group A) and six healthy controls (group H) underwent clinical, endoscopic and cytologic examinations of upper airways to confirm the active phase of asthma. TW and EBC samples were collected from each animal and investigated by proton nuclear magnetic resonance (H-NMR) metabolomic analysis. A total of ten out of 38 metabolites found in the TW were significantly different between the groups (p < ...
Newton JR, Wood JL.In an epidemiological study of risk factors for exercise-induced pulmonary haemorrhage (EIPH) in young Thoroughbreds in the UK, in which 148 horses contributed 1614 horse-months of data, there were 64 (4%) episodes of endoscopically visible tracheal bleeding and 824 (51%) episodes of increased quantities of haemosiderophages in tracheal washes. There were increases in prevalence and risk of EIPH by both definitions with age from or = 4 years, season of sampling from winter (Nov-Jan) to autumn (Aug-Oct) and several different measures of airway inflammation, including tracheal mucus, neutrophil...
Sellon DC, Besser TE, Vivrette SL, McConnico RS.Recently, a technique was described for amplification of Rhodococcus equi-specific chromosomal and vapA DNA from blood and tracheal wash fluids. It was hypothesized that this technique would be more sensitive than standard culture techniques or serology for diagnosis of R. equi pneumonia in foals. Tracheal wash fluid, nasal swabs, whole blood samples, and serum samples from 56 foals with pneumonia were analyzed. Final clinical diagnosis was determined by the attending clinician on the basis of final interpretation of all available information about each foal, including clinical presentation, d...
Sanz M, Loynachan A, Sun L, Oliveira A, Breheny P, Horohov DW.While Rhodococcus equi remains the most common cause of subacute or chronic granulomatous bronchopneumonia in foals, development of a relevant model to study R. equi infection has proven difficult. The objective of this study was to identify a challenge dose of R. equi that resulted in slow progressive disease, spontaneous regression of lung lesions and age-dependent susceptibility. Foals less than one-week of age were challenged intratracheally using either 10(6), 10(5), 10(4), 10(3) or 10(2) cfu of R. equi. Two doses (10(3) cfu and 10(5) cfu) were used to challenge 2 and 3-week-old, and 3 an...
Whitwell KE, Greet TR.A flexible endoscope was used to obtain 223 tracheal washes from 191 horses in three clinical categories. Total cell counts, cytological and bacteriological examinations are reported and the features of the main cell types encountered described. The presence and degree of inflammatory airway disease was determined by a semiquantitative assessment of the neutrophil response and was an important consideration in the interpretation of the bacteriological results. Potential pathogens were isolated from approximately 30 per cent of samples. Cytological changes suggestive of lungworm infestation, vi...
Raidal SL, Love DN, Bailey GD.Tracheal mucociliary clearance was determined in horses by measuring the rostrad transport of the radiopharmaceutical 99mtechnetium-sulphur colloid following deposition on the tracheal epithelium by intratracheal injection. The effects of head position (head elevated to normal standing position vs head lowered) and of accumulated purulent secretions on tracheal mucociliary clearance were evaluated for the first time in the horse. In normal horses tracheal mucociliary clearance was greatly accelerated by lowering the head so that the cranial trachea was lower than the caudal trachea. Horses con...
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...
Widmer A, Doherr MG, Tessier C, Koch C, Ramseyer A, Straub R, Gerber V.The objective of this study was to examine the association of pharyngeal lymphoid hyperplasia (PLH), recurrent laryngeal neuropathy (RLN), mucus accumulation (MA) score and tracheobronchial secretion neutrophil percentage (TBS-N) with rider-assessed performance in sport horses. Airway endoscopy scores, tracheobronchial secretion cytology, rider-assessed general impression and willingness to perform were investigated in 171 top-level sport horses. Increased MA appears to be associated with poor willingness to perform in sport horses. Older horses had decreased PLH scores and increased TBS-N. Mu...
Wilkie BN.Effective resistance to respiratory tract infection depends principally on specific immunity on mucosal surfaces of the upper or lower respiratory tract. Respiratory tract immune response comprises antibody and cell-mediated systems and may be induced most readily by surface presentation of replicating agents but can result from parenteral or local presentation of highly immunogenic antigens. Upper and lower respiratory tract systems differ in immunologic competence, with the lungs having a greater inventory of protective mechanisms than the trachea or nose. Several effective vaccines have bee...
Willoughby R, Ecker G, McKee S, Riddolls L, Vernaillen C, Dubovi E, Lein D, Mahony JB, Chernesky M, Nagy E.The response of horses exposed to three common respiratory viruses was studied by measuring tracheal mucociliary clearance rates in the trachea. Tracheal clearance rates (TCR) were determined before, during illness and following recovery in horses exposed to equine rhinovirus (ERhV-2), equine influenza virus (EIV) and equine herpesvirus (EHV-4) by means of lateral scintigraphs made following an injection of technetium-99m sulphide colloid into the tracheal lumen. In six horses exposed to ERhV-2, TCR remained within normal limits. Exposure to EIV resulted in reduced TCR in six of seven horses, ...
Matusovsky OS, Kachmar L, Ijpma G, Bates G, Zitouni N, Benedetti A, Lavoie JP, Lauzon AM.Heaves is a naturally occurring equine disease that shares many similarities with human asthma, including reversible antigen-induced bronchoconstriction, airway inflammation, and remodeling. The purpose of this study was to determine whether the trachealis muscle is mechanically representative of the peripheral airway smooth muscle (ASM) in an equine model of asthma. Tracheal and peripheral ASM of heaves-affected horses under exacerbation, or under clinical remission of the disease, and control horses were dissected and freed of epithelium to measure unloaded shortening velocity (Vmax), stress...
