Lung health in horses encompasses the study of respiratory system function, disease, and maintenance in equine species. The equine respiratory system is vital for oxygen exchange and plays a significant role in overall health and athletic performance. Conditions affecting lung health include inflammatory airway disease (IAD), recurrent airway obstruction (RAO), and exercise-induced pulmonary hemorrhage (EIPH). These conditions can impact a horse's respiratory efficiency and performance capabilities. Research in this area often focuses on understanding the pathophysiology, diagnosis, and management of respiratory diseases, as well as the impact of environmental factors on lung function. This page compiles peer-reviewed research studies and scholarly articles that explore the mechanisms, diagnostic approaches, and therapeutic strategies related to lung health in horses.
Morley PS, Bromberek JL, Saulez MN, Hinchcliff KW, Guthrie AJ.Exercise-induced pulmonary haemorrhage (EIPH) occurs commonly in Thoroughbred racehorses worldwide. While EIPH is believed to be an important cause of impaired performance in these horses, there is limited evidence from sufficiently powered studies to evaluate this association. Objective: To evaluate whether EIPH is associated with finishing position, distance finished behind race winners and differences in race earning among Thoroughbred horses racing in South Africa. Methods: Prospective cross-sectional study. Methods: One thousand Thoroughbred horses racing in South Africa were enrolled pri...
Hansen S, Baptiste KE, Fjeldborg J, Horohov DW.The equine aging process involves many changes to the immune system that may be related to genetics, the level of nutrition, the environment and/or an underlying subclinical disease. Geriatric horses defined as horses above the age of 20, exhibit a decline in body condition, muscle tone and general well-being. It is not known whether these changes contribute to decreased immune function or are the result of declining immune function. Geriatric years are characterized by increased susceptibility to infections and a reduced antibody response to vaccination as a result of changes in the immune sy...
Reich H, Moens Y, Braun C, Kneissl S, Noreikat K, Reske A.Quantitative computer tomographic analysis (qCTA) is an accurate but time intensive method used to quantify volume, mass and aeration of the lungs. The aim of this study was to validate a time efficient interpolation technique for application of qCTA in ponies. Forty-one thoracic computer tomographic (CT) scans obtained from eight anaesthetised ponies positioned in dorsal recumbency were included. Total lung volume and mass and their distribution into four compartments (non-aerated, poorly aerated, normally aerated and hyperaerated; defined based on the attenuation in Hounsfield Units) were de...
Nogradi N, Couetil LL, Messick J, Stochelski MA, Burgess JR.Omega-3 polyunsaturated fatty acid (PUFA) may benefit humans and animals with chronic inflammatory diseases. Objective: Omega-3 PUFA supplementation improves clinical signs, lung function, and airway inflammation in horses with recurrent airway obstruction (RAO) and inflammatory airway disease (IAD). Methods: Eight research horses and 35 client-owned horses. Methods: A pilot study examined the dose of PUFA that can alter plasma PUFA composition. Then, a randomized, controlled clinical trial was performed in horses with RAO and IAD. Horses were fed a complete pelleted diet with no hay and rando...
Richard EA, Depecker M, Defontis M, Leleu C, Fortier G, Pitel PH, Couroucé-Malblanc A.Multiple cytological patterns occur in bronchoalveolar lavage fluid (BALF) of horses with inflammatory airway disease (IAD). Only few data on BALF cytokine profiles are available for horses with IAD, and are limited to mRNA expression. Objective: Cytological profiles of IAD are associated with different BALF immunological pathways. To investigate BALF cytokine concentrations in a large number of horses with neutrophilic IAD. Methods: One hundred and thirty-eight client-owned Standardbred racehorses in active training. Methods: Prospective observational study. BALF samples were obtained from le...
Preston SA, Riggs CM, Singleton MD, Troedsson MH.Exercise-induced pulmonary haemorrhage (EIPH) is reported as a performance limiting condition in racehorses, yet few longitudinal studies characterising EIPH have been reported. Objective: To characterise EIPH during training and racing in the absence of prophylactic medication with furosemide among horses imported to Hong Kong during 2007-2012. Methods: Retrospective descriptive study of clinical endoscopy, EIPH status, and racing records. Methods: Thoroughbred geldings (n = 822) imported from New Zealand between 2007 and 2012 were retrospectively assigned to 4 groups: diagnosed with EIPH via...
Dubuc J, Lavoie JP.The objective of this study was to determine whether eosinophils infiltrate the airway wall of horses with heaves. Eosinophils were evaluated using paraffin embedded lung tissues from six heaves-affected horses in crisis and six aged-matched controls. Slides were stained using Luna's method and eosinophils enumerated using histomorphometric techniques. Total eosinophil counts (expressed per mm(2) of basement membrane) were significantly higher in the airways of controls horses than in horses with heaves. Intraluminal, intraepithelial, and airway smooth muscle eosinophils counts were also incre...
Johnson L, Montgomery JB, Schneider JP, Townsend HG, Ochs M, Singh B.To understand the mechanisms of airway inflammation associated with equine diseases such as Rhodococcus equi infection, we must identify baseline "normal" structural characteristics of the horse lung. To develop a detailed understanding of the morphology of the horse lung, we adapted and applied stereological methods to the lungs from healthy adult horses (N = 4) and 1-day (N = 5) and 30-day (N = 5) old foals. The left lung was fixed in situ by intrabronchial instillation of glutaraldehyde/paraformaldehyde fixative at 25 cm H2 O column and sampled using a fractionator design follow...
Stack A, Derksen FJ, Williams KJ, Robinson NE, Jackson WF.Exercise-induced pulmonary hemorrhage is a performance-limiting condition of racehorses associated with severe pathology, including small pulmonary vein remodeling. Pathology is limited to caudodorsal (CD) lung. Mechanical properties of equine pulmonary microvasculature have not been studied. We hypothesized that regional differences in pulmonary artery and vein mechanical characteristics do not exist in control animals, and that racing and venous remodeling impact pulmonary vein mechanical properties in CD lung. Pulmonary arteries and veins [range of internal diameters 207-386 ± 67 μm (mean...
Miele A, Dhaliwal K, Du Toit N, Murchison JT, Dhaliwal C, Brooks H, Smith SH, Hirani N, Schwarz T, Haslett C, Wallace WA, McGorum BC.Donkey pulmonary fibrosis (DPF) is a spontaneous syndrome of aged donkeys with a high prevalence (35%). No previous detailed characterization of DPF has been performed. We sought to determine the similarities between DPF and recognized patterns of human pulmonary fibrosis. Methods: Whole lungs were collected from 32 aged donkeys at routine necropsy. Gross examination revealed pulmonary fibrosis in 19 donkeys (DPF cases), whereas 13 (control cases) had grossly normal lungs. Eighteen whole inflated ex vivo lungs (11 DPF cases, seven control cases) were imaged with high-resolution CT (HRCT) scan,...
Setlakwe EL, Lemos KR, Lavoie-Lamoureux A, Duguay JD, Lavoie JP.The consequences on lung function and inflammation of alterations in the extracellular matrix affecting the peripheral airway wall in asthma are largely unknown. We hypothesized that remodeling of collagen and elastic fibers in the peripheral airway wall leads to airway obstruction and contributes to neutrophilic airway inflammation. Animals used were six heaves-affected horses and five controls. Large peripheral lung biopsies were obtained from horses with heaves in clinical remission (Baseline) and during disease exacerbation and from age-matched controls. The area of collagen and elastic fi...
Moens Y, Schramel JP, Tusman G, Ambrisko TD, Solà J, Brunner JX, Kowalczyk L, Böhm SH.The use of alveolar recruitment maneuvers during general anaesthesia of horses is a potentially useful therapeutic option for the ventilatory management. While the routine application of recruitments would benefit from the availability of dedicated large animal ventilators their impact on ventilation and perfusion in the horse is not yet well documented nor completely understood. Methods: A healthy 533 kg experimental horse underwent general anaesthesia in lateral recumbency. During intermittent positive pressure ventilation a stepwise alveolar recruitment maneuver was performed. Results: Anae...
González-Iglesias P, Scortti M, MacArthur I, Hapeshi A, Rodriguez H, Prescott JF, Vazquez-Boland JA.The pathogenic actinomycete Rhodococcus equi causes severe purulent lung infections in foals and immunocompromised people. Although relatively unsusceptible to R. equi, mice are widely used for in vivo studies with this pathogen. The most commonly employed mouse model is based on systemic (intravenous) infection and determination of R. equi burdens in spleen and liver. Here, we investigated the murine lung for experimental infection studies with R. equi. Using a 10(7)CFU intranasal challenge in BALB/c mice, virulent R. equi consistently survived in quantifiable numbers up to 10 days in the lun...
Dunowska M, Hardcastle MR, Tonkin FB.A 10-year-old polo mare presented with a history of weight loss, poor condition and inappetance. Results: The mare was tachycardic, tachypnoeic and febrile. Harsh lung sounds were auscultated over all lung fields. The mare initially responded to treatment with antibiotics, anti-inflammatory drugs and bronchodilators. Throughout the course of treatment, there was a variable lymphocytosis, monocytosis and fluctuation in concentrations of fibrinogen. The mare also developed a mild anaemia, most likely due to chronic disease. Despite treatment, the mare's condition deteriorated over the following ...
Williams KJ.Progressive lung fibrosis in humans, typified by idiopathic pulmonary fibrosis (IPF), is a serious cause of morbidity and mortality in people. Similar diseases have been described in dogs, cats, and horses. The cause and pathogenesis of such diseases in all species is poorly understood. There is growing evidence in human medicine that IPF is a manifestation of abnormal wound repair in response to epithelial injury. Because viruses can contribute to epithelial injury, there is increasing interest in a possible role of viruses, particularly gammaherpesviruses, in the pathogenesis of pulmonary fi...
de Lagarde M, Rodrigues N, Chevigny M, Beauchamp G, Albrecht B, Lavoie JP.Bronchospasm results in airway obstruction in horses with heaves. Atropine is the most potent bronchodilator drug currently available for horses, but is associated with side effects that limit its use. Like atropine, N-butylscopolammonium bromide (NBB) is an anticholinergic agent with bronchodilatory properties. Objective: To compare the bronchodilating effects and side effects of atropine and NBB in horses with heaves. Methods: Cross-over experiment using horses with heaves. Methods: Eight horses with heaves were administered atropine and NBB, using a cross-over design. Heart rate, pupillary ...
Diaz-Méndez A, Hewson J, Shewen P, Nagy E, Viel L.To develop a method for experimental induction of equine rhinitis A virus (ERAV) infection in equids and to determine the clinical characteristics of such infection. Methods: 8 ponies (age, 8 to 12 months) seronegative for antibodies against ERAV. PROCEDURES-Nebulization was used to administer ERAV (strain ERAV/ON/05; n = 4 ponies) or cell culture medium (control ponies; 4) into airways of ponies; 4 previously ERAV-inoculated ponies were reinoculated 1 year later. Physical examinations and pulmonary function testing were performed at various times for 21 days after ERAV or mock inoculation. Va...
Kaur N, Townsend H, Lohmann K, Marques F, Singh B.Rhodococcus equi establishes long-term pulmonary infection, survives in phagolysosomes of alveolar macrophages and causes pneumonia in foals. The failure of the foal to clear R. equi bacteria is believed to be due to its inability to produce IFN-γ and defects in Toll-like receptor(TLR) signaling. Lipid rafts sequester immune receptors such as TLRs and facilitate efficient cell signaling and therefore, a deficiency in accumulation of receptors in lipid rafts may result in failure to activate. We tested whether a Virulence Associated Protein A (VapA)/CpG vaccine against R. equi would impact the...
Hughes SB, Quan M, Guthrie A, Schulman M.The insulin-like growth factor system (insulin-like growth factor 1, insulin-like growth factor 2, insulin-like growth factor 1 receptor, insulin-like growth factor 2 receptor and six insulin-like growth factor-binding proteins) and insulin are essential to muscle metabolism and most aspects of male and female reproduction. Insulin-like growth factor and insulin play important roles in the regulation of cell growth, differentiation and the maintenance of cell differentiation in mammals. In order to better understand the local factors that regulate equine physiology, such as muscle metabolism a...
Bolfa P, Nolf M, Cadoré JL, Catoi C, Archer F, Dolmazon C, Mornex JF, Leroux C.EIA (Equine Infectious Anemia) is a blood-borne disease primarily transmitted by haematophagous insects or needle punctures. Other routes of transmission have been poorly explored. We evaluated the potential of EIAV (Equine Infectious Anemia Virus) to induce pulmonary lesions in naturally infected equids. Lungs from 77 EIAV seropositive horses have been collected in Romania and France. Three types of lesions have been scored on paraffin-embedded lungs: lymphocyte infiltration, bronchiolar inflammation, and thickness of the alveolar septa. Expression of the p26 EIAV capsid (CA) protein has been...
Depecker M, Richard EA, Pitel PH, Fortier G, Leleu C, Couroucé-Malblanc A.The aim of this study was to determine whether the lung side being sampled would significantly influence bronchoalveolar lavage (BAL) cytological profiles and subsequent diagnosis in Standardbred racehorses. One hundred and thirty-eight French Trotters in active training and racing were included in a prospective observational study. BAL was performed using videoendoscopy in both right and left lungs during summer meetings in 2011 (64 horses) and 2012 (74 horses). Cytological data performed 24h later from right and left lungs were compared and specifically used to classify horses as affected wi...
Williams KJ, Robinson NE, Lim A, Brandenberger C, Maes R, Behan A, Bolin SR.Gammaherpesviruses (γHV) are implicated in the pathogenesis of pulmonary fibrosis in humans and murine models of lung fibrosis, however there is little direct experimental evidence that such viruses induce lung fibrosis in the natural host. The equine γHV EHV 5 is associated with equine multinodular pulmonary fibrosis (EMPF), a progressive fibrosing lung disease in its natural host, the horse. Experimental reproduction of EMPF has not been attempted to date. We hypothesized that inoculation of EHV 5 isolated from cases of EMPF into the lungs of clinically normal horses would induce lung fibr...
Lohmann KL, Lopez AM, Manning ST, Marques FJ, Brownlie R, Allen AL, Sangster AE, Mutwiri G, Gerdts V, Potter A, Townsend HG.We evaluated the immunogenic and protective potential of a recombinant VapA/CpG oligodeoxynucleotide (ODN) 2395 vaccine in neonatal foals undergoing experimental Rhodococcus equi challenge. Foals (n = 8) were vaccinated by intramuscular injection on days 1 and 15 of the study; control foals (n = 7) received a phosphate-buffered saline (PBS) solution. All foals were challenged by intrabronchial administration of 5 × 10⁶ R. equi 103⁺ on day 29. Bronchoalveolar lavages were done on days 15, 29, and 36 and total cell count, differential cell count, rVapA-stimulated cell proliferation and inte...
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...
Montgomery JB, Hamblin B, Suri SS, Johnson LE, New D, Johnston J, Kelly J, Wilson DG, Singh B.Ischemia followed by reperfusion leads to release of toxic molecules into the circulation, and these molecules may cause injury in remote organs such as the lung. Horses commonly suffer from episodes of intestinal ischemia-reperfusion (IR) due to intestinal twisting/strangulation followed by repair. Because there is no evidence of lung injury associated with IR in horses, we designed a study to characterize the intestinal IR-associated lung inflammation and determine the effect of lidocaine on lung inflammation in IR horses. Lung tissues were collected from non-anesthetized (n=4) and anestheti...
Fultz L, Giguère S, Berghaus LJ, Davis JL.Current labelling for the use of ceftiofur crystalline free acid (CCFA) in horses states that 2 i.m. doses must be administered 4 days apart to provide 10 days of therapeutic coverage. A 10 day treatment regimen is not sufficient for the long-term treatment of horses with severe lung consolidation or pleuropneumonia. There are currently no data to guide an appropriate dosing interval when a longer treatment regimen is warranted. Objective: To determine steady-state plasma and pulmonary epithelial lining fluid (PELF) concentrations of desfuroylceftiofur acetamide (DCA) after weekly i.m. adminis...
Lascola KM, O'Brien RT, Wilkins PA, Clark-Price SC, Hartman SK, Mitchell MA.To qualitatively describe lung CT images obtained from sedated healthy equine neonates (≤ 14 days of age), use quantitative analysis of CT images to characterize attenuation and distribution of gas and tissue volumes within the lungs, and identify differences between lung characteristics of foals ≤ 7 days of age and foals > 7 days of age. Methods: 10 Standardbred foals between 2.5 and 13 days of age. Methods: Foals were sedated with butorphanol, midazolam, and propofol and positioned in sternal recumbency for thoracic CT. Image analysis software was used to exclude lung from nonlung str...
Stack A, Derksen FJ, Sordillo LM, Williams KJ, Stick JA, Brandenberger C, Steibel JP, Robinson NE.To determine the effects of 2 weeks of intense exercise on expression of markers of pulmonary venous remodeling in the caudodorsal and cranioventral regions of the lungs of horses. Methods: 6 horses. Methods: Tissue samples of the caudodorsal and cranioventral regions of lungs were obtained before and after conditioning and 2 weeks of intense exercise. Pulmonary veins were isolated, and a quantitative real-time PCR assay was used to determine mRNA expression of matrix metalloproteinase-2 and -9, tissue inhibitor of metalloproteinase-1 and -2, collagen type I, tenascin-C, endothelin-1, platelet...
Schwarz B, Klang A, Bezdekova B, Sárdi S, Kutasi O, Hoven R.Equine multinodular pulmonary fibrosis (EMPF), a progressive fibrosing interstitial lung disease has been associated with gammaherpesviruses. This case series describes five horses with EMPF. Three of the horses (two in Hungary, one in the Czech Republic) were diagnosed with EMPF ante mortem. They presented with typical clinical signs of EMPF including dyspnoea and weight loss. Arterial blood gas analysis revealed hypoxaemia. Blood work showed signs of inflammation like neutrophilia and hyperfibrinogenaemia. An endoscopic examination of the respiratory tract including cytology and culture of t...
Hermange T, Le Corre S, Bizon C, Richard EA, Couroucé A.Cytology of bronchoalveolar lavage fluid (BALF) from one lung may not predict findings in the contralateral lung of the same horse. The aim of this study was to determine whether a pooled BALF from both lungs was representative of corresponding individual samples. Fifty-one horses referred for poor performance and/or respiratory signs and for which a BALF was collected from both lungs, were included in the study. Cytology of pooled and individual BALF samples were performed using a masked protocol. Based on clinical signs and individual BALF cytologies, horses were classified as control (CTL),...
Blutke A, Hamel D, Hüttner M, Gehlen H, Romig T, Pfister K, Hermanns W.In Europe, cystic echinococcosis is rare in horses and is mostly diagnosed at slaughter or postmortem examination. Equine cystic echinococcosis can be caused by various Echinococcus taxa, but only Echinococcus equinus (the "horse strain") is known to produce fertile cysts. In Europe, E. equinus appears to be endemic in Great Britain, Ireland, Spain, and Italy and has sporadically been reported in Belgium and Switzerland. The present report describes the first case of a molecularly confirmed E. equinus infection in a horse foaled and raised in Germany. The 19-year-old mare was presented for exa...
Sorenson PR, Robinson NE.Quasi-static pressure-volume curves and single-breath nitrogen washouts were performed simultaneously on eight anesthetized horses (average body wt = 485 kg) in left lateral, right lateral, prone, and supine postures (sequence randomized). The shift from prone to lateral or supine posture decreased expiratory reserve volume (ERV), vital capacity (VC), residual volume (RV), functional residual capacity (FRC), and total lung capacity (TLC); RV and FRC expressed as %TLC were unchanged, suggesting that in the lateral and supine postures a significant portion of the lung volume was not recruited by...
Cornelisse CJ, Robinson NE, Berney CE, Kobe CA, Boruta DT, Derksen FJ.Although the efficacy of dexamethasone for the treatment of recurrent airway obstruction (RAO) has been documented, the speed of onset of effect and duration of action are unknown, as is the efficacy of orally administered dexamethasone with or without fasting. Objective: To document the time of onset of effect and duration of action of a dexamethasone solution i.v. or orally with and without fasting. Methods: Protocol 1 used 8 RAO-affected horses with airway obstruction in a crossover design experiment that compared the effect of i.v. saline and dexamethasone (0.1 mg/kg bwt) on pulmonary func...
Pirie RS, McLachlan G, McGorum BC.Currently, heaves is investigated by exposing susceptible horses to dusty hay. Consequently, the response will be dependent on the organic dust content and composition of the hay. It was hypothesised that the use of a hay dust suspension (HDS) would reduce the variability of the challenge and therefore standardise experimental protocols. Furthermore, analysis of HDS would also permit further investigation of the organic dust components responsible for the response. Three hay dust suspensions (HDS-1, 2 and 3) were prepared for use in the diagnosis and investigation of heaves. HDS were produced ...
Desjardins I, Theoret C, Joubert P, Wagner B, Lavoie JP.Airway remodeling may play an important role in heaves pathophysiology. Transforming growth factor-beta 1 (TGF-beta1) is a potent profibrotic cytokine, which might contribute to airway wall thickening and fibrosis of bronchiolar and alveolar submucosa. An ELISA designed for the measurement of human TGF-beta1 was used to measured total TGF-beta1 released in bronchoalveolar lavage fluid (BALF) of normal horses and of those affected with heaves in remission. The specificity of the assay for TGF-beta1 of the horse was confirmed using recombinant equine TGF-beta1. The influence of hay exposure on T...
Dixon PM, Railton DI, McGorum BC.Examination of historical and clinical details of 270 adult horses suffering from a variety of mainly chronic pulmonary diseases showed that the chronic obstructive pulmonary disease (COPD) group (median age 9 years) were the oldest, and that the COPD, chronic idiopathic hypoxaemia and exercise induced pulmonary haemorrhage (EIPH) groups had the longest duration of disease (median durations 7, 12 and 9 months, respectively) with a median disease duration of 2 months for the remaining horses. A history of antecedent respiratory infection was present in 24.3% of all horses. Six out of 12 horses ...
Mainguy-Seers S, Picotte K, Lavoie JP.Tamoxifen, a selective estrogen receptor modulator, decreased airway neutrophilia and improved clinical signs in an experimental model of equine asthma, and induced neutrophilic apoptosis in vitro. Objective: Tamoxifen reduces airway neutrophilia and improves lung function in severe asthmatic horses. Methods: Twelve severe asthmatic horses from a research herd. Methods: Randomized controlled blinded study design. The effects of a 12-day oral treatment with tamoxifen (0.22 mg/kg, q24h) or dexamethasone (0.06 mg/kg, q24h) on lung function, endoscopic tracheal mucus score and bronchoalveolar ...
Deaton CM, Deaton L, Jose-Cunilleras E, Vincent TL, Baird AW, Dacre K, Marlin DJ.Equine recurrent airway obstruction (RAO) has been used as a naturally occurring model of human asthma. However, it is unknown whether there is an early-phase response in RAO. The aim of this study was to determine whether exposure to organic dust induces immediate changes in lung function in RAO-affected horses, which could be mediated by airway mast cells. Six RAO-affected horses in remission and six control horses were challenged with hay-straw dust suspension by nebulization. Total respiratory resistance at 1 Hz, measured by forced oscillation, was increased from 0.62 +/- 0.09 cmH(2)O.l(-1...
Perkins GA, Viel L, Wagner B, Hoffman A, Erb HN, Ainsworth DM.In diagnosing inflammatory airway disease (IAD) in performance horses, a histamine bronchoprovocation (HBP) test is often performed. In previously published studies, HBP is usually undertaken prior to cytological examination of the bronchoalveolar lavage (BAL) cells. The purpose of this study was to determine if HBP alters (1) the total nucleated cell numbers and distribution in BAL fluid (BALF) and (2) the mRNA and protein concentrations of selected cytokines in BAL cells and BALF, respectively. BALF was initially collected endoscopically from the right middle or diaphragmatic lung lobe in ei...
Lakritz J, Wilson WD, Berry CR, Schrenzel MD, Carlson GP, Madigan JE.Twenty-three foals, between 1 and 7 months old, with signs of acute respiratory distress, were examined at the Veterinary Medical Teaching Hospital (VMTH), University of California, Davis, between 1984 and 1989. Characteristic features included sudden onset of severe respiratory distress and tachypnea, cyanosis unresponsive to nasal oxygen, pyrexia, hypoxemia, hypercapneic respiratory acidosis, poor response to treatment, and histopathologic lesions of bronchiolitis and bronchointerstitial pneumonia. Seven of the 23 foals were normal before the onset of respiratory distress, 3 foals were found...
Diaz-Méndez A, Hewson J, Shewen P, Nagy E, Viel L.To develop a method for experimental induction of equine rhinitis A virus (ERAV) infection in equids and to determine the clinical characteristics of such infection. Methods: 8 ponies (age, 8 to 12 months) seronegative for antibodies against ERAV. PROCEDURES-Nebulization was used to administer ERAV (strain ERAV/ON/05; n = 4 ponies) or cell culture medium (control ponies; 4) into airways of ponies; 4 previously ERAV-inoculated ponies were reinoculated 1 year later. Physical examinations and pulmonary function testing were performed at various times for 21 days after ERAV or mock inoculation. Va...
Klein HJ, Deegen E.After inhalation of increased concentrations of histamine solutions, equids had a decrease in dynamic compliance (Cdyn) and an increase in airway resistance, work of breathing, and maximum intrathoracic differences in pressure. Because the change in Cdyn correlated best with the inhaled histamine concentrations, airway reactivity was assessed by the decrease in Cdyn. With the use of linear regression, histamine concentrations were calculated; this resulted in a 35% reduction of Cdyn and these concentrations were defined as 35% provoking concentration Cdyn. The histamine inhalation provocation ...
Gehr P, Erni H.The lungs of two half-bred geldings were fixed in situ by instillation of a glutaraldehyde solution into the airways during deep anaesthesia. The body weight of both animals was 510 kg and their average lung volume about 38 l. Stratified random samples from 22 regions were morphometrically analysed from electron microscopic films. Eighty-six per cent of the total lung volume was gas exchange parenchyma. It contained 26.9 l air space and 5.6 l interalveolar septa which were composed of equal parts of capillaries and tissue. The average alveolar and capillary surface areas were 2457 m2 and 1663 ...
Lascola KM, O'Brien RT, Wilkins PA, Clark-Price SC, Hartman SK, Mitchell MA.To qualitatively describe lung CT images obtained from sedated healthy equine neonates (≤ 14 days of age), use quantitative analysis of CT images to characterize attenuation and distribution of gas and tissue volumes within the lungs, and identify differences between lung characteristics of foals ≤ 7 days of age and foals > 7 days of age. Methods: 10 Standardbred foals between 2.5 and 13 days of age. Methods: Foals were sedated with butorphanol, midazolam, and propofol and positioned in sternal recumbency for thoracic CT. Image analysis software was used to exclude lung from nonlung str...
Derksen FJ, Williams KJ, Pannirselvam RR, de Feijter-Rupp H, Steel CM, Robinson NE.Regional veno-occlusive remodelling of pulmonary veins in EIPH-affected horses, suggests that pulmonary veins may be central to pathogenesis. The current study quantified site-specific changes in vein walls, collagen and haemosiderin accumulation, and pleural vascular profiles in the lungs of horses suffering EIPH. Objective: In the caudodorsal lung regions of EIPH-affected horses, there is veno-occlusive remodelling with haemosiderosis, angiogenesis and fibrosis of the interstitium, interlobular septa and pleura. Methods: Morphometric methods were used to analyse the distribution and accumula...
Christmann U, Livesey LC, Taintor JS, Waldridge BM, Schumacher J, Grier BL, Hite RD.Lung surfactant function and composition are varied and adapted to the specific respiratory physiology of all mammalian species. Objective: Lung surfactant function and composition are different in neonatal foals as compared to adult horses. Methods: Six adult horses, 7 term foals (<24 hours old), and 4 premature foals were used. Animals were part of the Auburn University teaching herd except for 3 client-owned premature foals. Methods: Bronchoalveolar lavage fluid (BALF) was obtained from all animals. Ultracentrifugation of cell-free BALF separated surfactant into crude surfactant pellets ...
Sweeney CR, Rossier Y, Ziemer EL, Lindborg SR.Bronchoalveolar lavage (BAL) was performed on 16 horses to determine whether it caused local or diffuse inflammation in the lungs. In 7 horses, BAL was performed in both lungs twice, 48 hours apart. Although total cell counts of the BAL samples did not change significantly, there were increased numbers and percentage of neutrophils in the second lavage fluid samples. In 5 horses, BAL was performed in 1 lung and repeated 48 hours later in the same lung and in the corresponding airway in the contralateral lung. The absolute cell count and percentage of neutrophils were significantly (P = < 0....
Fairbairn SM, Page CP, Lees P, Cunningham FM.Previous studies have shown that bronchoalveolar lavage fluid from horses with allergic respiratory disease and showing clinical symptoms contains increased numbers of neutrophils. In some cases, the eosinophil count is also increased. In this study the time course of changes in lung function and the accumulation of radiolabelled leucocytes and platelets in the lungs of allergic and normal horses has been examined during a 7 hr allergen exposure. Antigen challenge had no effect on pleural pressure or the distribution of radiolabelled neutrophils, eosinophils or platelets in normal horses. In c...
Nevalainen M, Raulo SM, Brazil TJ, Pirie RS, Sorsa T, McGorum BC, Maisi P.We report the effects of mouldy hay/straw exposure, inhaled hay dust suspension (HDS) and inhaled lipopolysaccharide (LPS) on bronchoalveolar lavage fluid (BALF) gelatinolytic matrix metalloproteinase (MMP) levels and degree of activation in healthy (n = 6) and heaves- (previously termed chronic obstructive pulmonary disease) affected (n = 6 or 7) horses. Gelatinolytic MMPs in BALF were quantified by zymography, and gelatinases were shown by Western immunoblotting to be MMP-2 and MMP-9. Hay/straw and HDS challenges increased BALF total gelatinolytic activity only in heaves horses, with the maj...
Léguillette R, Désévaux C, Lavoie JP.To determine the effects of pentoxifylline (PTX) administration on lung function and results of cytologic examination of bronchoalveolar lavage fluid in horses affected by recurrent airway obstruction (RAO). Methods: 10 RAO-affected horses. Methods: 6 horses were orally administered PTX (16 g) mixed with corn syrup, and 4 horses were administered corn syrup alone, twice daily for 14 days. Pulmonary function was evaluated before administration (day 0) and on days 8 and 15. Bronchoalveolar lavage (BAL) was performed on days 0 and 15. Reversibility of airway obstruction was assessed by measuring ...
Ito S, Hobo S, Eto D, Sato H.To evaluate a hypothese that use of bronchoalveolar lavage (BAL) for early treatment of pneumonia would improve their prognosis by reducing bacterial numbers and excessive numbers of neutrophils in the lung, initial experiences with BAL in the diagnosis and treatment of pneumonia were performed in 36 racehorses that became ill within 24 hr of long distance travel (1,200-1,600 km, 26-32 hr) by road. Comparisons were made of the outcomes of the 36 horses and those of 42 horses (81.0% recovered, 50.0% returned to racing) treated for transport associated pneumonia without BAL. The total amount of ...
Mainguy-Seers S, Vargas A, Labrecque O, Bédard C, Hélie P, Lavoie JP.Neutrophilic inflammation is believed to contribute to the airway obstruction and remodelling in equine asthma. Azithromycin, an antibiotic with immunomodulatory properties, reduces pulmonary neutrophilia and hyper-responsiveness in human asthmatics and decreases airway remodelling in rodent models of asthma. It was therefore hypothesised that azithromycin would improve lung function, mucus accumulation and central airway remodelling by decreasing luminal neutrophilia in severe equine asthma. The effects of a 10-day treatment with either azithromycin or ceftiofur, an antimicrobial without immu...
Mainguy-Seers S, Lavoie JP.Despite substantial research efforts to improve the treatment and outcome of horses with asthma, glucocorticoids (GC) remain the cornerstone of drug treatment of this prevalent disease. The high efficacy of GC to relieve airway obstruction explains their extensive use despite potential deleterious effects. However, much is yet to be uncovered concerning GC use in horses with asthma, including the comparative efficacy of the different drugs, the determination of minimal effective doses and the mechanisms underlying their variable modulation of airway inflammation. The objectives of this structu...
Secombe C, Waldmann AD, Hosgood G, Mosing M.Electrical impedance tomography (EIT) generates thoracic impedance images of the lungs and has been used to assess ventilation in horses. This technique may have application in the detection of changes in airflow associated with equine asthma. Objective: The objective was to determine if histamine-induced airflow changes observed with flowmetric plethysmography (Δflow) could also be explained using global and regional respiratory gas flow signals calculated from EIT signals. Methods: Experimental in vivo study. Methods: Six horses, sedated using detomidine were fitted with a thoracic EIT b...
Anderson SL, Singh B.Horses are susceptible to a multitude of inflammatory conditions that are characterized by a strong neutrophilic response. Here, we review basic equine neutrophil biology and explore the role of neutrophils in inflammatory conditions with emphasis on intestinal ischemia and reperfusion injury and lung inflammation. In addition, unique aspects of equine neutrophil biology have been highlighted. Neutrophils comprise the highest proportion of circulating white blood cells in equine blood. The concentration of circulating equine neutrophils is a primary indicator of systemic inflammation. Addition...
Borland C, Dunningham H, Bottrill F, Vuylsteke A.To model lung nitric oxide (NO) and carbon monoxide (CO) uptake, a membrane oxygenator circuit was primed with horse blood flowing at 2.5 l/min. Its gas channel was ventilated with 5 parts/million NO, 0.02% CO, and 22% O2 at 5 l/min. NO diffusing capacity (Dno) and CO diffusing capacity (Dco) were calculated from inlet and outlet gas concentrations and flow rates: Dno = 13.45 ml.min(-1).Torr(-1) (SD 5.84) and Dco = 1.22 ml.min(-1).Torr(-1) (SD 0.3). Dno and Dco increased (P = 0.002) with blood volume/surface area. 1/Dno (P < 0.001) and 1/Dco (P < 0.001) increased with 1/Hb. Dno (P = 0.01...
Lavoie JP, Fiset L, Laverty S.A retrospective study of 40 horses with primary lung abscesses without pleuropneumonia showed that lung abscesses occurred predominantly in young horses, usually in foals aged < or = 6 months. Hyperfibrinogenaemia was present in all but 2 horses, and other common clinical and haematological findings were hyperthermia, tachycardia, polypnoea, and neutrophilic leucocytosis. The most common bacterial species isolated from transtracheal aspirates were Streptococcus zooepidemicus (20/34) and Rhodococcus equi (13/34). Most horses (23/27) discharged from the hospital were long term survivors. Of t...
Simonen-Jokinen T, Pirie RS, McGorum BC, Maisi P.Airway matrix metalloproteinases (MMPs) increase following inhalation of organic dust. The relative contribution of dust components to this elevation is unknown. Objective: To identify components of organic dust responsible for elevated MMP levels in equine airways. Methods: Bronchoalveolar lavage (BALF) from 7 heaves-susceptible horses, collected 6 h following inhalation challenges with saline, 2 different hay dust suspensions (HDS-1 and -2) and soluble and particulate fractions of HDS-1, were analysed for MMP-2 and -9 using SDS-page gelatin zymography. Results: HDS-1 challenge increased BALF...
