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.
Raïsky C, Vives BM, Leduc L, Symoens A, Tavanaeimanesh H, Richard H, Juette T, Bédard C, Leclère M.Steaming hay reduces respirable particles and is commonly used to feed horses with asthma. However, it showed inconsistent benefits in clinical studies. Objective: (1) To assess the effects of steamed hay on lung function and airway inflammation in horses with severe equine asthma (SEA) in remission; (2) To compare these effects with a dry hay diet. Methods: Cross-over in vivo experiment. Methods: Horses were fed steamed and dry hay for 4 weeks in a prospective, cross-over study, with a 4-week washout period. Lung function, bronchoalveolar lavage (BALF) cytology, and a 23-point weighted clin...
Berghaus LJ, Venner M, Helbig H, Hildebrandt D, Hart K.Rhodococcus equi causes pneumonia in young foals, but disease susceptibility and severity vary. Cortisol and vitamin D modulate immune responses and cytokine production during bacterial infection, and altered concentrations are associated with sepsis in neonatal foals. We hypothesised an age and disease effect on circulating steroid hormone concentrations in foals, and that differences in cytokines and steroid hormone concentrations would predict disease severity in pneumonic foals. Objective: To investigate circulating concentrations of various cytokines, cortisol and vitamin D as predictors ...
Andrews KM, Berghaus LJ, Hart KA.Equine Asthma Syndrome (EAS) is a chronic inflammatory respiratory disease of adult horses. While dietary polyphenols have shown anti-inflammatory effects in human asthma, their use in equine asthma has not been studied. Objective: To evaluate the effects of a mixed polyphenol supplement on systemic and pulmonary inflammation, bronchoalveolar lavage (BAL) cytology, and clinical respiratory signs in healthy and asthmatic horses. We hypothesized that polyphenol supplementation would decrease systemic and pulmonary inflammation in both healthy and asthmatic horses and would improve BAL cytology a...
Bozzola C, Sala G, Stancari G, Ferrucci F, Zucca E.Exercise-Induced Pulmonary Hemorrhage (EIPH) results from alveolar capillary stress failure after strenuous exercise, leading to bleeding and pulmonary inflammation. Bronchoalveolar lavage fluid (BALF) cytology is considered the gold standard for the assessment of airway inflammation; however, it is often considered more invasive compared to tracheal wash (TW). It has been demonstrated that TW is a reliable diagnostic tool that may substitute BALF to diagnose and grade the severity of EIPH in racehorses; however, no information about airway inflammation in EIPH-affected horses has been reporte...
Čebulj-Kadunc N, Frangež R, Kruljc P.The aim of the study was to determine the fluctuations of selected physiological parameters in young Lipizzan stallions ( = 10) during the initial phase of their training as indicators of adaptation to a graded exercise load and stress exposure. For this purpose, four exercise tests (ExT) with lunging were carried out over a period of one year. Physiological parameters (gait speed, heart and respiratory rate (HR and RR), rectal and body surface temperature (RT and BST), and cortisol and lactate concentration (CORT and LAC)) were measured before and after training. In all ExT, gait speeds incre...
Hopster K, Soares JHN, Levine D, Ortved K, Driessen B, Araos J.Flow-controlled expiration (FLEX) has been shown to significantly enhance oxygenation in horses under laboratory conditions. Objective: This study aims to corroborate these findings by evaluating the effects of FLEX on gas exchange in a randomised clinical trial involving a large population of clinical horses undergoing orthopaedic surgery. Methods: Prospective randomised clinical trial. Methods: A total of 406 healthy adult horses scheduled for elective orthopaedic procedures were recruited for this prospective clinical trial. Horses were randomly assigned to FLEX or VCV (volume-controlled ve...
Lendl L, Wirth C, Merle R, Barton AK.Mild-moderate equine asthma (MEA) is a very common but underdiagnosed pulmonary disease in horses, with mild cases not showing clinical respiratory signs. This study evaluates the influence of a standardized lunging exercise test (SLET) on bronchoalveolar lavage fluid (BALF) cytology in MEA horses. We hypothesized that SLET would increase the total nucleated cell count (TNCC) and/or percentages of inflammatory cells associated with EA. In a prospective, randomized, non-blinded, between-subjects study design of two independent groups, 39 horses (17 mild and 22 moderate) were included. They were...
Dlugopolska D, Siwinska N, Noszczyk-Nowak A.Asthma is a multifactorial respiratory disease that naturally occurs in horses, humans, and cats, presenting common clinical signs and species-specific mechanisms. This review addresses the impact of asthma on the cardiovascular and neurological systems, with a primary focus on horses. It highlights the need for new biomarkers beyond the respiratory system due to diagnostic difficulties in animals. A comprehensive literature search was conducted using PubMed and Google Scholar, focusing on cardiovascular and neurological manifestations of asthma in humans, horses, cats, and experimental animal...
Wenzel CJ, Mochal-King CA, Eddy AL, Bowser JE, Wills RW, Jumper WI, Claude A, Swiderski CE.The aim of this retrospective clinical study was to assess surgical duration and surgical and post-operative complications associated with Video-Assisted Thoracoscopic Surgery (VATS) and lung biopsy in horses with severe Equine Pasture Asthma (EPA) and paired control horses. Twelve horses (6 EPA-affected, 6 control) were sex, age and breed matched. Twenty-four thoracic surgeries were performed. Surgery of each matched pair (EPA-affected and healthy) was performed during asthma exacerbation (summer) and remission (winter). Surgical times were shorter with uncomplicated thoracoscopy (85 min) and...
Iduu NV, Raiford D, Cohen ND, Landrock KK, Wang C.We developed a fluorescence resonance energy transfer (FRET)-based real-time PCR (qPCR) assay coupled with high-resolution melting (HRM) analysis to differentiate subsp. (SEE) from subsp. (SEZ), two closely related equine pathogens with distinct clinical implications. The assay targets a region of the 23S rRNA gene containing single-nucleotide polymorphisms that differentiate the subspecies. By combining subspecies-specific probes with melting temperature () analysis, the assay accurately distinguished SEE, SEZ, and mixed infections without the need for post-PCR processing. The entire work...
Drespling J, Berwanger L, Kühn H, Schwarz B, Doherr M, Mundhenk L.Mucus parameters are hallmark diagnostic features of equine asthma (EA). Objective: To investigate the relationship between mucus quantity score and mucus viscosity score with signalment, history, clinical findings and cytological parameters. Methods: Retrospective cross-sectional study. Methods: Mucus quantity and viscosity scores, signalment, history and clinical findings recorded for diagnostic purposes from up to 1599 samples, and cytological values of the corresponding bronchoalveolar lavage fluid (BALF) and tracheobronchial secretions were analysed. The cut-off value of a mucus quantity ...
Haase L, Winter J, Grummt S, Sedlmayr M, Sedlmayr B.Many people seek health-related information online, not only for themselves but also on behalf of others who cannot articulate their symptoms. This proxy information-seeking behavior is particularly relevant for animal owners, who must interpret their animals' symptoms without direct verbal feedback. While online health information-seeking in the context of one's own health is well-studied, the specific challenges of searching by proxy, especially for animal health information, remain largely unexplored. Unassigned: This study aimed to determine the specific information needs and search behavi...
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...
Gomes C, Coheur L, Tilley P.Equine asthma is a prevalent respiratory disease that negatively impacts horses' health and athletic performance. Traditional diagnostic methods are invasive and require specialised equipment. There is a need for a non-invasive, cost-effective screening tool that can be used by veterinarians and horse handlers in ambulatory settings. Objective: To assess the willingness of veterinarians and horse handlers to adopt such a tool (Questionnaire 1) and the challenges associated with visually recognising equine asthma (Questionnaire 2) and to develop EquiBreathe, an artificial intelligence (AI)-powe...
Hildebrandt D, Venner M, Hart KA, Berghaus L.Early and specific diagnosis of bronchopneumonia in foals is important to prevent severe disease. In human medicine, C-reactive protein (CRP) and interleukin-6 (IL-6) are important diagnostic and prognostic biomarkers in neonatal pneumonia in other species. Evaluation of these markers in foals with naturally occurring respiratory diseases is lacking. Objective: To determine if CRP and IL-6 were useful predictors of respiratory disease in foals from birth to weaning. Methods: Prospective cohort study. Methods: Periodic blood samples from 200 initially healthy foals were collected from birth to ...
Gonzalez-Obando J, Jaimes-Dueñez J, Zuluaga-Cabrera A, Forero JE, Diaz A, Rojas-Arbeláez C, Ruiz-Saenz J.Equine influenza is a highly contagious disease caused by the equine influenza virus (EIV). The occurrence of EIV outbreaks in America is associated with low levels of vaccination coverage. In Colombia, no seroprevalence evaluation has been carried out to estimate the distribution of the virus within the country. Our aim was to perform a sero-epidemiological survey of equine influenza infections and to identify associated risk factors in horses from four departments of Colombia. Serological testing was carried out by using an ELISA for the detection of IgG antibodies against the influenza A vi...
Strand E, Vermedal H, Olsen HMB, Fjordbakk CT, Fretheim-Kelly ZL.Clinical evaluation of alar fold (AF) collapse is presently based upon subjective evaluation of improvement in breathing and respiratory noise after suturing the AFs dorsally. Objective: To evaluate use of nasopharyngeal airway pressure (NAP) as an objective method of assessing for the presence of AF collapse during exercise. NAPs should also potentially provide a precise means to grade the degree of airway obstruction present and response to surgical treatment. Methods: Prospective clinical study of actively racing Standardbred horses. Methods: Standardbreds undergoing this test were outfitte...
Albornoz A, Morales B, Fernandez VB, Henriquez C, Quiroga J, Alarcón P, Moran G, Burgos RA.Equine asthma is a chronic respiratory disease characterised by neutrophilic inflammation, airway hyperresponsiveness, and impaired pulmonary function. Obesity, increasingly prevalent among domestic horses, has been identified as a potential risk factor for exacerbating inflammatory conditions. This study aimed to explore whether obesity modifies neutrophil metabolism and inflammatory responses in horses affected by asthma. Six asthmatic horses in clinical remission were categorised into two groups: obese and non-obese, based on body condition score. Serum levels of interleukin-1β (IL-1β) an...
Al Shehab G, Naji R, Alali F, Alali A, Allowaim A, Almohammed A, Aljasim D, Alkhalifah A, Alhammad YMA, Marzok M, Mohamad ZA, Almuhanna AH.The equine larynx can be affected by a variety of diseases that may interfere with upper respiratory tract patency. Laryngeal hemiplegia is a well-known disease in large-sized equine breeds and its occurrence in Arabian horses has not been thoroughly investigated. Unassigned: To endoscopically assess arytenoid movements in pure Arabian horses. Unassigned: A total number of 38 pure Arabian horses were examined. When the horse was unsedated, the laryngeal arytenoid movement was assessed using a laryngoscope, and a grading score was assigned accordingly. Unassigned: Evidence of laryngeal movement...
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...
Rossi HS, Mykkänen AK, Teppo AM, Junnila JJT, Hyytiäinen HK.Pneumonia is a common condition in young, hospitalized foals, causing accumulation of inflammatory secretions to the airways. In humans, respiratory physiotherapy is commonly used as a supplementary treatment for pneumonia with varying results regarding its efficacy, but the efficacy in foals has not been assessed to date. Objective: This study aimed to evaluate the safety and efficacy of respiratory physiotherapy as a supplementary therapy method for young foals with pneumonia. Methods: A total of 44 foals with pneumonia aged under a month were used. The prospective intervention group receivi...
Vicenti C, Cercone M, Nieman G, Habashi NM, Andrews P, Satalin J, Velarde P, Mitchell KJ, Louie EW, Albano V, Ali H, King A, Staffieri F, Gleed R....To compare early versus late time-controlled adaptive ventilation (TCAV) for setting airway pressure release ventilation (APRV) on arterial oxygenation in dorsally recumbent anesthetized horses. Methods: A crossover, nonrandomized, experimental study. Methods: Six healthy adult horses. Methods: Each horse underwent two anesthetics: 1) volume-controlled ventilation (VCV) began for 30 minutes before switching to APRV using the TCAV method (late TCAV, TCAV); and 2) ventilation began immediately with TCAV (early TCAV, TCAV). The study lasted 180 minutes, with arterial blood gases and respiratory m...
Legere RM, Ott JA, Poveda C, Vanover D, Borba KER, Yeon Joo J, Martin CL, da Silveira BP, Bray JM, Landrock K, Wright GA, Blazier JC, Hillhouse AE....Inhalation of Rhodococcus equi causes severe pneumonia in humans and animals worldwide, most commonly affecting horse foals. The standard for preventing R. equi pneumonia in foals is transfusion of hyperimmune plasma, which is expensive and carries the risk of adverse effects. Our goal was to passively immunize foals against R. equi by nebulizing mRNA encoding an equine monoclonal antibody (mAb) against the virulence-associated protein A (VapA) directly into the lungs. VapA-specific memory B cells from an immunized horse were used to identify and select the sequence for an equine immunoglobuli...
Bannai H, Kambayashi Y, Kume K, Takebe N, Endo Y, Kawanishi N, Nemoto M, Tsujimura K.The endemic situation of respiratory disease caused by equine herpesvirus type-1 (EHV-1) and type-4 (EHV-4) was investigated in a training facility for Thoroughbred yearlings in Japan. Vaccination typically starts in mid-September or early October-only after all yearlings have arrived-leaving those introduced earlier unprotected. To bridge this immunity gap, a revised vaccination program that started earlier was implemented. In 2021-2022 and 2022-2023, yearlings were allocated to three groups according to their introduction dates. Each group received a live EHV-1 vaccine (Equi N Tect ERP, Niss...
van Maanen K, van den Wollenberg L, de Haan T, Frippiat T.Monitoring infectious diseases is essential for safeguarding equine health and ensuring the sustainability of the horse industry. In 2019, the Royal Veterinary Association of the Netherlands (KNMvD) and Royal GD (GD Animal Health) launched SEIN (Surveillance of Equine Infectious diseases in the Netherlands), a voluntary surveillance system for laboratory-confirmed outbreaks of equid alphaherpesvirus 1 (EHV-1), equid alphaherpesvirus 4 (EHV-4), equine influenza virus (EIV), and subsp. . This retrospective study analyzed 364 confirmed outbreaks reported through SEIN between June 2019 and April ...
Alves LSS, Hasuda AL, Giordano LGP, Frederico I, Dos Santos IH, Pereira PFV, Lisbôa JAN, Flaiban KKMDC.This study investigated isolation of equine neutrophils and the assessment of their antioxidant function using the nitroblue tetrazolium (NBT) reduction test, an indicator of reactive oxygen species (ROS) activation. The objective was to test the viability of neutrophils isolated from equine whole blood and their ability to undergo respiratory burst, comparing the results with whole blood. The hypothesis tested was that isolation of equine neutrophils allows for effective functional evaluation, even after isolation process, with no significant differences between whole blood and isolated cells...
Mrzdovnik N, Babič J, Lužnik D, Žigon D, Mrzdovnik M, Tavčar-Kalcher G, Tomič V, Prescott JF, Vengust M.Several bacteria associated with chronic lung pathology use quorum sensing (QS) signaling molecules to regulate their virulence in pure cultures and poly-microbial communities. Their excessive growth and biofilm formation in the respiratory tract increase the morbidity and mortality of inflammatory airway diseases in humans, such as chronic obstructive pulmonary disease (COPD), asthma and cystic fibrosis (CF). In horses, severe equine asthma (SEA) has many parallels to these human diseases. We hypothesized that QS molecules associated with the most common biofilm-forming lung pathogens in huma...
Jimenez C, Hogan P, Belaghi R, Curtiss A.Epiglottitis is an uncommon upper airway pathology manifested endoscopically by mucosal oedema, reddening and thickening of the epiglottic mucosa. Literature on epiglottitis in horses is sparse. Objective: To describe the diagnosis, treatment and outcome of Thoroughbred and Standardbred racehorses diagnosed with epiglottitis at a single centre. A secondary objective is to demonstrate the efficacy of inhaled and topical anti-inflammatories for this condition. Methods: Retrospective case series. Methods: Medical records (2009-2023) were reviewed for racehorses treated for epiglottitis. Data coll...
James K, Chappell DE, Craig B, Pariseau C, Wright C, van Harreveld P, Barnum S, Pusterla N.The purpose of this study was to determine any associations of EHV-2, EHV-5, and dual infection with EHV-2/-5 with demographic parameters, clinical signs, and coinfection with other common respiratory pathogens. Nasal swabs collected from 9737 horses were tested for EHV-2 and EHV-5, as well as EHV-1, EHV-4, EIV, , ERAV, and ERBV, by qPCR. Clinical signs and demographic parameters were recorded, and prevalence factors were evaluated for significance regarding EHV-2 and/or EHV-5 infection. Out of the 9737 horses in this study, 17.8% tested EHV-2-positive ( = 1731), 15.8% tested EHV-5-positive ( ...
Himmele M, Engl JPM, Schwarz BC.The present report describes an 8-week-old warmblood foal presented following two episodes of epistaxis. The foal had a history of an umbilical infection, which had been treated with antibiotics when it was 8 days old. Four days before admission the filly showed severe, self-limiting epistaxis. The second hemorrhage occurred on the day of admission. The foal was lethargic and the remainder of the clinical examination unremarkable. A latero-lateral radiograph of the head revealed a fluid line within the guttural pouch. Endoscopy showed large amounts of blood within the pharynx and the upper thi...
Newton JR, Daly JM, Spencer L, Mumford JA.Between March and May 2003, equine influenza virus infection was confirmed as the cause of clinical respiratory disease among both vaccinated and unvaccinated horses of different breeds and types in at least 12 locations in the UK. In the largest outbreak, 21 thoroughbred training yards in Newmarket, with more than 1300 racehorses, were affected, with the horses showing signs of coughing and nasal discharge during a period of nine weeks. Many of the infected horses had been vaccinated during the previous three months with a vaccine that contained representatives from both the European (A/eq/Ne...
Wood JL, Newton JR, Chanter N, Mumford JA.Respiratory disease is important in horses, particularly in young Thoroughbred racehorses, and inflammation that is detected in the trachea and bronchi (termed inflammatory airway disease [IAD]) is more significant in this population in terms of impact and frequency than other presentations of respiratory disease. IAD, which is characterized by neutrophilic inflammation, mild clinical signs, and accumulation of mucus in the trachea, may be multifactorial, possibly involving infections and environmental and immunological factors, and its etiology remains unclear. This 3-year longitudinal study ...
Hotchkiss JW, Reid SW, Christley RM.Information is scarce as to how horses are kept and managed in the general horse population of Great Britain. Objective: To characterise the demographics of horses in Great Britain and assess their care (with particular reference to the respiratory system). Methods: Horse owners were surveyed using a self-administered postal questionnaire. These owners were selected randomly, following geographical stratification, using 2-stage cluster sampling of veterinary practices and their clients. Results: The overall response proportion to the survey was 68.2%. An investigation of nonresponse bias detec...
Cohen ND.A prospective study was conducted to describe the causes of and farm management factors associated with disease and death in a population of foals in Texas. Data from 2,468 foals at 167 farms were provided by veterinarians for all 12 months during 1991. Among 2,468 foals, 116 deaths were reported (4.7%). Pneumonia was the most commonly reported cause of death, followed by septicemia. When considered as a group, musculoskeletal disorders (traumatic, infectious, or deforming problems) represented the most common cause of all reported deaths. Daily risk of death was greatest during the first 7 da...
Hoffman AM.Bronchoalveolar lavage (BAL) is a method for the recovery of respiratory secretions that line the peripheral airways and alveoli. Overall, BAL is considered very safe and sufficiently sensitive to detect inflammation at the cytologic level. The good correlation between BAL differential cell counts and exercise-induced hypoxemia or lactic acidosis, airway obstruction, or airway responsiveness attests to the relevance of BAL cytology to the structure and function of the equine airways. Thus, an important advantage of BAL over tracheal wash cytology is that BAL cytology relates well to the clinic...
Paillot R, Hannant D, Kydd JH, Daly JM.Equine influenza virus is a leading cause of respiratory disease in the horse. Equine influenza vaccines containing inactivated virus were first developed in the 1960s. Despite their intensive use, equine influenza outbreaks still continue to occur and therefore new strategies of vaccination are necessary to improve vaccine efficacy. Numerous methods of vaccination have been evaluated and commercialised in the horse, the most recent being the cold-adapted influenza virus and poxvirus-based vaccines. As a large animal model, the horse is also a useful species in which to evaluate the potential ...
Ainsworth DM, Grünig G, Matychak MB, Young J, Wagner B, Erb HN, Antczak DF.In horses prone to developing recurrent airway obstruction (RAO), we tested the hypotheses that the cytokine profile in the bronchoalveolar lavage (BAL) cells of affected horses would reflect a polarized Th-2 response; that cytokine and chemokine alterations would occur within 24 h of allergen exposure; and that allergen exposure would induce alterations in the expression of the transcription factor t-bet (t-box-expressed in T-cells). The expression levels of interleukin-4 (IL-4), IL-13, Interferon-gamma (IFN-gamma), t-bet, IL-8 and granulocyte-macrophage colony stimulating factor (GM-CSF) wer...
Ivester KM, Couëtil LL, Zimmerman NJ.Inhalant exposure to airborne irritants commonly encountered in horse stables is implicated in the pathogenesis of inflammatory airway disease (IAD) and recurrent airway obstruction (RAO), non-infectious, inflammatory pulmonary disorders that impact the health and performance of horses across all equine disciplines. IAD and RAO have overlapping clinical, cytological, and functional manifestations of the pulmonary response to organic dust and noxious gases encountered in the barn environment. Study of these diseases has provided important but incomplete understanding of the effect of air qualit...
Paillot R.Equine influenza (EI) is a major respiratory disease of horses, which is still causing substantial outbreaks worldwide despite several decades of surveillance and prevention. Alongside quarantine procedures, vaccination is widely used to prevent or limit spread of the disease. The panel of EI vaccines commercially available is probably one of the most varied, including whole inactivated virus vaccines, Immuno-Stimulating Complex adjuvanted vaccines (ISCOM and ISCOM-Matrix), a live attenuated equine influenza virus (EIV) vaccine and a recombinant poxvirus-vectored vaccine. Several other strateg...
van Maanen C, Cullinane A.Equine influenza is one of the most economically important contagious respiratory diseases of horses. In this paper the current state of knowledge of equine influenza virus and the most important aspects of these virus infections, e.g. epidemiology, clinical aspects, pathogenesis and pathology, immunity, diagnosis, treatment, management and vaccination, are reviewed with an emphasis on epidemiology, diagnosis and vaccinology. Many questions have remained and with the advent of improved technology new questions have arisen. Consequently, research priorities should be set in an attempt to answer...
Cullinane A, Elton D, Mumford J.Equine influenza virus (EIV) is considered the most important respiratory virus of horses because it is highly contagious and has the potential to disrupt major equestrian events. Equine influenza (EI) can be controlled by vaccination but it has been demonstrated repeatedly in the field that antigenic drift impacts on vaccine efficacy. EI surveillance maintains awareness of emergence and international spread of antigenic variants. It not only serves as an early warning system for horse owners, trainers and veterinary clinicians but is fundamental to influenza control programmes based on vaccin...
Hillidge CJ.The selection of lipid-soluble antibiotics capable of intracellular penetration is considered critical for the successful treatment of Rhodococcus equi pneumonia and lung abscesses in foals. Two such antibiotics: erythromycin (25 mg kg-1, three times daily) and rifampin (5 mg kg-1 twice daily) have been used in combination for this purpose at the University of Florida since 1981. Positive evidence of R. equi was present on culture of tracheal aspirates in 57 foals, most of which exhibited radiographic evidence of extensive lung abscessation. The duration of therapy ranged from 4 to 9 weeks. Mi...
Wang LF, Michalski WP, Yu M, Pritchard LI, Crameri G, Shiell B, Eaton BT.In 1994, a new member of the family Paramyxoviridae isolated from fatal cases of respiratory disease in horses and humans was shown to be distantly related to morbilliviruses and provisionally called equine morbillivirus (K. Murray et al., Science 268:94-97, 1995). To facilitate characterization and classification, the virus was purified, viral proteins were identified, and the P/V/C gene was cloned and sequenced. The coding strategy of the gene is similar to that of Sendai and measles viruses, members of the Paramyxovirus and Morbillivirus genera, respectively, in the subfamily Paramyxovirina...
Reed SM, Toribio RE.Equine herpesvirus infections in horses remain a significant cause of abortion and neurologic disease. These viruses are also responsible for mild signs of respiratory disease. The ability to establish latent infections with periodic reactivation or transmission to other horses is an important feature of these herpesviruses. One of the most unique aspects of this report is the description of horses demonstrating neurologic signs serving as the source of infection for other horses. Accurate diagnosis and better means of protection for horses remain problems facing veterinarians and horse owners...
Beekman L, Tohver T, Dardari R, Léguillette R.The stability of reference genes has a tremendous effect on the results of relative quantification of genes expression by quantitative polymerase chain reaction. Equine Inflammatory Airway Disease (IAD) is a common condition often treated with corticosteroids. The diagnosis of IAD is based on clinical signs and bronchoalveolar lavage (BAL) fluid cytology. The aim of this study was to identify reference genes with the most stable mRNA expression in the BAL cells of horses with IAD irrespective of corticosteroids treatment. Results: The expression stability of seven candidate reference genes (B2...
Pirie RS, Collie DD, Dixon PM, McGorum BC.Equine heaves is a naturally occurring organic dust-induced asthma characterized by airway neutrophilia, mucus hypersecretion and obstructive lung dysfunction. However, the relative role of different dust components in disease severity remains unclear. Objective: This study investigated the relative contribution of inhaled endotoxin and organic dust particulates (mainly mould spores) in inducing heaves in heaves-susceptible horses. Methods: Control and heaves-susceptible horses received inhalation challenges with hay dust suspension (HDS) before and after lipopolysaccharide (LPS) depletion. He...
Léguillette R.Heaves, or recurrent airway obstruction (RAO), is a chronic respiratory disease featuring lower airway inflammation, bronchoconstriction, and mucus accumulation. Inhaled organic dusts and T helper 2 type immunologic reactions are involved in the complex pathophysiology of RAO. Clinical signs vary and alternate with remission periods. The diagnosis is often based on history and clinical examination in severe cases, but bronchoalveolar lavage may be useful for the detection of early cases. The most important aspect of treatment is to avoid exposure to allergens. Corticosteroids may be administer...
Leclere M, Lavoie-Lamoureux A, Gélinas-Lymburner E, David F, Martin JG, Lavoie JP.Recent studies suggest that airway smooth muscle remodeling is an early event in asthma, but whether it remains a dynamic process late in the course of the disease is unknown. Moreover, little is known about the effects of an antigenic exposure on chronically established smooth muscle remodeling. We measured the effects of antigenic exposure on airway smooth muscle in the central and peripheral airways of horses with heaves, a naturally occurring airway disease that shares similarities with chronic asthma. Heaves-affected horses (n = 6) and age-matched control horses (n = 5) were kept on pastu...
Kydd JH, Smith KC, Hannant D, Livesay GJ, Mumford JA.Twelve adult ponies and 2 conventional foals were exposed intranasally to EHV-1, strain Ab4 (TCID50 10(-6.6) and samples of respiratory tract associated lymphoid tissues were recovered between 12 h and 13 days after infection. Infectious virus was detected in tissue homogenates using susceptible cell monolayers and expression of viral antigens was monitored using indirect immunoperoxidase histochemistry on paraffin sections. The results showed both infectious EHV-1 and viral antigens in respiratory tract associated lymph nodes 12 h after exposure. Infected leucocytes were identified morphologi...
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...
Ivester KM, Couëtil LL, Moore GE, Zimmerman NJ, Raskin RE.Inflammatory airway disease (IAD) in horses is a widespread, performance-limiting syndrome believed to develop in response to inhaled irritants in the barn environment. Objective: To evaluate changes in bronchoalveolar lavage fluid (BALF) cytology and exposure to particulates, endotoxin, and ammonia during horses' first month in training. Methods: Forty-nine client-owned 12- to 36-month-old Thoroughbred horses entering race training. Methods: In this prospective cohort study, a convenience sample of horses was assigned to be fed hay from a net (n = 16), whereas the remaining horses were fed ha...
Wutz G, Auer H, Nowotny N, Grosse B, Skern T, Kuechler E.Equine rhinoviruses (ERVs) are picornaviruses which cause a mild respiratory infection in horses. The illness resembles the common cold brought about by rhinoviruses in humans; however, the presence of a viraemia during ERV-1 infection, the occurrence of persistent infections and the physical properties are all more reminiscent of foot-and-mouth disease virus (FMDV). cDNA cloning and sequencing of the genomes of ERV-1 and ERV-2 between the poly(C) and poly(A) tracts showed that the serotypes are heterogeneous. Nevertheless, the genomic architecture of both serotypes is most similar to that of ...
Wang L, Raidal SL, Pizzirani A, Wilcox GE.A nested multiplex PCR was developed as a rapid (<12h), sensitive test for the simultaneous identification of equine herpesviruses (EHV1, EHV4, EHV2 and EHV5) in clinical samples from horses. Peripheral blood and nasal swab (NS) samples from 205 weanling Thoroughbred foals on 6 different studs over 3 consecutive seasons and from 92 adult horses without clinical signs of respiratory disease were examined using direct multiplex PCR of clinical samples (direct PCR) and conventional cell culture with differentiation of EHV in cell cultures by multiplex PCR. Multiplex PCR proved a sensitive and ...
Nemoto M, Oue Y, Morita Y, Kanno T, Kinoshita Y, Niwa H, Ueno T, Katayama Y, Bannai H, Tsujimura K, Yamanaka T, Kondo T.Recently, outbreaks associated with equine coronavirus (ECoV) have occurred in Japan and the United States. While ECoV is likely to be pathogenic to horses, it has not been shown that experimental inoculation of horses with ECoV produces clinical signs of disease. In this study, we inoculated three Japanese draft horses with an ECoV-positive diarrheic fecal sample to confirm infection after inoculation and to investigate the clinical course and virus shedding patterns of ECoV. Virus neutralization tests showed that all three horses became infected with ECoV. Two of the three horses developed c...
Bullone M, Lavoie JP.Human asthma is a complex and heterogeneous disorder characterized by chronic inflammation, bronchospasm and airway remodeling. The latter is a major determinant of the structure-function relationship of the respiratory system and likely contributes to the progressive and accelerated decline in lung function observed in patients over time. Corticosteroids are the cornerstone of asthma treatment. While their action on inflammation and lung function is well characterized, their effect on remodeling remains largely unknown. An important hindrance to the study of airway remodeling as a major focu...
Burrell MH, Wood JL, Whitwell KE, Chanter N, Mackintosh ME, Mumford JA.A longitudinal study of respiratory disease in racehorses was carried out to assess its relative associations with different infectious agents and to examine any role that the environmental conditions might play. The relationships between coughing, nasal discharge, pyrexia and lower respiratory tract disease were also examined to provide information for improving clinical diagnosis, particularly of disease of the lower respiratory tract. Lower airway disease was closely associated with infection with Streptococcus zooepidemicus. It was also found that equine herpesvirus seroconversions and S p...
Beekman L, Tohver T, Léguillette R.The pathophysiology of inflammatory airway disease (IAD) is unknown, but in some cases involves the accumulation of mast cells, neutrophils, or both in the bronchoalveolar lavage fluid (BALF). The objective of this study was to characterize cytokine gene expression in the BALF cells of horses with IAD, including a comparison of cytokine gene expression between IAD horses with increased BALF mast cells (IAD-Mast) or neutrophils (IAD-Neutro). Methods: The mRNA expression of IL-4, IFN-γ, IL-17, IL-8, IL-1β, IL-5, IL-6, IL-10, IL-12p35, and eotaxin-2 was studied by quantitative polymerase chain ...
Singh RK, Dhama K, Karthik K, Khandia R, Munjal A, Khurana SK, Chakraborty S, Malik YS, Virmani N, Singh R, Tripathi BN, Munir M, van der Kolk JH.Among all the emerging and re-emerging animal diseases, influenza group is the prototype member associated with severe respiratory infections in wide host species. Wherein, Equine influenza (EI) is the main cause of respiratory illness in equines across globe and is caused by equine influenza A virus (EIV-A) which has impacted the equine industry internationally due to high morbidity and marginal morality. The virus transmits easily by direct contact and inhalation making its spread global and leaving only limited areas untouched. Hitherto reports confirm that this virus crosses the species ba...
Bryant NA, Wilkie GS, Russell CA, Compston L, Grafham D, Clissold L, McLay K, Medcalf L, Newton R, Davison AJ, Elton DM.Equine herpesvirus 1 (EHV-1) causes respiratory disease, abortion, neonatal death and neurological disease in equines and is endemic in most countries. The viral factors that influence EHV-1 disease severity are poorly understood, and this has hampered vaccine development. However, the N752D substitution in the viral DNA polymerase catalytic subunit has been shown statistically to be associated with neurological disease. This has given rise to the term "neuropathic strain," even though strains lacking the polymorphism have been recovered from cases of neurological disease. To broaden understan...
