Diagnostic Approaches for the Assessment of Equine Chronic Pulmonary Disorders

Even though the respiratory system is one of the most accessible organs for diagnostic testing, it is not always easy to define chronic lower airway disease in the horse. Diagnostic procedures performed by first opinion veterinarians in the field are often restricted to taking the history and performing clinical examination. Respiratory tract endoscopy, tracheal or bronchoalveolar lavage, and blood sampling are sometimes used but other specific ancillary examinations are seldom performed in stable settings. Therefore, our objectives were to evaluate the diagnostic value of different techniques and examination types routinely used in the diagnostic workup of chronic equine lower airway cases in both stable and clinical circumstances. Another aim of this study was to estimate the prevalence of different chronic pulmonary disorders among horses admitted to a Hungarian referral clinic. According to the conditional inference tree method, age of the horse, history, clinical examination, respiratory tract endoscopy, and bronchoalveolar lavage cytology proved to be the most valuable tools to define pathology. It was also concluded that in 22% of cases, more specific ancillary diagnostic modalities, unavailable for the field veterinarian, were needed to establish the final diagnosis. According to our study, the most frequently diagnosed chronic pulmonary disorders in Hungary are of noninfectious origin, principally recurrent airway obstruction. Regardless of the cause, and interestingly including recurrent airway obstruction as well, these diseases occur primarily during the warm months.     

马鼻肺炎诊断方法研究进展

马鼻肺炎的病原是马疱疹病毒l型和马疱疹病毒4型,属于疱疹病毒目,疱疹病毒科,a疱疹病毒亚科,通常会引起呼吸道疾病和病毒性流产,严重时引发神经性疾病。该病毒在世界范围内流行,对养马业和赛马业的危害很大。本文总结国内外近些年关于马疱疹病毒的病原学和血清学诊断方法的研究成果,了解国际上关于马鼻肺炎检测诊断方法的研究进展,为出入境赛马的马鼻肺炎的检验检疫提供可靠的检测方法。     

Application and indications of magnetic resonance imaging and computed tomography of the equine head

The equine head is an anatomically highly complex area affected by a range of disorders, making the diagnosis of head conditions challenging. Imaging techniques play a crucial role in the diagnostic work-up of head disorders. Tomographic imaging methods, such as computed tomography (CT) and magnetic resonance imaging (MRI) are particularly useful in avoiding problems associated with superimposition of multiple structures in this highly complex region. Both techniques are becoming more widely available in equine medicine. However, the choice between CT and MRI for imaging the equine head is not always straightforward. Each modality has advantages and disadvantages in terms of practicality, costs and diagnostic value for particular problems. The aim of this review is to describe the application of CT and MRI for imaging the equine head and to provide a practical guide for their use in different anatomical structures and clinical indications. This should allow the equine practitioner to make an informed decision on which modality to choose.     

Biofluid Markers of Equine Neurological Disorders Reviewed From Human Perspectives

Neurological disorders (NDs) are often fatal to horses. Thus, symptoms of equine NDs commonly indicate euthanasia. Current diagnostic approaches for equine NDs is based on clinical signs, differential diagnoses, analysis of cerebrospinal fluid (CSF), assessment of histopathological lesions, and imaging. However, advances in biofluid biomarkers in the diagnosis of human neurological diseases can potentially be applied to equine NDs. In this review, we described the established human blood and CSF neurobiomarkers that could potentially be used to diagnose equine NDs.     

Diagnostic imaging of the equine tarsal region using radiography and ultrasonography. Part 1: the soft tissues

The equine tarsus is the most commonly affected hindlimb region associated with lameness. Diagnostic imaging is routinely applied but because of its complexity, being composed of 10 multifaceted bones and different joints, multiple ligaments, tendons and bursae, imaging this region can be a challenge. This is the first part of a two-part review of the structures and disorders of the equine tarsus. It describes the principal disorders affecting the soft tissues of the tarsal region and addresses some of the technical aspects in taking radiographic, ultrasonographic and scintigraphic images of the different soft tissue lesions. Where applicable, comments on the diagnostic use of contrast radiography, arthroscopy and tenoscopy are made. In current clinical practice a combination of radiography and ultrasonography is still most frequently used to arrive at a diagnosis.     

Respiratory diseases and their effects on respiratory function and exercise capacity

Given that aerobic metabolism is the predominant energy pathway for most sports, the respiratory system can be a rate‐limiting factor in the exercise capacity of fit and healthy horses. Consequently, respiratory diseases, even in mild forms, are potentially deleterious to any athletic performance. The functional impairment associated with a respiratory condition depends on the degree of severity of the disease and the equestrian discipline involved. Respiratory abnormalities generally result in an increase in respiratory impedance and work of breathing and a reduced level of ventilation that can be detected objectively by deterioration in breathing mechanics and arterial blood gas tensions and/or lactataemia. The overall prevalence of airway diseases is comparatively high in equine athletes and may affect the upper airways, lower airways or both. Diseases of the airways have been associated with a wide variety of anatomical and/or inflammatory conditions. In some instances, the diagnosis is challenging because conditions can be subclinical in horses at rest and become clinically relevant only during exercise. In such cases, an exercise test may be warranted in the evaluation of the patient. The design of the exercise test is critical to inducing the clinical signs of the problem and establishing an accurate diagnosis. Additional diagnostic techniques, such as airway sampling, can be valuable in the diagnosis of subclinical lower airway problems that have the capacity to impair performance. As all these techniques become more widely used in practice, they should inevitably enhance veterinarians' diagnostic capabilities and improve their assessment of treatment effectiveness and the long‐term management of equine athletes.     

Diagnostic imaging of the equine fetlock region using radiography and ultrasonography. Part 1: Soft tissues

The equine fetlock is the joint most commonly associated with lameness. Although the fetlock is regarded as a simple joint, diagnosis of a fetlock disorder can be a challenge and various imaging modalities are routinely used to arrive at an accurate diagnosis. This review describes the principal disorders affecting the soft tissues of the fetlock region and addresses some of the technical aspects involved in taking radiographic and ultrasonographic images of the different soft tissue lesions. A combination of radiography and ultrasonography is still the most commonly used diagnostic approach in clinical practice.     

Exercise testing in the equine athlete

In the last decade there have been significant technological advances and increases in the availability of portable diagnostic equipment for use in the assessment of athletic performance. The design and application of appropriate exercise tests are critical factors for the diagnosis of conditions affecting equine performance and it is therefore necessary for veterinary surgeons using such equipment to develop an understanding of appropriate exercise testing methods. This is the first in a series of three papers covering exercise testing in the equine athlete, interpretation of heart rate and rhythm during exercise and interpretation of dynamic upper respiratory tract function. In this first paper, both performance and clinical exercise testing in the equine athlete are reviewed.     

Immunologic diseases

Selected equine cutaneous diseases for which there is strong evidence of an immunological aetiology are discussed in this section. The reactive disorders of urticaria, Culicoides hypersensitivity, erythema multiforme, drug eruptions and systemic granulomatous disease are included. The autoimmune diseases of the horse with cutaneous manifestations (pemphigus foliaceus, pemphigus vulgaris, bullous pemphigoid and cutaneous lupus erythematosus) are discussed. The clinical signs and diagnostic features of these immunologically induced equine dermatoses are defined, and the challenges in making a definitive diagnosis and managing the clinical signs are confirmed.     

Ancillary testing for the ruminant respiratory system.

With greater use of a wide variety of diagnostic tools, such as transtracheal washing, respiratory endoscopy, chest radiography, thoracic ultrasonography, blood gas analysis, and lung biopsy, veterinarians are gaining tremendous insight into pathogenic mechanisms of the ruminant respiratory system. We have available many diagnostic aids; some fairly simple and inexpensive, others highly sophisticated and presently at far greater cost than justifiable on most individual food animals. Some methods recently developed, such as same-day viral particle detection in BAL samples,6 have tremendous potential for rapid and accurate diagnosis in ruminant pulmonary medicine. Undoubtedly, future research in this area will provide an ever widening array of powerful and rapid diagnostic aids to deal with respiratory disease of ruminants.     

Uses of ultrasound in equine internal medicine

Ultrasound examination allows the diagnostician to examine peripheral soft tissues and many internal organs in a noninvasive manner. In most instances, ultrasound can be utilized to complement other diagnostic aids, but its increased use has revealed the unique advantages of this technique over more established diagnostic tools. The ease with which ultrasound interpretation can be learned and the increased availability of instruments make this approach to diagnosis a valuable asset in the diagnosis of many equine medical diseases.     

Equine tapeworm infections: Disease,diagnosis and control

Equine tapeworm infection has gained increasing attention over the past few decades and a number of research studies have already been published. These focus primarily on the most common of the 3 tapeworm species, Anoplocephala perfoliata, although some new information has also been generated for the other two species, Anoplocephala magna and Anoplocephaloides mamillana. The preponderance of research studies have focused on development and validation of diagnostic techniques for tapeworm detection and the role of these parasites in equine gastrointestinal disease. Several diagnostic techniques have been found useful for diagnosis of A. perfoliata but each has its strengths and weaknesses. Egg counting techniques have been modified to achieve acceptable to good diagnostic performance but the trade‐off is often a more time‐consuming method. Validation studies indicate that these methods can reliably detect tapeworm burdens above 10 worms. Several enzyme‐linked immunosorbent assays (ELISAs) have been developed and made commercially available. These can generate useful information about tapeworm exposure on the herd level but are less reliable for individual diagnosis. Unfortunately, none of the available diagnostic techniques are useful for evaluating anthelmintic treatment efficacy. Coproantigen testing may find use as a future diagnostic modality but further characterisation is required. The large body of scientific evidence supports an association between A. perfoliata infection and certain types of equine colic, although some discrepancy exists between studies. Tapeworm surveillance and control should be considered as part of the overall parasite control strategy. When properly used, the currently available diagnostic tools can guide the veterinarian to make strategic decisions regarding tapeworm control.     

Equine infectious respiratory disease.

During the past 20 years the equine population of Great Britain and Ireland has increased with the result that the practising veterinary surgeon is more frequently called upon to advise on equine problems. A significant portion of this advice is concerned with the examination of horses showing signs of this advice is concerned with the examination of horses showing signs of respiratory disease. Numerous pathogens, which include viruses, bacteria, parasites and moulds invade the respiratory tract causing similar signs of illness. It is therefore difficult to provide an aetiological diagnosis based on a clinical examination. Field studies supported by laboratory investigations have established that influenza and herpes viruses are frequently responsible for outbreaks of disease. Epidemiological studies suggest that other factors including the immune state of the equine population influence the distribution and severity of respiratory disease. The aetiology, diagnosis, treatment and control of equine infectious respiratory disease are discussed below.     

Identification of equine herpesvirus 3 (equine coital exanthema virus), equine gammaherpesviruses 2 and 5, equine adenoviruses 1 and 2, equine arteritis virus and equine rhinitis A virus by polymerase chain reaction

OBJECTIVE: To develop rapid (< 8 hour) tests using polymerase chain reaction (PCR) for the diagnosis of equine herpesvirus 3 (EHV3; equine coital exanthema virus), equine gammaherpesviruses 2 (EHV2) and EHV5, equine adenovirus 1 (EAdV1), EAdV2, equine arteritis virus (EAV), equine rhinitis A virus (ERAV; formerly equine rhinovirus 1) DESIGN: Either single round or second round (seminested) PCRs were developed and validated. METHODS: Oligonucleotide primers were designed that were specific for each virus, PCR conditions were defined and the specificity and sensitivity of the assays were determined. The application of the tests was validated using a number of independent virus isolates for most of the viruses studied. The PCRs were applied directly to clinical samples where samples were available. RESULTS: We developed a single round PCR for the diagnosis of EHV3, a seminested PCR for EHV2 and single round PCRs for EHV5, EAdV1, EAdV2 and RT-PCRs for EAV and ERAV. The PCR primer sets for each virus were designed and shown to be highly specific (did not amplify any recognised non-target template) and sensitive (detection of minimal amounts of virus) and, where multiple virus isolates were available all isolates were detected. CONCLUSION: The development and validation of a comprehensive panel of PCR diagnostic tests, predominantly for viruses causing equine respiratory disease, that can be completed within 8 hours from receipt of clinical samples, provides a major advance in the rapid diagnosis or exclusion diagnosis of these endemic equine virus diseases in Australia.     

Equine herpesvirus 1 and 4 infections: an update

Equine herpesvirus 1 (EHV1) and equine herpesvirus 4 (EHV4) are important ubiquitous equine viral pathogens, causing much damage to the horse industry. EHV1 strains are associated with respiratory disease, abortion, and paresis/paralysis, whereas EHV4 strains are predominantly associated with respiratory disease. In the past decades much research effort has been put into improving knowledge about these viruses. In this paper the current state of knowledge of these viruses and the most important aspects of these virus infections, e.g. epidemiology, clinical aspects, pathogenesis and pathology, immunity, diagnosis, preventive management and management in the course of an outbreak and vaccination, is reviewed. Because we performed some research ourselves in the areas of diagnosis, epidemiology and vaccinology these aspects are reviewed in more depth than the other aspects. Still many questions have remained and new questions have risen. Consequently, research priorities should be made in an attempt to answer these questions. Therefore, this review ends with some personal recommendations for important priorities for future research.     

Diagnostic imaging of the equine tarsal region using radiography and ultrasonography. Part 2: bony disorders

This is the second part of a two-part review of the structures and disorders of the equine tarsus. In this part the bones of the tarsal region are considered and the technical aspects of taking radiographic, ultrasonographic and scintigraphic images of the different lesions are addressed. The diagnostic use of arthroscopy, computed tomography and magnetic resonance are discussed. In current clinical practice the most frequently used combination to arrive at a diagnosis is still radiography and ultrasonography.     

Eyelid and nasolacrimal disease.

An understanding of normal structure and function of the equine eyelid is essential to make an accurate diagnosis and appropriately treat equine eyelid diseases. Entropion, eyelid trauma, neoplasia, and nasolacrimal disorders are reviewed. Methods of diagnosis and treatment are presented.     

Diagnostic imaging of the equine fetlock region using radiography and ultrasonography. Part 2: the bony disorders

The metacarpophangeal/metatarsophalangeal (fetlock) joint in the horse is commonly associated with equine lameness and diagnostic imaging is routinely used to investigate disorders of the joint and its surrounding tissues. This review describes the osseous disorders of the fetlock as well as the technical aspects of taking radiographic and ultrasonographic images of the different lesions. In current clinical practice, a combination of radiography and ultrasonography is still the most frequently used approach to arrive at a diagnosis.     

Hereditary skeletal muscle diseases in the horse. A review

Since riders nowadays are expecting the highest level of performance from their horses, muscular disorders therefore represent a major problem for the equine athlete. A lot of research has been done to identify muscular disorders and their etiopathogenesis. Both acquired and inherited forms of muscle diseases have been described. In this review only the latter forms will be mentioned. Major signs of all muscle disorders are muscular stiffness, cramping or pain, muscular fasciculations, muscular atrophy and exercise intolerance. Muscle biopsies can help to identify the cause of rhabdomyolysis or muscular atrophy. However, especially in hereditary muscular diseases, a lot of questions are still to be answered. Increasing knowledge of the etiopathogenesis and newer diagnostic tests may lead to a more accurate diagnosis of the individual diseases in future.     

The use of lasers for treatment of upper respiratory tract disorders.

Lasers have become important tools for the equine surgeon in the treatment of upper respiratory tract disease in the horse. Multiple wavelengths and delivery systems are available. Indications for the use of lasers in the upper respiratory tract primarily include minimally invasive procedures not possible with conventional surgical instrumentation. New applications for the use of lasers to treat upper respiratory disease are likely to evolve with the development and introduction of new wavelengths and delivery systems.