Topic:Clinical Signs
Clinical signs in horses refer to observable physical or behavioral manifestations that may indicate the presence of disease or injury. These signs can include a range of symptoms such as changes in appetite, alterations in gait, abnormal respiratory patterns, or variations in body temperature. Recognizing clinical signs is an integral part of equine veterinary practice, as they provide initial insights into the health status of the animal. Veterinarians rely on these signs to formulate differential diagnoses and guide further diagnostic testing. This page gathers peer-reviewed research studies and scholarly articles that explore the identification, interpretation, and diagnostic value of clinical signs in equine health management.
A novel kirkovirus may be associated with equine gastrointestinal disease. Many cases of equine enterocolitis are suspected to be infectious in nature, but no pathogen is identified in many cases. Objective: Perform next-generation sequencing on faeces collected from cases of equine enterocolitis for the presence of novel viruses and determine if an identified novel virus is associated with cases of equine enterocolitis. Methods: Retrospective cohort study. Methods: Next generation sequencing was performed targeting viral genomes from n = 13 pooled faecal samples (n = 5 horses/pool) with enterocolitis. Subsequent qPCR was performed targeting the highly conser...
Fibrocartilaginous Emboli in a 15-Year-Old Pony Mare. Fibrocartilaginous embolic myelopathy (FCE) was diagnosed in a 15-year-old pony mare by histopathologic examination of the spinal cord. The horse was euthanized and submitted for necropsy following focal seizures and lateral recumbency for approximately 12 h. Histopathology of spinal cord segments C5-C7 revealed severe ischemic myelomalacia with intravascular amorphous material that stained positive with Alcian Blue, consistent with cartilaginous matrix. These features in addition to the acute onset of clinical signs are characteristic for FCE. This case report describes the clinical and histo...
Granulosa cell tumor in Arabian mares: prevalence, risk factors, clinical and histopathological findings and outcome of surgical removal. Granulosa cell tumors (GCTs) represent the most common ovarian neoplasms in mares, yet data on their epidemiology, risk factors, and clinical outcomes in Arabian horses are limited. Understanding their prevalence and diagnostic features is crucial for improving fertility management in this breed. Unassigned: Clinical records from 807 Arabian mares housed on 35 stud farms in central Saudi Arabia were retrospectively reviewed to determine the prevalence of GCT and potential risk factors, including age, parity, and anabolic steroid use. Twenty-four confirmed cases were further investigated using ...
Lethal Sycamore maple intoxication in a grazing three-month-old foal. The case of a young foal poisoned by maple toxin is described. It showed signs of myopathy caused by ingesting life-threatening amounts of maple toxin. Some maple trees (Acer species) can pose a health risk to grazing horses. The leaves, seeds and shoots contain hypoglycin A (HGA) and methylencyclopropylglycine (MCPRG) and can cause life-threatening atypical myopathy.
Intraocular Tumors in Horses: Diagnosis, Tumor Classification, Oncologic Assessment and Therapy. Intraocular neoplasia in horses is rare and only few case reports and small case series exist. Intraocular neoplasia has various clinical signs and includes important differential diagnoses in ocular disease. This narrative review of the current literature aims to provide a clinically relevant overview and classification of intraocular tumors in horses and adds a comparative oncological perspective concerning diagnosis, treatment and future considerations. The available clinical and imaging examination techniques allow for a reliable and differentiated investigation of the tumor, even in the s...
Evaluation of Owner-Reported Clinical Signs and Fecal Occult Blood Tests as Predictors of Equine Gastric Ulcer Syndrome in Competition Dressage Horses. Equine gastric ulcer syndrome (EGUS) adversely affects the health, welfare, and performance of sports horses, requiring gastroscopy for definitive diagnosis. Owners frequently consider girth aversion as highly suggestive of EGUS. Objective: To evaluate whether owner-reported clinical signs or fecal occult blood tests (FOBTs) can help identify horses needing gastroscopy for EGUS diagnosis or monitoring treatment, thereby reducing unnecessary procedures in unaffected horses. Methods: Eighty competition dressage horses referred by veterinarians for EGUS evaluation. Methods: Case-control study in...
Complications of the Recumbent Horse: Diagnosis and Management. This issue focuses on the potential complications caused by prolonged recumbency in horses. It discusses how managing a recumbent horse involves treating the primary illness while also preventing and addressing secondary issues that can arise from recumbency itself. The authors explore the underlying pathophysiology of these complications, along with strategies for prevention and treatment. By understanding these aspects, veterinarians can improve care and outcomes for horses that are immobilized for extended periods. The issue provides insights into the most common complications and emphasize...
Adverse Effects and Drug Reactions in Equids. Adverse drug events (ADEs) are any harms caused by medical interventions used for treatment, prevention, or diagnosis. These events can happen due to human error or as unintended, harmful reactions to drugs when given at normal therapeutic doses. This review focuses on common ADEs associated with drugs frequently used in equine practice. Recognizing and understanding the manifestations of ADEs can help with early detection and more effective management, ultimately leading to better outcomes for equine patients. Additionally, knowledge of the potential harmful effects of drugs also aids in appr...
Computed tomographic signs of hyoid apparatus disease in 165 horses. Horses with hyoid bone disease may present with clinical symptoms such as exercise intolerance, resistance to ridden work, anorexia, or headshaking. This study aims to describe the computed tomographic (CT) signs and prevalence of hyoid disease and to evaluate their association with other CT changes of the head. Unassigned: In this study, four investigators conducted a retrospective analysis of their findings after reviewing the medical records of 200 horses that had undergone CT scans between 2009 and 2019. A total of 32 parameters were analyzed, and associations were evaluated between those ...
Owners’ everyday interactions with their horse: Pain-related issues and those of veterinary concern. The decisions made by horse owners on behalf of their animal, including decisions to involve a veterinarian, play an important role in the management of pain. This study explored horse owners' experiences to understand how they conceptualised chronic pain within the context of their horse-human relationship, what led them to seek veterinary involvement, and how veterinary interactions shaped their perceptions of pain and its management. An ethnographic approach using constructivist grounded theory methods was adopted. This paper draws upon field notes generated through 200 h of observation und...
Impinging and Overriding Spinous Processes in Horses: A Narrative Review. The term overriding spinous processes (ORSPs), commonly known as "kissing spine syndrome," refers to a skeletal abnormality in horses that is characterized by the narrowing (<4 mm) of the interspinous space and touching or overlapping of the spinous processes (SPs). This condition primarily affects the mid- and caudal thoracic vertebrae; however, ORSP can also affect the lumbar SPs. In the veterinary community, kissing spine is widely recognized as a common condition in sport horses, as it is often associated with chronic back pain and contributes to poor performance. Despite its significant c...
The Viremic Phase and Humoral Immune Response Against African Horse Sickness Virus That Emerged in Thailand in 2020. African horse sickness (AHS), a life-threatening disease caused by African horse sickness virus serotype 1 (AHSV-1), emerged in Thailand in February 2020 with 607 cases and a 93% fatality rate. The outbreak was mitigated by vector control and a live attenuated virus (LAV) vaccine. Information regarding viremia and immunity after infection and vaccination during outbreaks are essential for controlling disease transmission. This study evaluated these parameters in 15 infected naïve horses and 11 vaccinated horses during the 2020 outbreak. Whole blood was collected and subjected to RT real-time ...
Equine maxillofacial intraosseous cystic lesions: a retrospective study of 17 cases. Cystic and pseudocystic masses of the equine maxilla and mandible are rare lesions that result in clinically significant morbidity and/or mortality for the patient. Previous literature consists of case reports or case series. Few studies have addressed the variety of cystic lesions and comparative features. The aim of this study was to retrospectively describe the clinical signs, imaging findings, histopathologic diagnoses, treatments, and clinical outcomes for cystic masses in the equine maxilla and mandible. Unassigned: Cases were recruited from six sources including a pathology laboratory, ...
Steamed hay for the prevention of severe equine asthma exacerbations. 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...
Effects of mixed polyphenol supplementation on lower airway inflammation in horses with Equine Asthma Syndrome. 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...
Seropositivity for Pathogenic Leptospira in Dogs, Cats, and Horses at a Teaching Veterinary Hospital in Southern Chile. At a veterinary hospital in southern Chile, we conducted an epidemiological study involving domestic dogs, cats, and horses to determine the seropositivity for pathogenic spp., identify the infecting serogroups, measure antibody titers, and characterize seropositive animals by sex and age. None of the sampled animals showed clinical signs of leptospirosis. The microscopic agglutination test, using a panel of eight serogroups, was used for diagnosis. The seropositivity was 36.5% (95% confidence interval [CI] = 24.5-48.4) in dogs, 12.9% (95% CI = 2.6-23.1) in cats, and 45.2% (95% CI = 30.1-60.2...
Ivermectin toxicosis in a foal: Use of intravenous lipid emulsion therapy. This report describes a case of ivermectin toxicosis in a 4-day-old thoroughbred colt successfully treated with intravenous lipid emulsion (ILE) without complications. This case supports the use of ILE as a safe and effective therapy for the management of lipophilic drug toxicosis in foals. Key clinical message: Ivermectin toxicosis, though rare in equine neonates, can occur following accidental overdose and induces severe neurologic signs. In this case, ILE administration resulted in rapid neurologic improvement and complete recovery without adverse effects, supporting its use as a safe and e...
Emergence of Autochthonous Leishmania (Mundinia) martiniquensis Infections in Horses, Czech Republic and Austria, 2019-2023. We report 4 cases of equine cutaneous leishmaniasis caused by Leishmania martiniquensis in Czech Republic and Austria, outside the known endemic range of leishmaniases. The parasite should be considered as a potential cause of cutaneous lesions in horses; the risk for zoonotic transmission to immunocompromised humans is anticipated throughout central Europe.
High-field magnetic resonance imaging enables diagnosis of central tarsal bone fractures in performance horses with lameness localized to the proximal metatarsus and tarsus. Central tarsal bone (CTB) fractures are challenging to diagnose, and cross-sectional imaging is required for definitive characterization and surgical planning. This retrospective case series aims to provide the first description of high-field (3-T) MRI characteristics of CTB fractures, concurrent pathology, and clinical presentation in 8 performance horses. Unassigned: 8 horses (9 limbs) diagnosed with a CTB fracture on high-field MRI at one tertiary referral hospital between 2013 and 2023 were identified via electronic medical records search. Unassigned: Quarter Horses (6 of 8) used for Weste...
Equine Pituitary Pars Intermedia Dysfunction. Pituitary pars intermedia dysfunction (PPID) is a common, slowly progressive, neurodegenerative disorder of the older horse. Oxidative damage to the hypothalamic periventricular neurons results in loss of dopaminergic inhibition of the pars intermedia region of the pituitary gland. Consequently, there is increased production of the pro-opiomelanocortin (POMC)-derived hormones normally produced by this region, as well as initial melanocyte hypertrophy and hyperplasia, followed by adenomatous change. Clinical signs that are highly suggestive of the disease are generalised and regional hypertrich...
Seroprevalence and Passive Clinical Surveillance of West Nile Virus in Horses from Ecological High-Risk Areas in Western Romania: Exploratory Findings from a Cross-Sectional Study. This cross-sectional study evaluated the seroprevalence and clinical impact of West Nile virus (WNV) infection in horses from three ecologically high-risk counties in western Romania (Timiș, Arad, and Bihor) between 2023 and 2025. A total of 306 unvaccinated horses were tested using a commercial ELISA, with 8.17% testing positive for WNV antibodies, indicating prior exposure. Passive surveillance for clinical signs during mosquito seasons identified 16 horses with acute neurological symptoms, four of which were confirmed as clinical cases based on WNV-specific IgM positivity, suggesting proba...
Emergence of a new alveolar dental element after extraction of a molar tooth in a horse. A 2-year-old mixed-breed mare was examined at the property due to swelling and fistula on the right mandible. Oral examination and radiographs revealed the presence of an apical abscess involving the 410 tooth. The tooth was extracted entirely and confirmed radiographically. One year later, the owner reported a reoccurrence of clinical signs. A new radiographic evaluation revealed a radiopaque area in the alveolar socket of the 410 tooth filled with spongy-looking bone. An extraoral approach to the alveolar socket was performed, and the content removed had the appearance of a dental element.
First Equine Herpes Myeloencephalopathy (EHM) Outbreak in Chile. Equine herpes myeloencephalopathy (EHM) is a neurological disease in horses caused by Equine herpesvirus type 1 (EHV-1). It is a serious condition, often resulting in severe neurological deficits, and can be fatal. In this report, we discuss the first outbreak of EHM in Chile (clinical signs, epidemiology, diagnosis, and control measures). A total of 567 polo horses were kept at the facility: 58.4% mares, 41.6% geldings, and stallions. Mean age was 9.7 ± 0.132 years. Thirteen horses showed clinical signs of EHV-1, eight had fevers (1.4%), and eleven developed EHM (1.9%). Only six of the eleve...
Retrospective Evaluation of Synchronous Diaphragmatic Flutter in Horses: 37 Cases (2004-2022). To describe the clinical presentation of horses with synchronous diaphragmatic flutter (SDF) and identify clinical and laboratory variables associated with survival. Methods: Retrospective study from January 2004 to September 2022. Methods: Five large animal referral hospitals in the United States. Methods: Thirty-seven horses of various breeds and ages presenting with clinical signs of SDF, excluding animals participating in an endurance competition. All horses were >1 year of age. Methods: None. Results: Variables recorded and analyzed included signalment, clinical and laboratory data, trea...
Radiographic area of large intestinal sand accumulation in horses may determine clinical significance. Sand enteropathy is a common disease in horses worldwide. The presence of sand does not always cause disease. The amount of sand required to cause clinical disease is not well established. Objective: To establish a weight-indexed cut-off for the diagnosis of clinically relevant sand enteropathy based on radiographic area. Methods: Cross-sectional. Methods: Abdominal radiographs were acquired from clinically normal horses and compared with horses with clinical sand enteropathy. Sand area and sand area per kilogram of body weight were calculated. A receiver operating characteristic (ROC) curve w...
Assessment of Salivary Biomarkers of Gastric Ulcer in Horses from a Clinical Perspective. This study arises from the search for non-invasive diagnostic alternatives for equine gastric ulceration (EGUS), which is prevalent, clinically variable and only confirmed by gastroscopy. The aim is to quantify five salivary biomarkers (IL1-F5, PIP, CA VI, serotransferrin, albumin) under clinical conditions by validated assays and analyse their diagnostic value. Horses were grouped in No EGUS (neither clinical signs of EGUS nor gastric lesions), EGUS non-clinical (apparently no clinical signs of EGUS but with gastric lesions), and EGUS clinical (obvious clinical signs of EGUS and with gastric ...
Injection site abscesses associated with commensal and environmental bacteria following intramuscular vaccination in horses. Five previously healthy horses in Korea, including a 19-year-old mixed-breed gelding, a 16-year-old mixed-breed mare, a 13-year-old Thoroughbred gelding, a 12-year-old Belgian warmblood mare, and a 12-year-old Andalusian mare, developed subcutaneous abscesses in the left neck after receiving intramuscular vaccination without prior skin disinfection. The vaccination used was Equivac® 2 in1, containing toxoid and cell-free extract. Within one week, the horses developed localised swelling and/or abscessation at the injection site. One case involved a ruptured abscess, while the others presente...
Endoscopically assessed mucus parameters in equine asthma: Relationship to clinical history and cytological findings data. 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 ...
Cardiac arrhythmia prevalence and risk factors in 24-h electrocardiograms of sedentary horses. Cardiac arrhythmias are common in horses, but their clinical relevance remains controversial. Objective: To describe prevalence and identify risk factors for arrhythmias that may warrant additional screening in a sedentary mixed-breed population of horses. Methods: Prospective cross-sectional. Methods: Ninety-four clinically healthy, university-owned, sedentary horses underwent 24-h ambulatory electrocardiograms and echocardiograms. Potential risk factors were recorded for all horses. Affected individuals were defined as those with >1 supraventricular premature complex/h or with any ventric...
Seroprevalence of Equine Influenza Virus Antibodies in Horses from Four Localities in Colombia. 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...