The study of diseases in horses encompasses a wide range of conditions affecting equine health, including infectious diseases, metabolic disorders, and genetic abnormalities. These diseases can impact various systems within the horse, such as respiratory, gastrointestinal, and musculoskeletal systems, and can lead to significant health challenges. Research in this area focuses on understanding the pathophysiology, diagnosis, prevention, and treatment of equine diseases. Common diseases studied include equine influenza, equine herpesvirus, and laminitis. This page provides access to peer-reviewed research studies and scholarly articles that explore the etiology, clinical presentation, and management strategies of diseases in horses, contributing to the advancement of equine veterinary medicine.
Ryan AF, Rainey JW.THE disease that forms the subject of this
paper was first described by one of us in 1944
( Rainey, 1944 ).
Observation by us since then. separately
and in consnltation, of ,further calses of t'his
disease has enabled us to correct -0y amplify
the original description. For instance, ye know
now that although young horses have constituted
the bulk of the cases seen by us, old animals
may also suffer. We observed recently an
acute case in a seventeen-year-old gelding.
In our experience only heavy or half-bred
horses have been affected j we have observed
no case among horses of the t...
DE SALES JF, JANSEN J.Xenodiagnosis for habronemosis was 96,6% positive in 87 stud horses at Instituto Oswaldo Cuz, Rio de Janeiro, Brazil, from July-November, 1944. The A A. were unable to identify the Habronema larvae obtained from parasitider fly maggots. Measurements and drawings of the larvae are presented.
Vainio KME, Määttänen MK, Mykkänen AK, Huupponen AK, Niinistö KE.Iatrogenic aspiration pneumonia is rarely reported in horses, with most cases involving lipoid pneumonia from accidental mineral oil administration. Objective: Our aim is to describe horses with iatrogenic aspiration, highlighting clinical findings, treatment, outcomes, and prognostic differences based on the aspirated material. Methods: Management of 6 horses treated at the University of Helsinki Equine hospital due to iatrogenic aspiration between 2018 and 2023 are reported. Results: Of the six horses, three survived, two of whom regained full athletic function. Survivors received water, or ...
Partusch L, Rutland CS, Martens A, Du Cheyne C, De Spiegelaere W, Michler JK.Exuberant granulation tissue (EGT) is a second intention wound healing disorder. It commonly occurs in the distal limb of horses. EGT causes significant increase in the duration and cost of treatment, potentially leading to the decision not to pursue treatment and euthanize the patient. The underlying pathomechanisms of this fibroproliferative disorder remain unclear, particularly in terms of collagen composition and the association between myofibroblasts and blood vessels. This study investigated the collagen composition in naturally occurring EGT following trimming in 19 horses (EGT group). ...
Rimayanti R, Khairullah AR, Mustofa I, Utomo B, Lestari TD, Utama S, Akintunde AO, Mulyati S, Hernawati T, Dawood AQ, Riady G, Khan IU, Rasad SD.... is a protozoan parasite that causes the sexually transmitted disease known as "dourine" in horses. This chronic illness is directly spread from one animal to another during mating. Doflein proposed the name in 1901. Despite being distributed worldwide, the broad use of artificial insemination technology over the past three decades has resulted in only a few cases being documented. The condition is typically fatal and is characterized by gradual emaciation, nervous system involvement, and edematous lesions of the genitals. The incubation period between exposure and the onset of clinical sympt...
McLachlan AD, Woolford L.Chlamydia psittaci was detected by real-time PCR in the lung, liver and kidney of an equine foetus that had aborted in South Australia in August 2023. The corresponding microscopic lesions included lymphocytic and histiocytic chorionitis, necrosis of placental villi associated with bacteria in the cytoplasm of trophoblastic epithelial cells, and multiple microgranulomas in the liver. Equine chlamydial abortion had not been diagnosed previously in South Australia. Eight days after examining the foetus and placenta, the veterinary pathologist developed fever and subsequently was admitted to hosp...
Alsultan A, Karim SM, Al-Saadi M, Alsallami D, Ben Said M, Belkahia H.Equine piroplasmosis (EP), caused by the intracellular protozoa Theileria equi, Babesia caballi, and Theileria haneyi, represents a major health and economic threat to the equine industry worldwide. Existing diagnostic methods, including PCR, serology, and microscopy, are constrained by their dependence on specialized equipment, lengthy protocols, and the requirement for skilled personnel. Objective: This study aimed to develop a rapid, accurate, and field-deployable molecular diagnostic assay for T. equi. Methods: A nucleic acid-based diagnostic platform combining recombinase polymerase ampli...
Linnegar B, Hoegh A, McCallum H, Peel AJ.Anthropogenic climatic and landscape change can drive behavioural shifts in wildlife and thus lead to increased risk of pathogen exposure for humans and domestic animals. While spillover research often focuses on the reservoir hosts or ongoing transmission in humans, livestock and companion animals can play important roles as bridging and amplifying hosts, facilitating the emergence of highly pathogenic diseases. Objective: To investigate the distribution and density of domestic horses in the context of their role as bridge hosts for Hendra virus and build models to study zoonotic emergence. M...
Kyle-LaBell E, Andersson A, Baughman B.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...
Khan MZ, Ji Y, Fan X, Liu Y, Liu W, Wang C.Equine herpesvirus (EHV) infections represent a significant global veterinary and economic challenge affecting both horses and donkeys across all inhabited continents. This narrative review comprehensively examines the nine distinct EHV species (EHV-1 through EHV-9), their taxonomic classification within Alphaherpesvirinae and Gammaherpesvirinae subfamilies, and their diverse host tropism patterns. The complex molecular pathogenesis involves sophisticated viral glycoproteins (gK, gB, gC, gH, gM, gL, gG, gD, gI, gE) that orchestrate cellular invasion, immune evasion, and intercellular transmiss...
Björnsdóttir S, Sigurðardóttir ÓG, Oddsdóttir C, Reynisdóttir I, Hanche-Olsen S, Gröndahl G.Acquired equine polyneuropathy is a neuromuscular syndrome characterized by digital extensor dysfunction, primarily affecting the pelvic limbs, with consistent, repeated knuckling. Despite being recognized as an emerging disease in Scandinavia since 1995, the aetiology remains unknown, and cases have been limited to Norway, Sweden, and Finland. Methods: On a combined breeding and training farm in Iceland, 30 out of 145 horses (21%) presented with acute pelvic weakness, pelvic limb digital extensor dysfunction, knuckling and/or recumbency, from May to August 2019. The affected horses, aged 2-9Â...
François AC, Taminiau B, Renaud B, Gonza-Quito IE, Massey C, Hyde C, Piercy RJ, Douny C, Scippo ML, Daube G, Gustin P, Delcenserie V, Votion DM.Hypoglycin A is a plant-derived protoxin that causes atypical myopathy in equids. In atypical myopathy-affected horses, metabolomic and microbiome studies have reported alterations in metabolic markers and faecal microbiota composition, pointing to a potential disruption of microbial homeostasis. However, in vivo observations are strongly confounded by host-related factors, underscoring the need for controlled in vitro approaches. To address this, we used an in vitro static batch fermentation model simulating the equine colon to investigate the direct effects of hypoglycin A on microbiota comp...
Pekkarinen HM, Simola U, Niinistö KE, Syrjä PES.Equine inflammatory bowel disease (IBD) is challenging to diagnose and treat. Although the number of horses examined due to suspicion of IBD is increasing, the different treatments in clinical patients and their responses are not well documented. We sought to characterize the demography, signs, clinical and rectal biopsy findings, and treatment response in Finnish horses suspected to have IBD. Horses undergoing clinical examination due to suspected IBD in 2022 and with a good-quality rectal biopsy were selected for the study. General information, signs, clinical and histological findings, and ...
McAdams ZL, Campbell EJ, Dorfmeyer RA, Turner G, Shaffer S, Ford T, Lawson J, Terry J, Raju M, Coghill L, Cresci L, Lascola K, Pridgen T....Horses and other equids are reliant on the gut microbiome for health, and studies have reported associations between certain clinical conditions and features of the fecal microbiome. However, research to date on the equine fecal microbiome has often relied on small sample sizes collected from single and relatively localized geographic regions. Previous work also largely employs single timepoint analyses, or horses selected based on limited health criteria. Results: To address these limitations and expand our understanding of the core microbiome in health, and the changes associated with advers...
White J, Thompson K, van den Berg D, O'Neill G, Mendez DH, Talwar J, Degeling C, Forsythe R, Durrheim DN.With more than 60% of emerging infectious diseases being zoonotic, we apply a One Health lens that connects human, animal, and environmental dimensions of the response to a Hendra virus (HeV) event. One Health promotes collaboration among health professionals, veterinarians, environmental scientists, and policymakers to strengthen health infrastructure and improve responses to complex health threats. HeV is an uncommon high-consequence and potentially fatal zoonotic disease endemic to parts of Australia. Previous research has largely focused on the uptake of preparedness measures by veterinari...
Pereira GF, Blimbliem MCH, Machado ALPR, Abdala JBR, Nogueira GM, Toma HS, de Carvalho TF, Delfiol DJZ.Arsenic poisoning in horses is rarely reported in the literature. However, arsenic compounds can be present in rodenticides, pesticides, and herbicides, representing a potential source of accidental exposure for horses. Objective: To describe the epidemiological, clinical, and laboratory findings from a herd of 31 horses exposed to pasture treated with an overdose of sodium hydrogen methylarsonate, and to compare results in a group of horses exposed to the recommended dosage of the same product. Methods: Observational field study. Methods: Thirty-one horses were evaluated after grazing on a pa...
Silva JG, Martins KR, Rahal NM, Schuch LFD, Cunha RC, Meireles MCA.Neorickettsia risticii, an obligate intracellular bacterium, is the causative agent of Potomac Horse Fever (PHF) - a systemic, acute, and potentially fatal diarrheal disease. This pathogen is an endosymbiont of digenetic trematodes, with freshwater snails playing a role in its biological cycle. The disease exhibits endemic and seasonal patterns, primarily affecting horses in wetlands during warmer months, and has been documented in the United States, Canada, Europe, and South America. Previous studies confirmed the pathogen's presence in herds from southern Brazil via serology and PCR; however...
Schank N, Cottone A, Wulf M, Seiter K, Thomas B, Miller LMJ, Anderson SL, Sahyoun A, Abidi AH, Kassan M, Verma A.Equine colic remains a prevalent and potentially life-threatening condition with multifactorial origins, including dietary imbalances, stress, and microbial dysbiosis. Central to equine gut health is the production of short-chain fatty acids (SCFAs), primarily acetate, propionate, and butyrate, generated through microbial fermentation of dietary fibers in the hindgut. These metabolites not only serve as vital energy sources but also play crucial roles in maintaining intestinal barrier integrity, modulating motility, and suppressing inflammation. This review explores the role of SCFAs in equine...
Gonzálvez M, Franco JJ, Cano-Terriza D, Barbero-Moyano J, Jose-Cunilleras E, GarcÃa J, Alguacil E, GarcÃa-Bocanegra I.Equine Infectious Anemia (EIA) is a notifiable disease caused by Equine Infectious Anemia Virus (EIAV), with major sanitary and economic importance for equids worldwide. There is limited and outdated information on the circulation of EIAV in many European countries. In the present study, we aimed to assess virus exposure in different equid species in Western Europe. Methods: Between 2011 and 2023, a cross-sectional study was conducted to investigate the seroprevalence of EIAV in 1676 equids (1444 horses, 106 donkeys and 126 mules/hinnies) from four European regions: Andalusia (Southern Spain; ...
Sohn Y, An SJ, Forbes E, Yoon J, Kim BS, Ryu SH, Lee I.Osteochondritis dissecans (OCD) is a developmental orthopedic condition in young horses. Exercise and management affect OCD development, but the impact of exercise patterns during the 6-12 months growth period remains unclear. This study examined the association between OCD lesions in Thoroughbred foals and irregular exercise patterns. Forty foals wore halter-mounted Global Positioning System devices that recorded velocity every five seconds during turnout. Foals were routinely turned out for approximately 13 h daily, except on rainy days. Radiographs were taken at six and twelve months of a...
Stapley E, Gillespie-Harmon C, Waxman S, Farr A, Bertin FR.The frequency of comorbidities in horses with pituitary pars intermedia dysfunction (PPID) in first-opinion practice is unknown. It is hypothesized that horses with PPID would have more frequent medical events and be euthanized at a younger age. Unassigned: This was a case-control retrospective study. Medical records ranging from 1996 to 2024 including 132 horses diagnosed with PPID and 274 controls matched by age and breed were reviewed. Variables associated with PPID were evaluated with a Fisher exact or Mann-Whitney U test followed by conditional logistic regression. Results were reported a...
Hiblu MA, Ahmed MO.This case report documents the first identified Brucella infection in a 6-year-old male Thoroughbred horse in Libya. The horse exhibited muscle and joint pain, inflammation over the shoulders with a pulpy texture (fistulous withers), stress, fatigue, and potential systemic infection. Its diagnosis was confirmed through serological testing, with agglutination titers of 1/80 for B. melitensis and 1/160 for B. abortus, and a blood culture revealing Gram-negative coccobacilli. After 3 weeks of combination therapy with rifampicin and doxycycline, the inflammation resolved, systemic signs disappeare...
Harpke M, Brangsch H, Melzer F.In Germany, Contagious Equine Metritis (CEM) is a persistent problem in equine populations. The often subclinical nature of the disease, which is caused by the bacterium Taylorella equigenitalis, poses a problem for the breeding industry. However, there is a lack of knowledge about the genomic diversity of the pathogen in Germany, as studies on the genome level are lacking. Thus, in this study we sequenced 63 T. equigenitalis isolates from a strain collection and contemporary clinical isolates from before 2007-2024. Most of these isolates came from Icelandic horses in southern Germany. Based...
Raftery AG, Gummery L, Garcia K, Mohite D, Capewell P, Sutton D.Equine trypanosomiasis is a neglected protozoal disease. Objective: To answer the study question: In equines what are the effects of disease management of trypanosomiasis on disease severity (individual level) and disease prevalence (population level) compared to no intervention? Methods: Systematic review. Methods: Studies were identified that described management of naturally occurring equine trypanosomiasis in any country following 'Preferred Reporting Items for Systematic Reviews and Meta-analyses' using eight international databases (1980-2022). Risk of bias was assessed using ROBINS-I. D...
Rossi TM, O'Sullivan TL, Greer AL.Competitions are an important source of entertainment and revenue in the horse industry but may contribute to disease introduction and spread. The objectives of this study were to, (i) describe the annual (2016 to 2018) contact networks of Equestrian Canada competitions in Ontario, Canada, and (ii) determine if the networks exhibit characteristics of 'small world' networks. Data on Equestrian Canada registered competitions in the province of Ontario, Canada between 2016 and 2018 were used to create three types of yearly contact networks: competition networks, horse networks, and venue networks...
Jager MC, Luethy D, Shallop S, Cathcart J, Divers TJ, Tan JY, Beasley EM, Johnson P, Leduc L, Smith C, Jamieson CA, Magdesian KG, Van de Walle GR....Equine hepacivirus (EqHV) is closely related to hepatitis C virus (HCV), which causes persistent infection and chronic hepatitis in people. Information on persistent EqHV infection and hepatitis is limited. Objective: To report 19 cases of chronic hepatitis and persistent EqHV infection. Methods: Mixed retrospective and prospective case series. Methods: Inclusion criteria were: (1) chronic hepatitis, defined as persistently increased serum liver biomarkers, increased serum liver biomarkers accompanied by histopathological evidence of chronicity, for example, fibrosis, or both; (2) positive ser...
Decoster C, Lefère L, Raes E, van Loon G, Dufourni A.Leptospirosis is a widespread zoonotic, infectious disease associated with abortion, stillbirth, as well as liver and kidney failure. Leptospiral Pulmonary Haemorrhage Syndrome (LPHS) has increasingly been reported in human and canine patients infected by Leptospira and is associated with a high fatality rate. In equine medicine, pulmonary haemorrhage has mainly been described in foals with leptospiral infections, but rarely in adult horses. Objective: To characterise the clinicopathological features of pulmonary haemorrhage as a distinct disease entity in adult horses with leptospirosis, term...
Rossi GAM, Sellera FP, Ferraz CM, Carvalho RS, Oliveira APL, Marques CA, Fávaro EBR, Rosa RDS, Silva LAM, Cardozo MV, Stehling EG, Furlan JPR. Infections caused by antimicrobial-resistant bacteria are difficult to treat and increase the risk of death in animals. This report describes a fatal case of diarrhea in a horse that, despite intensive treatment including surgery and broad-spectrum antimicrobials (ceftiofur and amikacin), experienced a worsening of its condition and subsequent death. A fecal swab sample was subjected to microbiological culture for the identification of bacteria and assessment of their phenotypical antimicrobial susceptibility profiles using the disk-diffusion and broth microdilution methods. The double-disk ...
Atasoy MO, Turan T, Özbek R, Işıdan H, Naggar RFE, Afify AF, Rohaim MA.The genus (HCV) has long been a dynamic group, increasing its number by myriads of species collectively referred to as non-primate hepaciviruses (NPHVs). NPHV exhibits a broad hepatotropism and is often attributed to chronic infection in horses and dogs. However, recent studies and meta-analyses on NPHV in horses have remained inconclusive regarding the determination of risk factors for infection. Therefore, our main goal was to investigate the frequencies and molecular characteristics of NPHV infection linked to geographical location, horse breeds, genders, and ages. For this purpose, we tes...
Sayre KC, Flores-Ahlschwede P, Wethington AB, Kahn SK, Bray JM, Volding DM, Ahlschwede S, Bordin AI, Cohen ND, Welsh TH.Transfusion of Rhodococcus equi hyperimmune plasma (REHIP) to neonatal foals is done to reduce the incidence of rhodococcal pneumonia. Objective: To determine effects in newborn foals of REHIP transfusion on serum cortisol concentrations; the association of serum cortisol concentrations with serum globulin concentration and anti-rhodococcal immunoglobulin activity; and cumulative incidence of rhodococcal pneumonia. Methods: Serum samples were collected from 356 newborn foals from 13 New York farms immediately before and after transfusion of 1 L or 2 L of REHIP. Serum samples were assayed for c...
Puccetti M, Beccati F, Pilati N.Femoral nerve neuropathy causes lameness, a condition clinically characterized by stifle's lack of extension with subsequent diminished lower limb function. This case report describes the ultrasonographic diagnosis of femoral neuropathy secondary to compression caused by myopathy of the iliopsoas muscle of an endurance horse during a competition. Transrectal ultrasonography played a pivotal role in diagnosis of the injury by assessment of the involved structures and monitoring of the healing process throughout the recovery period. The horse achieved complete recovery and successfully returned ...
Riquelme LF, de Araújo VO, da Silva TKF, de Sousa MS, da Silva MA, da Silva WDQ, Lucena RB.Malachra fasciata Jacq. (Malvaceae) is an invasive plant widely found in Northeastern Brazil and has been experimentally demonstrated to cause severe dermatitis in sheep. However, its toxic effects in horses have not previously been documented. This report describes primary photosensitization in four Quarter Horses grazing on a pasture heavily infested with M. fasciata in ParaÃba, Brazil. Affected animals developed alopecic, erythematous, crusted, and ulcerated lesions on sun-exposed areas, accompanied by severe pruritus and behavioral signs of distress. Histopathology revealed epidermal ulce...
