Pathology in horses involves the study of diseases and abnormalities affecting equine health, encompassing a range of conditions that can impact various systems within the horse's body. This field examines the causes, mechanisms, and effects of diseases, as well as the structural and functional changes they induce in equine tissues and organs. Common pathological conditions in horses include laminitis, colic, equine infectious anemia, and respiratory disorders. Understanding these diseases involves evaluating clinical signs, diagnostic methods, and treatment options. This page compiles peer-reviewed research studies and scholarly articles that explore the etiology, pathogenesis, and clinical implications of pathological conditions in horses.
Yang G, Chen Y, Chen K, Hu Z, Li J, Wang J, Guo W, Wang X, Du C.Equine piroplasmosis (EP), caused by Theileria equi (T. equi) and Babesia caballi (B. caballi), is a tick-borne disease with significant economic impacts on the equine industry. Theileria haneyi (T. haneyi), a newly identified pathogen of EP, is globally distributed but has not been reported in China, where its epidemiological patterns remain undefined. Objective: To develop diagnostic techniques for T. haneyi and to assess its prevalence and risk factors in China. Methods: Assay development and cross sectional survey. Methods: A nested PCR (nPCR) nucleic acid diagnostic technique targeting th...
Gómez-Torres F, Ballesteros-Acuña L, Ruíz-Sauri A.Arrhythmic sudden cardiac death in dogs and horses often results from ventricular arrhythmia secondary to myocardial damage. Despite this, limited data exist on the histomorphometric changes in cardiac conduction fibers (CCFs) and cardiac conduction cells (CCCs) following spontaneous myocardial infarction (MI). This study aimed to characterize morphometric and histological alterations in conduction fibers and their junctions with cardiomyocytes in infarcted hearts of horses and dogs. Unassigned: Ten hearts from horses and 10 from dogs that had died suddenly were examined. Histological and immu...
Giorgio SD, Monti S, Palmieri V, Marino G, Napoli E, Vullo C, Catone G.A 3-year-old Quarter horse stallion with unilateral left cryptorchidism was referred for the absence of the left testis in the scrotal bursa and an enlarged right testis. The ultrasonographic examination revealed the presence of the left testis at the abdominal level. Two small hyperechogenic lines were observed running parallel and resembling a cylindrical cavitary foreign body, within a non-homogeneous area with blurred margins. The testis was removed by laparoscopy and macroscopically, the testis's cut section revealed the presence of two live adult nematodes emerging from 2 mm blood-filled...
Labens R, Saba C, Williams J, Hollis A, Ensink J, José-Cunilleras ELV, Jordana-Garcia M, Bergvall K, Ruppin M, Condon F, Spelta C, Elce Y....Intralesional chemotherapeutic administration represents an important treatment option for equine cutaneous neoplasia. Tigilanol-tiglate (TT), a novel molecule extracted from Fontainea picrosperma, an Australian rainforest plant, is registered for intratumoural treatment of canine MCT, leading to rapid oncosis and tumour slough. Evidence from horses is limited but suggests that efficacy may be similar. Objective: To evaluate the response to intratumoural TT treatment in horses with sarcoids (fibroblastic/nodular) and cutaneous melanomas. Methods: Two noncontrolled prospective multicentre clini...
Gravey F, Sévin C, Langlois B, Maillard K, Foucher N, Duquesne F, Léon A, Le Hello S, Petry S.Misidentifications as Klebsiella pneumoniae were observed during a French retrospective study of a necropsy-associated K. pneumoniae bacterial collection from horses. Accordingly, the present study aimed to further characterise the 12 Raoultella spp. and Klebsiella spp. strains involved in these misidentifications. The strains were identified and characterised using the Api 20E system, K. pneumoniae PCR detection, matrix-assisted laser desorption/ionisation time-of-flight mass spectroscopy and whole-genome sequencing. Antimicrobial susceptibilities were tested by the disc diffusion method with...
Bain ME, Alsop EJ, Knox CA, Tweedie MA, Knottenbelt DC.Mycobacterium ulcerans infection in horses is under-reported. Objective: To document the successful multimodal treatment of M. ulcerans and highlight the need for further investigation due to the zoonotic nature of M. ulcerans with its related potential public health concerns. Methods: Case report CASE DESCRIPTION: A 14-year-old gelding in the Southeastern region of Australia was diagnosed with M. ulcerans infection, initially presenting as a non-healing wound of the right flank progressing to extensive necrotic ulceration. Ziehl-Neelsen and Wade-Fite stained incisional biopsies revealed large...
Fischetti L, Perina F, Sarli G, Ellero N, Freccero F, Castagnetti C, Mariella J.A 286-day pregnant mare was referred for signs of impending abortion. The ultrasonographic evaluation revealed a high normal combined thickness of the utero-placental unit (CTUP), oligohydroallantois and a living fetus. No vulvar discharge was observed, and the cervical swab culture was negative. After a choke, the mare received NSAIDs and antibiotics and then developed systemic inflammatory response syndrome (SIRS) and aborted. The amniotic portion of the umbilical cord was excessively long and twisted and the chorionic side of the placenta showed a brown discoloration and rough surface area....
Morgan J, Curtis Shaw G, Weisman J, Cecere T, Carvallo-Chaigneau FR.A 2-d-old Warmblood colt was submitted for autopsy with a spectrum of bilateral ocular abnormalities. At postmortem examination, a constellation of lesions within the anterior segment included retention of ectodermal elements, compatible with choristoma. Ocular choristomas can be localized to different intraocular structures and are rare in equids. The morphologic features in our case were suggestive of abnormal corneal differentiation.
Engiles JB, Stefanovski D, van Eps A.To examine the effects of prolonged preferential weight bearing (PWB) and reduced ambulation (RA) on hoof lamellae using a nonpainful in vivo experimental model. Unassigned: 12 healthy Standardbred horses were housed in stocks continuously for 92 hours. A platform shoe was placed on 1 forelimb in the PWB group (n = 6) to increase the load on the supporting limb (SL) by approximately 10% bodyweight, whereas the RA group (n = 6) had normal weight bearing. Archived healthy horse (n = 8) samples were used as controls. Histomorphometry and histochemistry (terminal deoxynucleotidyl transferase dUTP ...
Primo ALM, Assis DM, Santos VGS, de Melo LRB, da Nóbrega LD, Medeiros Dantas AF, Maciel TA.Cerebellar abiotrophy is a neurodegenerative disease that affects the Purkinje cells of the cerebellum, resulting in premature neuronal death. In horses, its occurrence has been reported mainly in the Arabian breed as a congenital mutation inherited in an autosomal recessive manner. The objective of this study was to describe the case of cerebellar abiotrophy in a Quarter Horse foal. An 8-day-old foal was treated after presenting signs of ataxia, hypermetria, difficulty maintaining a standing position, and decreased menace response. The foal was hospitalized for 26 days, received treatment wit...
Johnson JP, Cardenas FA, Asakawa MG, Oikawa MA.Myofibroblastic fibrosarcoma (MFS) is a malignant soft tissue tumour that is rare in domestic animals. Here we report a case of congenital MFS in an Arabian foal at birth. A large solitary subcutaneous mass arising in the left temporal region was found in the foal. On cut section, an unencapsulated hemispheric, white-yellowish, elastic fibrous mass was attached to the temporal bone. Histologically, the mass was composed of a neoplastic proliferation of spindle-shaped fibroblasts arranged in fasciculate or interwoven streams and bundles, with low nuclear atypia and mitotic rate, local invasion ...
Pozor MA, Macpherson ML, Kelleman AA, Smith H, McNaughten JW.This retrospective study aimed to validate the usefulness of spectral Doppler ultrasonography in diagnosing testicular dysfunction in stallions. The first part of the study included a pony stallion with age-related testicular degeneration (18 - 21 yrs. old). Testicular dimensions, spectral Doppler parameters of testicular blood flow, and semen parameters were obtained numerous times from this pony over four consecutive years. While testicular volume decreased dramatically, and the stallion became azoospermic, there were no changes in any of the spectral Doppler parameters of testicular blood f...
Valberg SJ.Although horses most commonly develop exertional rhabdomyolysis, there are numerous causes for nonexertional rhabdomyolysis (nonER) that pose a serious health threat to horses. Their etiologies can be broadly categorized as toxic, genetic, inflammatory/infectious, nutritional, and traumatic and a variety of diagnostic tests are available to discern among them. This study discusses causes of nonER as well as diagnostics and treatments that are specific to each etiology. General treatment of acute rhabdomyolysis is covered in detail in the study in this issue on sporadic and recurrent exertional...
McKenzie E.The equine muscle system is complex and prone to a large range of hereditary and acquired diseases that often have overlapping clinical signs with orthopedic, neurologic, and other disorders. Obtaining a clinical history that fully outlines the client concerns and any known information about the disorder and following with a comprehensive physical examination and screening clinical pathology tests are fundamental to achieve definitive diagnosis. A methodical and comprehensive approach aids accurate diagnosis and development of an optimal treatment and management plan. This article describes th...
McGowan C.Traumatic muscle injuries are likely to be frequent in athletic horses yet are often overlooked. These injuries usually involve internal (intrinsic) trauma, and particularly occur in athletic horses exercising at higher intensities, at unaccustomed workloads, or performing work requiring sudden acceleration, deceleration, and/or direction changes. These injuries can present with signs ranging from acute pain and lameness in a localized region to unexplained elevations of muscle enzymes on routine blood tests with or without poor performance. They include exercise-induced muscle damage such as ...
Finno CJ.In the field of equine muscle disorders, many conditions have a genetic basis. Therefore, genetic testing is an important part of the diagnostic evaluation. Validated genetic tests are currently available for 5 equine muscle disorders: hyperkalemic periodic paralysis, malignant hyperthermia, glycogen branching enzyme disease, type 1 polysaccharide storage myopathy, and myosin heavy chain myopathy. These diseases should be tested for in the appropriate breeds with clinical signs of disease or as part of breeding management. Genetic testing in veterinary medicine is not regulated, and therefore,...
Durward-Akhurst SA, Valberg SJ.Several inflammatory myopathies have an infectious or immune-mediated basis in the horse. Myosin heavy chain myopathy is caused by a codominant missense variant in MYH1 and has 3 clinical presentations: immune-mediated myositis, calciphylaxis, and nonexertional rhabdomyolysis in Quarter Horse-related breeds. An infarctive form of purpura hemorrhagica affects numerous breeds, presenting with focal firm, painful muscle swelling, and subsequent infarction of multiple tissues. While Streptococcus equi equi is often the inciting cause, anaplasmosis, sarcocystis, piroplasmosis, viruses, and vaccines...
Valberg SJ, Williams ZJ.Myofibrillar myopathy (MFM) is characterized by segmental disarray of myofibrils and ectopic accumulation of a protein called desmin. Previously thought to be a glycogen storage disease, MFM is now recognized as a stand-alone myopathy. Endurance Arabians with MFM usually present with exertional rhabdomyolysis (MFM-ER) at the end of races, elevated serum muscle enzymes, and myoglobinuria. Warmblood horses with MFM (MFM-WB) usually present with pain-associated behaviors such as exercise intolerance, reluctance to engage hind quarter muscles, shifting lameness and normal serum muscle enzymes. Bot...
Pusterla N, Barnum S, Lawton K, Craig B, James K.Equid alphaherpesvirus 4 (EqAHV4; Orthoherpesviridae, Varicellovirus equidalpha4; equine rhinopneumonitis virus) has seldom been associated with complications such as abortion and myeloencephalopathy, given the low tendency of this virus to induce viremia. We investigated the frequency of EqAHV4 viremia in horses with fever and respiratory signs. Case selection included all equids with EqAHV4 quantitative real-time PCR (qPCR)-positive nasal secretions (defined as EqAHV4 qPCR-positive cases) submitted to a diagnostic laboratory. Controls consisted of each case submitted before and after each Eq...
Kublicka A, Lorek D, Mikołajczyk-Martinez A, Chodaczek G, Chwirot A, Bażanów B, Matczuk AK.The process of viral entry into host cells is crucial for the establishment of infection and the determination of viral pathogenicity. A comprehensive understanding of entry pathways is fundamental for the development of novel therapeutic strategies. Standard techniques for investigating viral entry include confocal microscopy and flow cytometry, both of which provide complementary qualitative and quantitative data. Imaging flow cytometry, which integrates the advantages of both methodologies, offers significant potential in virological studies. In this investigation, we employed imaging flow ...
Drzewiecka EM, Molcan T, Sadowska A, Piotrowska-Tomala K, Słyszewska M, Dias GF, Skarżyński DJ, Szóstek-Mioduchowska A.Mares with endometrosis exhibit histological changes not only in the endometrium but also in the myometrium that suggest possible functional impairment. The molecular background of these changes is not well understood. We hypothesize that the transcriptomic profile of the mare myometrium varies depending on the degree of endometrosis in mares. Myometria were collected from mares in the mid-luteal phase of the estrous cycle with endometrium categories I, IIA, IIB, and III (∑n = 23), according to Kenney and Doig´s histopathological classification. Myometrial RNA was isolated and subjected...
Jurisic L, Auerswald H, Marcacci M, Di Giallonardo F, Coetzee LM, Curini V, Averaimo D, Ortiz-Baez AS, Cammà C, Di Teodoro G, Richt JA, Holmes EC....Members of the RNA virus order infect hosts ranging from marine invertebrates to terrestrial mammals. As such, understanding the determinants of host range in this group of viruses, as well as their patterns of emergence and disease potential, is of clear importance. The are a recently documented family within the . To date, mesoniviruses have only been associated with the infection of arthropod species, particularly mosquitoes, and hence are regarded as insect-specific viruses (ISVs). Herein, we report the first detection of a mesonivirus-Alphamesonivirus-1 -in mammals. Specifically, we uti...
Shi Y, Maga EA, Mienaltowski MJ.Diarrhea is a common disease that could threaten the welfare of newborn foals. While there are several forms of foal diarrhea, the etiologies can be considered known pathogenic or non-pathogenic in nature. Moreover, there are likely differences in the composition of microbial populations in the gastrointestinal tracts of foals depending upon the etiology of diarrhea. Our study aims to examine the microbial population in the feces of foals with both pathogenic and non-pathogenic diarrheas to discern differences in their microbial compositions. Results: Foal diarrhea samples tested positive or n...
Fakheri A, Esmaeilnejad B, Akbari H, Molaei R.Strongyle nematodes pose a major challenge in veterinary parasitology, causing significant economic losses in livestock due to resistance to conventional treatments. Current anthelmintics, like Ivermectin, often encounter resistance issues. This study aims to address these gaps by synthesizing Carbon Quantum Dots (CQDs) and Copper-Doped CQDs (Cu@CQDs) using glucose extract, and evaluating their nematicidal properties against strongyles in vitro. We assessed the nematicidal effects of CQDs and Cu@CQDs through larval feeding inhibition of first-stage larvae (L1), egg hatch inhibition (EHI), and ...
Stumpfe MC, Horch RE, Müller-Seubert W.Pressure ulcers are a persistent and growing challenge in modern medicine, with prevalence rates ranging from 3.4% to 32.4% globally. Demographic changes suggest an increasing number of patients at risk, emphasizing the need for effective prevention and advanced treatment strategies. These ulcers, particularly stages III and IV, often require surgical intervention due to severe tissue damage. Among the surgical options, the Posterior Thigh Flap has emerged as a reliable fasciocutaneous flap, frequently referred to as a "work-horse flap", for defect coverage in the ischial region. To improve ou...
Millares-Ramirez EM, Dupuis-Dowd F, Mainguy-Seers S, Lavoie JP.In severe equine asthma, structural remodeling of the airways ultimately leads to bronchial wall thickening and airflow obstruction. Increased bronchial vascularization has been described in horses affected by the severe form of the disease, but whether it contributes to bronchial remodeling in milder forms of asthma remains to be determined. In a blinded, retrospective case-control study, we evaluated the presence of bronchial angiogenesis in horses with mild and moderate equine asthma (MEA) and its correlation to airway smooth muscle remodeling. Methods: Endobronchial biopsies from the Equin...
Carvalho Serena G, Marchezan Piva M, Viezzer Bianchi M, Fernandes da Fonseca HC, Chitolina Pupin R, Martins Basso R, Secorun Borges A....In horses, systemic calcinosis is a rare syndrome characterised by muscle lesion associated with the mineralisation of large muscle groups or other organs, in the absence of an alternative cause for the calcification, such as toxic, enzootic or metabolic. Molecular and histopathological aspects of the disease are still poorly elucidated. Objective: To describe the epidemiological, pathological and molecular aspects of systemic calcinosis in a convenience sample of six horses submitted to necropsy in the Southern and Midwestern regions of Brazil. Methods: Retrospective exploratory study. Method...
Fletcher KA, Padalino B, Felici M, Bigi D, Limon-Vega G, Grist A, Gibson TJ.There is limited research into horse slaughter, particularly ante mortem welfare, and the effectiveness of captive-bolt gun (CBG) stunning, despite this being a widely used method worldwide. To address this evidence gap and explore associations between ante and post mortem factors, the welfare of 62 horses was assessed at a commercial Italian abattoir. Animal-based measures were used to identify stress-related behaviours and stunning effectiveness. A sub-sample (44%; 27/62) of heads were assessed for gross brain pathology. All animals in the study showed stress-related behaviours at all stage...
Piotrowska-Tomala KK, Szóstek-Mioduchowska A, Jonczyk AW, Drzewiecka EM, Wrobel MH, Hojo T, Ferreira-Dias G, Skarzynski DJ.Endometrosis (chronic degenerative endometritis) results in morphological changes in the equine endometrium and impairs its secretory function. However, the effect of this condition on the myometrium remains unclear. Lysophosphatidic acid (LPA) may affect female reproductive function and embryo transport by influencing uterine contractility through its receptors (LPARs). The objective of this study was to determine myometrial LPAR1-6 mRNA transcription, and the effects of LPA on myometrial contractions in mares with endometrosis during the mid-luteal and follicular phases of the estrous cycle....
Clabough DL, Gebhard D, Flaherty MT, Whetter LE, Perry ST, Coggins L, Fuller FJ.An adult horse infected with a virulent, cell culture-adapted strain of equine infectious anemia virus (EIAV) developed cyclical thrombocytopenia in which the nadir of platelet counts coincided with peak febrile responses. In order to investigate the mechanism of thrombocytopenia during acute febrile episodes, four adult horses were experimentally infected with the wild-type Wyoming strain of EIAV. Platelet counts decreased from baseline as rectal temperature increased. Serum reverse transcriptase activity increased above background levels in all horses, coincident with increase in rectal temp...
Friedhoff KT, Soulé C.A review of the distribution of Babesia equi and Babesia caballi, the
transmission of these protozoa by ticks and the immune response of infected
horses, in addition to a brief survey of diagnostic. tests and chemotherapy.
Hyatt AD, Selleck PW.The ultrastructure of the equine morbillivirus (EMV) which was implicated in the death of one human and fourteen horses in Queensland, Australia during September 1994 and a 36 year old man from Queensland in October 1995 is described. The ultrastructure of the virus and the intracellular virus-specific structures are characteristic for the family Paramyxoviridae. Cytoplasmic nucleocapsids were observed within the infected cells monolayers, endothelial cells (lung) of infected horses and the neurons within the brain of the 36 year old Queensland man. Aggregates of smaller nucleocapsid-like stru...
Monthoux C, de Brot S, Jackson M, Bleul U, Walter J.Skin malformations that resembled manifestations of Ehlers-Danlos-Syndrome were described in a variety of domestic animals during the last century as cutis hyperelastica, hyperelastosis cutis, dermatosparaxis, dermal/collagen dysplasia, dermal/cutaneous asthenia or Ehlers-Danlos-like syndrome/s. In 2007, the mutation responsible for Hereditary Equine Regional Dermal Asthenia (HERDA) in Quarter Horses was discovered. Several case reports are available for similar malformations in other breeds than Quarter Horses (Draught Horses, Arabians, and Thoroughbreds) including four case reports for Warmb...
James FM, Engiles JB, Beech J.A 12-year-old Thoroughbred was examined because of signs of depression, neck stiffness, and poor performance. Results: Physical examination revealed that the horse was dull, appeared depressed, was reluctant to raise its neck and head above a horizontal plane, and had a temperature of 38.5°C (101.3°F). No radiographic or scintigraphic abnormalities of the neck were found; however, high plasma fibrinogen concentration and relative lymphopenia were identified and the horse was seropositive for antibodies against Borrelia burgdorferi. Analysis of CSF revealed neutrophilic inflammation, and resu...
Martens A, De Moor A, Ducatelle R.The purpose of this study was to examine if bovine papilloma virus (BPV) DNA can be detected in superficial swabs or scrapings from equine sarcoids. Samples were obtained from 92 sarcoids and 20 non-sarcoidal control lesions. The polymerase chain reaction technique was used with a first primer set to check whether DNA extraction was successful, and with a second primer set specific for BPV-DNA. DNA isolation was successful in 88% of the swabs and 93% of the scrapings. All control lesions were negative for BPV-DNA.
Carr EA, Théon AP, Madewell BR, Griffey SM, Hitchcock ME.To determine the incidence of bovine papillomavirus (BPV) type 1 or 2 in sarcoids and other samples of cutaneous tissues collected from horses in the western United States. Methods: 55 horses with sarcoids and 12 horses without sarcoids. Methods: Tissue samples (tumor and normal skin from horses with sarcoids and normal skin, papillomas, and nonsarcoid cutaneous neoplasms from horses without sarcoids) were collected. Tissue samples were analyzed for BPV-1 or -2 DNA, using a polymerase chain reaction (PCR) and restriction fragment length polymorphism. The PCR products from 7 sarcoid-affected ho...
Mendoza L, Alfaro AA.Thirty-nine pythiosis equine cases, were studied at the Veterinary Medicine School of the National University of Costa Rica, between 1981 and 1984. Lesions were located in different parts of their anatomy: anterior and posterior extremities, abdomen, thorax, breast and mammary gland, and were characterized by their tumoral appearance with necrotic tissue in which yellow-white coral-like necrotic masses, called kunker or leeches were shown. Splendore-Hoeppli like phenomenon and eosinophilic inflammatory reaction around the hyphae, was microscopically observed. Pythium sp. (Hyphomyces destruens)...
Li F, Leroux C, Craigo JK, Cook SJ, Issel CJ, Montelaro RC.Equine infectious anemia virus (EIAV) is genetically one of the simplest lentiviruses in that the viral genome encodes only three accessory genes, tat, rev, and S2. Although serological analyses demonstrate the expression of the S2 protein in persistently infected horses, the role of this viral gene remains undefined. We recently reported that the S2 gene is not essential for EIAV replication in primary equine macrophages, as EIAV mutants lacking the S2 gene replicate to levels similar to those of the parental virus (F. Li, B. A. Puffer, and R. C. Montelaro, J. Virol. 72:8344-8348, 1998). We n...
Pirie RS, Couëtil LL, Robinson NE, Lavoie JP.In their editorial in Equine Veterinary Journal (EVJ) almost a quarter of a
century ago, Hall and Stark [1] referred to the inability of clinicians, both
human and veterinary, to separate and recognise the different clinical
entities responsible for chronic diseases of the airways, with the
subsequent development of several different approaches to terminology,
as well as treatment. In relation to equine nonseptic lower airway disease,
and despite many attempts to identify the most appropriate nomenclature,
this challenge remains as topical today as it did then. ‘Equine asthma’ has
...
Henderson BE, Chappell WA, Johnston JG, Sudia WD.Henderson, B. E., W. A. Chappell, J. G. Johnston, Jr. and W. D. Sudia (CDC, Atlanta, Ga. 30333). Experimental Infection of horses with three strains of Venezuelan equine encephalomyelitis virus. I. Clinical and virological studies. Amer J Epidem 93: 194–205, 1971.—Clinical effect, viremias and antibody responses were compared in horses inoculated with the following strains of Venezuelan equine encephalomyelitis (VEE) virus: Fe3-7C, isolated from Culex (Melano-conion) spp. mosquitoes collected In 1963 in the Florida Everglades; TC-83, the Fort Detrick live, attenuated vaccine strain; and GJ...
Olomski F, Fettelschoss V, Jonsdottir S, Birkmann K, Thoms F, Marti E, Bachmann MF, Kündig TM, Fettelschoss-Gabriel A.Insect bite hypersensitivity (IBH) is the most common seasonal pruritic allergic dermatitis of horses occurring upon insect bites. In recent years, a major role for IL-31 in allergic pruritus of humans, monkeys, dogs, and mice was acknowledged. Here, we investigate the role of IL-31 in IBH of horses and developed a therapeutic vaccine against equine IL-31 (eIL-31). IL-31 levels were quantified in allergen-stimulated peripheral blood mononuclear cells (PBMCs) and skin punch biopsies of IBH lesions and healthy skin from IBH-affected and healthy horses. The vaccine consisted of eIL-31 covalently ...
Renshaw RW, Glaser AL, Van Campen H, Weiland F, Dubovi EJ.A virus that could not be identified as a previously known equine virus was isolated from the mononuclear cells of a horse. Electron microscopy revealed enveloped virions with nucleocapsid structures characteristic of viruses in the Paramyxoviridae family. The virus failed to hemabsorb chicken or guinea pig red blood cells and lacked neuraminidase activity. Two viral genes were isolated from a cDNA expression library. Multiple sequence alignments of one gene indicated an average identity of 45% as compared to Morbillivirus N protein sequences. A weaker relationship was found with Tupaia paramy...
O'Brien C, Marr N, Thorpe C.The forelimb superficial digital flexor tendon (SDFT) is an energy-storing tendon that is highly susceptible to injury during activities such as galloping and jumping, such that it is one of the most commonly reported causes of lameness in the performance horse. This review outlines the biomechanical and biothermal effects of strain on the SDFT and how these contribute to the accumulation of microdamage. The effect of age-related alterations on strain response and subsequent injury risk is also considered. Given that tendon is a slowly healing and poorly regenerative tissue, prompt detection o...
Berg LC, Thomsen PD, Andersen PH, Jensen HE, Jacobsen S.mRNA expression of the acute phase protein serum amyloid A (SAA) in histologically normal tissues derived from horses (n=13) and cattle (n=4) was investigated by quantitative reverse-transcriptase real-time polymerase-chain reaction. As expected, high constitutive SAA mRNA expression was demonstrated in hepatic tissue in both species. In horses, moderate (>1% of the hepatic expression) SAA mRNA expression was detected in the lung, mammary gland, pancreas, synovial membrane, thymus, thyroid gland and uterus. Other equine tissues and organs sampled included adipose tissue, adrenal gland, aort...
Jolly RD, Palmer DN, Dalefield RR.Analytical studies of three lipopigments show that much can be achieved. Lipopigment from ovine ceroid-lipofuscinosis is composed of discrete protein and lipid molecules in orderly arrays and lipid peroxidation is not involved in its formation. Subunit c of mitochondrial ATP synthase accounts for approximately 50% of accumulated material and is specific to the disease process in this and other forms of the disease. Lipofuscin from bovine heart was mostly soluble and also contained discrete proteins, lipids and metals. Equine thyroid lipofuscin was less soluble but also had a relatively high pr...
MacNamara B, Bauer S, Iafe J.Endoscopic examinations were performed on 965 Standardbred racehorses competing at Yonkers Raceway between June 16 and Aug 3, 1988, to demonstrate an association between exercise-induced pulmonary hemorrhage or chronic obstructive pulmonary disease and poor racing performance. Findings suggested that both exercise-induced pulmonary hemorrhage and chronic obstructive pulmonary disease adversely affect performance, whereas a combination of the 2 conditions more severely affects racing performance than do either of the conditions individually.
Proudman CJ, Edwards GB.A centrifugation/flotation technique for the identification of equine tapeworm eggs is described. It was validated by using faeces samples from 80 horses of known tapeworm status, and had a sensitivity of 61 per cent and a specificity of 98 per cent. The exclusion of false negative results in animals with less than 20 tapeworms increased the sensitivity to 92 per cent. No significant correlation was found between the number of eggs observed and the number of tapeworms present in the horses.
Rousseau K, Kirkham S, McKane S, Newton R, Clegg P, Thornton DJ.Horses frequently suffer from respiratory diseases, which, irrespective of etiology, are often associated with airway mucus accumulation. Studies on human airways have shown that the key structural components of the mucus layer are oligomeric mucins, which can undergo changes of expression and properties in disease. However, there is little information on these gel-forming glycoproteins in horse airways mucus. Therefore, the aims of this study were to isolate equine airways oligomeric mucins, characterize their macromolecular properties, and identify their gene products. To this end, pooled tr...
Sallé G, Guillot J, Tapprest J, Foucher N, Sevin C, Laugier C.Horses are infected by a wide range of parasite species that form complex communities. Parasite control imposes significant constraints on parasite communities whose monitoring remains, however, difficult to track through time. Postmortem examination is a reliable method to quantify parasite communities. Here, we compiled 1,673 necropsy reports accumulated over 29 years, in the reference necropsy centre from Normandy (France). The burden of non-strongylid species was quantified and the presence of strongylid species was noted. Details of horse deworming history and the cause of death were reg...
Grooters AM, Whittington A, Lopez MK, Boroughs MN, Roy AF.The purpose of this study was to evaluate the effects of sample handling, storage, and culture techniques on the isolation of Pythium insidiosum from infected equine tissues. Tissue and kunker samples obtained immediately posteuthanasia from a horse with subcutaneous pythiosis were used to assess the effects of sample type (kunkers vs. tissues), media type (selective vs. nonselective), storage technique, and storage time on P. insidiosum isolation rate. Overall, isolation rates were higher from fresh kunkers (94.6%) and stored kunkers (76.4%) than from fresh tissues (8.3%) or stored tissues (4...
Knight CG, Dunowska M, Munday JS, Peters-Kennedy J, Rosa BV.Equus caballus papillomavirus type 2 (EcPV-2) infection has been associated with equine genital squamous cell carcinomas (SCCs). However, quantitative PCR (qPCR) has not been performed to determine viral copy numbers within these lesions. Additionally, the frequency with which EcPV-2 can be detected in other common sites of equine SCC development remains uncertain. The aim of this study was to develop a qPCR assay to estimate the viral load in a variety of equine tissue samples. These included 40 SCC lesions, 19 penile non-SCC or precursor disease lesions, and 222 tissues without observable le...
Richard EA, Fortier GD, Lekeux PM, Van Erck E.Any disorder impairing a performance horse's ability to ventilate its lungs and exchange oxygen compromises exercise performance in any discipline. Since bronchoalveolar lavage was described in horses in the early 1980s, laboratory evaluation of respiratory fluids, along with clinical and functional assessment of the respiratory system, has become a relevant step in the diagnosis of respiratory disease affecting performance. The aim of this review is to provide objective information to assist clinicians in interpreting laboratory findings by (1) summarising published cytological references val...
Finno CJ, Estell KE, Katzman S, Winfield L, Rendahl A, Textor J, Bannasch DL, Puschner B.Equine neuroaxonal dystrophy/equine degenerative myeloencephalopathy (NAD/EDM) is a neurodegenerative disorder affecting genetically predisposed foals maintained on α-tocopherol (α-TP)-deficient diet. Objective: Intramuscular α-TP and selenium (Se) administration at 4 days of age would have no significant effect on serum or cerebrospinal fluid (CSF) α-TP in healthy foals. Serum and CSF α-TP, but not Se, would be significantly decreased in NAD/EDM-affected foals during first year of life. Methods: Fourteen Quarter horse foals; 10 healthy foals supplemented with 0.02 mL/kg injectable α-TP ...
Smith KC, Mumford JA, Lakhani K.Four Welsh Mountain pony mares at 3 months of gestation and one mare at 5 months were inoculated intranasally with equid herpesvirus-1 (EHV-1: Ab4 isolate) at doses of 10(5) to 10(6.6) TCID50. All five mares became infected, but no cases of paresis or abortion occurred. On days 8, 9, 11, 12 (3-month-pregnant mares) and 13 (5-month-pregnant mare) after infection, a detailed examination of the pregnant uterus was made. Small numbers of vascular lesions with EHV-1 antigen expression in endothelial cells were present in the uteri of the early gestational mares; thrombi were rare and foci of thromb...
Galey FD, Holstege DM, Plumlee KH, Tor E, Johnson B, Anderson ML, Blanchard PC, Brown F.Since mid-1989, 37 cases of oleander poisoning in livestock have been diagnosed at the California Veterinary Diagnostic Laboratory System. The most frequent source for oleander exposure was plant clippings. Sudden death was the most common presenting complaint. Other signs reported included diarrhea, pulmonary edema, tachycardia, cardiac arrhythmias, colic, and lethargy. In the past, a presumptive diagnosis of oleander poisoning could be based only on matching clinical signs with evidence of consumption of oleander. A new 2 dimensional Thin-layer chromatography analysis of ingesta for oleandri...
Uzal FA, Arroyo LG, Navarro MA, Gomez DE, Asín J, Henderson E.Enteritis, colitis, and enterocolitis are considered some of the most common causes of disease and death in horses. Determining the etiology of these conditions is challenging, among other reasons because different causes produce similar clinical signs and lesions, and also because some agents of colitis can be present in the intestine of normal animals. We review here the main bacterial and viral causes of enterocolitis of horses, including Salmonella spp., Clostridium perfringens type A NetF-positive, C. perfringens type C, Clostridioides difficile, Clostridium piliforme, Paeniclostridium so...
