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Topic:Disease Etiology
Disease etiology in horses refers to the study of the causes and development of diseases within equine populations. It encompasses various factors, including genetic predisposition, environmental influences, infectious agents, and nutritional imbalances, that contribute to the onset and progression of diseases in horses. Understanding disease etiology is essential for identifying risk factors and implementing preventative measures in equine health management. This topic includes research on pathogen-host interactions, the impact of management practices on disease incidence, and the role of genetic and environmental factors in disease susceptibility. This page compiles peer-reviewed research studies and scholarly articles that explore the mechanisms, contributing factors, and implications of disease etiology in horses.
vCLAP, a caspase-recruitment domain-containing protein of equine Herpesvirus-2, persistently activates the Ikappa B kinases through oligomerization of IKKgamma. vCLAP, the E10 gene product of equine herpesvirus-2, is a caspase-recruitment domain (CARD)-containing protein that has been shown to induce both apoptosis and NF-kappaB activation in mammalian cells. vCLAP has a cellular counterpart, Bcl10/cCLAP, which is also an activator of apoptosis and NF-kappaB. Recent studies demonstrated that vCLAP activates NF-kappaB through an IkappaB kinase (IKK)-dependent pathway, but the underlying mechanism remains unknown. In this report, we demonstrate that vCLAP associates stably with the IKK complex through direct binding to the C-terminal region of IKKgamma....
[Gastric ulceration in horses: etiology, diagnosis, and therapy: a review]. Since it has become possible to make an ante-mortem diagnosis of gastric ulceration in horses by means of endoscopy, interest in the presence and treatment of this syndrome has increased. Several endoscopic surveys have indicated that the frequency of gastric ulceration in Thoroughbreds in training is fairly high. Less is known about other breeds and horses that are kept under different (training) conditions. The equine stomach is covered by two different kinds of mucous membranes: squamous and glandular. These two areas differ from one another in the incidence and aetiology of ulceration and,...
Interleukin-8 concentration and neutrophil chemotactic activity in bronchoalveolar lavage fluid of horses with chronic obstructive pulmonary disease following exposure to hay. To analyze effects of hay dust exposure on interleukin-8 (IL-8) concentration, percentage of neutrophils, and neutrophil chemotactic activity in bronchoalveolar lavage fluid (BALF) of horses with chronic obstructive pulmonary disease (COPD). Methods: 16 healthy horses and 29 horses with COPD. Methods: IL-8 concentration, percentage of neutrophils, and neutrophil chemotactic activity in BALF were measured. Values were analyzed with respect to hay dust exposure. These variables were also measured in 5 asymptomatic horses with COPD after the induction of clinical signs by changing feed from silag...
Trichinella in horses: a low frequency infection with high human risk. After the initial report in 1976 of a trichinellosis epidemic caused by the consumption of infected horsemeat, 12 other outbreaks have been described in Europe. Since the first serious human outbreak several experiments have confirmed the susceptibility of horses to Trichinella species and the rapid disappearance of specific antibodies in this host that prevents the use of serological methods for routine screening. A review of the distribution of parasite burdens in muscles of naturally or experimentally infected horses indicates that the tongue is the most likely sample to contain detectable ...
Clinical findings associated with chronic ischial fracture in a gelding. An 8-year-old show-jumper gelding was referred for examination as a result of a purchase dispute for reported back pain. Clinical examination identified back pain and atrophy of the left semimembranosus and semitendinosus muscles, but no lameness. Standing pelvic radiography demonstrated a chronic nonunion fracture of the left ischium, the clinical significance of which was uncertain. The apparent back pain was thought to be probably unrelated to the pelvic lesion. We conclude that chronic ischial fracture in the horse can lead to specific atrophy of the semimembranosus and semitendinosus musc...
Evidence for surfactant contributing to the gastric mucosal barrier of the horse. This study was undertaken to determine the hydrophobicity of the luminal surface of the equine stomach and to elucidate the ultrastructure of the lining imparting that property. Gastric and duodenal mucosal samples from 5 horses were collected immediately after euthanasia and subjected to surface contact angle measurement using a goniometer. Gastric mucosal samples from 4 horses and a foal were examined by electron microscopy following a fixation procedure known to preserve phospholipids and oligolamellar structures. Contact angles for the equine gastric glandular mucosal surface (mean +/- s.e...
Serum markers of lamellar basement membrane degradation and lamellar histopathological changes in horses affected with laminitis. In order better to evaluate the extent to which degradation of the lamellar basement membrane (LBM) by matrix metalloproteinases (MMP) occurs in equine laminitis, we determined the concentration of type IV collagen and laminin in normal and laminitic horses, using specific immunoassays. Blood samples were obtained from both the jugular and the cephalic veins of horses (n = 10) before and after the induction of acute alimentary laminitis by carbohydrate overload. Jugular and cephalic venous blood samples were also obtained from horses affected with naturally occurring laminitis (n = 16) and non...
Internal ribosomal entry site-mediated translation initiation in equine rhinitis A virus: similarities to and differences from that of foot-and-mouth disease virus. Equine rhinitis A virus (ERAV) has recently been classified as an aphthovirus, a genus otherwise comprised of the different serotypes of Foot-and-mouth disease virus (FMDV). FMDV initiates translation via a type II internal ribosomal entry site (IRES) and utilizes two in-frame AUG codons to produce the leader proteinases Lab and Lb. Here we show that the ERAV 5' nontranslated region also possesses the core structures of a type II IRES. The functional activity of this region was characterized by transfection of bicistronic plasmids into BHK-21 cells. In this system the core type II structures, ...
Benzimidazole resistance in equine cyathostomes in Slovakia. The present study included 19 stud farms, including 243 horses, that were investigated for the occurrence of anthelmintic resistant cyathostomes. The number of horses on the farms varied from nine to more than 100, and horses of all ages were included. A minimum of seven horses were used for faecal egg count reduction (FECR) tests. The anthelmintics included were: fenbendazole (paste formulation), ivermectin (paste formulation) and pyrantel (powder). Resistance to benzimidazoles was detected on 14 farms, with FECR values ranging from 65.1 to 86.3%. Larval cultures after fenbendazole treatment ...
Operation-management factors associated with early-postnatal mortality of US foals. Of 7320 equine foals reported born alive during 1997 on 1043 operations that had equids on 1 January 1997, and that participated in the United States National Animal Health Monitoring System (NAHMS) Equine 1998 Study, 120 foals were reported to have died (by either euthanasia or natural causes) within the first 2 days of a live birth. The weighted estimate was 1.7% mortality (standard error=0.5) within the first 2 days of live birth for all foals born on operations in the 28 states included in the study.A multivariable logistic-regression model revealed that foals born in the southern region w...
Studies on the experimental induction of ptosis in horses. The precise appearance of ptosis due to lesions at different sites was investigated in experimental ponies. The angles of the eyelashes to the head was used as an objective measurement of ptosis after local anaesthesia of the sympathetic trunk or the palpebral nerve and the administration of an ocular alpha agonist or antagonist. It was shown that ptosis is not an inevitable consequence of palpebral nerve pathology, that ocular alpha antagonists can induce ptosis, and that alpha agonist eyedrops have an inconsistent effect on the equine pupil, but are consistent at reversing ptosis induced by ...
Acinetobacter baumannii-infected vascular catheters collected from horses in an equine clinic. Acinetobacter baumannii was isolated from tips clipped from seven intravenous jugular catheters collected from horses in the Ghent University equine clinic. They originated from seven different horses. Three of the seven showed evidence of local infection.
Analysis of risk factors for the development of equine protozoal myeloencephalitis in horses. To investigate risk factors for development of equine protozoal myeloencephalitis (EPM) in horses. Methods: Case-control study. Methods: 251 horses admitted to The Ohio State University Veterinary Teaching Hospital from 1992 to 1995. Methods: On the basis of clinical signs of neurologic disease and detection of antibody to Sarcocystis neurona or S neurona DNA in cerebrospinal fluid, a diagnosis of EPM was made for 251 horses. Two contemporaneous series of control horses were selected from horses admitted to the hospital. One control series (n = 225) consisted of horses with diseases of the neu...
[Severe combined immunodefiency disease (SCID) in the Arabian horse]. Severe-Combined-Immunodeficiency-Disease (SCID) is discussed with special reference to its pathogenesis, clinical symptoms, pathology, and diagnosis. The disorder has been observed in the USA, Canada, Great Britain, and Australia and is characterized by an autosomal recessive mode of inheritance. The clinical features of the disease seen in Arab foals under 46 days of age are intermittent fever, (adenoviral) pneumonia, and weight loss sometimes associated with diarrhoea. From 1998 on, the SCID gene can be detected in the Netherlands by means of DNA analysis.
Anaemia, diarrhoea and opportunistic infections in Fell ponies. This report summarises clinical and pathological observations on Fell pony foals with a range of signs that included ill thrift, anaemia, respiratory infection, glossal hyperkeratosis and diarrhoea. Some of the foals had normochromic, normocytic anaemia and some had low levels of plasma proteins, including immunoglobulin G. Antibiotic and supportive treatment was ineffective and all affected foals died or were killed on humane grounds. Postmortem examination of 12 foals and tissues from 2 other foals revealed a range of lesions that included glossal hyperkeratosis, typhlocolitis, intestinal cr...
Equine proliferative enteropathy: a cause of weight loss, colic, diarrhoea and hypoproteinaemia in foals on three breeding farms in Canada. Proliferative enteropathy (PE) is a transmissible enteric disease caused by Lawsonia intracellularis. An outbreak of equine PE was diagnosed in foals from 3 breeding farms. Most foals had been weaned prior to the appearance of clinical signs, which included depression, rapid and marked weight loss, subcutaneous oedema, diarrhoea and colic. Poor body condition with a rough haircoat and a potbellied appearance were common findings in affected foals. Respiratory tract infection, dermatitis and intestinal parasitism were also found in some foals. Haematological and plasma biochemical abnormalities...
Tracheobronchial mucus viscoelasticity during environmental challenge in horses with recurrent airway obstruction. The goal of this study was to compare the rheological properties of mucus from horses with recurrent airway obstruction (RAO) to that from healthy controls during environmental challenge by stabling in stalls with straw as bedding and hay as feed. We determined viscoelasticity (log G* dyn/cm2, at 10 radian/s) and calculated mucociliary clearability index (MCI) and cough clearability index (CCI), which are derivative parameters of G* and the ratio of viscosity and elasticity measured at 1 and 100 radian/s, respectively. We also investigated the solids content of mucus, and cytology of bronchoal...
Evidence supporting an increased presence of reactive oxygen species in the diseased equine joint. Reactive oxygen species (ROS) are capable of degrading many components of the joint in the presence of insufficient antioxidant defences, and as a result have been implicated in the pathogenesis of joint disease in horses. However, to our knowledge, evidence of ROS occurring in diseased joints of horses has not been reported. The objective of this experiment was to compare differences in synovial fluid protein carbonyl content (as a marker of oxidative modification of synovial fluid proteins by ROS) and the antioxidant status of synovial fluid between clinically normal and diseased equine join...
Homogeneity of Trypanosoma evansi isolates from domestic and sylvatic mammals from the Pantanal of Mato Grosso. 'Mal de Cadeiras' is a disease which causes great mortality in horses in the Pantanal Matogrossense region, Brazil. The agent of this disease is Trypanosoma evansi, a kinetoplastid flagellate which belongs to the Trypanosomatidae family, classified into the Salivarian section. Transmission occurs mechanically by haematophagous Diptera, mainly by Stomoxys sp. and Tabanus sp. and vampire bats. Outbreaks of Mal de Cadeiras in horses result in economic losses, thus limiting their use in cattle raising. Ten isolates of T. evansi recently derived from coati (Nasua nasua, Carnivora, Procyonidae), hor...
The exceptionally large genome of Hendra virus: support for creation of a new genus within the family Paramyxoviridae. An outbreak of acute respiratory disease in Hendra, a suburb of Brisbane, Australia, in September 1994 resulted in the deaths of 14 racing horses and a horse trainer. The causative agent was a new member of the family Paramyxoviridae. The virus was originally called Equine morbillivirus but was renamed Hendra virus (HeV) when molecular characterization highlighted differences between it and members of the genus Morbillivirus. Less than 5 years later, the closely related Nipah virus (NiV) emerged in Malaysia, spread rapidly through the pig population, and caused the deaths of over 100 people. W...
Serologic confirmation of Ehrlichia equi and Borrelia burgdorferi infections in horses from the northeastern United States. To determine whether horses living in tick-infested areas of northeastern United States with clinical signs of borreliosis or granulocytic ehrlichiosis had detectable serum antibodies to both Borrelia burgdorferi and Ehrlichia equi. Methods: Prospective study. Methods: Serum samples from 51 clinically normal horses, 14 horses with clinical signs of borreliosis, and 17 horses with clinical signs of granulocytic ehrlichiosis. Methods: Serum B burgdorferi or E equi antibodies were measured by use of an ELISA, immunoblot analysis, or indirect fluorescent antibody (IFA) staining. Results: Of the 82...
Fibrous tissue of subchondral cystic lesions in horses produce local mediators and neutral metalloproteinases and cause bone resorption in vitro. To define the release of nitric oxide (NO), prostaglandin E2 (PGE2), and the neutral metalloproteinases (NMPs) in horses with subchondral cystic lesions (SCL) and to study bone resorption triggered by conditioned media of fibrous tissue of SCL in vitro. Methods: Equine explant cultures of fibrous tissue of SCL, and synovial membrane and articular cartilage of normal horses and horses affected with moderate and severe osteoarthritis were performed. NO, PGE2, and NMP concentrations of media samples were measured, and osteoclast formation and activation was studied in vitro. Methods: Experiment 1...
The effect of exercise on the distribution and manifestation of osteochondrotic lesions in the Warmblood foal. Osteochondrosis (OC) in the horse has been defined as a disturbance in the process of endochondral ossification which is of multifactorial origin, becoming evident in a large number of joints. Exercise is one of the environmental factors that may influence the clinical manifestation of the disorder, but has never been thoroughly investigated. In this study we investigated the influence of exercise during the first 5 months on the development and distribution of OC lesions in foals of age 5 and 11 months. Forty-three foals, all from sires having OC in either the femoropatellar or tibiotarsal jo...
Radiographic development of osteochondral abnormalities, in the hock and stifle of Dutch Warmblood foals, from age 1 to 11 months. In a longitudinal study the hocks and stifles of Dutch Warmblood foals were radiographed at age 1 month and subsequently at intervals of 4 weeks. Forty-three foals were radiographed until age 5 months and 19 foals until age 11 months. The chance for the development of osteochondrosis was enhanced by using only offspring from diseased sires with radiographically proven OC at either the intermediate ridge of the distal tibia or the lateral ridge of the femoral trochlea. The radiographic appearances of the intermediate ridge of the distal tibia, the distal aspect of the lateral trochlear ridge of...
Conclusions regarding the influence of exercise on the development of the equine musculoskeletal system with special reference to osteochondrosis. This paper summarises and interrelates the findings of a large-scale multidisciplinary investigation to assess the influence of exercise on the development of the equine musculoskeletal system in general and of osteochondrosis in particular, up to age 5 months. Forty-three foals, genetically predisposed to develop OC, were divided into 3 exercise groups: box-rest, box-rest with training and free pasture exercise. At 5 months, all foals were weaned and 8 foals per group were subjected to euthanasia for postmortem examination. The remaining 19 foals were placed together and subjected to euthanas...
Idiopathic focal eosinophilic enteritis associated with small intestinal obstruction in 6 horses. To report the history, clinical findings, and outcome of horses with idiopathic focal eosinophilic enteritis associated with acute small intestinal obstruction. Methods: Retrospective study. Methods: Six horses with idiopathic focal eosinophilic enteritis. Methods: Retrospective review of medical records of horses with idiopathic focal eosinophilic enteritis, with acute abdominal pain and small intestinal obstruction, associated with a focal region of eosinophilic enteritis of unknown cause. Information retrieved from the medical records included signalment, physical examination, laboratory fi...
