Omneity® Pellets
All-In-One Vitamin & Mineral Pellet
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.
An investigation of the prevalence of the toxigenic types of Clostridium perfringens in horses with anterior enteritis: preliminary results. Equine anterior enteritis is an acute syndrome with unknown aetiology, although salmonellosis and infection with Clostridium perfringens have both been suggested as potential causes. The main aim of this preliminary study was to compare the prevalence of toxigenic types of C. perfringens in clinically healthy horses and in horses with anterior enteritis. From horses admitted with colic at Phillip Leverhulme Large Animal Hospital in 1995-1996, samples of gastric reflux, small intestinal contents and faeces were taken for isolation of C. perfringens. Five of those horses were admitted as anterio...
Morphologic and quantitative evaluation of the myenteric plexuses and neurons in the large colon of horses. To determine the number of myenteric plexuses and neurons in the large colon of clinically normal horses and whether the number was decreased in the large colon of horses with colon disease. Methods: Prospective study. Methods: Colon samples from 15 clinically normal horses and 31 horses with colon disease. Methods: Samples were obtained, fixed, and stained with H&E. The number of myenteric plexuses and neurons and longitudinal muscle thickness were determined in each segment of colon for clinically normal horses. Counts for segments were compared with each other and with counts in the sam...
Otitis media and interna and temporohyoid osteoarthropathy. Otitis media/interna in the equine most commonly is a chronic, insidious infection with the unique sequella of temporohyoid osteoarthropathy in some horses. Head shaking may be the only clinical sign of the early stages of this disease. The arthritic condition often leads to fusion of the temporohyoid joint with resultant stress fractures of the petrous temporal bone. When this occurs, the horse presents as an acute neurologic case with clinical signs of vestibular and facial nerve dysfunction. Diagnosis, treatment, and prognosis are discussed. Recognition of this syndrome is important because...
Intrinsic atrioventricular conductive function in horses with a second degree atrioventricular block. The atrioventricular (AV) conductive functions were investigated before and after the pharmacological autonomic nervous blockade (PAB) through the electrophysiological study on six horses (AV block group) in which the dropped beats occurred more frequently (over 200 beats/24 hr) and on five horses (control group) in which the dropped beats occurred sporadically (under 200 beats/24 hr) or in which the arrhythmias were not recognized at all on the long-term electrocardiogram. As a result, AV conductivity, conduction time and refractoriness in the AV block group were lower, longer and higher, res...
[A case of cutaneous epitheliotropic malignant lymphoma (mycosis fungoides) in a horse]. This article describes an eleven year old mare with apathy, fever, enlarged mandibular lymph nodes, skin lesions on the upper lip and edematous, grey-red mucous membranes in the nose, mouth and vulva. Histopathology revealed infiltrates with atypical lymphocytes forming Pautrier's microabscesses. The neoplastic cells had large, often indented nuclei. Immunohistology showed that some cells were CD3-positive (Pan T-cell-marker). The diagnosis of cutaneous epitheliotropic malignant lymphoma (Mycosis fungoides) was made. The etiology in the horse is unknown.
Oxidative energy metabolism in equine tendon cells. Hypoxia has been suggested as a possible cause of tissue degeneration and subsequent rupture in equine tendons. To determine whether low oxygen tension is likely to be detrimental to tendon cell function, experiments were designed to investigate oxidative energy metabolism in freshly isolated and cultured equine tendon cells. Freshly isolated tenocytes and cultured fibroblasts possessed activities of the mitochondrial enzyme citrate synthase similar to those of other mammalian cells, with well defined oxidative metabolism. D-[6(-14)C]-glucose oxidation was measurable in both freshly isolated a...
Prevalence of fetal maldispositions in equine referral hospital dystocias. A retrospective investigation was performed to determine the population characteristics of horses presented for dystocia at 2 equine referral hospitals and the types of fetal maldispositions among these horses. The study population consisted of a similar number of Thoroughbreds (25%), Standardbreds (24%) and draft horses (22%). Most of the current literature pertaining to equine obstetrics is based on a predominately draft horse population (63%). The latter population appeared to have more transverse presentations (P = 0.06), possibly because of the higher number of draft mares. In our study, ...
Genetic markers in standardbred trotters susceptible to the rhabdomyolysis syndrome. The equine rhabdomyolysis syndrome (RHA) is believed to be multifactorial in origin; and could be caused by an interaction between genetic and environmental factors. In order to analyse its genetic background an association study was undertaken. Two sample groups of Standardbreds (Stb) which had suffered from RHA were compared to the total population of Swedish Standardbred trotters using recorded polymorphic genetic markers. The results showed that gene frequencies for several markers in the RHA groups differed significantly from those estimated for the total population. A rhabdomyolysis risk...
Failure to establish chronic infection of the reproductive tract of the male horse with a South African asinine strain of equine arteritis virus (EAV). Eight sexually mature horse stallions were inoculated intranasally with a South African asinine strain of EAV, a strain that was isolated from the semen of a donkey carrier. All horses developed fever, with maximum rectal temperatures of 38.9-39.9 degrees C recorded 3-6 d post challenge. Six horses showed very mild clinical signs of equine viral arteritis and two were asymptomatic. The virus was recovered from the nasopharynxes of six horses 2-7 d after inoculation, and from buffy-coat samples of all horses, 2-11 d after inoculation. Seroconversion to EAV was detected on days 8 and 10 and peak...
Orbital neuroendocrine tumors in three horses. Three horses were examined because of exophthalmos and others signs indicative of a space-occupying orbital mass. In 2 horses, exenteration was used to remove the orbital mass. In a third horse, an orbital tumor and lung metastases were found at necropsy. Routine histologic and Grimelius' histochemical staining were used on fixed tissues; immunohistochemical staining for chromogranin and electron microscopy also were performed. Masses were orbital neuroendocrine tumors. Horses that underwent exenteration were alive 19 and 24 months after surgery. Hypotension was encountered at surgery in both ...
Pasteurella caballi infection following a horse bite. The isolation of Pasteurella caballi from an horse-bite wound in a 56-year-old man is reported. Biochemical characteristics are described and compared with the other species representing the genus Pasteurella. This strain probably represents the first human isolate of P. caballi in France.
Artifactual nonlinearity due to wear grooves and friction in four-point bending experiments of cortical bone. Experiments and analyses were performed to determine the cause of a nonlinear force-deflection response observed in four-point flexural fatigue of beams of cortical bone machined from the mid-diaphysis of the equine third metacarpus. Observable grooves which formed on the beam surface at supports and load noses were found to be the primary cause of the nonlinearity. An additional geometric nonlinearity at large deflections revealed by finite element modeling may be minimized by using the smallest diameter supports and load noses recommended in ASTM 790. However, frictional constraint of the be...
Experimental induction of equine protozoal myeloencephalitis in horses using Sarcocystis sp. sporocysts from the opossum (Didelphis virginiana). Sarcocystis sp. sporocysts isolated from eight feral opossums (Didelphis virginiana) were pooled and fed to 18 commercially reared budgerigars (Melopsittacus undulatus), 14 wild-caught sparrows (Passer domesticus), one wild-caught slate-colored Junco (Junco hyemalis) and five weanling horses (Equus caballus). All budgerigars died within 5 weeks post inoculation (wpi). Histologic examination revealed meronts within the pulmonary epithelia and typical Sarcocystis falcatula sarcocysts developing in the leg muscles. Sparrows were euthanized 13 and 17 wpi and their carcasses were fed to four labora...
The Michigan equine monitoring system. II. Frequencies and impact of selected health problems. A prospective study was designed to document the frequencies of equine health problems in the state of Michigan, USA. A total of 2469 horses from a random sample of 138 equine operations were monitored in the study in two 12-month periods: 1992-1993 and 1993-1994. All the major breeds of horses in the state were proportionately represented in the sample. Using weighted annual incidence densities as measures of disease frequencies, the 10 most frequently observed groups of health problems were (from most to least frequent) leg lameness, dermatological problems, respiratory problems, hoof and fo...
Fatal encephalitis due to novel paramyxovirus transmitted from horses. In September, 1994, an outbreak of severe respiratory disease affected 18 horses, their trainer, and a stablehand in Queensland, Australia. Fourteen horses and one human being died. A novel virus was isolated from those affected and named equine morbillivirus (EMV). We report a case of encephalitis caused by this virus. Results: A 35-year-old man from Queensland had a brief aseptic meningitic illness in August, 1994, shortly after caring for two horses that died from EMV infection and then assisting at their necropsies. He then suffered severe encephalitis 13 months later, characterised by unc...
[Attack of black flies (Diptera, Simuliidae) on horses in Basel (Switzerland)]. In April 1996 an attack of black flies (Diptera, Simuliidae) to horses was observed in the region of Basle, Switzerland. Females of Simulium erythrocephalum and Simulium ornatum were involved in this attack, part of them had taken a blood meal. For S. ornatum this is the first record in Switzerland that this species takes blood meals on horses.
Age, breed, sex and seasonality as risk factors for equine laminitis. A case-control study was conducted at the Texas Veterinary Medical Center between January 1, 1986 and December 31, 1991. Logistic regression was used to assess age, breed, sex, and seasonality as risk factors for equine laminitis. There were 70 acute cases, 183 chronic cases, and 779 controls. No statistical association was found between age, breed, sex, or seasonality and the diagnosis of acute laminitis. For chronic cases, the estimated odds ratio was statistically significant for age (OR = 1.05, 95% CI (1.02, 1.08)) and for the diagnosis of laminitis in the third quarter of the year (OR = 2...
Chronic tenosynovitis of the carpal extensor tendon sheaths in 15 horses. The history, clinical features, radiological findings, treatment and outcome of 15 horses with chronic tenosynovitis of the carpal extensor tendon sheaths are reported. The condition was seen most commonly in horses used for jumping and penetration of the tendon sheaths by thorns was the most common aetiology. Treatment involved surgical resection of the hyperplastic synovial membrane, and adhesions within the tendon sheath, with primary closure. When combined with early postoperative physiotherapy this was found to be an effective method of treatment. All horses in this series were not lame a...
Medroxyprogesterone acetate antagonizes inhibitory effects of conjugated equine estrogens on coronary artery atherosclerosis. Although estrogen replacement therapy is associated with reduced risk of coronary heart disease and reduced extent of coronary artery atherosclerosis, the effects of combined (estrogen plus progestin) hormone-replacement therapy are uncertain. Some observational data indicate that users of combined hormone replacement consisting of continuously administered oral conjugated equine estrogens (CEE) and oral sequentially administered (7 to 14 days per month) medroxyprogesterone acetate (MPA) experience a reduction in risk similar to that of users of CEE alone. However, the effects of combined, con...
