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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.
Multiple atrial dysrhythmias in a horse. A variety of atrial dysrhythmias including paroxysmal atrial tachycardia, atrial tachycardia with 2nd-grade atrioventricular block, atrial fibrillation, and atrial flutter developed in a 5-year-old Quarter Horse gelding. Quinidine and propranolol were not successful in restoring normal sinus rhythm. Sinus rhythm was re-established during digoxin therapy, but later reverted to atrial dysrhythmia. At necropsy, multiple, discrete pale areas were found on both atria and the interatrial myocardium. Histologic examination of these lesions demonstrated myocytolysis and replacement by fibrous connecti...
Sequence of the low activity equine erythrocyte carbonic anhydrase and delineation of the amino acid substitutions in various polymorphic forms. the sequence of the low activity form of equine erythrocyte carbonic anhydrase has been determined. The most common electrophoretic form, designated D, has been found to have five substitutions. Amino acid exchanges in the electrophoretic variants known as A1, A2, B, and T have been found at six other positions. The data do not permit calculation of the number of polymorphic forms of this enzyme. The equine D isozyme and the analogous human enzyme are quite homologous, 211 of their 260 residues, or 81%, being identical.
Equine pelvic flexure impaction. A model used to evaluate motor events and compare drug response. Pelvic flexure fistulas (2.5 cm diameter) were established in eight 160 kg Shetland X ponies. Impaction was induced at the pelvic flexure 25 times in the 8 animals through partial obstruction by a 1 litre rubber rebreathing bag fixed at the fistula site. Blood flow probes were implanted on the dorsal and ventral colic arteries (right colic artery and colic branch of ileocolic artery) in two of the ponies. Intraluminal pressure changes were measured at 8 different locations in the large colon during episodes of colic and following administration of flunixin or xylazine. Episodes of colic charac...
Rotavirus infection in foals. Fecal samples from 86 foals with diarrhea were examined by electron microscopy during a 2.5 year period. Of these, 26 (30%) were positive for rotavirus. All of the cases were found in epizootic areas. The disease was produced in an experimental foal by inoculation via stomach tube of a bacteria-free fecal filtrate containing rotavirus. Examination of postmortem tissues from the duodenum and jejunum of 2 naturally infected foals and an experimentally infected foal revealed replicating virus in the intestinal epithelial cells. A limited survey of complement-fixing antibody to rotavirus in horses...
Turnover of 131I-labelled albumin in horses with gastrointestinal disease. Four horses with a history of chronic diarrhoea and weight loss were studied. Three of them revealed malabsorption, as indicated by decreased absorption of D(+)-xylose. Three patients had distinct hypoalbuminaemia, and 131I-albumin turnover rates of these three horses were increased, compared to two normal control horses. However, the increases were not very marked, probably because actual signs of enteric disease were few in the patients, all of which were studied during convalescence. It is suggested that the observed hypoalbuminaemia is due to a gastrointestinal protein loss during the chro...
Pathogaenicity of Toxoplasma gondii oocysts to ponies. Nine ponies were fed 100,000 infective Toxoplasma gondii oocysts and were given corticosteroid injections before and after feeding the T gondii oocysts. Titers to the Sabin-Feldman dye tests (1:2 to 1:16,384) developed within postinoculation days (PID) 7 to 21 and antibodies persisted to PID 133. Toxoplasma organisms were isolated from the tissues of 4 ponies (heart of 4, brain of 2, spinal cord of 3, diaphragm of 1, skeletal muscle of 1, liver of 1, kidneys of 1) killed between PID 36 and 63, but not from 5 ponies killed between PID 117 and 150. Seemingly, ponies are one of the more resistant...
Contagious equine metritis: isolation and characterization of the etiologic agent. Uterine, cervical, and clitoral specimens on swabs from pony mares infected with contagious equine equine metritis (CEM) bacteria were streaked on agar plates. Colonies of CEM bacteria were observed under CO2 incubation in 2 days on Eugon chocolate agar and Eugon blood agar plates. The diameter of the colonies varied from 0.2 mm to 1 mm in 2 days which increased to 0.3 mm to 2.0 mm on day 4. The colonies on Eugon chocolate agar plates on days 2 to 4 were shiny, brown, round, and convex, and easily glided when pushed with a loop. The diameter of the colonies on chocolate and blood agar plates m...
Equine Getah virus infection: isolation of the virus from racehorses during an enzootic in Japan. A primary enzootic of equine Getah virus infection involving 722 of 1,903 racehorses occurred at a training center in Japan between September and November of 1978. Sixty-two viral agents were isolated from the plasma of 209 sick horses which exhibited pyrexia with rectal temperatures ranging from 38.5--40 degrees C, urticarial rash on various portions of the body, and edema of the hind legs. The viruses were antigenically related to the AMM 2021, Haruna, and Sagiyama strains of Getah virus. Infection and disease were produced experimentally in horses when inoculated by the intramuscular or int...
Equine connective tissue tumors contain unintegrated bovine papilloma virus DNA. Bovine papilloma virus (BPV) appears to be the etiological agent of common equine connective tissue tumors. We investigated the physical state of the viral DNA within such tumors and found no indication for integration into the host genome. The BPV genomes were present as free circular episomes. Two equine sarcoids were shown to contain multiple copies of free circular BPV type 1 (BPV-1) DNA. When the tumors were digested with several single-cut restriction enzymes, there were only form III BPV-1 DNA sequences could be revealed. One of the sarcoids contained, apart from wild-type BPV-1 DNA, a ...
An epidemic of Getah virus infection among racehorses: properties of the virus. A virus (Sakai) which had been recovered from an outbreak of disease in horses was found to be a small spherical enveloped RNA virus with a diameter of approximately 70 nm and a buoyant density of 1.22 g per ml. It grew well and produced a cytopathic effect in a variety of cell cultures; it was sensitive to organic solvents, heat and low pH. It agglutinated goose erythrocytes in a 0.35 M sodium chloride solution at an optimum pH of 6.2 and was antigenically identical or closely related to Getah virus, a member of the alphavirus subgroup of the Togaviridae.
Studies on the physiopathology of chronic obstructive pulmonary disease in the horse. II. Right heart haemodynamics. Pressure curves obtained by cardiac catheterization of the pulmonary artery, right ventricle and right atrium of 9 horses and ponies with chronic obstructive pulmonary disease (COPD) were compared with those similarly recorded from 6 clinically normal control subjects. The mean pulmonary peak systolic, pulmonary minimum diastolic and ventricular peak systolic pressures of the COPD subjects were significantly higher (P less than 0,01) than the corresponding mean pressures of the clinically normal control subjects. The mean pressure calculated from pressure curves obtained from 8 Thoroughbreds i...
Equestrian cold panniculitis in women. We describe four patients with panniculitis attributable to a combination of cold exposure and equestrian activities. All were young, healthy women who rode horses for at least two consecutive hours per day throughout the winter. Initially, several small, erythematosus, pruritic papules appeared on the superior-lateral portions of one or both thighs. During one week, the lesions progressed to indurated, red-to-violaceous,tender plaques and nodules. Studies for cryofibrinogens and cryoglobulins were negative. The histologic picture was that of a panniculitis with prominent inflammation of veins...
Pyloric stenosis in a foal. A two month old Thoroughbred filly was presented with signs of depression, grinding of the teeth, frothing of the mouth and abdominal pain. These signs had persisted for two weeks despite treatment with mineral oil, dioctyl sodium sulfosuccinate, meperidine and antibiotics. A variety of diagnostic tests were done, the only abnormal finding was a stress leukon. On exploratory laparotomy the stomach was dilated with fluid and gas and the pyloric canal was constricted. Pyloroplasty resulted in correction of the condition. The etiological possibilities are discussed. This is believed to be the fir...
Evidence for Sarcocystis as the etiologic agent of equine protozoal myeloencephalitis. Equine protozoal myeloencephalitis (EPM) was diagnosed in 10 horses. By electron microscopy, schizonts were found in intact host cells of the spinal cords or, more frequently, free in the extracellular spaces. Developmental stages of schizonts differed morphologically, and the late stage of schizogony was characterized by endopolygeny. These findings permitted tentative identification of the protozoon as a Sarcocystis sp. Free merozoites were present in the extracellular spaces or in cells of the spinal cord. Pericytes of capillaries were most frequently parasitized by merozoites were present ...
