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.
Prasse KW, Topper MJ, Moore JN, Welles EG.Eight tests of hemostasis were measured in 233 horses with colic. Blood samples were obtained at admission and for 4 consecutive days of hospitalization. Data were analyzed retrospectively by outcome, by broad-category diagnosis group, by small intestinal disorder, and by smaller categories for comparing specific diseases. Nonsurviving horses and horses with the most severe forms of intestinal ischemia had changes interpreted as hypercoagulative, the intensity of which was increased on the first and second mornings (sample times 2 and 3) after admission, when most significant differences for r...
Hoffman LH, Wooding FB.The cellular origin, structure, and function of trophoblastic giant cells (GC) and binucleate cells (BNC) are reviewed. Mammals in which these cells have received the greatest attention include rodents, rabbits, and humans (GCs), and ruminants and equids (BNCs). In almost all cases these cells arise from the cytotrophoblast. All are large cells and contain either two diploid nuclei (BNCs), multiple nuclei (human placental bed GCs), or single nuclei with amplified DNA content (rodent and rabbit GCs). Giant and binucleate cells typically exhibit the capacity for migration or invasion, although t...
Freestone JF, Paccamonti DL, Eilts BE, McClure JJ, Swiderski CE, Causey RC.A 5-year-old stallion was referred because of signs of abdominal pain. During the initial examination, signs of pain were elicited when the right seminal vesicle was palpated per rectum. Signs of pain were also elicited during sexual arousal and attempts at semen collection. The right seminal vesicle was subsequently determined to be abnormal by ultrasonographic and endoscopic examination. The stallion was treated with trimethoprim/sulfamethoxazole for 6 weeks. Five months later, there had been no recurrence of the condition.
Madigan JE.This article reviews epizootiology, public health considerations, antibody testing, and molecular biology of Lyme borreliosis. Correlation of clinical signs with titer response is discussed.
House JA.AHS is a noncontagious vector-borne disease of Equidae caused by Orbiviruses. Species susceptibility in decreasing order is horses, mules, donkeys, and zebras. The main vectors of AHS are culicoides. The disease is endemic in sub-Saharan Africa, but epizootics have occurred outside of this area on several occasions. The most recent outbreaks outside of the endemic area were in Spain, Morocco, and Portugal between 1987 and 1990. AHS causes mortality up to 95% and is classically divided into four clinical forms: the pulmonary, cardiac, mixed, and horse fever forms. Pathologic changes are subcuta...
Dargatz DA, Salman MD.Epidemiology is a tool much like any other diagnostic tool that the practitioner uses as an aid in the complete physical examination of the group of animals. It can be used to generate a specific differential diagnosis list. Epidemiology is especially useful to design a disease control and prevention program by helping to elucidate the key determinants of disease occurrence.
Green SL.With the continued increase in the number of wildlife rabies cases reported across the United States and Canada, this disease will remain a threat to the horse as the potential for exposure to infected wildlife and other domestic animals is likely to also increase. Because there are no rapid, definitive antemortem diagnostic tests, the tentative diagnosis is based upon the variable and sometimes nonspecific clinical signs. Although the CSF analysis may be helpful in some cases, it may not be abnormal. Nor is collection of the specimen always practical in the field situation. The FAT on neural ...
Brück I, Anderson GA, Hyland JH.The records of 1630 mare years from 6 Thoroughbred stud farms in south eastern Australia were analysed for the years 1981 to 1986. Overall pregnancy and foaling rates were 83.9% and 69.3%, respectively. When calculated per served oestrous cycle, pregnancy and foaling rates were 54.7% and 43.1%, respectively. Pregnancy and foaling rates were higher (P < 0.001) for mares 3 to 10 years of age than for older mares. There was no difference in the pregnancy rates of maiden, barren and foaling mares. The foaling rate was significantly higher (P < 0.001) in mares that became pregnant during the ...
Sloet van Oldruitenborgh-Oosterbaan MM, van Duijkeren E.Salmonellosis is a worldwide problem of both men and animals. Equine salmonellosis is an increasing problem and a review of the recent knowledge is given. Etiology, symptomatology, diagnostic procedures, therapy and prevention are discussed.
Lubczyk B, Nothelfer HB.A case of generalized equine leucosis is presented. The most important clinical signs were cachexia, loss of condition, fever, tachycardia, subcutaneous tumors and severe lameness accompanied by edema of the right thoracic limb. Hematology showed anemia and neutrophilia; clinical biochemistry indicated hypalbuminemia, hyperphosphatemia and hyperfibrinogenemia. Necropsy revealed multiple tumors throughout the body which mainly originated from lymph nodes. Histopathologically the tumors consisted of two cell-types: a. uniform lymphocytoid cells with a highly infiltrative growth pattern; b. heter...
Firth EC, Alley MR, Hodge H.Two cases of Rhodococcus equi infection in foals are described, in which osteomyelitis was a feature. Because rhodococcal infection is usually low grade and chronic, and because the signs of early metaphysitis can be subtle, any articular or periarticular swelling in a foal from a farm with a history of rhodococcosis should be strongly suspected to be associated with R equi until proven otherwise.
Steiner N, Lindner A.By means of a survey, the reproductive rate of mares and the foal losses in ten Thoroughbred, Saddlebred and Pony studs in Germany, mainly from North-Rhine-Westfalia, were collected and evaluated. Data for the survey were recorded for 1985-1990. The study also examined the hygienic management in the surveyed studs, and the morbidity rate of suckling foals was obtained for 1990. In addition to the survey questionnaire each stud was visited once. Two studs of each horse group were visited several times every week from March to August in order to evaluate as exactly as possible the husbandry and ...
House JA.AHS is a noncontagious vector-borne disease of Equidae caused by Orbiviruses. Species susceptibility in decreasing order is horses, mules, donkeys, and zebras. The main vectors of AHS are culicoides. The disease is endemic in sub-Saharan Africa, but epizootics have occurred outside of this area on several occasions. The most recent outbreaks outside of the endemic area were in Spain, Morocco, and Portugal between 1987 and 1990. AHS causes mortality up to 95% and is classically divided into four clinical forms: the pulmonary, cardiac, mixed, and horse fever forms. Pathologic changes are subcuta...
House JA.AHS is a noncontagious vector-borne disease of Equidae caused by Orbiviruses. Species susceptibility in decreasing order is horses, mules, donkeys, and zebras. The main vectors of AHS are culicoides. The disease is endemic in sub-Saharan Africa, but epizootics have occurred outside of this area on several occasions. The most recent outbreaks outside of the endemic area were in Spain, Morocco, and Portugal between 1987 and 1990. AHS causes mortality up to 95% and is classically divided into four clinical forms: the pulmonary, cardiac, mixed, and horse fever forms. Pathologic changes are subcuta...
Green SL.Vesicular stomatitis (VS) is a viral disease of livestock that results in vesicles and ulcerations on the teats, oral mucosa, tongue, and coronary bands. All three main serotypes of the VS virus can infect the horse. Although VS does not have a major impact on the equine industry, it is clinically identical to the other more economically devastating vesicular diseases of cattle and swine and can produce influenza-like symptoms in humans. VS in horses is reportable, as are all vesicular diseases of livestock.
Wright IM, Douglas J.In recent years much attention has been paid to vascular studies of the navicular bone in health and disease; however, the relative importance of these studies has overshadowed biomechanical factors which may yet prove to be of importance. This paper outlines the pertinent anatomy, and discusses current concepts in the aetiology and pathogenesis of the disease. It describes the treatment regimens which are based on biomechanical considerations and compares the results of some currently employed techniques. All aspects of navicular disease remain controversial. This paper is not intended to rev...
Scholes SF, Vaillant C, Peacock P, Edwards GB, Kelly DF.Ileal biopsies were obtained from 18 horses with grass sickness, 15 horses with other alimentary disease and three horses without gastrointestinal disease. Samples of small intestine were also obtained from nine cases of obstruction due to small intestinal strangulation. Histological examination revealed that severe enteric neuropathy in the absence of other significant morphological changes was confined to the horses with grass sickness.
Dennis VA, Klei TR, Chapman MR.Supernatants generated by stimulation of peripheral blood mononuclear cells (PBMC) from Strongylus vulgaris sensitized or immunized ponies were assayed in vitro for eosinophil chemotactic activity (ECA) using the filter system in blind well chambers. The supernatants from these cultures were chemotactic for eosinophils, but not for neutrophils. Supernates from cultures of unsensitized PBMC stimulated with S. vulgaris antigen were not chemotactic for eosinophils. ECA was first detected in culture supernatants after 1.5 h of incubation and was dependent on both antigen and PBMC concentrations, b...
McGorum BC, Dixon PM.Local transendoscopic endobronchial antigen challenge, which has proved to be a valuable clinical and research technique in the study of human pulmonary hypersensitivity, was evaluated in control and asymptomatic COPD--affected horses. Transendoscopic endobronchial challenges with phosphate-buffered saline (PBS), Micropolyspora faeni extract at 60 and 600 micrograms/ml and mouldy hay extract elicited neutrophilic airway inflammatory responses in control (N = 5-7) and asymptomatic COPD-affected (N = 5-7) horses, as determined by cytological examinations of bronchoalveolar lavage fluid (BALF) ha...
Wood JL, Burrell MH, Roberts CA, Chanter N, Shaw Y.The likelihood of finding evidence of inflammation in 551 tracheal washes collected endoscopically from 278 Thoroughbred racehorses increased with the number of bacterial colony forming units (cfu) per ml of wash (P < 0.001). The aerobic bacteria Streptococcus zooepidemicus, Pasteurella/Actinobacillus-like species and Streptococcus pneumoniae were significantly associated with lower airway inflammation whereas coagulase-negative Staphylococcus spp., alpha-haemolytic Streptococcus spp., Acinetobacter spp., Bacillus spp., Escherichia coli, Pseudomonas aeruginosa, non-haemolytic Streptococcus spp...
Divers TJ, Schappel KA, Sweeney RW, Tennant BC.Persistent hyperbilirubinemia and icterus are described in a healthy 4-year-old Thoroughbred horse. Hyperbilirubinemia was not related to food intake and was not associated with evidence of increased hemolysis or with acquired hepatic disease. The hyperbilirubinemia was thought to be a result of inappropriate conjugation of bilirubin rather than any abnormality in bilirubin uptake or excretion. The bilirubinemia in this horse appears most similar to a human syndrome, caused by a familial deficiency of bilirubin-uridine diphosphate glucuronyl transferase.
Brooks SA, Bailey E.Inflammatory damage to the digital laminae, a structure responsible for suspension of the distal skeleton within the hoof capsule, results in a painful and often life-threatening disease in horses called laminitis. There can be many diverse causes of laminitis; however, previous work in the horse has suggested that in each case, the inflammation and resulting tissue damage is consistent with the action of mediators released from mast cells (MC), as well as the downstream consequences of their activation. The recent development of molecular genetics tools to characterize cells based on their tr...
Scott EA, Todhunter R.In 2 cases of chronic intestinal intussusception in horses, one involved jejunum and the other, ileum. The only clinical signs observed were intermittent colic. Surgery was performed on both horses, with successful outcomes.
Shibahara T, Kuwano A, Ueno T, Katayama Y, Ohya T, Taharaguchi S, Yamamoto S, Umemura T, Ishikawa Y, Kadota K.Studies of equine intestinal spirochetes have long focused on intestinal contents alone, but intestinal spirochetosis has been reported recently in a 21-month-old Thoroughbred colt in Japan. To define the clinical and pathological significances of intestinal spirochetosis in several horses, an epizootiologic survey with histologic, immunohistochemical, and ultrastructural methods was conducted for Brachyspira antigen-containing intestinal spirochetes in 12 diseased or injured Thoroughbred horses, aged from 35 days to 17 years. Brachyspira antigen-containing spirochetes were found in 7 of 12 ho...
Johnson SA, Richards RB, Frisbie DD, Esselman AM, McClure SR.Over the past three decades, electrohydraulic extracorporeal shock wave therapy (ESWT) as a treatment modality for equine orthopaedic disorders has sparked exponential interest among practitioners, but its clinical applications are quickly evolving and a current review highlighting modernised equine clinical use is lacking. The objective of this review is to summarise the most current ESWT technology, evidence for its use, proposed mechanisms of action and clinical applications in horses while also highlighting the areas requiring further investigation. The three ways to generate a shock wave ...
Bowie J, Mason PC, Oudemans G, Montgomery RH.Cysts found in the liver of a horse which had never been out of New Zealand were used to infect two dogs which were slaughtered 35 days after infection. Large numbers of Echinococcus granulosus were recovered. These cestodes were compared with mature dog-sheep cestodes, using light and scanning electron microscopy and identified as the dog-horse strain of E.granulosus.
Adams SB, Fessler JF, Thacker HL.FIBROMAS arise from connective tissue and occur in all domestic animals (Smith, Jones and Hunt 1972; Stannard and Pulley 1978). They are most frequently noted in the dermis or subcutis, but may be present wherever connective tissue occurs. In the dermis and subcutis of the horse fibromas are grossly similar to sarcoids and may be difficult to differentiate (Baker and Leyland 1975). Fibromas have been described as tumours of the tendon sheath or tendon proper in man (Flynn 1975), but have not been described in this location in the horse.
Angsubhakorn S, Poomvises P, Romruen K, Newberne PM.Two episodes of acute aflatoxin poisoning in horses suggest that horses are susceptible to the toxic effects of this mycotoxin. Lesions associated with exposure to aflatoxin included encephalomalacia of cerebral hemispheres, fatty degeneration, necrosis, bile duct hyperplasia, fibrosis of the liver, fatty infiltration of the kidney, hemorrhagic enteritis, and myocardial degeneration. Hypoglycemia, hyperlipidemia, and depletion of lymphocytes accompanied these lesions. The diagnosis was based on gross and histopathologic observations, consistent with observations of other species poisoned with ...