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Topic:Clinical Pathology
Clinical pathology in horses involves the study and analysis of biological samples to diagnose and monitor diseases and health conditions. This discipline encompasses various laboratory tests and procedures that assess the physiological and biochemical status of equines. Common analyses include hematology, biochemistry, urinalysis, and cytology, each providing insights into different aspects of equine health. Hematology evaluates blood components, such as red and white blood cells and platelets, to identify conditions like anemia or infection. Biochemistry tests measure enzymes, electrolytes, and metabolites to assess organ function and metabolic status. Urinalysis examines urine samples for indicators of renal function and systemic diseases. Cytology involves the microscopic examination of cells from tissues or fluids to detect abnormalities. This page aggregates peer-reviewed research studies and scholarly articles that explore the methodologies, applications, and diagnostic value of clinical pathology in equine medicine.
Experimental infection of four horses with Ehrlichia phagocytophila. Four clinically healthy horses which were negative for antibodies to Ehrlichia phagocytophila, the agent of bovine ehrlichiosis, were infected experimentally with E phagocytophila-containing bovine leucocytes, administered intravenously. The horses were examined daily for four weeks, and blood samples were collected daily for cytological, haematological and biochemical examination and for a nested polymerase chain reaction (PCR). An indirect immunofluorescence test was used to determine when the horses seroconverted and the duration of positive titres. There were no abnormal clinical, haematol...
Osteochondritis dessicans and subchondral cystic lesions in draft horses: a retrospective study. The clinical features, radiographic findings, treatment, and outcome in 51 draft horses with osteochondritis dessicans (OCD) or subchondral cystic lesions (SC) are reported. Clydesdale and Percheron were the most commonly affected breeds, and affected animals represented only 5% of the hospital population of draft horses. Horses were most frequently affected in the tibiotarsal joints and 73% (24 of 33 cases) of the horses with tibiotarsal effusion were affected bilaterally. Osteochondritis dessicans of the distal intermediate ridge was the most common lesion found in the tibiotarsal joint. The...
Laparoscopic diagnosis of subcapsular splenic hematoma in a horse. A 5-year-old Quarter Horse was examined after it developed signs of abdominal discomfort as a result of a training accident. Oral mucous membranes were pale, and capillary refill time was > 3 seconds. Hematologically, the PCV was low, and abdominocentesis yielded a serosanguineous fluid. Abdominal ultrasonography was performed and revealed a large hypoechoic mass associated with the cranial margin of the spleen. Because differentiation between subcapsular hematoma and extracapsular hematoma could not be made with certainty, further evaluation of the spleen was indicated. Abdominal laparosco...
Influence of fecal shedding of Salmonella organisms on mortality in hospitalized horses. To predict mortality of horses by use of clinical data from the first day of hospitalization, to determine whether fecal shedding of Salmonella organisms is related to severity of clinical disease, and to determine the impact of fecal shedding of Salmonella organisms on mortality. Methods: Prospective study. Methods: 1,446 hospitalized horses. Methods: Medical information was obtained from horses hospitalized in an intensive care unit or isolation facility during a 4.5-year period. A model was created to predict mortality, using covariates determined on the day of admission. Predicted mortalit...
Occult osseous metastasis of a colonic adenocarcinoma visualized with technetium tc 99m hydroxymethylene diphosphate scintigraphy in a horse. A 5-year-old Arabian horse was admitted with a 5-day history of undulant pyrexia of unknown origin, inappetence, obtundation, and acute collapse. Physical examination results were unremarkable except for a grade II/VI left-sided systolic cardiac murmur and abdominal splinting. Mild chronic inflammatory changes were evident on clinicopathologic evaluation. Echocardiography revealed moderate aortic insufficiency. A solitary soft tissue opacity was found on thoracic radiography but not on ultrasonography. Palliative treatment was ineffective. Nuclear scintigraphy with WBC labeled with technetium ...
Clinical, serologic, and histopathologic characterization of experimental Borna disease in ponies. Borna disease was originally described as an equine neurologic syndrome over 200 years ago, although the infectious etiology of the disorder was unproven until the early 20th century. Borna disease virus (BDV) was finally isolated from horses dying of the disorder, and that virus has been used to experimentally reproduce Borna disease in several species of laboratory animals. However, BDV has never been inoculated back into horses to experimentally and etiologically confirm the classic clinical, pathologic, and serologic characteristics of the disease in that species. Three ponies were intrace...
Donkeys as reservoirs of African horse sickness virus. Investigations have been carried out to elucidate the possible role of the donkey in the epidemiology of African horse sickness (AHS). These studies have shown that despite the absence of pyrexia or other observable clinical signs, donkeys become infected with virulent AHS virus serotype 4 (AHSV 4) and that they develop a viraemia which can persist for at least 12 days, albeit at a comparatively lower titre than that recorded for similarly infected ponies. AHSV 4 showed a similar tissue tropism in the pony and donkey but the virus appeared to replicate less efficiently in donkey tissues. The o...
Histamine-induced gastric acid secretion in horses. To determine gastric secretory responses in horses treated with histamine and to determine the dose of histamine needed to elicit maximal gastric secretion. Methods: 6 adult horses with an indwelling gastric cannula. Methods: Gastric contents were collected in 15-minute periods, and volume, pH, hydrogen ion concentration, hydrogen ion output, sodium concentration, and sodium output were determined. Values were determined without any treatment (baseline), after administration of pyrilamine maleate (1 mg/kg of body weight, i.v., given during a 15-minute period), and during 1-hour infusions of hi...
Hematologic and serum biochemical variables and plasma corticotropin concentration in healthy aged horses. To compare hematologic and serum biochemical variables and plasma ACTH concentration between healthy horses 5 to 12 years old and those more than 20 years old. Methods: 30 healthy horses 5 to 12 years old and 30 healthy horses more than 20 years old. Methods: Venous blood was collected from all horses, and CBC and serum biochemical analysis were performed for each horse. Plasma ACTH concentration was determined by radioimmunoassay. Student's paired t-test or the Mann-Whitney rank sum test was used to compare values between control and aged horse groups. Results: Compared with values for contro...
Changes in plasma protein concentrations in ponies with experimentally induced alimentary laminitis. To determine whether plasma protein concentrations were altered in ponies with alimentary laminitis. Methods: 12 adult ponies. Methods: Acute laminitis was induced in 6 ponies by oral administration of carbohydrate (85% corn starch, 15% wood flour); the other 6 ponies were used as controls. A physical examination was performed and blood samples were collected immediately before and 4, 8, 12, 24, and 28 hours after administration of carbohydrate. Plasma protein concentrations were determined by means of sodium dodecyl sulphate-polyacrylamide gel electrophoresis. Results: 19 plasma proteins rang...
Propylene glycol toxicosis in a mare. Propylene glycol and mineral oil are commonly used in the veterinary profession for treatment of bovine ketosis and equine impactions, respectively. Accidental administration of 6.0 ml propylene glycol/kg of body weight in horses causes severe depression, ataxia and malodorous breath and feces. However, appropriate medical therapy can result in successful treatment of this toxicosis.
Pharmacokinetics of a high dose of gentamicin administered intravenously or intramuscularly to horses. To evaluate pharmacokinetics of a high dose of gentamicin administered i.v. or i.m. to horses. Methods: Repeated-measures study. Methods: 6 clinically normal female adult stock-type horses. Methods: All horses were given gentamicin (6.6 mg/kg [3 mg/lb] of body weight), i.v. and i.m., in a two-way cross-over design. Serum gentamicin concentrations were measured during a 24-hour period. Results: Plasma concentration curves were consistent with a two-compartment model. Maximum plasma gentamicin concentrations were 71.9 +/- 15.7 micrograms/ml (0 hours after injection) and 22.0 +/- 4.9 micrograms/m...
Reliability of using results of abdominal fluid analysis to determine treatment and predict lesion type and outcome for horses with colic: 218 cases (1991-1994). To assess clinical utility of abdominal fluid analysis in predicting outcome, lesion type, and whether medical or surgical treatment is indicated for horses with colic. Methods: Retrospective study. Methods: 218 horses > 1 year old. Methods: Horses were classified on the basis of age, site of lesion, lesion type (nonstrangulating vs strangulating), type of treatment (medical vs surgical), and outcome (survival vs nonsurvival). Sensitivity and specificity of using age and results of abdominal fluid analysis, individually and in combination, to predict lesion type, type of treatment, and outc...
Halicephalobus gingivalis (Stefanski, 1954) from a fatal infection in a horse in Ontario, Canada with comments on the validity of H. deletrix and a review of the genus. Although the original description given by Stefanski (1954) was satisfactory, Anderson & Bemrick (1965), in describing H. deletrix (= Micronema deletrix), claimed Stefanski's description was "inadequate" and the species a "species inquirenda". Thus, infections in horses and humans have been assigned to H. deletrix. We believe the species reported in horses and humans is H. gingivalis and that H. deletrix is its synonym. H. gingivalis is separated herein from forms found free-living. The genital tract in the advanced fourth stage of H. gingivalis is didelphic and amphidelphic and terminal e...
The accuracy of the dorsoproximal-dorsodistal projection in assessing third carpal bone sclerosis in standardbred trotters. Thirty-five carpal joints from 20 standardbred trotters, age 1 to 7 years, all euthanized for nonorthopedic reasons, were examined to investigate the correlation between assessments of subchondral bone sclerosis in the third carpal bone from radiographs in the dorsoproximal-dorsodistal (DPr-DDi) projection and histomorphometric bone volume density measurements. The agreement between assessments of sclerosis from antemortem versus postmortem radiographs was also evaluated. Bones graded as sclerotic in the DPr-DDi projection had significantly higher bone volume density values for all areas of me...
Quantification of penicillin-G and procaine in equine urine and plasma using high-performance liquid chromatography. A rapid and sensitive method for the extraction and quantification of penicillin-G and procaine in horse urine and plasma samples has been successfully developed. The method involves the use of solid-phase extraction (SPE) for penicillin-G, liquid-liquid extraction (LLE) for procaine, and high-performance liquid chromatography (HPLC) for the quantification of penicillin-G and procaine. The new method described here has been successfully applied in the pharmacokinetic studies of procaine, penicillin-G and procaine-penicillin-G administrations in the horse.
Equine endothelial cells support productive infection of equine infectious anemia virus. Previous cell infectivity studies have demonstrated that the lentivirus equine infectious anemia virus (EIAV) infects tissue macrophages in vivo and in vitro. In addition, some strains of EIAV replicate to high titer in vitro in equine fibroblasts and fibroblast cell lines. Here we report a new cell type, macrovascular endothelial cells, that is infectible with EIAV. We tested the ability of EIAV to infect purified endothelial cells isolated from equine umbilical cords and renal arteries. Infectivity was detected by cell supernatant reverse transcriptase positivity, EIAV antigen positivity wit...
Cytology of 100 samples of abdominal fluid from 100 horses with abdominal disease. A total of 100 samples of abdominal fluid (AF) from 100 horses with abdominal disease were evaluated by cytology. Cytology results were subsequently correlated with the final outcome of the disease. The horses were classified into 4 groups: Group I, horses that were treated with conventional (nonsurgical) therapy and recovered; Group II, horses that had surgery and survived; Group III, horses that had surgery but died; and Group IV, horses that were subjected to euthanasia prior to surgery. Statistical analysis showed that both nucleated cell count and total neutrophils were significantly high...
Dextran-70 inhibits equine platelet aggregation induced by PAF but not by other agonists. Dextrans of mean molecular weight 70 kDa (dextran-70) have had clinical use as anti-thrombotics in man. A major part of the anti-thrombotic action is mediated via inhibition of platelet function. Greatorex (1975, 1977) treated thromboembolic colic in horses with infusions of dextran-70 and reported a 90% recovery rate, but this treatment is nonetheless rarely used. We have used an in vitro method to examine the effect of dextran-70 on equine platelet suspensions, in the hope that understanding the mechanism of action of dextran-70 might lead to the development of alternative therapeutic agents...
Clinical assessment of gas exchange in mature horses. There are limited methods of assessing pulmonary function in horses at rest. We developed clinical techniques to measure gas exchange efficiency in horses and evaluated 3 groups of horses that were 1) asymptomatic based on auscultation with rebreathing, transtracheal aspirate cytology, and thoracic radiographs (n = 6), 2) asymptomatic at rest but symptomatic with rebreathing (n = 11) and 3) symptomatic at rest (n = 9). Blood samples were obtained from the transverse facial artery and jugular vein. Maximal end-tidal CO2 tension (PETCO2) was measured by an infrared capnograph through a facemask....
Complete fractures of the third metacarpal or metatarsal bone in horses: 25 cases (1980-1996). To compare treatments of complete fractures of the third metacarpal (MC) or metatarsal (MT) bone in horses and to identify factors that could impact prognosis. Methods: Retrospective case series. Methods: 25 horses with fractures of the third MC or MT bone that were treated by use of internal fixation, external coaptation, or both. Methods: Medical records from the Veterinary Medical Data Base of horses treated for fractures of third MC or MT bone at Texas A&M University from 1980 to 1994 and Purdue University from 1980 to 1996 were reviewed. Information on signalment, results of physical ...
Effect of three types of half-limb casts on in vitro bone strain recorded from the third metacarpal bone and proximal phalanx in equine cadaver limbs. To determine effect of 3 half-limb casts on bone strains recorded from the proximal phalanx (P-1) and third metacarpal bone (MCIII) of equine cadaver limbs, using a mechanical testing machine. Methods: 12 equine cadaver limbs and 4 live horses. Methods: Bone strains were recorded at middorsal P-1 and the dorsal cortical aspect of the distal third of MCIII while limbs were variably loaded with 100 to 1,000 lb of force. To determine ability of the cast to protect the distal portion of the limb from weight-bearing loads, strains were recorded with the limb in 1 of the 3 casts and with it unsuppor...
Experimental infection of the human granulocytic ehrlichiosis agent in horses. Human blood collected from two patients from Westchester County, New York with human granulocytic ehrlichia (HGE) infection was inoculated into two ponies. Inoculated ponies developed clinical signs similar to a previous report (Madigan et al., 1995). Histopathological changes involved follicular hyperplasia of lymphoid tissues. HGE DNA was detected by PCR in muscle, fascia, peritoneum, and adrenal gland after the ponies produced a high level of antibodies to HGE. We suggest that HGE may reside in poorly vascularized connective tissues, where the antibodies may have some difficulties to penetr...
Herpesvirus myeloencephalopathy in horses: 11 cases (1982-1996). To determine results of CSF analysis in horses with equid herpesvirus myeloencephalopathy (EHM) and to determine whether results of CSF analysis were associated with outcome. Methods: Retrospective study. Methods: 11 horses. Methods: Medical records of all horses admitted to the veterinary teaching hospital between February 1982 and March 1996 in which EHM was diagnosed were reviewed. Results: 7 horses were < or = 4 years old; 8 were admitted during January, February, or March. Six horses were febrile prior to admission, but none was febrile on the day of admission. Five horses had been sta...
Evaluation of a portable clinical analyzer in a veterinary hospital setting. Evaluation of a portable clinical analyzer for determination of blood gas tensions, electrolyte and glucose concentrations, and Hct in a hospital setting. Methods: Prospective study. Methods: 50 dogs, 50 cats, and 28 horses, all clinically normal. Methods: Blood samples were analyzed on a portable clinical analyzer to determine concentrations of sodium, potassium, chloride, BUN, glucose, and ionized calcium and values of Hct, pH, PCO2, and PO2. Values obtained were compared with those obtained from the same blood samples, using a standard automatic analyzer (serum sodium, potassium, chloride, ...
