Analyze Diet

Topic:Diagnostic Technique

Diagnostic techniques in equine medicine encompass a range of procedures and tools used to identify diseases, injuries, or other health conditions in horses. These techniques include imaging methods such as radiography, ultrasonography, and magnetic resonance imaging (MRI), as well as laboratory tests like blood work and tissue biopsies. Each diagnostic method provides specific information that can aid in the assessment and management of equine health issues. Radiography is commonly used for evaluating bone structures, while ultrasonography is useful for soft tissue examination. MRI offers detailed images of both soft and hard tissues, though its use is limited by cost and availability. Laboratory tests can detect biochemical and hematological changes indicative of disease. This page compiles peer-reviewed research studies and scholarly articles that explore the development, application, and efficacy of various diagnostic techniques in equine veterinary practice.
Evaluation of decision criteria for detection of spinal cord compression based on cervical myelography in horses: 38 cases (1981-2001).
Equine veterinary journal    February 6, 2004   Volume 36, Issue 1 14-20 doi: 10.2746/0425164044864642
van Biervliet J, Scrivani PV, Divers TJ, Erb HN, de Lahunta A, Nixon A.Different criteria have been described based on height reduction of the total myelographic contrast column and components of it as tests for compression of the spinal cord due to cervical stenotic myelopathy (CSM). Fifty percent height reduction of the dorsal myelographic column (DMC), <2 mm empiric height of the DMC and a 40% reduction of the ratio of stenosis calculated based on the height reduction of the entire dural diameter (DD) have been described as decision criteria for considering the test result positive. The reasons for selecting these decision criteria or their accuracies have ...
Transcranial magnetic stimulation: normal values of magnetic motor evoked potentials in 84 normal horses and influence of height, weight, age and sex.
Equine veterinary journal    February 6, 2004   Volume 36, Issue 1 51-57 doi: 10.2746/0425164044864660
Nollet H, Deprez P, van Ham L, Dewulf J, Decleir A, Vanderstraeten G.Cervical spinal cord dysfunction is a common problem in equine medicine and the currently available tests give no objective information about the functionality of the nervous tracts. Therefore, transcranial magnetic stimulation (TMS) was performed in 84 healthy horses of different height in order to have an objective measure for the integrity of the descending motor tracts in normal horses. Objective: To obtain reference values for onset latency and peak-to-peak amplitude of magnetic motor evoked potentials (MMEPs) and to evaluate the possible effect of height, age and gender on the neurophysi...
Measurement of respiratory function by impulse oscillometry in horses.
Equine veterinary journal    February 6, 2004   Volume 36, Issue 1 21-28 doi: 10.2746/0425164044864714
van Erck E, Votion D, Art T, Lekeux P.Due to technical implementations and lack of sensitivity, pulmonary function tests are seldom used in clinical practice. Impulse oscillometry (IOS) could represent an alternative method. Objective: To define feasibility, methodology and repeatability of IOS, a forced oscillation technique that measures respiratory resistance (Rrs) and reactance (Xrs) from 5 to 35 Hz during spontaneous breathing, in horses. Methods: Using 38 healthy horses, Rrs and Xrs reference values were defined and influence of individual biometrical parameters was investigated. In addition, IOS measurements of 6 horses sho...
Color Doppler ultrasound evaluation of testicular blood flow in stallions.
Theriogenology    February 6, 2004   Volume 61, Issue 5 799-810 doi: 10.1016/s0093-691x(03)00227-9
Pozor MA, McDonnell SM.The objectives of this study were to evaluate the potential use of color Doppler ultrasound to characterize blood flow to the stallion testis, and to establish reference values for Doppler measures of blood flow in the testicular artery of the stallion. Both testes from each of 52 horses were examined using a pulsed-wave color Doppler ultrasound with a sector array 5/7.5 MHz transducer with a 1mm gate setting. Peak systolic velocity (PSV), end diastolic velocity (EDV), resistive index (RI), and pulsatility index (PI) of the testicular artery were measured in each of two locations, the convolut...
Prevalence of parasite eggs (Strongyloides westeri, Parascaris equorum, and strongyles) and oocysts (Emeria leuckarti) in the feces of Thoroughbred foals on 14 farms in central Kentucky in 2003.
Parasitology research    February 4, 2004   Volume 92, Issue 5 400-404 doi: 10.1007/s00436-003-1068-2
Lyons ET, Tolliver SC.Prevalence of internal parasites was determined by fecal examination for eggs and oocysts in Thoroughbred foals in central Kentucky in 2003. Fecal samples were examined from 733 foals on 14 farms. This included 70 trips to the farms and a total of 2,346 fecal samplings. Monthly collection of fecal samples was begun for four farms in February, six in March, three in April, and one farm in May. Termination of the study for all farms was the end of July. A criterion was that the foals be at least 10 days old for initial samplings. If available, the same foals were sampled each time, in addition t...
Serum osteocalcin in donkeys as evaluated with an equine-specific radioimmunoassay.
Journal of animal physiology and animal nutrition    February 1, 2004   Volume 88, Issue 1-2 1-6 doi: 10.1111/j.1439-0396.2004.00443.x
Carstanjen B, Amory H, Youssao I, Remy B.The purpose of this study was to validate an equine-specific osteocalcin (OC) radioimmunoassay (RIA) for use in donkeys and to establish age-related changes in serum OC concentrations in healthy donkeys. Serial dilutions of donkey serum showed parallelism with standard curves obtained with the equine-specific OC RIA. There was a tight linear regression between donkey serum OC values obtained with the equine specific OC RIA and a commercially available bovine-specific OC RIA. Serum OC levels of 27 healthy donkeys, analysed with the equine-specific OC RIA, showed a tight negative logarithmic reg...
Management of comminuted fractures of the proximal phalanx in horses: 64 cases (1983-2001).
Journal of the American Veterinary Medical Association    January 23, 2004   Volume 224, Issue 2 254-263 doi: 10.2460/javma.2004.224.254
Kraus BM, Richardson DW, Nunamaker DM, Ross MW.To report the outcome of surgical treatment of comminuted fractures of the proximal phalanx in horses. Methods: Retrospective study. Methods: 64 horses. Methods: Medical records and radiographs were reviewed to obtain information regarding signalment, fracture classification, and treatment. Follow-up information was obtained by telephone conversation or evaluation of production records. Results: Thirty-eight horses had moderately comminuted fractures of the proximal phalanx. Two horses were euthanatized immediately. Fractures of the proximal phalanx in 36 horses were repaired with open reducti...
Exostoses of the caudal perimeter of the radial physis as a cause of carpal synovial sheath tenosynovitis and lameness in horses: 10 cases (1999-2003).
Journal of the American Veterinary Medical Association    January 23, 2004   Volume 224, Issue 2 264-270 doi: 10.2460/javma.2004.224.264
Nixon AJ, Schachter BL, Pool RR.To determine the clinical, radiographic, ultrasonographic, and arthroscopic findings associated with tenosynovitis of the carpal synovial sheath induced by exostoses that originate from the caudal surface of the physeal scar of the distal radius and determine the results of surgical removal of those exostoses in horses. Methods: Retrospective study. Methods: 10 horses. Methods: Medical records of horses with effusion in the carpal synovial sheath and lameness evaluated from 1999 to 2003 were examined. Results: All horses had a history of intermittent mild to moderate effusion of the carpal syn...
Evaluation of urine sucrose concentration for detection of gastric ulcers in horses.
American journal of veterinary research    January 15, 2004   Volume 65, Issue 1 31-39 doi: 10.2460/ajvr.2004.65.31
O'Conner MS, Steiner JM, Roussel AJ, Williams DA, Meddings JB, Pipers F, Cohen ND.To evaluate the use of sucrose permeability testing to detect ulcers in the gastric squamous mucosa of horses. Methods: 13 adult horses ranging from 5 to 19 years of age. Methods: Following induction of gastric ulcers by intermittent feed deprivation, horses underwent sucrose permeability testing (administration of sucrose by nasogastric intubation followed by collection of urine at 2 and 4 hours after intubation) and gastric endoscopy. Squamous ulcers were assigned a severity score (range, 0 to 3) by use of an established scoring system. Horses were subsequently administered omeprazole for 21...
Nucleotide sequence of equine erythropoietin and characterization of region-specific antibodies.
American journal of veterinary research    January 15, 2004   Volume 65, Issue 1 15-19 doi: 10.2460/ajvr.2004.65.15
Sato F, Yamashita S, Kugo T, Hasegawa T, Mitsui I, Kijima-Suda I.To determine the full-length complementary DNA (cDNA) sequence of equine erythropoietin (EPO) and to develop region-specific antibodies to differentiate equine EPO (eEPO) and human EPO (hEPO). Methods: RNA and lysate extracted from renal tissues of an adult Thoroughbred. Methods: Full-length cDNA was determined by use of a reverse transcriptase-polymerase chain reaction assay and a rapid amplification of cDNA ends method. The deduced amino acid sequence was compared with sequences of EPO reported for other species. Furthermore, 4 synthetic peptides were designed in 2 distinctive parts of the e...
Evaluation of plasma carboxy-terminal cross-linking telopeptide of type I collagen concentration in horses.
American journal of veterinary research    January 15, 2004   Volume 65, Issue 1 104-109 doi: 10.2460/ajvr.2004.65.104
Carstanjen B, Hoyle NR, Gabriel A, Hars O, Sandersen C, Amory H, Remy B.To evaluate a human assay for quantification of carboxy-terminal cross-linking telopeptide of type I collagen (CTX-I), assess the influence of age on plasma CTX-I concentration, investigate the relationship between plasma CTX-I and serum osteocalcin concentrations, and determine whether concentrations of plasma CTX-I or serum osteocalcin fluctuate in circadian manner in horses. HORSES: 75 clinically normal horses. Methods: Cross-reactivity between equine serum CTX-I and CTX-I antibodies in an automated electrochemiluminescent sandwich antibody assay (ECLIA) was evaluated via a specificity test...
Molecular cloning of a Babesia caballi gene encoding the 134-kilodalton protein and evaluation of its diagnostic potential in an enzyme-linked immunosorbent assay.
Clinical and diagnostic laboratory immunology    January 13, 2004   Volume 11, Issue 1 211-215 doi: 10.1128/cdli.11.1.211-215.2004
Tamaki Y, Hirata H, Takabatake N, Bork S, Yokoyama N, Xuan X, Fujisaki K, Igarashi I.A Babesia caballi gene encoding the 134-kDa (BC134) protein was immunoscreened with B. caballi-infected horse serum. An enzyme-linked immunosorbent assay (ELISA) using recombinant BC134 protein could effectively differentiate B. caballi-infected horse sera from Babesia equi-infected or noninfected control horse sera. These results suggest that the recombinant BC134 protein is a potential diagnostic antigen in the detection of B. caballi infection.
Development of an immunochromatographic test with recombinant EMA-2 for the rapid detection of antibodies against Babesia equi in horses.
Journal of clinical microbiology    January 13, 2004   Volume 42, Issue 1 359-361 doi: 10.1128/JCM.42.1.359-361.2004
Huang X, Xuan X, Xu L, Zhang S, Yokoyama N, Suzuki N, Igarashi I.An immunochromatographic test (BeICT) for the rapid detection of antibodies against Babesia equi was developed. It clearly differentiated B. equi-infected horses from B. caballi-infected and uninfected horses. The agreement with enzyme-linked immunosorbent assay results was 96.7% in the detection of field sera. The results suggest that BeICT is rapid, simple, reliable, and suitable for use to detect B. equi infection in the field.
Characterisation of IgG(T) serum antibody responses to two larval antigen complexes in horses naturally- or experimentally-infected with cyathostomins.
International journal for parasitology    January 9, 2004   Volume 34, Issue 1 101-108 doi: 10.1016/j.ijpara.2003.09.008
Dowdall SM, Proudman CJ, Klei TR, Mair T, Matthews JB.Cyathostomins are the most common parasitic nematodes of horses. Larval stages, which inhabit the intestinal wall, are particularly pathogenic and can cause severe colitis and colic. Despite their clinical importance, diagnostic techniques for the prepatent stages do not exist. A method that could estimate mucosal infection intensity would have a major impact on the control and diagnosis of cyathostominosis. Here, serum IgG(T) responses to two larval antigen complexes of 25 and 20 kDa were quantified in horses with experimental infections, natural infections and in horses that presented with c...
Scintigraphic abnormalities of the pelvic region in horses examined because of lameness or poor performance: 128 cases (1993-2000).
Journal of the American Veterinary Medical Association    January 9, 2004   Volume 224, Issue 1 88-95 doi: 10.2460/javma.2004.224.88
Davenport-Goodall CL, Ross MW.To identify scintigraphic abnormalities in the pelvic region of horses examined because of hind limb lameness or poor performance and determine the clinical relevance of areas of abnormal radiopharmaceutical uptake (ARU) in these horses. Methods: Retrospective study. Methods: 128 horses. Methods: Medical records were reviewed, and information on signalment, history, admitting complaints, physical examination findings, and results of lameness examinations was recorded. Clinical relevance of areas of ARU was determined by comparison with results of other diagnostic tests. For horses with clinica...
Dual photon absorptiometry using a gadolinium-153 source applied to measure equine bone mineral content.
Physics in medicine and biology    January 2, 2004   Volume 48, Issue 23 3851-3863 doi: 10.1088/0031-9155/48/23/004
Moure A, Reichmann P, Gamba HR.The application of the dual photon absorptiometry (DPA) technique, using gadolinium-153 as the photon source, to evaluate the bone mineral density (BMD) of the third metacarpal bone of horses is presented. The radiation detector was implemented with a NaI(TI) scintillator coupled to a 14 stage photomultiplier. A modular mechanical system allows the position of the prototype to be adjusted in relation to the animal. A moveable carrier makes it possible to scan the third metacarpal with a velocity adjustable between 1 and 12 mm s(-1), in steps of 1 mm s(-1), for a total distance of 250 mm. The p...
Scintigraphy of the sacroiliac joint region in asymptomatic riding horses: scintigraphic appearance and evaluation of method. Erichsen C, Eksell P, Widström C, Berger M, Holm KR, Johnston C.The sacroiliac region in 33 clinically normal riding horses was examined with scintigraphy to determine the normal scintigraphic appearance, to evaluate a semiquantitative method used to calculate a sacroiliac joint (SI joint) ratio, and to identify factors that affect the scintigraphic appearance of the pelvis. The scintigraphic examination included dorsal views of each SI joint region and one lateral view of the urinary bladder. Two predefined areas (the SI joint and the area between the tuber sacrale and the SI joint) were evaluated subjectively by comparing the intensity in each area to th...
Effect of trabecular orientation on mechanical resistance and ultrasound propagation in specimens of equine vertebrae.
Ultrasound in medicine & biology    December 31, 2003   Volume 29, Issue 12 1777-1785 doi: 10.1016/j.ultrasmedbio.2003.08.003
Cavani F, Fini M, de Terlizzi F, Cadossi M, Ciminelli L, Ortolani S, Cherubini R, De Aloysio D, Giavaresi G, Cadossi R, Canè V.Osteoporosis involves alterations, not only in density, but also in the architectural organisation of the bone; in particular, trabecular orientation, following the skeletal load directions, lends a high degree of stiffness to the whole bone. We investigated the relationship between trabecular orientation, density, stiffness and ultrasound (US) propagation in two orthogonal directions (par. = parallel to, and ort. = orthogonal to the main orientation of the trabeculae) in cylindrical equine bone specimens (thoracic vertebrae) where a preferential orientation is present. A total of 15 cylinders...
On the ultrasonic properties of tendon.
Ultrasound in medicine & biology    December 31, 2003   Volume 29, Issue 12 1787-1797 doi: 10.1016/s0301-5629(03)01069-x
Garcia T, Hornof WJ, Insana MF.The strong dependence of tendon echogenicity on insonation angle is explored by analyzing echo spectra. Combining echo spectra with high-resolution images from several modalities reveals that fluid spaces surrounding fascicles and bundles are likely sources of ultrasonic scatter. Mathematical models of tendon structure are proposed to explain how the anisotropic microstructure of tendon gives rise to angle-dependent echogenicity. Echo spectra from spontaneously damaged equine tendon samples were compared with normal equine tendon and found to exhibit a dramatic decrease in anisotropic properti...
Decreased expression of equine herpesvirus-1 early and late genes in the placenta of naturally aborted equine fetuses.
Journal of comparative pathology    December 25, 2003   Volume 130, Issue 1 41-47 doi: 10.1016/s0021-9975(03)00068-9
Kimura T, Hasebe R, Mukaiya R, Ochiai K, Wada R, Umemura T.Intrauterine infection with equine herpesvirus-1 (EHV-1) has been considered to be the consequence of transplacental transmission of the virus following maternal cell-associated viraemia. In this study the state of EHV-1 gene expression in the placenta of seven naturally aborted equine fetuses was examined. Neither lesions nor viral antigens were detected in the placenta of the fetuses. The amount of infectious virus in the placentas was considerably lower than that in the fetal lungs, which showed pneumonia and typical herpesvirus inclusions. Quantitative dot blot hybridization with probes sp...
Effect of focused and radial extracorporeal shock wave therapy on equine bone microdamage.
Veterinary surgery : VS    December 23, 2003   Volume 33, Issue 1 49-55 doi: 10.1111/j.1532-950x.2004.040005.x
Da Costa Gómez TM, Radtke CL, Kalscheur VL, Swain CA, Scollay MC, Edwards RB, Santschi EM, Markel MD, Muir P.To determine whether bone microcracks are altered after application of focused and radial extracorporeal shock wave therapy (ESWT) to the equine distal limb. Methods: An ex vivo experimental model. Methods: A contralateral limb specimen was obtained from 11 Thoroughbred racehorses with a unilateral catastrophic injury. Distal limb specimens were also obtained from 5 non-racing horses. Methods: Three separate skin-covered bone segments were obtained from the mid-diaphysis of the metacarpus (MC3) or metatarsus (MT3). Focused (9,000 shockwaves, 0.15 mJ/mm2, 4 Hz) and radial (9,000 shockwaves, 0.1...
Scanning electron microscopic examination of third metacarpal/third metatarsal bone failure surfaces in thoroughbred racehorses with condylar fracture.
Veterinary surgery : VS    December 23, 2003   Volume 33, Issue 1 2-10 doi: 10.1111/j.1532-950x.2004.04007.x
Stepnik MW, Radtke CL, Scollay MC, Oshel PE, Albrecht RM, Santschi EM, Markel MD, Muir P.To examine the fracture failure surfaces from Thoroughbred horses that had sustained a catastrophic condylar fracture. Methods: Bone specimens from the failure surface were obtained from 12 Thoroughbred racehorses with catastrophic injury and 2 non-racing horses with accidental long bone fracture. Methods: Bone specimens from the failure surface of each fracture were incubated with gold microspheres to label microcracks before examination at x50 to x60,000 using scanning electron microscopy. Microcracking at the failure surface was assessed using a visual analog scale. Results: Branching array...
Novel classical MHC class I alleles identified in horses by sequencing clones of reverse transcription-PCR products.
European journal of immunogenetics : official journal of the British Society for Histocompatibility and Immunogenetics    December 17, 2003   Volume 30, Issue 6 387-396 doi: 10.1111/j.1365-2370.2003.00420.x
Chung C, Leib SR, Fraser DG, Ellis SA, McGuire TC.Improved typing of horse classical MHC class I is required to more accurately define these molecules and to extend the number identified further than current serological assays. Defining classical MHC class I alleleic polymorphism is important in evaluating cytotoxic T lymphocyte (CTL) responses in horses. In this study, horse classical MHC class I genes were analyzed based on reverse transcription (RT)-PCR amplification of sequences encoding the polymorphic peptide binding region and the more conserved alpha 3, transmembrane and cytoplasmic regions followed by cloning and sequencing. Primer s...
Validation of a method for collection and assay of pentane in the exhaled breath of the horse.
Research in veterinary science    December 16, 2003   Volume 76, Issue 2 109-112 doi: 10.1016/j.rvsc.2003.08.007
Wyse CA, Love S, Christley RM, Yam PS, Cooper JM, Cumming DR, Preston T.Oxidative stress refers to an imbalance between the production of oxidising free radicals and the antioxidant defenses of the cell, and is associated with many pathogenic processes. Oxidative damage to cellular lipids results in the evolution of pentane and ethane gas, and detection of these hydrocarbons in the exhaled breath can be used to monitor in vivo oxidative stress. The aim of this study was to validate a gas chromatography (GC) method for measurement of breath pentane in the horse. The GC-system developed showed good specificity for discrimination of pentane from other breath hydrocar...
Evaluation of iohexol clearance used to estimate glomerular filtration rate in clinically normal foals.
American journal of veterinary research    December 16, 2003   Volume 64, Issue 12 1486-1490 doi: 10.2460/ajvr.2003.64.1486
Gonda KC, Wilcke JR, Crisman MV, Ward DL, Robertson JL, Finco DR, Braselton WE.To determine whether pharmacokinetic analysis of data derived from a single i.v. dose of iohexol could be used to predict creatinine clearance and evaluate simplified methods for predicting serum clearance of iohexol with data derived from 2 or 3 blood samples in clinically normal foals. Methods: 10 healthy foals. Methods: Serum disposition of iohexol and exogenous creatinine clearance was determined simultaneously in each foal (5 males and 5 females). A 3-compartment model of iohexol serum disposition was selected via standard methods. Iohexol clearance calculated from the model was compared ...
Use of high-resolution ultrasound as a diagnostic tool in veterinary ophthalmology.
Journal of the American Veterinary Medical Association    December 11, 2003   Volume 223, Issue 11 1617-1599 doi: 10.2460/javma.2003.223.1617
Bentley E, Miller PE, Diehl KA.The recent development of a 20-MHz, high-frequency ultrasound probe has allowed tissue to be visualized at resolutions of 20 to 80 microm, which is similar to a low-power histologic view. This high degree of resolution, however, limits tissue penetration to 5 to 10 mm, which is ideal for examination of the anterior segment of the eye. The detail provided by high-resolution ultrasound readily permits the clinician to distinguish between various anterior segment entities that may appear similar but are treated quite differently, such as anterior uveal tumors, iridociliary cysts, and iris bombé....
Transrectal Doppler sonography of uterine and umbilical blood flow during pregnancy in mares.
Theriogenology    December 10, 2003   Volume 61, Issue 2-3 499-509 doi: 10.1016/s0093-691x(03)00225-5
Bollwein H, Weber F, Woschée I, Stolla R.Transrectal color Doppler sonography was used to investigate uterine and umbilical blood flow during pregnancy (duration, 46-48 weeks) in four mares. The resistance index (RI) and blood flow volume (VOL) of the uterine arteries ipsilateral and contralateral to the conceptus, and the presence of an early diastolic notch in the Doppler wave, were evaluated every 4 week throughout pregnancy. Fetal blood flow was calculated semiquantitatively every 2 week (from 20 to 40 weeks), using the RI of the umbilical arteries. During the entire period of investigation, there were no significant individual v...
Dose-response study of intrafollicular injection of insulin-like growth factor-I on follicular fluid factors and follicle dominance in mares.
Biology of reproduction    December 10, 2003   Volume 70, Issue 4 1063-1069 doi: 10.1095/biolreprod.103.024844
Ginther OJ, Gastal EL, Gastal MO, Checura CM, Beg MA.The effect of insulin-like growth factor-I (IGF-I) on the concentrations of follicular fluid factors during follicle deviation and the development of dominance was studied in mares in two experiments. Transvaginal ultrasound guidance was used for intrafollicular injection and subsequent sequential sampling of follicular fluid. Treatment involved a single injection of IGF-I into the second-largest follicle (F2) at the expected beginning of deviation (Hour 0) based on diameter (> or =20 mm) of the largest follicle (F1). Mares in IGF-I groups were given a dose of 500 microg (experiment 1) or 2...
Factors affecting plasma progesterone concentration and the retrospective determination of time of ovulation in cyclic mares.
Theriogenology    December 10, 2003   Volume 61, Issue 2-3 203-214 doi: 10.1016/s0093-691x(03)00211-5
Nagy P, Huszenicza G, Reiczigel J, Juhász J, Kulcsár M, Abaváry K, Guillaume D.Factors influencing plasma progesterone concentration were investigated in seven mares. Two-phase logistic curves were fitted (r=0.98) to plasma progesterone concentrations of blood samples collected once daily. In addition to the effect of time (P<0.001), there were differences (P<0.01) among mares in the peak height of the progesterone plateau and in the (area under the curve) AUC. Plasma progesterone concentrations were higher (P<0.001) after a multiple versus single ovulation. There was an effect of season (P<0.001), but no significant effect of luteal morphology. The retrospec...
Generation and characterization of an EICP0 null mutant of equine herpesvirus 1.
Virus research    December 9, 2003   Volume 98, Issue 2 163-172 doi: 10.1016/j.virusres.2003.09.007
Yao H, Osterrieder N, O'Callaghan DJ.The EICP0 gene (gene 63) of equine herpesvirus 1 (EHV-1) encodes an early regulatory protein that is a promiscuous trans-activator of all classes of viral genes. Bacterial artificial chromosome (BAC) technology and RecE/T cloning were employed to delete the EICP0 gene from EHV-1 strain KyA. Polymerase chain reaction, Southern blot analysis, and DNA sequencing confirmed the deletion of the EICP0 gene and its replacement with a kanamycin resistance gene in mutant KyA. Transfection of rabbit kidney cells with the EICP0 mutant genome produced infectious virus, indicating that the EICP0 gene is not...