The study of diseases in horses encompasses a wide range of conditions affecting equine health, including infectious diseases, metabolic disorders, and genetic abnormalities. These diseases can impact various systems within the horse, such as respiratory, gastrointestinal, and musculoskeletal systems, and can lead to significant health challenges. Research in this area focuses on understanding the pathophysiology, diagnosis, prevention, and treatment of equine diseases. Common diseases studied include equine influenza, equine herpesvirus, and laminitis. This page provides access to peer-reviewed research studies and scholarly articles that explore the etiology, clinical presentation, and management strategies of diseases in horses, contributing to the advancement of equine veterinary medicine.
Beard WL, Waxman S.The purpose of this article is to review the veterinary literature for various surgical procedures of the equine upper respiratory tract in an effort to evaluate the evidence supporting various therapies. This article focuses on the therapeutic benefit from more widely occurring conditions, such as laryngeal hemiplegia, dorsal displacement of the soft palate, arytenoid chondritis, and epiglottic entrapment.
Naureen A, Saqib M, Muhammad G, Hussain MH, Asi MN.The Rose Bengal plate agglutination test (RBT) was evaluated for the diagnosis of equine glanders, and its diagnostic efficiency was compared with that of mallein and other serological tests, including indirect hemagglutination test (IHAT), complement fixation test (CFT), and modified counter immunoelectrophoresis test (mCIET). Sera from 70 naturally infected culture-positive, 96 potentially exposed cohorts, and 110 healthy equines were tested. All tests but mCIET showed 100% specificity when testing the sera from glanders-negative equines. The calculated sensitivities of RBT, IHAT, CFT, mCIET...
Kreutzer R, Wohlsein P, Staszyk C, Nowak M, Sill V, Baumgärtner W.Cementoma is a very rare odontogenic neoplasm of mesenchymal origin. Clinically, in 3 horses, multiple bony enlargements of the upper and lower jaw extending into the oral cavity were observed. Radiographically, multiple, well-circumscribed, radiopaque masses surrounding the roots of the upper and lower incisors or an upper premolar tooth were present. Due to malocclusion and local pain, single teeth were extracted in each case. Grossly, a hard grayish-white mass surrounding the root of the incisors and the premolars was identified. Histopathologically, the tumors consisted of excessive deposi...
Naem S.Drashia megastoma Rudolphi, 1819, Habronema muscae Carter, 1861 and Habronema microstoma Schneider, 1866 are found in the stomach of equine definitive hosts and are known to cause pathogenic effects in the stomach wall, skin, eye and occasionally other sites. These nematodes utilise either house flies or stable flies as their intermediate hosts. Apart from molecular findings that have demonstrated some of the differences between H. muscae and H. microstoma, no detailed morphological description of equine habronematid nematodes has been presented. This article describes most surface features of...
Hamza E, Doherr MG, Bertoni G, Jungi TW, Marti E.Equine insect bite hypersensitivity (IBH) is an immediate-type hypersensitivity reaction provoked by insect-derived allergens. Icelandic horses living in Iceland do not have IBH due to absence of relevant insects, but acquire it at high frequency after being imported to mainland Europe. In contrast, their offspring born in mainland Europe has reduced IBH incidence. T helper 1 (Th1) and Th2 cells and cytokines were determined in Icelandic horses born in Iceland and on the continent and which either have IBH or are healthy. Methods: Peripheral blood mononuclear cells (PBMC) from these horses wer...
Allsopp MT, Lewis BD, Penzhorn BL.The intra-erythrocytic parasite Theileria equi is one of two tick-transmitted causative agents of equine piroplasmosis. Piroplasms of T. equi can be transmitted across the equine placenta and once a horse is infected, it appears to remain a lifelong carrier, since anti-theilerial drugs suppress but do not eliminate the parasite. Carrier mares may transmit the organism to their offspring and this may result in abortion or neonatal piroplasmosis, but observations by some researchers suggest that foals may be born as carriers yet remain apparently healthy. Using a T. equi-specific oligonucleotide...
Léon A, Fortier G, Fortier C, Freymuth F, Tapprest J, Leclercq R, Pronost S.The major role of EHV-1 in equine abortion is widely reported in the literature but the contribution of EHV-2, EHV-3, EHV-4 or EHV-5 remains less well documented. The objective of this study is to evaluate the contribution of these five different EHVs to equine abortion in a variety of biological tissues using a consensus polymerase chain reaction (PCR). The test was validated for specificity and sensitivity in horses before screening specimens from 407 foetuses, stillbirths and premature foals collected over a 2.5-year interval. Positive results obtained with this assay were compared to other...
Crawford C, Sepulveda MF, Elliott J, Harris PA, Bailey SR.Pasture-induced laminitis in the horse is associated with the overconsumption of fermentable carbohydrate, in the form of simple sugars, fructans, or starch. The fermentation of carbohydrate in the cecum and large intestine results in the production of lactic acid and other toxins or "laminitis trigger factors." Vasoactive amines have been suggested as possible initiating factors. The aim of this study was to feed a commercially available form of fructan carbohydrate (inulin, 3 g/kg of BW per day) to normal ponies and to ponies predisposed to laminitis, to mimic a change from a basal hay diet ...
Kulikova EE, Isaeva AS, Rotkina AS, Manykin AA, Letarov AV.The complex cellulolytic microbial community of the horse intestines is a convenient model for studying the ecology of bacteriophages in natural habitats. Unlike the rumen of the ruminants, this community of the equine large intestine is not subjected to digestion. The inner conditions of the horse gut are much more stable in comparison to other mammals, due to the fact that the horse diet remains almost unchanged and the intervals between food consumption and defecation are much shorter than the whole digestive cycle. The results of preliminary analysis of the structure and dynamics of the vi...
Njiru ZK, Constantine CC.To investigate the population genetic structure of Trypanosoma evansi from domesticated animals, we have analysed 112 stocks from camels, buffaloes, cattle and horses using the tandemly repeated coding sequence (MORF2) and minisatellite markers 292 and cysteine-rich acidic integral membrane protein (CRAM). We recorded a total of six alleles at the MORF2 locus, seven at 292 and 12 at the CRAM loci. Nei's genetic distance showed reduced allelic diversity between buffaloes and cattle stocks (1.2) as compared to the diversity between camels and buffaloes (3.75) and camels and cattle stock (1.69). ...
Aleman M, Magdesian KG, Peterson TS, Galey FD.A 4-month-old American Paint filly was evaluated because of sudden onset of ataxia that progressed to recumbency. Five additional horses from the same and neighboring premises developed signs of poor performance, generalized weakness, ataxia, and recumbency; 2 of those horses were also evaluated. A new batch of a commercial feed supplement had been introduced to the horses' diet on each farm within the preceding 3 days. Results: Other than recumbency, findings of physical and neurologic examinations of the foal were unremarkable. The other 2 horses had generalized weakness and mild ataxia, and...
Yasui M, Suzuki N, Liu X, Okamoto Y, Kim SY, Laxmi YR, Shibutani S.4-Hydroxyequilenin (4-OHEN)-dC is a major, potentially mutagenic DNA adduct induced by equine estrogens used for hormone replacement therapy. To study the miscoding property of 4-OHEN-dC and the involvement of Y-family human DNA polymerases (pols) eta, kappa and iota in that process, we incorporated 4-OHEN-dC into oligodeoxynucleotides and used them as templates in primer extension reactions catalyzed by pol eta, kappa and iota. Pol eta inserted dAMP opposite 4-OHEN-dC, accompanied by lesser amounts of dCMP and dTMP incorporation and base deletion. Pol kappa promoted base deletions as well as ...
Barton MH, LeRoy BE.Reference ranges for serum bile acids (SBA) concentration are well established in healthy adult horses. Increased values are indicative of hepatic disease. Objective: SBA concentrations are significantly greater in the neonatal period compared with mature horses, and illness in the neonatal period will further increase SBA. Methods: Ten healthy mature horses, 12 healthy foals, and 31 clinically ill foals. Methods: Prospective cross-sectional study. Blood samples were obtained once from the mature horses, from healthy foals immediately after birth, at 2 days, and at 1, 2, 3, 4, and 6 weeks of a...
Adams AP, Oriol JG, Campbell RE, Oppenheim YC, Allen WR, Antczak DF.This research tested the hypothesis that immunological sensitization of mares by skin allografting, followed by the establishment of pregnancy using semen from the skin-graft donor, would give rise to secondary immune responses to the developing horse conceptus, resulting in an earlier demise of the fetally derived endometrial cups. Maiden mares received skin allografts from a stallion homozygous for Major Histocompatibility Complex (MHC) antigens and/or equivalent autografts and were subsequently mated to the skin-graft donor stallion during the next two breeding seasons. Mares that had been ...
Ghanem YM, Ibrahim el-SM, Yamada S, Matsumura T, Osterrieder N, Yamaguchi T, Fukushi H.The pathogenicities of RacL11 and Kentucky D strains of equine herpesvirus 1 in the hamster infection model are different from those of Ab4p and the Japanese isolates. Virus genome restriction fragment length polymorphism analysis and sequence comparison of an intergenic region, glycoproteins and tegument genes showed higher conservation but with some strain-specific differences. These results indicate that point nucleotide differences in RacL11 and Kentucky D might be responsible for their pathogenicity in rodent models.
Diesterbeck US, Hertsch B, Distl O.The aim of this study was to identify quantitative trait loci (QTLs) for pathologic changes in the navicular bone in Hanoverian warmblood horses. Seventeen paternal half-sib groups comprising 192 individuals were analyzed in a whole-genome scan. These families included 144 progeny and grandchildren, which were randomly chosen from the Hanoverian warmblood. Three different traits were considered: deformed canales sesamoidales and radiographic changes in the contour and in the structure of the navicular bone. The genome scan included in total 214 highly polymorphic microsatellite markers. The pu...
Climent F, Carmona JU, Cuenca R, Prades M.Eosinophilic synovitis (ES) is a rare disease described in human and veterinary medicine. Only three cases have been reported in the horse. A case of tarsocrural synovitis in an Hispano-Arabian gelding is presented in this report. The patient presented with severe joint effusion and lameness of the right tarsocrural joint on admission. Synovial fluid analysis revealed an increased WBC of 12800 leukocytes/microliter with 76% of eosinophils. Lavage of the diseased joint and medical treatment with antibiotics and non-steroidal anti-inflammatory drugs produced remission of the clinical problem.
Epp TL.A 4.5-month-old quarter horse colt was presented with severe right hind metatarsophalangeal varus, present since birth. On radiographs, it was determined that there was a 16 degree deviation with the pivot point at the distal physis of the 3rd metatarsal bone. A step ostectomy in the sagittal plane corrected the deformity. Un poulain Quarter horse âgé de 4,5 mois a été présenté pour une difformité congénitale métatarsophalangienne varus du membre postérieur droit. Une déviation de 16° par rapport au point de pivotement au niveau de la plaque de croissance distale du 3 métatarse a...
Frederico LM, Gerard MP, Pinto CR, Gradil CM.An Arabian mare was referred for right granulosa-theca cell tumor (GTCT) evaluation. The mare was presented 4.5 years later for a left GTCT, after successfully conceiving and delivering a normal foal in the interim. The concurrent or nonconcurrent occurrence of bilateral GTCT in mares appears to be rare. Une jument Arabe a été référée pour l’évaluation d’une tumeur de la granulosa et de la thèque du côté droit (TGT). La jument avait été présentée 4,5 ans plus tôt pour une TGT du côté gauche, ayant entre temps conçu et mis au monde un poulain normal. La présence, simultan...
Kawcak CE, Frisbie DD, McIlwraith CW, Werpy NM, Park RD.To evaluate the use of a combination of avocado and soybean unsaponifiable (ASU) extracts for the treatment of experimentally induced osteoarthritis in horses. Methods: 16 horses. Methods: Osteoarthritis was induced via osteochondral fragmentation in 1 middle carpal joint of each horse; the other joint underwent a sham operation. Horses were randomly allocated to receive oral treatment with ASU extracts (1:2 [avocado-to-soybean] ratio mixed in 6 mL of molasses; n = 8) or molasses (6 mL) alone (placebo treatment; 8) once daily from days 0 to 70. Lameness, response to joint flexion, synovial eff...
Morein B, Blomqvist G, Hu K.The maintenance of pregnancy requires suppression of the maternal immune system which would naturally recognize the developing fetus as an allograft and seek to destroy it by mounting a Th1 regulated cytotoxic immune response. During pregnancy a range of soluble factors are produced by the placenta which switch maternal immune regulation towards a protective Th2 phenotype. These factors also influence the developing fetal immune system and all newborns initially have an immunological milieu skewed towards Th2 immunity. Vaccination during the neonatal period must therefore overcome the dual cha...
Tu YB, Zhou T, Yuan XF, Qiu HJ, Xue F, Sun CQ, Wang L, Wu DL, Peng JM, Kong XG, Tong GZ.The long terminal repeats (LTRs) of equine infectious anemia virus donkey leukocyte-attenuated virus (EIAV-DLA) were substituted with those of the wild-type EIAV-L (wt EIAV-L, the parent virus of EIAV-DLA). The resulting chimeric plasmid was designated pOK-LTR DLA/L. Purified pOK-LTR DLA/L was transfected into monocyte-derived macrophage (MDM) cultures prepared from EIAV-negative, heparinized whole blood from a donkey. Eighth-passage cell cultures developed the typical cytopathogenic effects (CPE) of EIAV infection, and virions with typical EIAV profiles were observed with an electron microsco...
Johnson PJ, Goetz TE.A 10-month-old Standard-bred colt was examined because of weight loss, fever, and extensive subcutaneous edema of the ventral aspects of its trunk. Diagnosis of granulomatous enteritis was based on D-xylose malabsorption, hypoproteinemia, and rectal mucosal biopsy. Campylobacter fetus subsp fetus was cultured from jugular venous blood when the horse was admitted to the hospital and 24 hours later. Appropriate antimicrobial agents and glucocorticoids failed to effect clinical remission. After euthanasia, granulomatous enteritis was confirmed at necropsy but C fetus subsp fetus was not isolated ...
Brown DL, Anderson M, Cullen JM.Mesenchymal hamartoma of the liver is a rare congenital disorder of biliary tract development. During the necropsy of a late-term equine fetus, a markedly enlarged liver of more than two times normal weight was found. Light microscopic review revealed that the normal hepatic parenchyma had been obliterated, replaced, and expanded by abnormal bile ducts surrounded by abundant, myxoid stroma. The lesion was diagnosed as a mesenchymal hamartoma. Small portions of the liver had bridging septa of fibrosis and proliferations of small-caliber abnormal bile ducts, resembling another congenital biliary...
Luethy D, Slack J, Kraus MS, Gelzer AR, Habecker P, Johnson AL.Third-degree atrioventricular block (AVB) and primary inflammatory myocarditis are uncommon findings in horses. The horse of this report presented for collapse at rest and was found to have multiple cardiac arrhythmias, most notably 3rd-degree AVB. The horse was subsequently diagnosed with eosinophilic myocarditis on necropsy, a rare form of myocarditis not previously reported in horses. Despite extensive testing, an etiologic agent could not be identified, illustrating the difficulty in identifying a specific cause of myocarditis in horses.
Roberts MC, Groenendyk S.Splenectomy was successfully performed on 2 aged horses to facilitate experimental studies of Babesia equi infection. Resection of part of the 17th rib provided the most acceptable approach and avoided many complications encountered on removing part of the 16th rib.
Musilova P, Kubickova S, Vychodilova-Krenkova L, Kralik P, Matiasovic J, Hubertova D, Rubes J, Horin P.Chromosomal locations of 19 horse immunity-related loci (CASP1, CD14, EIF5A, FCER1A, IFNG, IL12A, IL12B, IL12RB2, IL1A, IL23A, IL4, IL6, MMP7, MS4A2, MYD88, NOS2A, PTGS2, TFRC and TLR2) were determined by fluorescence in situ hybridization. For IFNG and PTGS2, this study is a confirmation of their previously reported position. In addition, microsatellite (HMBr1) was localized in the same region as IFNG. All genes were assigned to regions of conserved synteny and the data obtained in this study enhance the comparative human-horse map. Cytogenetic localization of IL6 to ECA4q14-q21.1 suggested a...
Pellegrini-Masini A, Dolente BA, Habecker PL, Jesty SA.A 5-year-old Quarter Horse mare was referred for evaluation of oral ulcers, limb edema, weight loss, and weakness. There was marked diffuse swelling extending from the stifle region to the tarsal region of the left hind limb, and the horse had a left hind limb lameness. Firm swellings ranging from 2 to 15 cm in diameter and consisting of nodules, plaques, and discrete masses were palpated on both sides of the neck, over the right shoulder region, over the left elbow region, and over the left caudoventral aspect of the abdomen. Laboratory abnormalities included hypoproteinemia, neutrophilia, an...
Jackson K, Kelty E, Staszyk C, Tennant M.Peripheral caries may cause significant oral pain and pathology and is very prevalent within the Western Australia horse population. Associations with periodontal disease have been indicated; however, further work is needed to assess the anatomical and histological aspects of the conditions, to better understand the pathophysiology. Objective: To assess the anatomical and histopathological changes associated with equine cheek teeth peripheral caries and disease of the periodontium to better understand the pathogenesis and any association between the conditions. Methods: Cross-sectional epidemi...
Perdrizet JA, Scott DW.Cellulitis and subcutaneous abscess formation was diagnosed in a 3-month-old Thoroughbred filly. Clinical signs consisted of a large ulcerated plaque, with satellite pustules on the medial aspect of the right hock and subcutaneous abscesses in the right inguinal and mammary gland areas. Laboratory analysis revealed mature neutrophilia. Rhodococcus equi was isolated from the cellulitis and the subcutaneous abscess. Oral administration of erythromycin and rifampin for 35 days resulted in a clinical cure.
Hayakawa Y, Komae H, Ide H, Nakagawa H, Yoshida Y, Kamada M, Kataoka Y, Nakazawa M.An acute death occurred in a racehorse with pneumonia after long-distance transportation in December, 1990. Pasteurella caballi, Streptococcus suis and Streptococcus zooepidemicus were isolated from the lung at high rate. Specific antigens of these bacteria were also demonstrated immunohistologically in the pneumonic lesion. These findings indicated that the disease is equine transport pneumonia caused by a mixed infection of the three bacterial species. This is the first report on the isolation of P. caballi and S. suis from a racehorse in Japan.
Kirchhoff H, Ammar AM, Heitmann J, Dubenkropp H, Schmidt R.Sera from horses with respiratory disease (RD) have been investigated using the complement fixation test, indirect hemagglutination test, enzyme immune assay, and the metabolic inhibition test, and sera from mares after abortion, using the complement fixation test, indirect hemagglutination test and enzyme immune assay, for antibodies against Mycoplasma equirhinis, M subdolum, M. equigenitalium, M. pulmonis, M. felis, Acholeplasma laidlawii, A. hippikon and A. equifetale. Antibodies were found against all mycoplasma and acholeplasma species tested, more often against acholeplasmas. The antibod...
Frazier K, Hullinger G, Hines M, Liggett A, Sangster L.A 10-y retrospective study of aldicarb intoxication in domestic animals from 1988 to 1998 is provided from animals submitted to the University of Georgia Veterinary Diagnostic and Investigational Laboratory. Within the period examined, 162 separate cases were confirmed and 18 additional cases were suspected based on bioassay but could not be confirmed. Some cases involving as many as 15 affected animals. Dogs were most often involved, but cats, horses, cattle and goats were also poisoned. Most intoxications appeared intentional or malicious. "Baits" including frankfurters, ham or ground beef w...
Théon AP.Surgery is the mainstay of treatment for equine tumors. Conservative treatment approaches which preserve function and appearance are increasingly used in clinical practice. This article covers the principles and applications of two conservative treatment modalities including local chemotherapy and immunotherapy. The therapeutic benefit of local chemotherapy is based on the direct drug delivery to tumor tissue, i.e., topical and intratumoral administration of cytotoxic agents in slow release formulation. This treatment modality is very effective for cutaneous tumors and does not result in any p...
St Denis KA, Waddell-Parks N, Belanger M.An 11-day-old pony became depressed, anorectic, and pyrexic 2 days after the topsoil of its paddock had been turned over. Rapid progression to colic and head pressing occurred, despite intensive therapy for Tyzzer's disease, and the foal died within 7 h of the appearance of central nervous system signs.
Baxter GM, Morrison S.The most common and significant complication of excessive unilateral weight bearing in adult horses is support limb laminitis. Young horses with unilateral lameness problems develop support limb laminitis infrequently compared with adult horses.
Kopper JJ, Kogan CJ, Cook VL, Schott HC.The objective of this study was to determine whether there was an association between type of colloid administered and survival of horses with enterocolitis (N = 92). A retrospective review of medical records of horses with enterocolitis treated with plasma or hetastarch (HES) between January 1, 2005 and December 31, 2011 was performed. Data collected included signalment, outcome, physical and clinicopathologic findings, and volume and type of colloid administered. Sixty-nine horses (75%) were treated with plasma and 23 horses (25%) were treated with HES. After accounting for confounding varia...
Bermudez V, Miller RB, Johnson W, Rosendal S, Ruhnke L.The growth of Mycoplasma equigenitalium and Mycoplasma subdolum from specimens collected from the clitoral fossa of each of four Standardbred mares was not diminished by freezing of the specimens in liquid nitrogen (-196 degrees C) for up to 30 days when compared to samples cultured immediately.
Hooper RN.Necropsy of a 12-year-old Quarter Horse mare revealed a blind-end segment of intestine originating from the antimesenteric border of the ileum. The blind-end segment had looped around and strangulated the ileum and 3.5 m of the jejunum.
Ness SL, Bain FT, Zantingh AJ, Gaughan EM, Story MR, Nydam DV, Divers TJ.Visualization of colonic mesenteric vasculature during transabdominal ultrasonographic examination of horses with colic can be a predictor of right dorsal displacement of the large colon or 180° large colon volvulus, or both. Medical records of 82 horses having had surgical treatment of colic and having received a transabdominal ultrasonographic examination on admission were reviewed. Colonic mesenteric vessels were sonographically identified coursing laterally on the right side of the abdomen in 24 of the 82 cases. Horses with colonic vessels identified on ultrasound were 32.5 times more lik...