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.
Singh M, Chaudhry MA, Yadava JN, Sanyal SC.This study was undertaken to assess the spectrum of drug resistance prevalent in Escherichia coli isolates from human and animal populations in Northern India. Three hundred and two isolates of Escherichia coli isolated from various infections of humans (47 from diarrhoea; 101 from urinary tract infection) and veterinary animals (17 from poultry septicaemia; 75 from bovine diarrhoea; 14 from ovine diarrhoea and 48 from equine metritis) were studied for their susceptibility to ampicillin, cephaloridine, amoxycillin, cloxacillin, oxytetracycline, doxycycline, chloramphenicol, gentamicin, and tri...
Hardt M, Teifke JP, Weiss E.Formalin-fixed and Paraplast-embedded tissue samples of 42 aborted equine fetuses were examined by polymerase chain reaction for the presence of equine herpesvirus DNA. The used set of primers was located in the glycoprotein 13 open reading frame and allowed the amplification of both EHV 1 und EHV 4. By cleaving pattern analysis after Hinf I digestion EHV 1 could be distinguished from EHV 4. In 9 of the cases investigated EHV 1-DNA was detected. This finding is in absolute context with the results of the virological investigations.
LeBlanc MM, Tran T, Baldwin JL, Pritchard EL.Effects of farm management, breed, mare age, gestation duration, and climatologic factors on colostral specific gravity, colostral IgG concentration, and foal serum IgG concentration were evaluated. Climatologic variables measured were daily maximal, minimal, and mean air temperature, precipitation, average relative humidity, and total solar radiation. Presuckle, postpartum colostrum samples were collected from 140 Standardbred, 94 Thoroughbred, and 59 Arabian mares from January through June during 1985 and 1986. Thoroughbred (farm A, n = 61; farm B, n = 33) and Arabian (farm C, n = 45; farm D...
McClure JT, Kobluk C, Voller K, Geor RJ, Ames TR, Sivula N.Four miniature foals admitted with signs of progressive nonresponsive abdominal pain and no fecal production had fecalith impaction of the small colon. Duration of clinical signs ranged from 10 hours to 5 days. Removal of the fecalith via small colon enterotomy was a successful treatment in all 4 cases. Miniature foals may be predisposed to fecalith impaction of the small colon. If a miniature foal has signs of progressive nonresponsive abdominal pain, fecalith impaction needs to be considered. Surgical correction may be required.
Ross MW, Bayha R.A 2-year-old Standardbred colt was examined because of signs of abdominal pain of 12 hours' duration. Clinical signs of disease, including tachycardia and abdominal distention, and rectal palpation findings of distention and thickening of the ventral colon, were consistent with displacement or early strangulation obstruction of the large colon. Surgical exploration revealed volvulus of the large colon around an axis formed by the dorsal mesenteric attachment of the transverse colon. The cecum could be completely exteriorized and lacked the cecocolic ligament and dorsal mesenteric attachments. ...
McCann JS, Caudle AB, Thompson FN, Stuedemann JA, Heusner GL, Thompson DL.Thirty mares in late gestation were used in a 3-yr study to assess effects of the tall fescue endophyte Acremonium coenophialum on serum prolactin (PRL) and progesterone. Two paddocks of each treatment, 0 or 100% infected 'Kentucky 31' tall fescue, were grazed by the mares for 21 d. Blood was collected three times per week until parturition. At 7-d intervals, mares were challenged with thyrotropin-releasing hormone (TRH) while grazing and blood was collected postinjection. Mares grazing 100% infected tall fescue (E+) had decreased serum PRL compared with mares grazing the 0% infected tall fesc...
Furr MO, Murray MJ, Ferguson DC.Sixteen neonatal foals stressed by disease underwent endoscopic examination of their stomachs and blood was assayed for triiodothyronine (T3), reverse T3 (rT3), thyroxine (T4) and cortisol, to determine the effects of severe physiological stress and the occurrence of gastric ulcers. compared with eight age-matched controls, six foals had abnormal cortisol, seven had abnormal T3 and 12 had abnormal T4. Eleven of 13 foals had rT3 outside the 95 per cent confidence interval for clinically normal foals of comparable ages. Gastric lesions were seen more frequently in stressed foals, and gastric gla...
Whitwell KE, Gower SM, Smith KC.An indirect immunoperoxidase (IMP) technique was applied to cryostat and paraffin sections of liver from ten aborted equine foetuses. Equid herpesvirus type 1 (EHV-1) had been isolated from seven of them and EHV-4 from one: the remaining two were virologically negative and were not used as controls. In the eight virus-infected cases the immunostaining revealed foci of cells exhibiting a distinct brown cytoplasmic and inclusion body pigmentation. No specific signal was present in the non-infected controls. The method also was adapted for incubation in a microwave oven, which allowed the total l...
Pospischil A, Lieb A, Corboz L.In Switzerland during the foaling season 1988 and 1989 the cause of abortion in 60 foals was investigated. Special attention was paid to infections with equine herpesvirus 1 (EHV 1). Diagnosis were based on post-mortem, histopathological, bacteriological and immunofluorescence investigation. The results confirm data from other countries, that EHV 1 is the most prevalent viral (20%) cause of abortion, followed by various bacterial agents (12%). Other causes were umbilical torsion, twin pregnancy and malformations. In 18% of the cases the investigation of fetuses did not give any results as to t...
Naylor JM, Robinson JA, Crichlow EC, Steiss JE.Electromyography (EMG) was used to detect myotonic discharges in Quarter Horse breeding stock and to follow the results of mating horses with hyperkalemic periodic paralysis (HPP). The studies were performed on two brood mare farms. A total of six breeding stock showed myotonic discharges and 15 were nonmyotonic. Myotonic discharges were seen in five of six horses belonging to the blood line previously implicated as being predisposed to HPP. Two of these horses had shown clinical signs of HPP. Only one of 15 breeding horses unrelated to the HPP predisposed blood line showed myotonic discharges...
Sharma PC, Cullinane AA, Onions DE, Nicolson L.The polymerase chain reaction (PCR) is a sensitive technique used to detect DNA of viral pathogens. We have applied the technique to the detection of Equid herpesviruses-1 and -4 (EHV-1 and EHV-4) DNA within nasopharyngeal swab samples from horses. Ninety-eight samples from suspected field cases and in-contact horses were analysed. The assays were conducted blind and later decoded and compared with virus isolation data. Our results indicate that PCR is a sensitive and rapid technique for the diagnosis of EHV-1 and EHV-4 infection.
Kalsow CM, Dwyer AE, Smith AW, Nifong TP.Although experimental models of autoimmune uveitis predict pinealitis coincident with uveitis, there is no direct evidence of pineal pathology accompanying a human uveitis. Horses with naturally occurring uveitis are a potential source of eye and pineal tissues that are not available from human patients with active uveitis. We have observed pinealitis in a mare with equine recurrent uveitis. By immunohistochemistry we demonstrated immunoglobulin and MHC Class II antigen on infiltrating and resident cells of eye and pineal gland. These results support the relevance of the animal models and sugg...
Felsburg PJ, Somberg RL, Perryman LE.This review describes the clinical, immunologic and pathologic features of two naturally-occurring models of severe combined immunodeficiency (SCID) in domestic animals that represent different forms of human SCID. Canine X-linked SCID (XSCID) has an X-linked recessive mode of inheritance and, as such, represents a model for the most common form of human SCID in the United States. Affected dogs have normal percentages of circulating B cells and low to normal percentages of phenotypically mature, but nonfunctional T cells. Severe combined immunodeficiency in the horse is an autosomal recessive ...
Browning GF, Chalmers RM, Fitzgerald TA, Corley KT, Campbell I, Snodgrass DR.Foal fecal group A rotavirus strains were characterized by electropherotype, serotype, and subgroup and shown to be distinctly different from rotaviruses of other mammals. Of 86 strains that were electropherotyped, 98% had similar profiles, with gene segments 3 and 4 close together and segments 7, 8, and 9 widely spaced. Of 70 strains that had sufficient detectable VP7 antigen to be serotyped by enzyme-linked immunosorbent assays (ELISAs), 63% were serotype G3 (39% were subtype G3A and 24% were subtype G3B), 4% were serotype G13, and 33% were untypeable. Serotypes G1, G2, G4, G5, G6, G9, G10, ...
Darenius K.Fifteen mares which had each lost their pregnancies 2 to 8 times during the preceding 6 years were used in a study comprising 1 or 2 breeding seasons for each mare. During the research period all 15 mares conceived and 10 of the mares had normal pregnancies in the 1st experimental year. Five mares resorbed/aborted once or twice during the 1st year. This was followed by a pregnancy that terminated in a live foal. Histopathological examinations of uterine biopsies showed a wide range of histopathological conditions, from absence of changes excessive for the mare's age and parity to the most seve...
Gibson JS, Slater JD, Awan AR, Field HJ.Six specific pathogen-free foals shown to be free of equine herpesvirus-1 and 4 (EHV-1 and -4) and lacking in maternally-derived antibodies were used to investigate the pathogenesis of EHV-1 in horses. Following primary intranasal inoculation with EHV-1 all foals showed signs of a mild, self-limiting upper respiratory tract infection. A leucopenia was observed, comprising both a lymphopenia and neutropenia. Virus was isolated from nasal mucus and buffy coat cells over several days during the clinical episode and after the animals became clinically normal. Notwithstanding the mildness of the cl...
Baba SS, Akinyele HA, Olaleye OD.The occurrence of antibodies against the African horse sickness virus was investigated in 246 domestic animals (horses, donkeys, camels, dogs) in various regions of Nigeria by means of the complement-fixing rate. 34% of the sera tested were positive: 75% in donkeys, 68% in horses, 19% in camels, and 9% in dogs. Among the horses, those of 6 to 15 years of age had higher than average prevalence rates than the other age groups. Stallions from the northern regions had higher prevalence rates than mares generally and stallions from other regions. These findings are important for the epidemiology of...
García-Tamayo J.Clinical findings on Venezuelan Equine Encephalitis virus infection and the teratogenic effects of several Togaviruses are described. Similarities between the intrauterine alterations induced by Venezuelan Equine Encephalitis virus and rubella virus are pointed out. Findings described by Wenger in 1967 were those of massive cerebral necrosis in fetuses of women presumably suffering of encephalitis and they are commented along with the development of an animal experimental model at the end of 1970-1980. Pathogenesis of the intrauterine infection seemed to be related to changes in the placental ...
Duncan ID.The left and right recurrent laryngeal nerves and peroneal nerves from two groups of foals, one less than 1 month of age and the other 6 months of age, were examined by light and electron microscopy. While there was no evidence of fiber loss on light microscopy, occasional onion bulbs, regenerating clusters and swollen axons were seen in the recurrent laryngeal nerves. To quantitate these changes, total counts of the main pathological structures were performed using the electron microscope. In all the foals the most common abnormality seen in the laryngeal nerves were Bungner bands, which were...
Ruggles AJ, Ross MW.Medical records of 28 horses with impaction of the small colon were reviewed; 20 horses were admitted during the winter months. Diagnosis of small-colon impaction was made in 21 horses by rectal examination, and in 7 horses at exploratory celiotomy. Ten horses were treated medically, and 18 were treated surgically. Horses that were treated surgically were more likely to have abdominal distention than were those that responded to medical treatment (P less than 0.025). Signs of greater degree of abdominal pain and higher heart rate were seen in horses treated surgically, but these values were no...
Blikslager AT, Wilson DA, Taylor DS, MacFadden KE, Fischer JR, Fales WH.An 11-year-old, 430-kg fox-trotter stallion was referred for evaluation of colic. A right-sided inguinal hernia was diagnosed. At exploratory laparotomy, the ileum was found to be herniated through the right inguinal canal. Compromised small intestine was resected, jejunocecal anastomosis was performed, and the horse was castrated. Three days after surgery, the stallion would not bear weight on the left hind limb. The musculature of the left thigh region became swollen. Aspiration of the left thigh region yielded serosanguineous fluid from which Salmonella typhimurium was isolated. Ultrasonogr...
Imagawa H, Sekiguchi K, Anzai T, Fukunaga Y, Kanemaru T, Ohishi H, Higuchi T, Kamada M.Rotavirus is one of causative agents for acute diarrhea in infants of several animal species including humans [1]. Detection or isolation of rotavirus from the feces of foals with diarrhea has been reported in England [2], the U.S.A. [3, 5, 6], Australia [14] and Japan [10, 12]. It has been shown through serological surveys in Japan [4, 8, 9] and the U.S.A. [3, 13] that rotavirus is widespread among horses and foals. However, there have been few detailed reports on the occurrence of foal diarrhea caused by rotavirus. This report focuses on the occurrence of foal diarrhea and the isolation of r...
Takai S, Ohbushi S, Koike K, Tsubaki S, Oishi H, Kamada M.The prevalence of virulent Rhodococcus equi in isolates from soil and feces of foals on a farm with endemic R. equi infections was significantly higher than that of a farm with no history of the disease. Foals bred on a farm with the endemic disease might be constantly exposed to virulent R. equi in their environment.
Putnam MR, Bransby DI, Schumacher J, Boosinger TR, Bush L, Shelby RA, Vaughan JT, Ball D, Brendemuehl JP.Effects of the endophyte Acremonium coenophialum in tall fescue on pregnant mares and foal viability were evaluated. Twenty-two mature pregnant mares were randomly chosen to graze either Kentucky-31 tall fescue that was free from A coenophialum (endophyte-free, EF) or tall fescue infected with A coenophialum (endophyte-present, EP) after the first 90 days of pregnancy through parturition. Concentrations of pyrrolizidine and ergopeptine alkaloids were significantly greater in EP grass, compared with EF pasture. Ten of 11 mares grazing EP pasture had obvious dystocia. Mean duration of gestation ...
Pierson RE, Sahu SP, Dardiri AH, Wilder FW.Contagious equine metritis was reproduced experimentally in 6 pony mares. The disease was characterized by rapidly developing cervicitis and by varying amounts of exudate. The exudate, apparent as early as 48 hours after inoculation, drained from the cervix as a tenacious, mucopurulent discharge for several days, then rapidly disappeared. In all mares, the clinical disease cleared within several weeks of inoculation, without treatment.
Anstey SI, Jenkins C, Jelocnik M.Chlamydia psittaci is a recognised cause of late-term equine foetal loss and poses a zoonotic risk in Australia. However, a management strategy is lacking to protect at-risk humans handling infected aborted material and pregnant mares. This study proposes a protocol for approaching C. psittaci foetal loss after investigating four foetal losses that occurred on a horse stud in the Hunter Valley, Australia in 2021. Swabs from the foetal loss cases (n = 4), close contact mares (n = 59), and foals of the close contact mares (n = 33) were collected and tested for C. psittaci using both isothe...
Mizukoshi N, Sakamoto K, Iwata A, Ueda S, Kamada M, Fukusho A.The reverse transcription followed by the polymerase chain reaction (RT-PCR) technique was applied to the detection of African horsesickness virus (AHSV) using primers specific for attenuated AHSV serotype 4 segment 5 (NS1 gene). Total RNA which contains both messenger RNA and genomic dsRNA was extracted by the acid guanidinium-phenol-chloroform method from the AHSV infected Vero cells and was used as templates to optimize the RT-PCR. A pair of primer (NP2-NP32) amplified the product of the expected size from all serotypes of attenuated AHSV when four pairs of primers were tested. Using this p...
Seco Diaz O, Desrochers A, Hoffmann V, Reef VB.An 8-day-old Arabian-Morgan cross colt underwent cardiac evaluation. The foal was tachycardic, tachypneic, exercise intolerant and had a loud right-sided heart murmur and cyanotic mucous membranes. Total anomalous pulmonary venous connection was diagnosed with echocardiography and confirmed at postmortem examination. Total anomalous pulmonary venous connection is a very rare congenital cardiac abnormality that has not been reported before in the horse.
Fransson BA.This article reviews the etiology, diagnosis, and treatment of rectal perforation and rectocutaneous fistula in small animals. In addition, the literature regarding use of enterostomy in small animals is reviewed and comparative aspects of this procedure in humans and horses are presented. A case report of rectal perforation leading to rectocutaneous fistula formation and the use of colostomy in the management of the case is presented.
Widders PR, Warner S, Huntington PJ.Normal mares were immunised by the intramuscular and intrauterine administration of an antigen with adjuvant and they and unimmunised control mares were later challenged by the intrauterine instillation of pathogenic Streptococcus zooepidemicus; the response of all the mares was monitored clinically and bacteriologically for seven days. Significantly fewer S zooepidemicus were present in cervical swabs taken from the immunised mares than from the control mares (P < 0.01) and the degree of inflammation in the genital tract of the immunised mares was also significantly less (P < 0.001). Th...
Watson J, Selleck P, Axell A, Bruce K, Taylor T, Heine H, Daniels P, Jeggo M.In August 2007, several horses showed pyrexia and respiratory signs while in post-arrival quarantine in Australia. Subsequent investigations diagnosed equine influenza by serology and PCR in two quarantine stations. A common origin in a shipment of horses from Japan was indicated.
Bell C.A 2-month-old warmblood filly was presented for a 1-week history of a large, nonpainful, fluctuant swelling of the parotid and laryngeal area. Bilateral guttural pouch tympany was diagnosed. Surgical correction resolved the guttural pouch tympany; however, postoperative pharyngeal neuromuscular dysfunction developed. Dysfonction pharyngée neuromusculaire associée à un tympanisme bilatéral des poches gutturales chez un poulain. Une pouliche de race Warmblood a été présentée pour examen d’une enflure marquée non-douloureuse et fluctuante, localisée dans la région laryngée et paroti...
Schryver HF.Horses are subject to poisoning from many sources. This article considers poisonings from minerals and vitamins of nutritional significance and from minerals as environmental contaminants.
Hoffman M, Cheong SH, Stokol T.Liver analyte measurement is important in the evaluation of sick animals. Liver injury in horses is recognized by increased glutamate dehydrogenase (GLDH), sorbitol dehydrogenase (SDH), and aspartate aminotransferase (AST) activities, whereas biliary pathology is identified by increased alkaline phosphatase and γ-glutamyl transferase (GGT) activities or bilirubin concentrations. We have observed high GLDH, but not SDH, activities in neonatal foals admitted for conditions other than liver disease. Only one previous study have evaluated GLDH activity over time in healthy neonatal foals; however...
Sazmand A, Yavari M, Babaei M, Nourian A, Otranto D.Migration of Ascaris lumbricoides through the papilla of Vater in humans, and entry into the biliary tree, is well-recognised. Ascaris suum and Toxocara vitulorum have been recovered from the liver of swine and buffalo. We necropsied a Persian Kurdish filly at age 6 months, weighing ∼100 kg. Death evidently was caused by oleander (Nerium oleander) intoxication. An 8-cm adult male Parascaris was found at the lobar-left hepatic bile duct junction. We suggest that the nematode entered anteriorly into the hepatic tree, via the duodenum, major duodenal papilla, bile duct, left hepatic duct and f...
Long MT, Goetz TE, Kakoma I, Whiteley HE, Lock TE, Holland CJ, Foreman JH, Baker GJ.Fetal infectivity of Ehrlichia risticii was investigated in 19 ponies that were E risticii negative on the basis of results of an indirect fluorescent antibody (IFA) test. Thirteen pregnant ponies were infected by IV administration of E risticii between 90 and 180 days of gestation. Six pregnant ponies served as noninfected controls. Each infected pony had clinical signs of equine monocytic ehrlichiosis, was confirmed to be ehrlichemic, and developed an IFA titer to E risticii. Two infected ponies became recumbent, were unresponsive to supportive care, and were euthanatized. After recovery fro...
Perdue BD, Collier MA, Dzata GK, Mosier DA.A one-year-old Thoroughbred filly was examined because of poor body condition and reluctance to move its neck. Complete blood count revealed leukocytosis (15,700 WBC/microliters) and hyperproteinemia (8 g/dl). Radiography of the cervical vertebrae revealed multifocal lesions of bone lysis surrounded by zones of sclerosis. The horse was euthanatized and necropsied. Granulomatous lesions were identified in the heart, spleen, lungs, bones, and lymph nodes. The multifocal granulomatous inflammatory lesions in this horse were suggestive of mycobacteriosis.