Infections in horses encompass a range of diseases caused by various pathogens, including bacteria, viruses, fungi, and parasites. These infections can affect different systems within the horse, such as the respiratory, gastrointestinal, and integumentary systems, leading to a variety of clinical signs depending on the pathogen and the severity of the infection. Common infectious diseases in horses include equine influenza, strangles, and equine herpesvirus. Diagnosis often involves clinical examination, laboratory testing, and sometimes imaging, to identify the causative agent and assess the extent of the disease. Treatment strategies may include antimicrobial therapy, supportive care, and preventive measures such as vaccination and biosecurity practices. This page aggregates peer-reviewed research studies and scholarly articles that explore the pathogenesis, diagnosis, treatment, and prevention of infectious diseases in equine populations.
O'Callaghan DJ, Hyde JM, Gentry GA, Randall CC.Infection of exponential-phase suspension cultures of mouse fibroblast cells (L-M) with equine abortion virus (EAV) resulted in inhibition of cell growth and marked alterations in host metabolic processes. The synthesis of deoxyribonucleic acid (DNA) and ribonucleic acid was inhibited within 4 hr after infection and was suppressed by more than 90% by the time of maximal virus replication (14 to 18 hr). The overall rate of protein synthesis, however, was similar in uninfected and virus-producing cells as determined by measurements of net protein and isotope incorporation. The time course of vir...
Byars TD, Dainis CM, Seltzer KL, Rantanen NW.The formation of cranial thoracic masses (CTM) as a sequel to infectious pleuropneumonia is described. Using ultrasound, masses were diagnosed subjectively as abscesses or loculations. Eight of 99 cases with pleuropneumonia had CTM. Clinical signs associated with the presence of a CTM included increased heart rate, jugular distention, forelimb 'pointing' and caudal displacement of the heart. Techniques used for diagnostic ultrasonographic examination of the cranial thorax are described. Five of the eight horses with CTM responded to conservative medical management; the other three required per...
Chase JP, Beard WL, Bertone AL, Goltz K.Peritonitis was induced in 12 horses by median celiotomy and 1 hour of small intestinal ischemia. Six horses had primary closure of the incision, whereas six horses had a plastic mesh sutured to the ventral abdominal wall leaving the abdomen open for ventral drainage. The mesh was removed after 5 days and the abdominal wall was closed by apposition of the linea alba and subcutaneous tissues and approximation ef the skin edges. Peritoneal fluid was collected and analyzed for nucleated cell count and total protein concentration on days 0 and 5. Serum biochemical profiles, serum electrolyte conce...
Stalheim OH, Stone SS, Blackburn BO, Foley J.In horses given whole cultures or cells of Mycoplasma mycoides subsp capri (by subcutaneous and intravenous injections), antibody responses were measured by serologic procedures. During an immunization period of 22 weeks, horses produced an antiserum that was used to identify M mycoides subsp capri by agglutination, complement-fixation, and fluorescent antibody (FA) tests, but not by the growth-inhibition test. Horses that were injected with whole cultures of M mycoides subsp capri responded better than horses that were injected with only cells, ie, antibodies were detectable sooner by agar ge...
Holguin-Rocha AF, Calle-Tobon A, Vásquez GM, Astete H, Fisher ML, Tobon-Castano A, Velez-Tobon G, Maldonado-Ruiz LP, Silver K, Park Y....Ticks are obligatory hematophagous ectoparasites that transmit pathogens among various vertebrates, including humans. The composition of the microbial and viral communities in addition to the pathogenic microorganisms is highly diverse in ticks, but the factors driving the diversity are not well understood. The tropical horse tick, , is distributed throughout the Americas and it is recognized as a natural vector of and , the causal agents of equine piroplasmosis. We characterized the bacterial and viral communities associated with partially-fed females collected by a passive survey on hors...
Richardson DW, Nunamaker DM, Sigafoos RD.Arthrodesis of the metacarpophalangeal joint was attempted in 9 adult horses, using a new external skeletal fixation device and autogenous cancellous bone graft. Four horses had excellent results, 2 horses had fair results, arthrodesis failed in 2 horses, and 1 horse fractured the third metacarpal bone. The advantages of the technique included minimal surgical trauma to the area of injury, immediate rigid fixation of the metacarpophalangeal joint, and access for treatment of soft-tissue lesions at the site of injury. Although pin loosening and pin-track infection were complications when the de...
Stanek C.A retrospective study (1984-1994) was made of 10 cases of septic arthritis of the distal interphalangeal joint in horses aged 7 months to 17 years. In 6 cases a hind limb was affected, in 4 cases a front limb. The arthritis was caused either by a puncture wound in the sole area (8 cases), by a perforating wound in the coronary region (1) or iatrogenic (1). All horses exhibited a severe lameness at the walk. Radiography showed no typical lesions in fresh cases, whilst later an increasing subluxation of the joint was observed followed by periosteal reactions. Therapy included partial resection o...
Buczkowska J, Kozdrowski R, Nowak M, Sikora M.Endometrial biopsy score is an accepted marker of uterine health and predicted fertility, and it has been suggested that endometrial alternations are correlated with susceptibility to persistent infectious endometritis. The objective of this study was to investigate associations of endometrial biopsy score with: 1) presence of polymorphonuclear cells (PMNs) in the epithelium and stratum compactum in histopathology; 2) presence of PMNs in cytology and 3) presence of infection in microbiology. Methods: The material for examination was collected from 69 mares suspected for subclinical endometriti...
Ahern BJ, Bayliss IPM, Zedler ST, Getman LM, Richardson DW.To report on a series of 4 horses with supraglenoid tubercle fractures repaired with locking compression plates. Methods: Case series. Methods: Four horses ranging in age from 6 weeks to 20 months and weighing from 121 to 425 kg with supraglenoid tubercle fractures of 1 day to 6 weeks in duration. Methods: Supraglenoid tubercle fractures were reduced and stabilized with transversely positioned locking compression plate(s) with and without additional tension band wiring. Results: All fractures reached bony union. Two postoperative surgical site infections were managed with drainage and antibiot...
Anderson BH, Ethell MT.A number of methods for the local delivery of drugs to musculoskeletal tissues in the horse are now available. Further research is required to document the disposition of drugs delivered by such methods and to correlate this information with efficacy. Perhaps the greatest potential area for the methods discussed is the treatment of synovial and bone infections. To be able to provide high and sustained therapeutic concentrations of antimicrobials to the site of infection should increase the chances of success in such cases. These methods of drug delivery need to be used in conjunction with othe...
Swiderski CE, McClure JJ.The immune system is a complex interactive network. Defects in its function can be characterized broadly as being the result of actual deficiencies in the network or misdirection of normal immunologic functions. The assays that are available to detect deficiencies in the immunologic network barely scrape the surface of the possibilities. These assays primarily evaluate humoral immune function, but undetected defects in innate and cellular immunity are sure to exist. Although assays of humoral immunity have allowed the characterization of a number of immunodeficiency syndromes in horses, closer...
Onen EA.The aim of this study was to evaluate formalin-inactivated autovaccination to treat cutaneous papillomatosis and to perform molecular typing of the papillomavirus in four horses (two foals, one 3-year-old filly and a 5-year-old stallion). Methods: Histopathological slides of lesions were prepared and stained with haematoxylin and eosin (H&E) to establish a diagnosis that was based on observation koilocytosis, which is a pathognomonic cytopathic change that is associated with papillomatosis, using light microscopy. Polymerase chain reaction (PCR) and DNA sequencing were performed using the ...
Cervantes DT, Ball JM, Edwards J, Payne S.Equine infectious anemia virus (EIAV) causes lifelong infections ranging from acutely fatal, to chronic, to asymptomatic. Within infected animals, EIAV is found as a quasispecies. Many experimental studies on EIAV, carried out in the U.S. over the past 70 years, have used either the highly virulent Wyoming (EIAVWYO) field strain or various derivatives of that strain. These infections have provided insights into the variety of genetic changes that accumulate in the env gene and LTR in experimentally infected horses. In the current study, we obtained EIAV sequences from blood samples collected f...
Hutchens DE, Paul AJ, DiPietro JA, Lock TF, Jones CJ, Rowley DD, Wallace RW.A controlled test was conducted to assess the efficacy bioequivalence of a single dose of 0.5% fenbendazole (FBZ) top dress pellets to a 10% FBZ suspension formulation (Panacur suspension 10%, Hoechst Roussel Vet). Thirty horses with naturally-acquired parasite infections, in replicates of three, were used. Strongyle egg per gram counts were not significantly different (P>0.1) between groups pretreatment, but FBZ treated groups were significantly different from the control group post-treatment. At necropsy, which occurred seven to nine days post-treatment, two methods of nematode recovery were...
Allen JL, Herbert G, Muscatello G, Gilkerson JR.Bronchopneumonia caused by Rhodococcus equi is an important disease of young horses throughout the world. Although early diagnosis and treatment improves the prognosis, this also increases the amount of antimicrobial usage and therefore increases the likelihood of resistance developing. Objective: The aim of this study was to determine the level of resistance to commonly prescribed antimicrobial agents of 97 virulent Rhodococcus equi isolates. Methods: Analysis of archived samples. Methods: Virulent Rhodococcus equi isolates were collected between 1991 and 2014 from clinically affected horses ...
Lány P, Pospísil Z, Zendulková D, Cíhal P, Jahn P.A mild outbreak of acute respiratory infection was reported in racing horses in the fall of 1995. Four studs were investigated for the sources and routes of infection. In five horses from two herds, virus isolates were obtained which, in preliminary typing experiments, were identified as the influenza A/equi 2 virus. The presence of this illness in all the examined herds was confirmed by a rise in specific antibody titres. The affected animals included both older vaccinated horses and young horses not yet vaccinated. Epidemiological studies suggested that the spread of infection occurred in si...
Herbst W, Görlich P, Danner K.Of 1081 acute and chronically respiratory diseased as well as clinically normal horses 824 sera and 257 paired serum samples collected 1986 and 1987 were tested for antibodies against several different respiratory viruses such as influenza virus A/equi 1 and 2 (Influenza 1 a. 2), equine herpesvirus type 1/4 (EHV 1/4), mammalian reovirus type 1-3 (Reovirus 1-3), equine rhinovirus type 1 (ERV 1), equine adenovirus type 1 (EAdV 1), and equine arteritis virus (EAV). The investigations resulted in an antibody prevalence of 57.2% (Influenza 1), 59.5% (Influenza 2), 81.5% (EHV 1/4), 50.3% (Reovirus 1...
Allano M, Grimes C, Boivin R, Smith G, Dumaresq J, Leclere M.A gelding from eastern Canada was presented for cough and exercise intolerance 14 months after it had travelled on Vancouver Island. Cryptococcus gattii pneumonia was diagnosed based on cytology, antigen titers, and polymerase chain reaction (PCR). The horse was treated with fluconazole for 10 months. Delayed C. gattii infection can occur after travel in an endemic area. Pneumonie à Cryptococcus gattii chez un cheval adulte ayant voyagé dans une région endémique. Un cheval hongre de l’est canadien fut présenté pour de la toux et de l’intolérance à l’exercice 14 mois après avoir ...
Lakritz J, Wilson WD, Marsh AE, Mihalyi JE.Plasma concentrations and pharmacokinetics of erythromycin and related compounds were determined after administration of erythromycin ethylsuccinate to six healthy male foals 3 to 5 months of age. Hay was withheld from the foals overnight and erythromycin ethylsuccinate (25 mg/kg of body weight) was administered intragastrically. Plasma erythromycin concentrations were determined at specific times after drug administration by high-performance liquid chromatography assay. Maximum peak plasma concentrations, time to maximum concentrations, area under plasma concentration versus time curves, elim...
Goto H, Yamamoto Y, Ohta C, Shirahata T, Higuchi T, Ohishi H.A total of 305 horse sera collected in the Hidaka district of Hokkaido in the years 1988-90 were tested for the presence of hemagglutination-inhibition (HI) antibodies to A/equine/Newmarket/1/77 (H7N7), A/equine/Tokyo/2/71 (H3N8) and A/equine/Kentucky/1/81 (H3N8, Kentucky) strains of equine influenza (EI) virus. Antibodies to the 3 strains were detected in hardly of the 45 sera from 2-years-old horses which were collected before vaccination. Many of the 51 horses, after vaccination with inactivated EI virus, had HI antibodies to the 3 strains in 37 to 88 per cent. However, the number of positi...
Adeyefa CA.Serological evidence of Equine Herpes virus type 1 (EHV-1) activity in Polo horses in Nigeria is reported for the first time. Eighty-two percent of horses tested with known antigen had precipitating antibodies to EHV-1 while 43% of sera tested against antigen prepared from nasal discharges were positive suggesting that the virus was being excreted in the nasal discharges and probably acting as a source of infection for incontact animals as occurs in on-going acute infections. The result of this study indicates a high prevalence of EHV-1 activity among Polo horses in Nigeria and demonstrates th...
De Clercq E, Den Hondt S, De Baere C, Martens AM.To compare the effect of multiple wound dressings on microbial growth in a perfused equine wound model. Methods: Abdominal musculocutaneous flaps from 16 equine cadavers. Methods: 8 full-thickness skin wound covered were created in each flap. Tissues were perfused with saline (0.9% NaCl) solution. Wounds were inoculated with methicillin-resistant Staphylococcus aureus (MRSA) or Pseudomonas aeruginosa (106 CFUs), incubated, and covered with a dressing containing activated charcoal, boric acid, cadexomer iodine, calcium alginate, manuka honey, nanoparticle silver, or polyhexamethylene biguanide ...
Taylor TS, Vaughan JT.A study was conducted in an effort to explain why digital necrosis sometimes follows neurectomy in the horse. Six horses were subjected to unilateral section of the medial and lateral palmar nerves. Arteriography was done on each digit prior to surgery. Terminally, arteriography was repeated. Sections of bone, nerve, artery, skin, coronary band, and deep flexor tendon were examined histologically. Changes in arterial pattern and bone quality were noted. During the study, 2 of the horses had clinical signs of digital necrosis. The composite findings suggested trauma or infection, or both, of th...
Oaks JL, Long MT, Baszler TV.Neurologic disease occurs sporadically in horses infected with the equine infectious anemia virus (EIAV). This report describes a case of clinically severe neurologic disease in a pony experimentally infected with EIAV. This pony did not have fever or anemia, which are the characteristic clinical signs of disease. The histopathologic changes were characterized as lymphohistiocytic periventricular leukoencephalitis. Polymerase chain reaction and in situ hybridization data showed that the brain lesions were directly associated with viral replication and that high-level viral replication occurred...
Matsuda K, Shimada T, Kawamura Y, Sakaguchi K, Tagami M, Taniyama H.A 2-year-old Thoroughbred horse presented with acute onset of colitis, and the intussuscepted jejunum was surgically resected. A transmural mass protruding into the lumen was found at the leading edge of the intussusceptum. Based on histological and immunohistochemical examinations, the mass was diagnosed as diffuse large B-cell lymphoma with metastasis to the mesenteric lymph nodes. Anatomical localization of the mass in the intussusception and absence of other obvious underlying diseases indicated that the intussusception had occurred in association with the mass. To our knowledge, this case...
Gosai F, Gosai N.Strangles is a contagious upper respiratory tract infection primarily affecting equines. It is rare disease with zoonotic transmission. It is caused by the bacterium, . We present the rare case of strangles in an elderly patient complicated by bacteraemia, osteomyelitis and native valve endocarditis. The patient was treated successfully with appropriate antibiotics and no surgical intervention was needed. In an age of accelerated emerging zoonosis, this is an important entity clinicians should be aware of to prevent delay in diagnosis and poor outcome. Conclusions: Strangles is a disease of eq...
Srivastava SK, Barnum DA.Lymphocyte stimulation was observed in whole equine blood in the presence of phytohaemagglutinin and M protein extracted from a typical strain of Streptococcus equi. Blood samples were collected from several healthy horses and horse and pony foals and cultured in vitro with varying concentrations of phytohaemagglutinin and M protein for several days. Phytohaemagglutinin was found to induce lymphocyte stimulation in these animals. Highest mean stimulation indices in horse foals (49.3 +/- 24.4) and pony foals (54.7 +/- 32.0) were observed with 0.625 and 1.25 micrograms/mL phytohaemagglutinin, re...
Sivula NJ, Trent AM, Kobluk CN.Nonsurgical correction of a renosplenic entrapment of the large colon was attempted in a mare, using a rolling technique. After correction, the mare had initial improvement in clinical signs, but later developed signs of abdominal discomfort. A ventral midline celiotomy was performed, and a pelvic flexure impaction and large intestinal volvulus were found and corrected.
van Nieuwstadt RA, Kalsbeek HC.In a horse with chronic unilateral nasal discharge guttural pouch mycosis caused by Aspergillus fumigatus was diagnosed. A percutaneous indwelling catheter was surgically installed in the left guttural pouch. Initial treatment with a povidone iodine solution proved to be unsatisfactory. Treatment was continued by administering enilconazole by ways of an indwelling through-the-nose-catheter. The latter treatment resulted in complete recovery.
Ekiri AB, House AM, Krueger TM, Hernandez JA.To assess awareness, perceived relevance, and acceptance of surveillance and infection control practices at a large animal referral hospital among referring veterinarians and clients who sent horses to the facility for veterinary care. Methods: Survey. Methods: 57 referring veterinarians and 594 clients. Methods: A 15-question survey targeting Salmonella enterica as an important pathogen of interest in horses was sent to clients who sent ≥ 1 horse to the University of Florida Large Animal Hospital for veterinary care during July 1, 2007, through July 1, 2011, and to veterinarians who had ref...
Brown SA, Barsanti JA.A quantitative buffy coat (QBC) analysis was evaluated for 175 canine, 125 feline, and 125 equine blood samples. The method used centrifuged whole blood and yielded rapid results expressed as respective band lengths for RBC, granulocytes, nongranulocytes, and platelets. Simple regression analysis of band lengths and reference laboratory methods yielded correlation coefficients (r) ranging from 0.72 to 0.99. The PCV, granulocyte count, and total WBC count, as determined by the 2 methods, correlated well (r greater than or equal to 0.93 in all cases). Platelet and nongranulocyte counts were less...
