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.
Weese JS, Rousseau J, Traub-Dargatz JL, Willey BM, McGeer AJ, Low DE.To evaluate the prevalence of nasal colonization with methicillin-resistant Staphylococcus aureus (MRSA) in horses and horse personnel. Methods: Prospective prevalence study. Methods: 972 horses and 107 personnel from equine farms in Ontario, Canada and New York state. Methods: Nasal swab specimens were collected from horses and humans on farms with (targeted surveillance) and without (nontargeted surveillance) a history of MRSA colonization or infection in horses during the preceding year. Selective culture for MRSA was performed. Isolates were typed via pulsed-field gel electrophoresis, and ...
Archambault D, St-Louis MC, Martin S.The genome of equine arteritis virus (EAV) produces a 3' coterminal-nested set of six subgenomic (sg) viral RNAs during virus replication cycle, and each set possesses a common leader sequence of 206 nucleotides (nt) in length derived from the 5' end of the viral genome. Given the presence of the leader region within both genomic and sg mRNAs, it is likely to contain cis-acting signals that may interact with cellular or viral proteins for RNA synthesis. Gel mobility shift assays indicated that proteins in Vero cell cytoplasmic extracts formed complexes with the positive (+) and negative (-) st...
Lind EO, Uggla A, Waller P, Höglund J.The aim of this study was to investigate the suitability of a larval development assay (LDA) for the determination of anthelmintic resistance in cyathostomin nematode populations of the horse. In addition, comparison of results between geographic regions, types of horse establishment, and the use of anthelmintics in Sweden, was established. Seventy horse herds from different parts of Sweden were sampled, and strongyle eggs from the faeces of 54 of those were investigated by an LDA (DrenchRite). The following anthelmintics were tested: thiabendazole (TBZ), levamisole (LEV), ivermectin monosacch...
Zerpa H, Vega F, Vasquez J, Ascanio E, Campos G, Sogbe E, Romero E, Ascanio M, García H.Endotoxaemia is a syndrome linked to the development of equine laminitis; however, the relationship between them is uncertain. The aim of this experiment was to evaluate the effect of an experimental acute sublethal endotoxaemia model on in vitro equine palmar digital vascular reactivity. Rings of arteries and veins of each forelimb were obtained from 11 clinically healthy horses submitted to two surgical procedures, 3 weeks apart. Before the second surgery, 0.25 microg/kg of lipopolysaccharide from Escherichia coli O55:B5 in saline, was administered i.v. in 30 min. After 3 h, the vessels were...
Haghighi HR, Prescott JF.There is a need to produce a vaccine against Rhodococcus equi pneumonia in foals in which immunity against infection is largely based on a type 1, cell-mediated, immune response. The VapA protein of the virulence plasmid of R. equi is highly immunogenic. To assess the potential of vapA-DNA to produce immunity, C57BL/6 and BALB/c mice were immunized with a DNA vaccine constructed from vapA incorporated into pcDNA3.1. The plasmid construct expressed VapA in a COS-7 cell line. Intramuscular immunization of mice resulted in enhanced clearance of R. equi from the liver of intravenously challenged m...
Bogaert L, Martens A, De Baere C, Gasthuys F.The purpose of the present study was to examine whether bovine papillomavirus (BPV) DNA can be detected on the normal skin and in the habitual surroundings of horses with and without equine sarcoids by means of superficially taken swabs. In affected horses, no significant difference in presence of BPV-DNA could be observed between samples obtained from the equine sarcoid surface, from normal skin close to the tumour and from a normal skin site in direct contact with the tumour. From the group of healthy horses living in contact with affected horses, 44% were BPV-DNA positive. The surroundings ...
Ward MP, Brady TH, Couëtil LL, Liljebjelke K, Maurer JJ, Wu CC.An outbreak of salmonellosis in a population of hospitalized horses resulted in the closure of a teaching hospital for a period of 10 weeks. Fecal samples were collected from suspected cases and cultured for Salmonella. Salmonella isolates were characterized using antimicrobial susceptibility testing, pulsed-field gel electrophoresis (PFGE) and phage typing. Thirty-three cases of infection by a multidrug-resistant strain of S. typhimurium were detected. The index case was admitted on 26 August 1999. Fifteen (45%) cases occurred between April and June 2000. PFGE results suggested that this stra...
Cook CP, Scott DW, Erb HN, Miller WH.A retrospective study using light microscopy was performed to assess the prevalence of surface and follicular bacteria and fungi in skin biopsy specimens from 247 horses with inflammatory dermatoses and from 27 horses with healthy skin. Cocci were found on the surface of specimens from 23% (95% confidence interval 18%, 29%) and 7% (95% confidence interval, 0%, 19%), respectively, of horses with skin disease and horses with healthy skin. Of the nine dermatoses with at least 10 cases in our series of horses, bacterial folliculitis had a higher prevalence of surface bacteria (57%; 95% confidence ...
Pagamjav O, Sakata T, Matsumura T, Yamaguchi T, Fukushi H.Equine herpesvirus 1 (EHV-1) is a pathogen causing rhinopneumonia in young horses, abortion in mares, and myeloencephalitis in adult horses. Two types, EHV-1 P and EHV-1 B, have recently been dominant among 16 electropherotypes. EHV-1 P and EHV-1 B viruses were compared by long and accurate polymerase chain reaction (LA-PCR) and restriction fragment length polymorphism (RFLP) analysis. Differences in restriction sites were found to be focused in ORF64, which encodes the infected cell protein 4 (ICP4), and downstream of the ICP4 gene. The 3 ' -end and downstream of ICP4 gene of EHV-1 B were fou...
Farah AW, Hegazy NA, Romany MM, Soliman YA, Daoud AM.Twenty-three blood samples were used in this study; five were from five naturally infected horses with Babesia equi (B. equi), while eighteen were from asymptomatic horses with equine babesiasis from different localities in Egypt. All samples were subjected to microscopic examination, indirect fluorescent antibody test (IFA) and polymerase chain reaction (PCR). The carrier animals were microscopically detected in 7 out of 18 samples (38.8%) and in 9 of 18 by using IFA (50%), whereas PCR revealed that 14 samples were positive (78%). Two synthetic oligonucleotide primers, based on the B. equi me...
Ensink JM, Bosch G, van Duijkeren E.Tissue chambers, implanted subcutaneously in the neck in six ponies, were inoculated with Streptococcus equi subsp. zooepidemicus in order to determine the clinical efficacy of prophylactic administration of trimethoprim/sulfadiazine (TMP/SDZ) against this infection. The TMP/SDZ treatment consisted of one intravenous (i.v.) injection of 5 mg/kg TMP and 25 mg/kg SDZ and the same dose of TMP/SDZ per os (p.o.), both given 3 h before inoculation. The oral dose was then repeated every 12 h for 5 days. TMP/SDZ concentrations in tissue chamber fluid (TCF) were above 10 times MIC at the moment of inoc...
Lankveld DP, Bull S, Van Dijk P, Fink-Gremmels J, Hellebrekers LJ.Ketamine is widely used in equine anaesthesia. Beside its anaesthetic and analgesic properties, ketamine possesses a cytokine-modulating activity. However, to date, no data are available regarding the inhibitory effect of ketamine on the cytokine response in horses. In horses, cytokines such as tumour necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6) play a pivotal role in the pathogenesis of equine endotoxaemia following gastrointestinal disorders. Hence, the objective of this study was to assess the influence of ketamine on LPS-induced TNF-alpha and IL-6 formation in an equine macro...
Carmalt JL, Wilson DG.To report arthroscopic debridement and lavage of a septic temporomandibular joint (TMJ) in a horse. Methods: Clinical case report. Methods: A 12-year-old Thoroughbred mare. Methods: Arthroscopic investigation of the dorsal joint pouch of the right TMJ was made through a stab incision into the dorsocaudal compartment. Mechanized resection of synovium and fibrinous debris combined with copious lavage, and intra-articular and systemic antibiotic administration was used to treat the septic TMJ. Results: Arthroscopic debridement and lavage of the TMJ, in combination with intra-articular and systemi...
Aleman M, Nieto JE, Carr EA, Carlson GP.This report describes 4 fatal cases of serum hepatitis associated with the administration of commercial plasma in the horse. Serum hepatitis in the horse is characterized by acute hepatic central lobular necrosis, and it has been associated with the administration of biological products of equine origin. None of these horses had a recent history of equine biologic-origin vaccination; however, they had received 1.5-5 L of commercial plasma, and in I horse, an additional 8 L of fresh blood. Acute, severe colic unresponsive to medical therapy, lethargy, or sudden death developed in these 4 horses...
Matthee S, Krecek RC, McGeoch MA.The intestinal helminth communities of 8 horses, 12 donkeys, 21 Hartmann's mountain zebras, and 44 Burchell's zebras were compared using the original data from 6 studies in South Africa and Namibia. Necropsy and worm recovery techniques were comparable between the studies. Sixty helminth species (58 nematode, 1 cestode, and 1 trematode species) were recorded. There were significant differences in the helminth community structures of the 4 Equus species. The helminth communities of the 2 closely related zebra subspecies were most similar, and they jointly shared 7 helminth species with donkeys ...
Vanniasinkam T, Barton MD, Heuzenroeder MW.Rhodococcus equi is a significant pathogen in foals predominantly causing a pyogranulomatous bronchopneumonia. Many vaccine candidates have been tested for the prevention of R. equi disease in foals. However, none of these have been developed for widespread commercial use. Previous studies have shown that a Th1 immune response is imperative for the protection of foals against R. equi disease. In this study a DNA and a protein vaccine based upon the well-characterised R. equi virulence-associated protein VapA were developed. The vaccines were tested in the BALB/c murine model and the results sh...
Saville WJ, Dubey JP, Oglesbee MJ, Sofaly CD, Marsh AE, Elitsur E, Vianna MC, Lindsay DS, Reed SM.Sarcocystis neurona and Sarcocystis fayeri infections are common in horses in the Americas. Their antemortem diagnosis is important because the former causes a neurological disorder in horses, whereas the latter is considered nonpathogenic. There is a concern that equine antibodies to S. fayeri might react with S. neurona antigens in diagnostic tests. In this study, 4 ponies without demonstrable serum antibodies to S. neurona by Western immunoblot were used. Three ponies were fed 1 x 10(5) to 1 x 10(7) sporocysts of S. fayeri obtained from dogs that were fed naturally infected horse muscles. A...
Davis DG, Schaefer DM, Hinchcliff KW, Wellman ML, Willet VE, Fletcher JM.Hypogammaglobulinemia as a result of failure of transfer of passive immunity (FTPI) is an important risk factor for infectious disease in neonatal foals. The current gold standard for determining serum immunoglobulin concentrations is radial immunodiffusion (RID). The purpose of this study was to compare immunoglobulin concentrations measured by RID with those determined by an automated turbidimetric immunoassay (TIA), which has a much shorter turnaround time. Immunoglobulin concentrations were measured by both RID and TIA in serum collected from 84 neonatal foals. Sixty-seven foals had result...
Saulez MN, Cebra CK, Heidel JR, Walker RD, Singh R, Bird KE.A 17-year-old gelding was evaluated because of dysuria, inappetence, and weight loss. Cystoscopy revealed severe mucosal ecchymoses with luminal hemorrhage and accumulations of crystalloid sludge. Analysis of a urine sample revealed isosthenuria, an alkaline pH, pyuria, hematuria, bacteriuria, and numerous calcium carbonate crystals. Histologic examination of bladder mucosa biopsy specimens revealed severe neutrophilic infiltration with mineralization. A diagnosis of encrusted cystitis exacerbated by sabulous urolithiasis was made. A Corynebacterium sp susceptible to penicillin, sulfonamide, a...
Craigo JK, Li F, Steckbeck JD, Durkin S, Howe L, Cook SJ, Issel C, Montelaro RC.Among the diverse experimental vaccines evaluated in various animal lentivirus models, live attenuated vaccines have proven to be the most effective, thus providing an important model for examining critical immune correlates of protective vaccine immunity. We previously reported that an experimental live attenuated vaccine for equine infectious anemia virus (EIAV), based on mutation of the viral S2 accessory gene, elicited protection from detectable infection by virulent virus challenge (F. Li et al., J. Virol. 77:7244-7253, 2003). To better understand the critical components of EIAV vaccine e...
Albrecht RA, Kim SK, O'Callaghan DJ.The equine herpesvirus 1 (EHV-1) EICP27 protein cooperates with either the immediate-early (IE) or the EICP0 protein to synergistically trans-activate viral promoters. GST-pulldown and co-immunoprecipitation assays revealed that the EICP27 protein's cooperation with the IE or the EICP0 protein involves its physical interaction with these viral proteins. In the case of the IE-EICP27 protein interaction, IE residues 424 to 826 and EICP27 residues 41 to 206 harbor the interactive domains. Electrophoretic mobility shift assays (EMSA) suggested that the EICP27 protein is not a sequence-specific DNA...
Bradbury LA, Archer DC, Dugdale AH, Senior JM, Edwards GB.A horse which had had a caecal impaction for 10 days was treated by means of an ileocolostomy [corrected] but failed to respond satisfactorily. Before a second laparotomy was performed it was observed to have dislodged the extension set from a jugular catheter and air was heard being sucked into the vein. It became very agitated but was anaesthetised again and the impaction was removed through an incision in the apex of the colon [corrected] After recovering from the anaesthesia it developed severe signs of pruritus which subsided only after 12 hours. These signs were considered most likely to...
Cohen ND, O'Conor MS, Chaffin MK, Martens RJ.To identify farm characteristics and management practices associated with development of Rhodococcus equi pneumonia in foals. Methods: Prospective case-control study. Methods: 5230 foals on 138 breeding farms with 9136 horses. Methods: During 2003, participating veterinarians provided data from 1 or 2 farms with > or =1 foal with R equi pneumonia and unaffected farms. Data from affected and unaffected farms were compared by use of logistic regression analysis. Results: A number of variables relating to farm size and desirable management practices were significantly associated with increased od...
Magnarelli L, Fikrig E.Blood samples were collected from 98 horses suspected of having borreliosis or granulocytic ehrlichiosis in Connecticut and New York State, USA during 1985, 1995, and 1996. Serum antibodies to Borrelia burgdorferi were detected by an enzyme-linked immunosorbent assay (ELISA), based on whole-cell and recombinant antigens, in 82 (84%) horses. Of the 181 sera tested, 59% were positive, using whole-cell antigens, compared to 48% with protein (p)37 and 35% with VlsE antigens. An ELISA containing either of these fusion proteins can be used as an adjunct to general screening by an ELISA or immunoblot...
van der Heide R, Koopmans MP, Shekary N, Houwers DJ, van Duynhoven YT, van der Poel WH.To gain more insight into interspecies transmission of rotavirus group A, human and animal fecal samples were collected between 1997 and 2001 in The Netherlands. A total of 110 human stool samples were successfully P and G genotyped by reverse transcriptase PCR. All strains belonged to the main human rotavirus genotypes G1 to G4, G9, [P4], [P6], [P8], and [P9]. [P8]G1 was predominant, and 5.5% belonged to the G9 genotype. Eleven percent of all P[8] genotypes could be genotyped only by a recently published modified primer. Rotavirus-positive fecal samples from 28 calf herds were genotyped by DN...
Liu IK, Turner JW, Van Leeuwen EM, Flanagan DR, Hedrick JL, Murata K, Lane VM, Morales-Levy MP.In this study of equids, we investigated the antibody response and the effect on the estrous cycle following a single inoculation of porcine zonae pellucidae (pZP) employing controlled-release methodology. We also investigated the use of two different water-soluble adjuvants as an alternative to oil-based adjuvants. Twenty-seven domestic mares were inoculated with various formulations of pZP and adjuvant. We showed that the anti-pZP antibodies generated as a result of the inoculations persisted for at least 43 weeks (length of the study). Of the various formulations used in the study, pZP and ...
Hendrix SM, Baxter GM.Most injuries, including those with significant tissue loss, can be successfully managed with proper therapy. With delayed healing, potential causes for the delay, such as sequestra, foreign bodies, and excessive motion,should be determined and treated to permit complete wound resolution. Horses have the innate ability to heal rapidly; however, minor injuries can quickly turn into complicated wounds, given the severity of the inciting trauma and the less than ideal environment in which the horses are housed. Wound management must focus on a combination of timely surgical and medical interventi...
Mora-Pereira M, Abarca EM, Duran S, Ravis W, McMullen RJ, Fischer BM, Lee YP, Wooldridge AA.Keratomycosis is a relatively common, sight threatening condition in horses, where treatment is often prolonged and costly. Subconjunctival (SCo) injections offer less resistance to drug diffusion than the topical route, resulting in better penetration to the ocular anterior segment. Voriconazole, a second generation triazole antifungal, is effective against common fungal organisms causing keratomycosis. If combined with a thermogel biomaterial, voriconazole can be easily injected in the SCo space to provide sustained drug release. The purpose of this study was to evaluate the drug concentrati...
Sternberg S.Swab samples were collected from the oral cavity of 174 horses in 10 farms and cultured selectively for Actinobacillus equuli. A. equuli could be isolated from 37% of all samples, varying between 12 and 88% in the different farms. Eight horses were sampled repeatedly for several days, with a variation in isolation frequency between 50 and 88%. Isolates were compared by restriction enzyme digestion and Pulsed-Field Gel Electrophoresis. A high degree of strain variability was found within each horse population as well as some variability over time between strains isolated from the same horse.
Muraro LS, Nogueira MF, Borges AMCM, Souza AO, Vieira TSWJ, de Aguiar DM.Bacteria of the genus Ehrlichia are transmitted by ticks and also are an important cause of infection in wild and domestic mammals. Infection with Ehrlichia spp. has been reported in horses, especially in the USA, Nicaragua and Brazil. In this study, we report the parasitism by Amblyomma sculptum, Rhipicephalus microplus and Dermacentor nitens ticks in horses from a ranch located in south Pantanal wetland. Molecular and serological analyzes to determine infection by Ehrlichia spp. in horses and their respective ticks were carried out. A total of 12 horses were submitted to blood collection to ...
Dwyer RM.Rotavirus poses a challenge each foaling season to farm managers and veterinarians in intensive horse breeding areas throughout the world. By understanding the epidemiology of the disease as well as characteristics of the virus, veterinarians can make sound recommendations on prevention and control of outbreaks. Even when effective prophylactic products are developed, farm management practices, including quarantine, disinfection, and hygiene, will always need to be in force to prevent any contagious disease outbreak.
Siles-Lucas M, Felleisen R, Cuesta-Bandera C, Gottstein B, Eckert J.Swiss and Spanish isolates of Echinococcus granulosus were compared using different molecular biological techniques: Genomic DNAs isolated from parasites originating from various intermediate hosts were subjected to Southern hybridization with different probes, the same source of DNA was used for DNA amplification using the Random Amplified Polymorphic DNA (RAPD) technique. With both methods the various isolates (metacestodes) of E. granulosus exhibited characteristic banding patterns which allowed us to assign them to the following groups of homologous profiles: (a) isolates of horse and donk...
Principato M.Comparative data collected over 4 years show the most frequent species of Gasterophilus infesting free-ranging horses in Umbria (Central Italy) to be G. intestinalis (93.8%), G. nasalis (76.5%) and G. inermis (71%). G. pecorum and G. haemorrhoidalis were less frequent and appeared in 39.3 and 10.8% of the animals, respectively. For each of the 5 species, the duration of gastric and enteric lesions, the average numbers of larvae isolated throughout the year and the probable duration of oral lesions were discussed.
Sutton GA, Viel L, Carman PS, Boag BL.The purpose of this experiment was to study the duration and distribution of equine influenza virus in actively infected ponies over a 3 wk period. Pony foals (6-8 mo old) were infected experimentally by nebulizing equine influenza subtype-2 virus ultrasonically through a face mask. Successful infection was clinically apparent as each of the foals (n = 6) had a febrile response, a deep hacking cough and mucopurulent nasal discharge for 7 to 10 d. The virus was isolated from nasopharyngeal swabs of all the ponies 3 and 5 d after infection and all the ponies seroconverted to the virus. Samples w...
Wang T, Magnarelli LA, Anderson JF, Gould LH, Bushmich SL, Wong SJ, Fikrig E.Recombinant West Nile virus envelope (E) protein was examined in enzyme-linked immunosorbent assay (ELISA) to detect antibodies elicited during West Nile virus infection. Horses (nine of 10) and humans (six of six) with confirmed West Nile virus infection had IgG and/or IgM antibodies to the E protein. Antibodies to the recombinant West Nile virus membrane and nonstructural 1 proteins were not detected in any of these sera. An E protein-based ELISA may aid in the serological diagnosis of West Nile virus infection.
Rampacci E, Mazzola K, Beccati F, Passamonti F.Feeding foals with poor quality colostrum predisposes them to failure of passive transfer (FPT). FPT is a major risk factor for neonatal infections. Objective: To assess the optimal cut-offs for the optical (OR) and digital (DR) refractometer and determine their accuracy for poor quality colostrum diagnosis. Methods: A diagnostic validation study. Methods: Eighty-one colostrum samples and sera were collected from broodmares and their neonatal foals, respectively. Colostral and serum IgG concentrations were measured by radial immunodiffusion (RID), DR and OR. Correlation coefficients were calcu...
Arnold CE, Chaffin MK.To determine clinical signs, diagnostic methods, treatment, and outcome for a series of adult horses with abdominal abscesses. Methods: Retrospective case series. Methods: 61 adult horses. Methods: Medical records of adult horses with abdominal abscesses treated at Texas A&M Veterinary Medical Teaching Hospital (1993 to 2008) were reviewed. Information was recorded regarding signalment, history, clinical signs, diagnosis, treatment, and short- and long-term outcomes. Risk factors for survival were determined. Results: 61 horses met the criteria for inclusion. Clinical signs included colic ...
Leszkowicz Mazuz M, Mimoun L, Schvartz G, Tirosh-Levy S, Savitzki I, Edery N, Blum SE, Baneth G, Pusterla N, Steinman A.In horses, and have been associated with fetal loss, and neurological disease, respectively. This study investigated the role of spp. infection in equine abortion in Israel. The presence of anti- spp. antibodies was evaluated in 31 aborting mares by indirect fluorescent antibody test (IFAT) and the presence of parasite DNA in their aborted fetuses was evaluated by polymerase chain reaction (PCR), using two target loci (ITS1 and Nc5). The seroprevalence found in aborting mares was 70.9% and the prevalence by DNA detection in the aborted fetuses was 41.9%. Transplacental transmission from pos...
McGowan JJ, Allen GP, Barnett JM, Gentry GA.Infection of horse KyED cells with equine herpesvirus type 3 (EHV-3) resulted in a sevenfold increase in cytosol deoxythymidine kinase (dTK) activity. The EHV-3 dTK was purified from KyED cytosol dTK by affinity chromatography on deoxythymidine-Sepharose and characterized with respect to its electrophoretic mobility, molecular weight, substrate specificity, phosphate donor specificity, and immunological specificity. The purified EHV-3 dTK migrated in polyacrylamide gels with an Rf of 0.30 and sedimented in glycerol gradients with an S value of 5.13, corresponding to a molecular weight of 83,00...
Wickhorst JP, Sammra O, Hassan AA, Alssashen M, Lämmler C, Prenger-Berninghoff E, Erhard M, Metzner M, Paschertz K, Timke M, Abdulmawjood A.In the present study an Arcanobacterium hippocoleae strain isolated from a uterus swab of an apparently healthy mare could be identified by phenotypic properties, by MALDI-TOF MS analysis and genotypically by investigating the molecular targets 16S rDNA, 16S-23S rDNA intergenic spacer region and the genes encoding the β subunit of bacterial RNA polymerase (rpoB), elongation factor tu (tuf) and glyceraldehyde 3-phosphate dehydrogenase (gap). The presented data are one of the few reports about the species A. hippocoleae and might help to elucidate the role this species plays in infections of ho...
Valentine BA, Löhr CV.Three horses with colic, clinical evidence of endotoxaemia and high serum activities of creatine kinase and aspartate aminotransferase were examined postmortem. The horses were diagnosed with severe ulcerative colitis, pyloric ulceration and stenosis with colonic sand impaction, and colonic obstruction due to faecaliths. There was no gross or histological evidence of muscle trauma. Their semimembranosus muscles had scattered acute to subacute segmental necrosis of the myofibres, suggestive of endotoxin-induced muscle injury.
Foil L, Foil C.In this discussion of parasitic skin diseases of horses, details on life cycles are given to aid the understanding and development of control strategies.
Pusterla N, Bowers J, Barnum S, Hall JA.The objective of this study was to detect Streptococcus equi subspecies equi (S. equi) (Lactobacillales: Streptococcaceae) using quantitative polymerase chain reaction (qPCR) in flies collected from a farm with a documented outbreak of strangles. A total of 1856 face flies [Musca autumnalis (Diptera: Muscidae)] were collected using conventional fly traps. The flies were processed for nucleic acid purification and tested for the presence of S. equi by qPCR. A total of 10/1856 flies (0.54%) tested qPCR-positive for S. equi. The results may implicate the presence of face flies as a risk factor...
Schumacher J, Yarbrough T, Pascoe J, Woods P, Meagher D, Honnas C.To examine the response of horses with progressive ethmoidal hematoma (PEH) to intralesional injection of 4% formaldehyde solution. Methods: Nasal passages of horses affected with PEH were examined endoscopically at different intervals to determine the effects of intralesional injection of formaldehyde solution. Methods: 21 horses with PEH. Methods: PEHs were injected transendoscopically with 4% formaldehyde solution. Horses were examined endoscopically and retreated at different intervals until the PEH was eliminated or was so small that reinjection was not possible. Results: Lesions diminish...
Ferreira JC, Pires RH, Costa GBD, Carrijo BN, Guiotto FG, Rodrigues VS.The goal of the present study was to characterize the antimicrobial action of different ozone (O) presentations against Pythium insidiosum isolated from horses. In experiment 1, P. insidiosum was treated with ozonated distilled water, ozonated sunflower oils with distinct peroxide indexes or O gas (72 μg O mL). In experiment 2, samples were exposed one or three times to oxygen (O) or O gas (72 μg O mL; 30 min/day). In experiment 3, P. insidiosum was treated with different concentrations of O gas (Ø, 32, 52, or 72 μg O mL) for three days (30 min/day). In experiment 4, samples were ex...
Johnson L, Montgomery JB, Schneider JP, Townsend HG, Ochs M, Singh B.To understand the mechanisms of airway inflammation associated with equine diseases such as Rhodococcus equi infection, we must identify baseline "normal" structural characteristics of the horse lung. To develop a detailed understanding of the morphology of the horse lung, we adapted and applied stereological methods to the lungs from healthy adult horses (N = 4) and 1-day (N = 5) and 30-day (N = 5) old foals. The left lung was fixed in situ by intrabronchial instillation of glutaraldehyde/paraformaldehyde fixative at 25 cm H2 O column and sampled using a fractionator design follow...
Burgess HJ, Lockerbie BP, Czerwinski S, Scott M.A 12-year-old female Argentinean Warmblood mare was evaluated because of respiratory noise. The horse resided in Calgary, Alberta, Canada, but had been imported from Argentina 28 months prior to presentation. Endoscopy of the upper respiratory tract revealed a single polypoid mass on the left arytenoid. The mass was surgically excised and was diagnosed histologically as rhinosporidiosis. Polymerase chain reaction and DNA sequencing were used to confirm the etiological agent. Four weeks postoperatively, endoscopy was repeated, revealing recurrence of the original lesion with multiple additional...
Nielsen MK, Vidyashankar AN, Hanlon BM, Diao G, Petersen SL, Kaplan RM.Anthelmintic resistance is an increasing challenge for the control of equine parasites. The fecal egg count reduction test (FECRT) is the practical gold standard method for evaluating reduction in anthelmintic efficacy, but the interpretation is complicated due to high levels of variability. A hierarchical statistical model was described for analysis of FECRT data from multiple farms to evaluate the role of biological factors in determining the strongyle efficacy of pyrantel pamoate in a study performed in Denmark. The model was then used to describe two notions of farm efficacy, namely condit...
Paterson S, Coumbe K.Chorioptic mange caused by Chorioptes bovis is a common pruritic skin condition of the horse. This surface-browsing parasite usually affects the lower legs (leg mange) but can present as a generalized skin disease. Numerous anecdotal reports exist in the literature about the benefit of lime sulphur as a treatment for surface ectoparasites in the horse. This report studies the use of lime sulphur when applied as a 5% solution, some with and some without prior shampooing and clipping, to treat confirmed cases of chorioptic mange in 22 horses. Horses included in the trial had clinical signs indic...
Costa PWLD, Vilela VLR, Feitosa TF.The objective of this study was to determine the parasitological profiles of traction equids from the semi-arid climate of Paraíba (PB) State. We analyzed 96 equids that performed traction work, with no defined breed, males and females, and all older than 24 months. Among the analyzed animals, 51% were donkeys, 41.7% mules, and 7.3% horses. Fecal material and blood were collected for parasitological examination and to determine the packed cell volume (PCV), respectively. The samples were sent to the Veterinary Parasitology Laboratory, Veterinary Hospital - IFPB, Sousa-PB campus, and epidemiol...
Marenzoni ML, Sforna M, Stefanetti V, Casagrande Proietti P, Brignone L, Del Sero A, Falcioni F, Orvieto S, Tamantini C, Tiburzi A, Valentini S....In recent years, there has been increasing evidence of the potential pathogenic significance of equine gammaherpesviruses in the horse. In humans, cattle and mice, gammaherpesviruses have already been associated with uterine infection. The aim of the present study was to investigate the presence of gammaherpesviruses in uterine flushings of mares with reproductive problems and to evaluate if there was a possible statistical association with clinical and laboratory findings in these cases. A total of 80 uterine flushings were collected from 61 mares with different reproductive problems and thes...
Onzere CK, Fry LM, Bishop RP, Silva MG, Bastos RG, Knowles DP, Suarez CE.Theileria equi is a widely distributed apicomplexan parasite that causes severe hemolytic anemia in equid species. There is currently no effective vaccine for control of the parasite and understanding the mechanism that T. equi utilizes to invade host cells may be crucial for vaccine development. Unlike most apicomplexan species studied to date, the role of micronemes in T. equi invasion of host cells is unknown. We therefore assessed the role of the T. equi claudin-like apicomplexan microneme protein (CLAMP) in the invasion of equine erythrocytes as a first step towards understanding the role...
Yuan Z, Gault EA, Campo MS, Nasir L.Equine sarcoids represent the most common skin tumours in equids worldwide, characterized by extensive invasion and infiltration of lymphatics, rare regression and high recurrence after surgical intervention. Bovine papillomavirus type-1 (BPV-1) and less commonly BPV-2 are the causative agents of the diseases. It has been demonstrated that BPV-1 viral gene expression is necessary for maintaining the transformation phenotype. However, the underlying mechanism for BPV-1 transformation remains largely unknown, and the cellular factors involved in transformation are not fully understood. Previousl...
Barrell EA, Asakawa MG, Felippe MJB, Divers TJ, Stokol T.Acute leukemia is rare in horses. Herein we describe historical, clinicopathologic, and postmortem findings in 6 horses with acute leukemia. Medical records of horses with >20% bone marrow blasts and cytochemical or immunophenotyping results were reviewed. Affected horses were 2-8 y of age and of different breeds and sex. Horses were presented acutely with nonspecific signs (e.g., fever, lethargy). Characteristic hemogram findings were bi- or pancytopenia with low blast numbers. Histologic examination revealed extramedullary infiltrates, especially in lymph nodes, spleen, kidney, liver, and lu...
Nunes J, Mackie JT, Kiupel M.A 3.5-year-old Thoroughbred mare presented at necropsy with a large mass at the root of the mesentery and multiple smaller mesenteric masses. The mucosa of the small intestine contained numerous raised nodules. Histologic examination revealed severe granulomatous mesenteric lymphadenitis and enteritis. Epithelioid macrophages and multinucleated giant cells frequently contained numerous intracytoplasmic yeast organisms, which were strongly positive on immunohistochemical staining when using a polyclonal antibody against Histoplasma spp. A diagnosis of abdominal histoplasmosis was made based on ...
Proietto LR, Plummer CE, Maxwell KM, Lamb KE, Brooks DE.The purpose of this investigation was to identify potential environmental risk factors for the diagnosis of equine deep stromal abscesses (DSA) in the subtropical climate at the University of Florida Veterinary Medical Center (UFVMC). Methods: Cases included were selected from the UFVMC medical record and imaging database, and included all cases of equine DSA diagnosed during the period from December 1991 to December 2013 in patients residing in north central Florida. Patient date of diagnosis and atmospheric data was obtained for north central Florida for the corresponding time period. Univar...
