Pathogens are microorganisms, such as bacteria, viruses, fungi, and parasites, that can cause disease in horses. These microorganisms interact with the equine immune system, often leading to a range of health issues that can affect individual horses or entire populations. Pathogens can be transmitted through various routes, including direct contact, vectors, or environmental exposure. Common equine pathogens include Streptococcus equi, Equine Herpesvirus, and Strongylus vulgaris. Understanding the interactions between equine hosts and pathogens is essential for disease prevention, management, and treatment. This page compiles peer-reviewed research studies and scholarly articles that explore the identification, transmission, and impact of pathogens on equine health.
Schnellmann C, Gerber V, Rossano A, Jaquier V, Panchaud Y, Doherr MG, Thomann A, Straub R, Perreten V.Because of the frequency of multiple antibiotic resistance, Staphylococcus species often represent a challenge in incisional infections of horses undergoing colic surgery. To investigate the evolution of antibiotic resistance patterns before and after preventative peri- and postoperative penicillin treatment, staphylococci were isolated from skin and wound samples at different times during hospitalization. Most staphylococci were normal skin commensals and belonged to the common coagulase-negative group. In some cases they turned out to be opportunistic pathogens present in wound infections. M...
Pusterla N, Wilson WD, Conrad PA, Barr BC, Ferraro GL, Daft BM, Leutenegger CM.This study was designed to determine the relative levels of gene transcription of selected pathogens and cytokines in the brain and spinal cord of 12 horses with equine protozoal myeloencephalitis (EPM), 11 with equine herpesvirus type 1 (EHV-1) myeloencephalopathy, and 12 healthy control horses by applying a real time pcr to the formalin-fixed and paraffin-embedded tissues. Total rna was extracted from each tissue, transcribed to complementary dna (cDNA) and assayed for Sarcocystis neurona, Neospora hughesi, EHV-1, equine GAPDH (housekeeping gene), tumour necrosis factor (TNF)-alpha, interfer...
Ivester KM, Adams SB, Moore GE, Van Sickle DC, Lescun TB.To determine synovial fluid gentamicin concentrations and evaluate adverse effects on the synovial membrane and articular cartilage of tarsocrural joints after implantation of a gentamicin-impregnated collagen sponge. Methods: 6 healthy adult mares. Methods: A purified bovine type I collagen sponge impregnated with 130 mg of gentamicin was implanted in the plantarolateral pouch of 1 tarsocrural joint of each horse, with the contralateral joint used as a sham-operated control joint. Gentamicin concentrations in synovial fluid and serum were determined for 120 hours after implantation by use of ...
Tulman ER, Delhon G, Afonso CL, Lu Z, Zsak L, Sandybaev NT, Kerembekova UZ, Zaitsev VL, Kutish GF, Rock DL.Here we present the genomic sequence of horsepox virus (HSPV) isolate MNR-76, an orthopoxvirus (OPV) isolated in 1976 from diseased Mongolian horses. The 212-kbp genome contained 7.5-kbp inverted terminal repeats and lacked extensive terminal tandem repetition. HSPV contained 236 open reading frames (ORFs) with similarity to those in other OPVs, with those in the central 100-kbp region most conserved relative to other OPVs. Phylogenetic analysis of the conserved region indicated that HSPV is closely related to sequenced isolates of vaccinia virus (VACV) and rabbitpox virus, clearly grouping to...
Takai S, Zhuang D, Huo XW, Madarame H, Gao MH, Tan ZT, Gao SC, Yan LJ, Guo CM, Zhou XF, Hatori F, Sasaki Y, Kakuda T, Tsubaki S.Little is known about the distribution of Rhodococcus equi in the soil environment of native horses in China. One hundred and eight soil samples were collected from native-horse farms in the Hulun Beier grasslands of eastern Mongolia, the Xilin Goler grasslands of southern Mongolia, and Tongliao City in Inner Mongolia, China. The isolation rates of R. equi from soil samples from the Hulun Beier and Xilin Goler grasslands ranged from 25.9% to 30.0%. In contrast, isolation rates from soil samples from Tongliao City were as high as 82.3% and the mean number of R. equi in soil samples from Tonglia...
Frye MA.Equine urinary tract infection (UTI) most commonly occurs as a sequela to structural or functional inhibition of normal urine flow. Although it is an infrequent diagnosis in equids, the incidence of UTI in human beings is high and has inspired great investigative effort. The resultant findings with potentially broad application as well as current equine studies are reviewed here. Recent developments in the understanding of host-agent interactions and renal defense mechanisms, emerging antimicrobial resistance, and novel therapeutic alternatives to prophylactic antibiotic use are emphasized.
Goodrich LR.Much has been learned in the past decade about osteomyelitis. The inhibitory mechanisms of the "biofilm slime" layer that is formed by bacterial extracapsular exopolysaccharides and binds to bone, joints, and implants are now better understood than in the past. The surface colonization of bacteria that occurs within these biofilms is a biologic phenomenon that is somewhat unique to orthopedic infections. This survival strategy of bacteria is effective, and it is important for veterinarians who treat osteomyelitis to be aware of current diagnostic and therapeutic treatment modalities. The pract...
Gerard MP, Wotman KL, Komáromy AM.Infectious conditions of the equine head are commonly encountered in clinical practice. Pathogenic bacterial, viral, and fungal organisms may localize in the extensive nasal passages, paranasal sinuses, and guttural pouches, creating a range of clinical signs and conditions that can be severe enough to lead to unexpected fatality. Renewed interest in equine dentistry has led to a greater recognition of dental disease that is associated with infection. This article focuses on bacterial and fungal infections of the main anatomic regions of the equine head, where advances in diagnosis and managem...
Duquesne F, Pronost S, Laugier C, Petry S.A direct-PCR assay was developed for the rapid detection of Taylorella equigenitalis, a Gram-negative bacterium responsible for contagious equine metritis (CEM) in Equidae. The bacteria may be detected in equine genital swabs without need for a preliminary step of DNA extraction or bacterial isolation. Specificity was determined with 125 isolates of T. equigenitalis, 24 isolates of Taylorella asinigenitalis, five commensal bacteria of the genital tract and a facultative intracellular pathogen of foals found in large concentration in soil. Our PCR is specific and amplified a 413-bp 16S ribosoma...
Walther B, Friedrich AW, Brunnberg L, Wieler LH, Lübke-Becker A.The problem of nosocomial infections is of increasing importance in veterinary medicine. As an example, this review summarizes current knowledge regarding methicillin-resistant Staphylococcus aureus (MRSA) as a typical example, as these pathogens are the most important agents of nosocomial infections in human medicine worldwide and are being increasingly reported in veterinary medicine. MRSA are classified by their ability to be resistant against oxacillin/methicillin, this feature being confered by mecA, a gene which was acquired by horizontal gene transfer of the staphylococcal gene cassette...
Muscatello G, Gerbaud S, Kennedy C, Gilkerson JR, Buckley T, Klay M, Leadon DP, Browning GF.Rhodococcoccus equi is a significant cause of bronchopneumonia in foals worldwide. Infection of the lungs is believed to result from inhalation of virulent R. equi in dust from contaminated environments. A measure of infectious risk in an environment is the level of airborne contamination. Objective: To assess and compare the level of airborne virulent R. equi in paddocks and stables. Methods: Air samples were collected sequentially over the 2003 foaling season from the paddocks and stables on 3 Irish horse breeding farms affected by R. equi pneumonia. Colony blotting and DNA hybridisation tec...
Båverud V, Nyström C, Johansson KE.Contagious equine metritis (CEM), caused by Taylorella equigenitalis, is a widely known highly contagious genital equine disease that is transmitted venereally. A new bacterium, Taylorella asinigenitalis resembling T. equigenitalis was recently isolated from three American donkey jacks, at routine testing for CEM. The purpose of this study was to identify and characterize a strain of Taylorella sp. from the genital tract of a stallion. Swab samples for culture of T. equigenitalis were taken from urethral fossa, urethra and penile sheath of a 3-year-old stallion of the Ardennes breed when it wa...
Keel MK, Songer JG.Clostridium difficile is a confirmed pathogen in a wide variety of mammals, but the incidence of disease varies greatly in relation to host species, age, environmental density of spores, administration of antibiotics, and possibly, other factors. Lesions vary as well, in severity and distribution within individuals, and in some instances, age groups, of a given species. The cecum and colon are principally affected in most species, but foals and rabbits develop severe jejunal lesions. Explanations for variable susceptibility of species, and age groups within a species, are largely speculative. ...
Phumoonna T, Muscatello G, Chicken C, Gilkerson JR, Browning GF, Barton MD, Heuzenroeder MW.A total of 227 field samples from naturally exposed foals aged between 3 weeks and 6 months were used in an evaluation of a peptide-based enzyme-linked immunosorbent assay (ELISA) for diagnosis of Rhodococcus equi infection. A biotinylated peptide derived from the virulence-associated protein A (VapA) of R. equi, a horse pathogen, was synthesized and designated as PN11-14. The peptide corresponds to the N-terminal B-cell epitope TSLNLQKDEPNGRASDTAGQ of the VapA protein. Based upon a serum immunoglobulin (Ig)G titre of 512 as a positive cut-off value for the R. equi infection, the ELISA provide...
Léon A, Pronost S, Tapprest J, Foucher N, Blanchard B, André-Fontaine G, Laugier C, Fortier G, Leclercq R.Studies were carried out to determine the cause of death in a prematurely born Thoroughbred foal that died 24 hours after birth. Necropsy revealed gross lesions suggestive of septicemia. A commercial Leptospira polymerase chain reaction (PCR) assay designed to specifically amplify the hemolysis-associated protein 1 (hap1) gene present only in pathogenic Leptospira strains detected the presence of Leptospira DNA in various tissues of the foal. Histologic examination of lung, liver, kidney, and myocardium revealed numerous spirochetes in Warthin-Starry-stained tissue sections. Results of PCR ana...
Breathnach CC, Sturgill-Wright T, Stiltner JL, Adams AA, Lunn DP, Horohov DW.The increased vulnerability of foals to specific pathogens such as Rhodococcus equi is believed to reflect an innate immunodeficiency, the nature of which remains poorly understood. Previous studies have demonstrated that neonates of many species fail to mount potent Th1 responses. The current research investigates the ability of circulating and pulmonary lymphocytes of developing foals to produce interferon gamma (IFNgamma). Peripheral blood mononuclear cells (PBMC) were prepared from up to 10 horse foals at regular intervals throughout the first 6 months of life. Bronchoalveolar lavage (BAL)...
Makrai L, Kira K, Kono A, Sasaki Y, Kakuda T, Tsubaki S, Fodor L, Varga J, Taka S.The plasmid profiles of virulent Rhodococcus equi strains isolated on three horse-breeding farms located in different parts of Hungary were investigated. From 49 soil samples collected on the three farms, 490 R. equi isolates (10 from each sample) were obtained and tested for the presence of 15- to 17-kDa antigens (VapA) by immunoblotting and PCR. Ninety-eight VapA-positive isolates were detected from 30 of the 49 culture-positive samples with a prevalence ranging from 13.1% to 23.2%. Of the 98 virulent isolates, 70 contained an 85-kb type I plasmid, 13 contained an 87-kb type I plasmid, and 1...
Arroyo LG, Stämpfli HR, Weese JS.Duodenitis-proximal jejunitis (DPJ) is an idiopathic condition in the horse characterized by inflammation and oedema of the duodenum and proximal jejunum. Clinical signs include colic, ileus, depression, fluid accumulation in the small intestine and stomach, and endotoxaemia. The objective of this study was to investigate prospectively the role of Clostridium difficile in this idiopathic disease. Nasogastric reflux from 10 consecutive cases with DPJ and 16 consecutive horses with other causes of nasogastric reflux was cultured for C. difficile, other Clostridium spp., and Salmonella. Toxigenic...
White SD, Vandenabeele SI, Drazenovich NL, Foley JE.Malassezia-type yeasts previously have been observed on cytologic examination of the intermammary region of mares that presented with tail-head pruritus; topical antiyeast treatment resolved the pruritus. Further, Malassezia dermatitis has been observed in horses in intertriginous areas such as the udder and prepuce; the species of yeast was not confirmed. It is not known whether healthy mares or male horses can be carriers of this yeast in these body areas. Objective: Malassezia spp. are present in the intermammary region in healthy mares and the preputial fossa in healthy geldings. Methods: ...
Weinstein WL, Moore PA, Sanchez S, Dietrich UM, Wooley RE, Ritchie BW.To determine whether a novel third-generation chelating agent (8 mM disodium EDTA dehydrate and 20 mM 2-amino-2-hydroxymethyl-1, 3-propanediol) would act as an antimicrobial potentiator to enhance in vitro activity of antifungal medications against fungal isolates obtained from horses with mycotic keratitis. Methods: Fungal isolates (3 Aspergillus isolates, 5 Fusarium isolates, 1 Penicillium isolate, 1 Cladosporium isolate, and 1 Curvularia isolate) obtained from horses with mycotic keratitis and 2 quality-control strains obtained from the American Type Culture Collection (ATCC; Candida albica...
Komar N, Clark GG.West Nile virus (Flavivirus: Flaviviridae; WNV) has spread rapidly throughout the Caribbean Basin since its initial detection there in 2001. This report summarizes our current knowledge of WNV transmission in tropical America. Methods: We reviewed the published literature and consulted with key public health officials to obtain unpublished data. Results: West Nile virus infections first appeared in human residents of the Cayman Islands and the Florida Keys in 2001, and in apparently healthy Jamaican birds sampled early in 2002. Serologic evidence of WNV infection in 2002 was detected in horses...
Lindsay DS, Mitchell SM, Yang J, Dubey JP, Gogal RM, Witonsky SG.Horses are considered accidental hosts for Sarcocystis neurona and they often develop severe neurological disease when infected with this parasite. Schizont stages develop in the central nervous system (CNS) and cause the neurological lesions associated with equine protozoal myeloencephalitis. The present study was done to examine the ability of S. neurona merozoites to penetrate and develop in equine peripheral blood leukocytes. These infected host cells might serve as a possible transport mechanism into the CNS. S. neurona merozoites penetrated equine leukocytes within 5 min of co-culture. I...
Uilenberg G.The history of the genus Babesia is briefly outlined. The classical differences with the main other genus of non-pigment-forming hemoparasites, Theileria, are the absence of extra-erythrocytic multiplication (schizogony) in Babesia and the cycle in the vector tick, which includes transovarial transmission in Babesia but only transstadial transmission in Theileria. Also, the multiplication in the red cell of Babesia, by budding, most often results in two daughter cells (merozoites), while that of Theileria gives four merozoites, often as a Maltese cross. In particular this means that what is st...
Stefancíková A, Derdáková M, Stepánová G, Pet'ko B, Szestáková E, Skardová I, Cisláková L.Geographically different strains of Borrelia burgdorferi sensu lato (B. burgdorferi sensu stricto Ir 105, B. burgdorferi s.s. + B. afzelii V 123, B. garinii Ir 112 - isolates from eastern Slovakia, B. garinii K24 - isolate from western Slovakia and B. burgdorferi s.s. B 31 - American strain) were compared as antigens for serological study of Lyme borreliosis by IgG ELISA on a group of horses from eastern Slovakia. In a set of 101 horse serum samples, positivity with the use of Ir 105 strain was 53 (52.4%), with V 123 51 (51.49%), with Ir 112 48 (47.5%), with K 24 47 (46.5%) and with B 31 only ...
Wang X, Kikuchi T, Rikihisa Y.Anaplasma phagocytophilum is an obligatory intracellular bacterium that causes human granulocytic anaplasmosis. The polymorphic 44-kDa major outer membrane proteins of A. phagocytophilum are dominant antigens recognized by patients and infected animals. However, the ability of anti-P44 antibody to neutralize the infection has been unclear due to a mixture of P44 proteins with diverse hypervariable region amino acid sequences expressed by a given bacterial population and lack of epitope-defined antibodies. Monoclonal antibodies (MAbs) 5C11 and 3E65 are directed to different domains of P44 prote...
van der Meulen KM, Favoreel HW, Pensaert MB, Nauwynck HJ.Equine herpesvirus (EHV)-1 is a pathogen of horses, well known for its ability to induce abortion and nervous system disorders. Clinical signs may occur despite the presence of a virus-specific immune response in the horse. The current review will summarize the research, on how, EHV-1-infected cells can hide from recognition by the immune system. Research findings on immune evasion of EHV-1 will be compared with those of other herpesviruses of veterinary importance.
Alencar J, Lorosa ES, Dégallier lN, Serra-Freire NM, Pacheco JB, Guimarães AE.New data on the feeding patterns of Haemagogus (Haemagogus) janthinomys Dyar from different geographical regions of Brazil, by using the precipitin test as the bloodmeal-identifying tool, are presented. The following antisera were used: bird, dog, human, rodent, cattle, horse, and opossum. The origins of 287 bloodmeals were identified, whereas 33 specimens were negative to the antiserums tested. Among the reactive specimens, 174 (60.6%) fed on only one food source, of which 35.1% originated from birds, 19.5% from rodents, 12.6% from humans, 10.3% from cattle, 10.3% from opossums, 7.5% from dog...
Scholz HC, Joseph M, Tomaso H, Al Dahouk S, Witte A, Kinne J, Hagen RM, Wernery R, Wernery U, Neubauer H.A polymerase chain reaction (PCR) assay targeting the flagellin P (fliP)-I S407A genomic region of Burkholderia mallei was developed for the specific detection of this organism in pure cultures and clinical samples from a recent outbreak of equine glanders. Primers deduced from the known fliP-IS407A sequence of B. mallei American Type Culture Collection (ATCC) 23344(T) allowed the specific amplification of a 989-bp fragment from each of the 20 B. mallei strains investigated, whereas other closely related organisms tested negative. The detection limit of the assay was 10 fg for purified DNA of ...
Thomas E, Thomas V, Wilhelm C.Cefquinome is known for its use as an antibacterial drug in cattle and pigs. The objective of this study was to evaluate the antibacterial activity of cefquinome against equine pathogenic bacteria. The minimum inhibitory concentration (MIC) of cefquinome was determined for a total of 205 strains, which had recently been isolated in Europe from diseased horses (respiratory infection, foal septicaemia). The bactericidal activity was tested against 19 strains using the time killing method. The post-antibiotic effect (PAE) and post-antibiotic sub-MIC effect (PA SME) were determined against 12 stra...
Pille F, Martens A, Schouls LM, Peelman L, Gasthuys F, Schot CS, De Baere C, Desmet P, Vandenberghe F.Standard culturing techniques are often unrewarding in confirming diagnosis of synovial infection in the equine patient. Several human studies report the use of sensitive polymerase chain reaction (PCR) techniques for the detection of bacterial involvement in acute synovitis. However, successful extraction of bacterial DNA directly from clinical samples from horses without prior culture has not been reported yet. The goal of this study was to develop a sensitive and reliable method for molecular detection and identification of bacterial species in synovial fluid from horses with infectious syn...
Willette JA, Kopper JJ, Kogan CJ, Seguin MA, Schott HC.We investigated the effects of season and geographic location on detection of nucleic acids of potential enteric pathogens (PEPs) or their toxins (PEP-Ts) in feces of horses ≥6-mo-old in the United States. Results of 3,343 equine diarrhea PCR panels submitted to Idexx Laboratories for horses >6-mo-old were reviewed. Submission months were grouped into 4 seasons, and states were grouped into 4 geographic regions. Logistic regression was performed to assess effects of season and region on detection rates of PEPs and PEP-Ts. Agresti-Coull CIs were determined. Detection rate of was higher in...
Vinogradov E, MacLean LL, Brooks BW, Lutze-Wallace C, Perry MB.Taylorella asinigenitalis sp. nov is a nonpathogenic gram-negative bacterium recently isolated from the genital tract of male donkeys. The bacterium is phenotypically indistinguishable from Taylorella equigenitalis, a pathogen that is the cause of contagious equine metritis, a highly communicable venereal disease of horses. The structural analysis of the lipopolysaccharide produced by T. asinigenitalis sp. nov (ATCC 700933) demonstrated that its O-polysaccharide (O-PS) component is a linear unbranched polymer of repeating disaccharide units composed of 1,3-linked pyranosyl residues of 2,4-diac...
Corrente M, D'Abramo M, Latronico F, Greco MF, Bellacicco AL, Greco G, Martella V, Buonavoglia D.A methicillin-resistant (MR) Staphylococcus epidermidis strain was isolated from a saddle horse affected by osteolysis. MR coagulase-negative staphylococci (MRCNS) were isolated from 11 of 14 (78.8%) horses housed in the same riding club. By typing of the SCCmec region, almost the strains displayed a non typeable (NT) pattern and possessed the ccr type 2. Altogether, the high prevalence of MRCNS and the detection of NT SCCmec types support the hypothesis that horses may represent a reservoir of MRCNS for humans and that equine MRCNS may act as potential source of resistance genes for other sta...
Giguère S, Jordan LM, Glass K, Cohen ND.Isolation of multiple bacterial species is common in foals with Rhodococcus equi pneumonia. Objective: There is no association between isolation of other microorganisms and outcome. Methods: 155 foals with pneumonia caused by R. equi. Methods: Case records of foals diagnosed with R. equi pneumonia based on culture of the respiratory tract were reviewed at 2 referral hospitals (University of Florida [UF] and Texas A&M University [TAMU]). Results: R. equi was cultured from a tracheobronchial aspirate (TBA) in 115 foals and from lung tissue in 38 foals. Survival was significantly higher at UF...
Martin LM, Johnson PJ, Amorim JR, Honaker AR, Donaldson RS, DeClue AE.Horses affected with gastrointestinal conditions such as colic or colitis are at substantial risk for translocation of bacterial components such as lipopolysaccharide (LPS, endotoxin) from the gastrointestinal tract into circulation resulting in systemic inflammation and subsequent morbidity and mortality. Therefore, there is a need for effective preventive and treatment strategies aimed at minimizing the host's inflammatory reaction to these pathogen-associated molecular patterns (PAMPs) from gastrointestinal disease. Resveratrol (RES, trans-3,5,4'-trihydroxystilbene) is a phytoalexin commonl...
Taha S, Johansson O, Rivera Jonsson S, Heimer D, Krovacek K.Clostridium difficile is a common nosocomial pathogen in humans and animals that causes diarrhea and colitis following antibiotic therapy. Isolates of C. difficile obtained from faecal material from 20 human patients and 6 equine subjects with antibiotic-associated diarrhea were investigated regarding production of toxins A and B, their capacity to adhere to the human intestinal Caco-2 cell line and equine intestinal cells, and for the presence of fimbriae. The results showed that most (17/20) of the human clinical isolates produced both toxins A and B. One of the human isolates proved toxin A...
Verma RD, Venkateswaran KS, Sharma JK, Agarwal GS.Malleo-proteins from synthetic broth mallein of six strains of Pseudomonas mallei were separated by trichloroacetic acid precipitation, ammonium sulfate precipitation and Ultrogel AcA 34 gel filtration chromatography. When tested comparatively with Dutch PPD mallein as standard on P. mallei-sensitized and normal horses all the strains were found to be malleinogenic, trichloroacetic acid precipitated proteins were comparable to Dutch PPD mallein in potency and innocuity whereas ammonium sulfate-precipitated proteins elicited non-specific reactions. Ultrogel AcA 34 chromatographed high molecular...
Subbiah M, Thirumalapura N, Thompson D, Kuchipudi SV, Jayarao B, Tewari D.Metagenomic sequencing of clinical diagnostic specimens has a potential for unbiased detection of infectious agents, diagnosis of polymicrobial infections and discovery of emerging pathogens. Herein, next generation sequencing (NGS)-based metagenomic approach was used to investigate the cause of illness in a subset of horses recruited for a tick-borne disease surveillance study during 2017-2019. Blood samples collected from 10 horses with suspected tick-borne infection and five apparently healthy horses were subjected to metagenomic analysis. Total genomic DNA extracted from the blood samples ...
Chisu V, Serra E, Foxi C, Chessa G, Masala G.Piroplasmoses are tick-borne diseases caused by hemoprotozoan parasites of veterinary and public health significance. This study focuses on the molecular identification and characterization of species belonging to the genera in 152 blood samples, collected from 80 horses and 72 cattle from several farms in Sardinia, by targeting the 18S rRNA gene. The PCR results highlighted that 72% of the samples were positive for spp., with a rate of infection of 68% and 75% for the horses and cattle, respectively. Sequencing and the BLASTn analysis showed that the 18S rRNA generated in this study has 99-...
Petry S, Breuil MF, Duquesne F, Laugier C.The performance of culture and PCR methods routinely used to diagnose contagious equine metritis (CEM) was evaluated and compared by two interlaboratory trials involving a total of 24 European laboratories, including 22 National Reference Laboratories for CEM. Samples were swab specimens artificially contaminated with bacteria present in the genital tract of Equidae, some with and some without Taylorella equigenitalis, the causative agent of CEM, and T asinigenitalis, responsible for possible misidentification as T equigenitalis Throughout both interlaboratory trials, PCR performed better in t...
Ueno M, Kuroda N, Yahagi K, Ohtaki T, Kawanaka M.Commercial western blot (WB) assay was used to detect serum antibodies specific to Echinococcus multilocularis in 23 horses in which infection was confirmed by postmortem inspection at a slaughterhouse. Livers contained from 1 to >20 nodular lesions; foci diameter ranged from 1 to 25 mm. Antibody tests of serum from all 23 animals were negative for antigen bands at 7, 16, 18, and 26-28 kDa, which show specificity in the serum of human patients. However, sera from two infected horses with the largest nodules (diameter, 25 mm) showed positive response to one of the 22-kDa and 30-kDa antigen band...
Lee Y, Kiupel M, Soboll Hussey G.Dendritic cells (DCs) are professional antigen-presenting cells that have multiple subpopulations with different phenotypes and immune functions. Previous research demonstrated that DCs have strong potential for anti-viral defense in the host. However, viruses including alphaherpesvirinae have developed strategies to interfere with the function or maturation of DCs, causing immune dysfunction and avoidance of pathogen elimination. The goal of the present study was to isolate and characterize equine lung-derived DCs (L-DCs) for use in studies of respiratory viruses and compare their features wi...
Kau S, Mansfeld MD, Šoba A, Zwick T, Staszyk C.Prevotella histicola is a facultative oral pathogen that under certain conditions causes pathologies such as caries and periodontitis in humans. Prevotella spp. also colonize the oral cavity of horses and can cause disease, but P. histicola has not yet been identified. Methods: A 12-year-old Tinker mare was referred to the clinic for persistent, malodorous purulent nasal discharge and quidding. Conservative antibiotic (penicillin), antiphlogistic (meloxicam), and mucolytic (dembrexine-hydrochloride) treatment prior to referral was unsuccessful and symptoms worsened. Oral examination, radiograp...
Peyrou M, Higgins R, Lavoie JP.Evolution of bacterial resistance to certain antibacterial agents in horses in a veterinary hospital. A total of 255 antibiograms, conducted according to the Kirby-Bauer method from bacterial isolates collected from horses at the Hôpital Vétérinaire d'Enseignement at the Université de Montréal between 1996 and 1998 were compared with the results obtained about 10 years ago with corresponding bacterial species. A significant increase in the percentage of strains resistant to trimethoprim-sulfamethoxazole (TMP-SXT), penicilline, tetracycline, and to gentamicin was observed. The percentages ...
Sweeney CR, Sweeney RW, Benson CE.Results of bacteriologic culture of specimens obtained from 14 horses with pneumonia and from 15 horses that were clinically healthy (nonpneumonia group) were compared. Specimens were obtained by use of an endoscopic guarded tracheal swabbing method and percutaneous tracheal aspiration. The percentage of agreement between the 2 tracheal specimens for the horses of the pneumonia group was 79% for aerobic isolates and 100% for anaerobic isolates. The percentage of agreement between results of the 2 tracheal specimens for horses of the nonpneumonia group was 80% for aerobic organisms and 93% for ...
Pascoe RR.Twelve medicaments were tested for their efficacy in the treatment of Trichophyton equinum var. autotrophicum; povidone iodine, thiabendazole ointment, captan ointment and Burroughs Wellcome Ringworm Ointment gave satisfactory results but their usefulness may be limited for treatment of large numbers of horses. Aqueous washes containing 0.5% hexetidine or 0.3% chloramine-T did not prevent fungi being isolated from lesions for up to 7 days after treatment. Similarly neither etisazole nor thiabendazole suspension prevented fungi from being isolated from lesions for up to 15 days after treatment....
Oreff GL, Tatz AJ, Dahan R, Segev G, Haberman S, Britzi M, Kelmer G.To determine the metacarpophalangeal joint fluid concentrations of ceftazidime administered via regional limb perfusion (RLP). Methods: Eight healthy horses. Methods: RLP was performed by injecting 2 g of ceftazidime and 60 mL of perfusate volume in the cephalic vein of standing, sedated horses. Serum and synovial fluid from the metacarpophalangeal joint were collected before perfusion and at 0.5, 2, 6, 12, 24 hours postperfusion. Ceftazidime concentrations were measured via liquid chromatography. Maximal concentration (C ), area under the curve (AUC), half-life of the drug (T ½), and the tim...
Sanz MG, Villarino N, Ferreira-Oliveira A, Horohov DW.Rhodococcus equi is a common cause of pneumonia in young foals worldwide and has considerable economic effects on the global equine industry. Despite ongoing efforts, no vaccine is currently available to prevent rhodococaal pneumonia. This is due, in part, to an incomplete understanding of the protective immune response to this bacterium. While antibodies to VapA, a lipoprotein produced by virulent R. equi, are useful in differentiating antibody production in response to pathogenic versus non-pathogenic strains, the significance of the humoral response of foals to this lipoprotein remains poor...
Dillmann JB, Cossetin LF, de Giacometi M, Oliveira D, de Matos AFIM, Avrella PD, Garlet QI, Heinzmann BM, Monteiro SG.The stable fly, Stomoxys calcitrans (Linnaeus 1758), is a hematophagous fly responsible for causing loss of performance in horses, causing losses in cattle productivity, and impacting the animals' health through the spread of pathogenic microorganisms. The objective of this work was to investigate the insecticidal activity of essential oil obtained from Melaleuca alternifolia (Cheel), presenting high 1,8-cineole content, against S. calcitrans adults. Insecticidal activity was determined using surface application methods and exposure to oil impregnated paper. It was observed that treatments at ...
Hlokwe TM, Sutton D, Page P, Michel AL.Tuberculosis caused by Mycobacterium bovis (M. bovis) is very uncommon in horses worldwide. Methods: In the current study, an eight-year-old male Thoroughbred in good body condition was admitted to the Equine Clinic at the Onderstepoort Veterinary Academic Hospital in 2005 due to bilateral epistaxis accompanied by coughing. Routine examinations were conducted to determine the cause of the condition. Endoscopic examination revealed the major source of the epistaxis as the trachea, whereas thoracic radiography indicated the presence of a primary pulmonary mass. M. bovis was isolated from a bronc...
Walker RL, de Peralta TL, Villanueva MR, Snipes KP, Madigan JE, Hird DW, Kasten RW.Isolates of Salmonella choleraesuis serotype ohio (S. ohio) recovered during an outbreak of equine neonatal salmonellosis on a Thoroughbred farm were compared with isolates of the same serotype from various animal, feed and environmental sources. Biochemical profiles, antimicrobial susceptibility patterns, phage susceptibility, plasmid profiles, restriction endonuclease analysis and ribotyping were used to compare relatedness of the strains. A total of 46 outbreak and non-outbreak associated isolates of S. ohio were studied. Differences in antimicrobial susceptibility patterns, phage susceptib...
Wong JW, Selvam A, Zhao Z, Yu SM, Law AC, Chung PC.Composting sewage sludge alone would reduce the decomposition efficiency due to free limited porosity in sludge. To alleviate this, the use of horse stable straw bedding waste (HSB) was evaluated as a co-composting material with sewage sludge in a 10 tonnes day(-1) in-vessel composter for a period of 7 days before curing in a static aeration pile. Sludge was mixed with HSB at 1 : 1.5 (HSL) and 1 : 2.9 (LSL) on a fresh weight basis. After a composting period of 56 days, both mixing ratios demonstrated to be feasible with LSL having a better organic decomposition and a shorter time to reach matu...
Kawakami V, Rietberg K, Lipton B, Eckmann K, Watkins M, Oltean H, Kay M, Rothschild C, Kobayashi M, Van Beneden C, Duchin J.On March 17, 2016, Public Health-Seattle & King County in Washington was notified of two persons who received a diagnosis of Streptococcus equi subspecies zooepidemicus (S. zooepidemicus) infections. S. zooepidemicus is a zoonotic pathogen that rarely causes human illness and is usually associated with consuming unpasteurized dairy products or with direct horse contact (1). In horses, S. zooepidemicus is a commensal bacterium that can cause respiratory, wound, and uterine infections (2). The health department investigated to determine the magnitude of the outbreak, identify risk factors, and o...
Schumacher J, Mullen J, Shelby R, Lenz S, Ruffin DC, Kemppainen BW.Duodenitis/proximal jejunitis syndrome (DPJ) is a small intestinal disease of horses that is associated with depression and copious gastric reflux. Since an infectious cause for DPJ remains unsubstantiated, these studies were designed to investigate the possible role of Fusarium moniliforme toxins in this disease. Fusarium moniliforme was isolated by culturing 2 samples of feed that had been fed to horses with clinical signs of DPJ. These isolates (AU 2/3) were subsequently grown concurrently on autoclaved corn and their toxicity evaluated in a feeding trial utilizing horses. Isolates of F mon...
Zhou R, Yang J, Zhang K, Qi Y, Ma W, Wang Z, Ente M, Li K.The absolute dominant species that infests wild population of Przewalski's horse (Equus przewalskii) is Gasterophilus pecorum, and feces of released Przewalski's horse, a habitat odor, plays an important role in mating and ovipositing locations of G. pecorum. To screen out unique volatiles for attracting G. pecorum, volatiles from fresh feces of released horses at stages of pre-oviposition (PREO), oviposition (OVIP), and post-oviposition (POSO) of G. pecorum, and feces with three different freshness states (i.e., Fresh, Semi-fresh, and Dry) at OVIP were collected by dynamic headspace adsorptio...
Tzipori S, Withers M, Hayes J, Robins-Browne R, Ward KL.Equine small intestinal brush-border membranes, from 40 adult horses were tested in vitro for the presence of receptors for the Escherichia coli adhesive antigens K88ab, K88ac and K99. Only K88-positive strains of E. coli adhered strongly to horse brush-border membranes. In contrast, a K88-negative mutant strain J2, 2 K99-positive strains and 3 E. coli strains isolated from foals failed to adhere to horse brush-border membranes. Purified K88ac pili when reacted with equine brush-border membranes inhibited to a great extent the adhesion of K88-positive E. coli. Similarly, K88-positive E. coli p...
Aufox EE, Frank LA, May ER, Kania SA.Dermatophilus congolensis is a facultative anaerobic actinomycete that causes papular to exudative dermatitis with crusting in horses. This organism is frequently implicated as a cause of pastern dermatitis, but few data are available validating the organism's association with this disease. Objective: The aim of this study was to evaluate if D. congolensis is associated with pastern dermatitis in horses utilizing RT-qPCR. Methods: Fifteen client-owned horses diagnosed with pastern dermatitis and eight client-owned unaffected control horses were utilized for this study. Methods: A cross-sectio...
Elsheikha HM, Mansfield LS.Sarcocystis neurona has become recognized as the major causative agent of equine protozoal myeloencephalitis (EPM) in the Americas. At least 3 pathogenic species of Sarcocystis, including S. neurona, can be isolated from opossums. Methods are needed to ascertain whether these isolates are viable and capable of causing infections. In this study, the nuclear stain propidium iodide (PI) was used to differentiate between live (viable) and heat-killed (nonviable) S. neurona sporocysts. PI was excluded by live sporocysts but penetrated compromised sporocyst membrane and stained sporozoite nuclei of ...
Cohen ND, Cywes-Bentley C, Kahn SM, Bordin AI, Bray JM, Wehmeyer SG, Pier GB.Strangles is a common disease of horses with worldwide distribution caused by the bacterium Streptococcus equi subspecies equi (SEE). Although vaccines against strangles are available commercially, these products have limitations in safety and efficacy. The microbial surface antigen β 1→6 poly-N-acetylglucosamine (PNAG) is expressed by SEE. Here we show that intramuscular (IM) injection alone or a combination of IM plus intranasal (IN) immunization generated antibodies to PNAG that functioned to deposit complement and mediate opsonophagocytic killing of SEE ex vivo. However, immunization st...
