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.
Cullor JS, Mannis MJ, Murphy CJ, Smith WL, Selsted ME, Reid TW.New approaches to antimicrobial therapy for ocular pathogens must overcome organisms that are resistant to current therapeutic modalities. This investigation examined the antimicrobial activity of novel antimicrobial neutrophil peptides (defensins NP-1 and NP-5) against isolates from clinical ocular microbial infections in humans and horses. The test panel of human clinical isolates included Candida albicans, an alpha-hemolytic Streptococcus, Streptococcus pneumoniae, Pseudomonas aeruginosa, and Morganella morganii. The test panel of equine pathogens included three clinical isolates of P aerug...
Brumbaugh GW, Davis LE, Thurmon JC, Savage DC.Opsonized Rhodococcus equi activated the respiratory burst of resident alveolar macrophages (AM) from adult horses in a logarithmic-linear, mass-related manner. The effect of R equi was not significantly different from that of equal masses of opsonized zymosan A. Therefore, R equi does not appear to attenuate the respiratory burst of equine AM. The stimulatory effect of R equi was not reflected by increased production of superoxide anion (O2-), but increased activity of the hexose monophosphate shunt was observed. These results suggest a similarity between the respiratory burst of AM from hors...
Berg M, Desselberger U, Abusugra IA, Klingeborn B, Linné T.Comparative analysis by RNA oligonucleotide fingerprints of total genomic RNA as well as the individual RNA segments of equine 2 influenza A virus strains from 1963, 1968, 1979, 1984, 1987 and 1988 revealed genetic diversity. Strains from the epizootic outbreak during 1978-1979 showed minor differences among their genomes. The Swedish isolates from 1979 up to 1988 showed increasing genomic heterogeneity indicating genetic drift.
De Waal DT.Babesia caballi, isolated from a horse that originated from South West Africa/Namibia, was transmitted transovarially by adult Hyalomma truncatum. B. caballi proved to be highly infective for adult H. truncatum. Forty-five per cent of ticks feeding on a reacting animal with an extremely low parasitaemia became infected. In spite of a low parasitaemia, the ticks were severely affected by the parasite. Seventy per cent of the infected ticks either died during oviposition or after laying only a few eggs. The features of the infection in horses were: a prepatent period of 10 days, very low parasit...
Kanoe M, Inoue S, Abe T, Anzai T, Kamada M, Imagawa H, Kanemaru T.Clostridium perfingens was isolated from four of 29 healthy foals and from all twelve foals with gastrointestinal diseases. The range of viable counts of C. perfringens in the faeces was 10(1)-10(5)/g and in the intestinal specimens 10(1)-10(7)/g. Of 41 isolates of C. perfringens, 37 were considered to be type A. Enterotoxin of the organism was demonstrated in the intestinal contents of five of eight foals with enteric diseases. These findings suggested that C. perfringens is a likely pathogen of foal intestinal diseases.
Erzinclioglu YZ.The unusual structure of the mouth hooks of the third instar larvae of the species of Gasterophilus and Gyrostigma, parasites of the alimentary canal of Equideae and Rhinocerotidae respectively, is described.
Wilson WD, Madigan JE.Diagnosis of bacterial septicemia was confirmed by results of bacteriologic culture of antemortem blood samples and/or necropsy specimens obtained from 47 foals up to 8 days old. Gram-negative bacteria were isolated from all 47 foals, and mixed infections with more than one organism were involved in 26 (55%). Escherichia coli, Actinobacillus spp, and Klebsiella pneumoniae were the most frequent isolates, infecting 55, 34, and 23% of foals, respectively. Gram-positive bacteria and anaerobic bacteria were isolated only from foals with mixed infections with gram-negative organisms. Clostridium pe...
Crane SA, Ziemer EL, Sweeney CR.Thirty-eight tracheobronchial aspirates (TBA) were collected from twenty 1 to 6-month-old foals, which were free of clinical signs of respiratory tract or other infectious disease. We collected TBA from 9 of the foals 3 times when they were approximately 8, 16, and 24 weeks old. Aspirates were examined cytologically after staining with modified Wright-Giemsa, Gram, toluidine blue, and prussian blue stains. Aerobic bacterial culturing was performed on all aspirates. Of the 20 initial TBA, 4 (20%) were normal cytologically on the basis of previously defined criteria for TBA from clinically norma...
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 ...
Taylor MA, Hunt KR.The term 'anthelmintic drug resistance' describes the heritable ability of some nematode parasites to survive treatment with anthelmintic drugs at the recommended therapeutic dose levels. Genes for resistance appear to be present in many of the important pathogenic nematodes of ruminants and horses. Under intensive management systems, where heavy reliance is placed on anthelmintic drugs for worm control, the selection of resistant genotypes may result in increased reports of the drugs failing to control the nematode populations against which they are aimed. Anthelmintic resistance has been rep...
Klebanoff SJ, Agosti JM, Jörg A, Waltersdorph AM.Stimulated eosinophils release cytotoxic granule constituents, including eosinophil peroxidase (EPO) and a group of granule basic proteins (GBP). EPO reacts with H2O2 formed by the respiratory burst and a halide to form cytotoxic oxidants. The relative potency of the EPO-H2O2-halide system and the GBP is considered here. Horse eosinophils were induced to degranulate, the degranulation products were separated by chromatography on Sephadex G-50 and comparable volumes of the column fractions were tested for toxicity to Escherichia coli and the schistosomula of Schistosoma mansoni in the presence ...
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.
Sweeney CR, Benson CE, Whitlock RH, Meirs DA, Barningham SO, Whitehead SC, Cohen D.The age-specific attack rates of Streptococcus equi infections of the upper respiratory tract and lymph nodes (strangles) in horses for the different age groups were 17.6% for broodmares, 47.5% for 1-year-old horses, and 37.5% for foals. Streptococcus equi was isolated from nasal, pharyngeal, or lymph node specimens in 31 (60.8%) of 51 sick horses. A male 1-year-old horse, shipped from Kentucky to farm A, was considered to be the index case. Six (19.4%) of 31 horses with strangles remained as shedders of S equi after clinical signs of the disease had ended. Shedders of S equi were not identifi...
Vesonder R, Haliburton J, Golinski P.Feed samples of corn, pelleted feed, and oats associated with equine leucoencephalomalacia (ELEM) were obtained from North Carolina, Illinois, Indiana, and Oklahoma. These samples contained a high colony density of Fusarium moniliforme Sheldon which ranged from 64 to 87% of the total fungi. Fifty-nine F. moniliforme strains were isolated. Isolates of F. moniliforme in feed samples from Illinois, Indiana, and Oklahoma were cultured on corn. The fermented corn, mixed with regular feed and fed to one-day-old ducklings, effected a high mortality coefficient (average 55%). Methanol extracts of corn...
Shadomy HJ, Dixon DM.An unusual fungus, probably traumatically introduced into the eye of a horse while grazing, was studied on various mycological media. Upon examination of colonies the organism produced bulbils and clearly exhibited the characteristics of a new species of Papulaspora, P. equi Shadomy & Dixon.
Allen D, Swayne D, Belknap JK.The clinical signs, medical and surgical management, and pathological findings are described for a ganglioneuroma, an atypical intestinal tumor, that caused colic because of small intestinal obturation.
Posnett ES, Ambrosio RE.This report describes DNA probes for the identification of Babesia equi. A genomic library of B. equi was constructed in pUC13. Several clones were identified that hybridized strongly to B. equi DNA. Clone pBE33 hybridized specifically to B. equi DNA and did not hybridize to horse DNA nor to DNA from Babesia caballi, Babesia bovis or Babesia bigemina. Two subclones of pBE33 (pSB20 and pEH21) containing B. equi repetitive sequences, could detect 0.49 ng and 0.97 ng B. equi DNA, respectively.
Mendoza L, Marin G.Antigens and rabbit-antisera from holotypes of Pythium insidiosum and P. destruens were prepared to elucidate their antigenic relationship. The antigens and rabbit-antisera of P. insidiosum as well as P. destruens used as a reference system showed that both shared three precipitin bands in common. The antigen and rabbit-antisera of P. destruens and P. insidiosum used as a reference system against other strains isolated from humans and animals with pythiosis, also showed three precipitin bands in common. When we used sera taken from horses with proven pythiosis against antigens of P. insidiosum...
Inzana TJ, Iritani B.A group C latex agglutination reagent, included as the negative control in the PathoDx Strep A latex agglutination test (Diagnostic Products Corp., Los Angeles, Calif), was compared with culture for rapid detection of group C streptococci (Streptococcus equi, S. equisimilis, S. zooepidemicus, and S. dysgalactiae) from swabs of veterinary specimens. The overall sensitivity of the latex test was 78%, and specificity was 97.6%. Only 25% of S. dysgalactiae isolates were detected, thereby accounting for the relatively low sensitivity. Ninety-three percent of the group C streptococci other than S. d...
Schlater LR.Thirteen strains of a gram-negative, fermentative bacterium that produced gas from glucose were isolated from horses with a variety of clinical conditions. The morphological and biochemical characteristics of this bacterium are similar to those described for the family Pasteurellaceae. These strains appear to constitute a new taxon within the genus Pasteurella; however, the final taxonomic position of this group depends upon more detailed genetic studies. Case histories indicate that this bacterium may be a primary respiratory pathogen and may play a secondary role in various other disease con...
Al-Izzi SA, Al-Bassam LS.Pseudomonas mallei was isolated from pus samples obtained from 34 mallein-positive horses. The isolates were subjected to in vitro sensitivity test using 16 different antimicrobial discs. All isolates (34) were sensitive to sulfamethizole, gentamycin, tetracycline, sulfathiazole, kanamycin, tobramycin, streptomycin and a combination of trimethoprim and sulfamethoxazole while none of them were sensitive to cephalothin, colistin, ampicillin, penicillin and nitrofurantoin. Rifapicin, chloramphenicol and carbenicillin were effective against 32, 26 and 18 isolates respectively. The minimum inhibito...
Karabatsos N, Lewis AL, Calisher CH, Hunt AR, Roehrig JT.A virus, strain 64A-1519, isolated from the brain of a horse dying of encephalitis in Florida in 1964, was identified as western equine encephalomyelitis (WEE) virus. Recently, we used polyclonal and monoclonal immune reagents to identify this isolate by comparing it to 2 strains of WEE virus and to Highlands J (HJ) virus in hemagglutination-inhibition, immunofluorescent antibody, and plaque-reduction neutralization tests. These tests demonstrate that strain 64A-1519 is a strain of HJ virus distinct from WEE virus.
Prescott JF, Staempfli HR, Barker IK, Bettoni R, Delaney K.Severe colitis was induced in two ponies after oral pretreatment with clindamycin and lincomycin, followed by intestinal content from two horses which had died from naturally-occurring idiopathic colitis. Two ponies treated with antibiotic alone, and two ponies treated with intestinal content alone, were unaffected. In a further study, three ponies treated on separate occasions with lincomycin, administered orally, died or were destroyed 67 to 72 h after initial treatment. No established salmonella, yersinia or campylobacter pathogens were isolated from these ponies, but a clostridium closely ...
Buergelt CD, Green SL, Mayhew IG, Wilson JH, Merritt AM.The clinical, bacteriologic and pathologic findings of three adult horses suffering from avian tuberculosis are presented. Chronic weight loss and hypoproteinemia were pertinent clinical abnormalities in all three horses. Gross pathologic lesions were characterized by chronic enterocolitis with mesenteric lymphadenopathy in two horses and hepatic granulomas in the third horse. The microscopic diagnoses were chronic, non-caseating granulomatous enterocolitis, and necrotizing, non-mineralizing granulomatous hepatitis, respectively. All three horses had granulomatous lymphadenitis of mesenteric l...
Stefańska I, Witkowski L, Rzewuska M, Dzieciątkowski T.Rhodococcus equi is the causative agent of rhodococcosis in horses, resulting in significant morbidity and mortality in foals. This bacterium has also been isolated from a variety of animals and is being increasingly reported as a cause of infection in humans, mainly in immunosuppressed individuals. Laboratory diagnostics of R. equi infections based only on conventional microbiological methods shows low accuracy and can lead to misidentification. The objective of the study was to develop and evaluate a real-time PCR assay for direct detection of R. equi in various clinical specimens, including...
Larrasa J, Garcia A, Ambrose NC, Alonso JM, Parra A, de Mendoza MH, Salazar J, Rey J, de Mendoza JH.Dermatophilus congolensis is the pathogenic actinomycete that causes dermatophilosis in cattle, lumpy wool in sheep and rain scald in horses. Phenotypic variation between isolates has previously been described, but its genetic basis, extent and importance have not been investigated. Standard DNA extraction methods are not always successful for D. congolensis due to its complex life cycle, one stage of which is encapsulated. Here we describe the development of rapid and reliable DNA extraction and random amplified polymorphic DNA (RAPD) methods that can be used for genotyping D. congolensis fie...
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...
Hirsh DC, Kirkham C, Wilson WD.Fifteen isolates of Escherichia coli obtained from the blood and tissues of septic foals had plasmid DNA of size ranging from 2.5 to 93 megadaltons. These isolates grew in normal equine serum (serum resistant), a trait previously documented to be expressed by isolates obtained from blood and tissues of septic foals, but not by isolates obtained from the feces of clinically normal horses. Of these isolates, 3 contained conjugal plasmids that encoded resistance to multiple antimicrobial agents linked to serum resistance and, in 1 isolate, to production of aerobactin as well. Serum resistance and...
Makinde AA.The reverse single radial immunodiffusion technique was used to detect Dermatophilus congolensis antibody in sera collected from animals previously infected to varying levels with D congolensis. Ammonium sulphate and trichloroacetic acid extracts of five different strains of D congolensis obtained from different geographical locations were used as antigens. All the extracts showed variations in their sensitivities in detecting D congolensis antibody in the various serum samples. Multiple antibodies were detected by some extracts while some showed negative antibody reaction to all extracts. Two...
Riley CB, Aldrich ED, Pemberton SL, Mirza AA. A 9-year-old warmblood gelding with a history of chronic intermittent tachypnoea and dyspnoea was presented for evaluation and removal of a mass on the left side of the neck. A fibrous mass adherent to the left jugular vein developed and was removed surgically 6 weeks later, at which time the owner requested an evaluation of the cause of the persistent respiratory signs first noted on primary admission. Clinical findings included coarse lung sounds on thoracic auscultation, tracheal wheeze, and an abnormal trans-tracheal aspirate. These findings, in addition to the results of ultrasonographi...
Anzai T, Timoney JE, Kuwamoto Y, Wada R, Oikawa M, Higuchi T.To develop polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis for molecular typing of strains of Streptococcus zooepidemicus and to use the new typing method to analyze a collection of isolates from the respiratory tract of Thoroughbreds. Methods: 10 strains of S zooepidemicus, 65 isolates from the respiratory tract of 9 yearlings following long distance transportation, and 89 isolates from tracheal aspirates of 20 foals with pneumonia. Methods: Phenotypic variations in the SzP protein were detected by western immunoblot analysis. Using PCR-RFLP analysis, ge...
Luque I, Fernández-Garayzábal JF, Blume V, Maldonado A, Astorga R, Tarradas C.The anti-microbial susceptibility and genetic diversity of 65 strains of Streptococcus equi ssp. zooepidemicus (Sez) isolated from mares presenting clinical signs of endometritis was determined by disk agar diffusion and pulsed field gel electrophoresis (PFGE) methods, respectively. Overall, Sez isolates were susceptible to beta-lactams, enrofloxacin, trimethoprim-sulfamethoxazole and gentamicin. These anti-microbials could be recommended as empiric anti-microbial therapy in cases of endometritis caused by Sez. Pulsed field gel electrophoresis typing revealed a great genetic diversity (56 diff...
Ferreira PFA, Xavier JF, Nunes JF, Fonseca IP, de Mattos de Oliveira Coelho S, Soares de Souza MM, da Silva Coelho I.Livestock waste is widely used in agriculture. Although they provide benefits to the soil, and consequently to plants, they have the potential to contaminate the environment, as they contain pathogenic microorganisms and determinants of antimicrobial resistance, if not properly managed. Therefore, this study aims to evaluate the effect of composting horse bedding and poultry litter in organic and conventional production systems on the occurrence of bacteria in the Enterobacteriales order and to identify their antimicrobial resistance profiles. Bacterial strains were isolated from Salmonella-Sh...
Hassan Kadi R, Baghdadi AM.Lactic acid bacteria are microorganisms that can be present in meat, milk and fermented products, as well as fermented drinks and vegetables, and they inhibit the growth of pathogenic and decaying microorganisms. Our aim was isolating, screening, characterization and estimation of bacteriocin/s of Lactic acid bacteria isolated from Horses milk in Jeddah city, Saudi Arabia. That have antagonistic activity against a wide range of pathogenic bacteria. On MRS agar medium 16 LAB isolates were examined using the agar well diffusion method against the pathogenic bacteria (Gram-positive bacteria: S. a...
Crane SA, Ziemer EL, Sweeney CR.Thirty-eight tracheobronchial aspirates (TBA) were collected from twenty 1 to 6-month-old foals, which were free of clinical signs of respiratory tract or other infectious disease. We collected TBA from 9 of the foals 3 times when they were approximately 8, 16, and 24 weeks old. Aspirates were examined cytologically after staining with modified Wright-Giemsa, Gram, toluidine blue, and prussian blue stains. Aerobic bacterial culturing was performed on all aspirates. Of the 20 initial TBA, 4 (20%) were normal cytologically on the basis of previously defined criteria for TBA from clinically norma...
Bauer SM, Santschi EM, Fialkowski J, Clayton MK, Proctor RA.To quantify the adhesion of Staphylococcus aureus to 4 equine bone surfaces passivated in a balanced polyionic solution (Plasmalyte) or hyperimmune equine plasma (Polymune plasma). Methods: In vitro comparative study. Methods: Third metacarpal bone (MC3) surface explants from 9 equine cadavers. Methods: Approximately 1 cm(2) sections of periosteum were removed from MC3 and stapled to sterile stainless steel screens. Three bone surface explants were cut using a surgical saw to present 1 cm(2) surfaces of subperiosteal bone, cut cortical bone, or endosteum. Duplicate explants of each surface wer...
Paulino PG, Peckle M, Mendonça LP, Massard CL, Antunes S, Couto J, Domingos A, Guedes Junior DDS, Cabezas-Cruz A, Santos HA. is the only tick species known to serve as a biological vector of for horses and other equids in Brazil. The protozoan is one of the causal agents of equine piroplasmosis, a major threat in horse breeding systems. Vector competence is closely linked to the pathogens' ability to evade tick defense mechanisms. However, knowledge of tick immune response against infections by hemoparasites of the genus is scarce. In the present study, the expression of genes involved in immune signaling pathways of adults' guts when challenged with a high or low parasitic load of was evaluated. This research...
Torres LEC, Florez CO, Oliveira JG, Vieira GD, Ribeiro IS, Keller KM, Leme FOP, Fantini P, Maranhão RPA.In equine ophthalmology, ulcerative keratitis is among the most common conditions and, in general, arises as a consequence of some trauma suffered. Secondarily, subsequent contamination by pathogenic or resident bacteria of the horse's ocular microbiota may have undesirable consequences. Under physiological conditions, the normal microbiota coexists with the immune status of the host, serving as a barrier, ensuring the health of the ocular surface, and inhibiting the proliferation of pathogens. However, in the imbalance of immune barriers, the normal microbiota can become pathogenic and lead t...
Takai S, Ogawa K, Fukunaga N, Sasaki Y, Kakuda T, Tsubaki S, Anzai T.R. equi was isolated from soil samples obtained from the environment of seven native Japanese horse breeds (Hokkaido, Kiso, Noma, Misaki, Tokara, Miyako and Yonaguni) and from fecal samples collected from three native horse breeds (Hokkaido, Kiso and Misaki). Virulent R. equi at various levels (ranging from 0.5 to 12.9%) was isolated from the feces or soil environment of Hokkaido, Kiso and Misaki horses. Isolates were investigated both for the presence of 15- to 17-kDa antigens (virulence-associated protein antigens; VapA) by colony blotting, using the monoclonal antibody 10G5, and the gene of...
Lindmark DG, Jarroll EL, Timoney PJ, Shin SJ.The energy metabolism of the English E-CMO strain of contagious equine metritis bacterium was studied in whole cells and cell extracts. This bacterium appears to have an active Krebs cycle and probably obtains energy by oxidative phosphorylation since glycolysis and the hexose monophosphate pathways appear to be absent. These conclusions are based on the findings that [U-14C]glucose incorporation by this bacterium is below the level of detection, and that respiration is stimulated by Krebs cycle intermediates (i.e., malate, citrate, and succinate), but not by glucose, fructose, maltose, or suc...
Milillo P, Traversa D, Elia G, Otranto D.Larvae of Rhinoestrus spp. (Diptera, Oestridae) infect nasal and sinus cavities of horses, causing a nasal myiasis characterized by severe respiratory distress. Presently, the diagnosis of horse nasal botfly relies on the observation of clinical signs, on the post mortem retrieval of larvae or on molecular assays performed using pharyngeal swabs. The present study was carried out to characterize larval somatic proteins and salivary glands of Rhinoestrus spp. in a preliminary assessment towards the immunodiagnosis of equine rhinoestrosis. Out of the 212 necropsied horses 13 were positive for th...
John HA, Laffling AJ, Marrs J, Baird A, Jat PS, Holdstock NB, Rossdale PD.To enable direct testing of a range of potential toxins or pathogens that might be involved in grass sickness, equine thoracic sympathetic chain ganglion cell lines were established from primary cell cultures by retroviral-mediated transduction of the temperature-sensitive mutant of the establishment oncogene encoding SV40 large T antigen. Morphological and behavioral features, temperature dependence, and immunocytochemical characteristics of the cell lines were investigated. The majority of cells were noradrenergic neurons in which dopamine-beta-hydroxylase, the enzyme that catalyzes norepine...
Epstein K, Cohen N, Boothe D, Nieuwoudt C, Chandler J.In many cases of equine infectious disease, long-term administration of antimicrobial drugs is required. Oral agents are preferred because of the relative ease of administration compared with other routes. Enrofloxacin has been shown to be effective against a variety of equine pathogens, but oral administration of this drug has proved difficult in horses. An oral gel formulation made from the injectable cattle product produces blood levels sufficient to resolve infections caused by a variety of common equine pathogens.
Kawamura Y, Fujimoto Y, Kutsuna R, Tomida J, Yamamoto KI, Miyoshi-Akiyama T, Okuno M, Ogura Y, Matsuoka M, Kawaguchi T, Tsutsuki H, Sawa T.A Gram-stain-negative, spiral bacterium (PAGU 1991T) was isolated from the blood of a patient with diffuse large B-cell lymphoma. Phylogenetic analysis based on 16S rRNA gene sequences showed that the isolate was very closely related to Helicobacter equorum LMG 23362T (99.1 % similarity), originally isolated from a faecal sample from a healthy horse. PAGU 1991T was also very closely related to PAGU 1750 in our strain library (=CCUG 41437) with 99.7 % similarity. Additional phylogenetic analyses based on the 23S rRNA gene sequence and GyrA amino acid sequence further supported the close rel...
Crandell RA, Drysdale S, Stein TL.The clinical and immunological response of ponies exposed to a bovine herpesvirus isolate and equine herpesvirus 1 were compared. Each virus was inoculated into two ponies by the intranasal route. One uninoculated pony was used with each group as a contact control. The four inoculated ponies developed a mild rhinitis with an increase in rectal temperature. Virus was recovered from nasal secretions collected from the four inoculated and one contact pony. All ponies developed a serum neutralizing antibody to each virus. The data show that the two viruses are similar.
Wang J, Wen S, Zhao R, Qi J, Liu Z, Li W, An J, Wood C, Wang Y.The conjugation of small ubiquitin-like modifier (SUMO) to the target protein, namely, SUMOylation, is involved in the regulation of many important biological events including host-pathogen interaction. Some viruses have evolved to exploit the host SUMOylation machinery to modify their own protein. Retroviral Gag protein plays critical roles in the viral life cycle. The HIV-1 p6 and the Moloney murine leukemia virus CA have been reported to be conjugated with SUMO. In this study, we report for the first time, to our knowledge, the covalent conjugation of equine infectious anemia virus (EIAV) G...
Jurek KA, Schoonover MJ, Williams MR, Rudra P.To determine the influence of perfusate volume on synovial fluid amikacin concentrations in the joints of the hind limb after standing saphenous intravenous regional limb perfusion (IVRLP). Methods: Randomized crossover design. Methods: Six adult horses. Methods: Saphenous IVRLP was performed in 6 standing horses with 1 g of amikacin diluted with 0.9% NaCl to volumes of 10 ml, 60 ml, and 120 ml. Samples of synovial fluid from the tarsocrural, metatarsophalangeal, and hind limb distal interphalangeal joints were collected at 15 and 30 min after perfusate administration. Concentrations ...
Dwyer RM.Disinfection of equine premises provides a challenge to farm managers, in view of the variety of surfaces which may be contaminated and the wide variety of horse pathogens. Of the commonly occurring infectious diseases for which disinfection and disease control are especially important, rotavirus diarrhoea, salmonellosis and strangles are the most difficult to control. Phenolic disinfectants have been scientifically demonstrated to be effective in the presence of organic matter and are also virucidal. When used after thorough cleaning and rinsing of stall surfaces, phenolics have proved effect...
Rossano MG, Schott HC, Kaneene JB, Murphy AJ, Kruttlin EA, Hines MT, Sellon DC, Patterson JS, Elsheikha HM, Dubey JP, Mansfield LS.To determine whether daily administration of pyrantel tartrate can prevent infection in horses experimentally challenged with Sarcocystis neurona. Methods: 24 mixed-breed specific-pathogen-free weanling horses, 10 adult horses, 1 opossum, and 6 mice. Methods: Sarcocystis neurona-naïve weanling horses were randomly allocated to 2 groups. Group A received pyrantel tartrate at the labeled dose, and group B received a nonmedicated pellet. Both groups were orally inoculated with 100 sporocysts/d for 28 days, 500 sporocysts/d for 28 days, and 1000 sporocysts/d for 56 days. Blood samples were collec...
Chaney SB, Marsh AE, Lewis S, Carman M, Howe DK, Saville WJ, Reed SM.Equine protozoal myeloencephalitis (EPM) remains a significant central nervous system disease of horses in the American continents. Sarcocystis neurona is considered the primary causative agent and its intermediate life stages are carried by a wide host-range including raccoons (Procyon lotor) in North America. S. neurona sarcocysts mature in raccoon skeletal muscle and can produce central nervous system disease in raccoons, mirroring the clinical presentation in horses. The study aimed to develop laboratory tools whereby the life cycle and various life stages of S. neurona could be better stu...
MacNeill AL, Alleman AR, Franklin RP, Long M, Giguère S, Uhl E, López-Martinez A, Wilkerson M.A 5-year-old Paso-Fino mare was presented for severe respiratory distress. The mare had foaled 2 months prior to presentation. The horse was in poor body condition with a dull hair coat. A mild fever was noted during physical examination and increased bronchovesicular sounds were auscultated. Thoracic radiographs showed an interstitial pattern and an alveolar infiltrate with distinct air bronchograms. Moderate purulent inflammation with increased mucus was observed in tracheal wash fluid, but no infectious agents were identified. A bronchoalveolar lavage (BAL) contained a large amount of mucus...
Rossano MG, Schott HC, Murphy AJ, Kaneene JB, Sellon DC, Hines MT, Hochstatter T, Bell JA, Mansfield LS.Equine protozoal myeloencephalitis (EPM) is a serious neurological disease of horses in Americans. Most cases are attributed to infection of the central nervous system with Sarcocystis neurona. Parasitemia has not been demonstrated in immunocompetent horses, but has been documented in one immunocompromised foal. The objective of this study was to isolate viable S. neurona from the blood of immunocompetent horses. Horses used in this study received orally administered S. neurona sporocysts (strain SN 37-R) daily for 112 days at the following doses: 100/day for 28 days, followed by 500/day for 2...
Edwards SH, Khalfan SA, Jacobson GA, Pirie AD, Raidal SL.OBJECTIVE To determine plasma drug concentrations after IV administration of a bolus followed by continuous rate infusion (CRI) of sodium benzylpenicillin and ceftiofur sodium to healthy adult horses. ANIMALS 6 Thoroughbred mares (3 to 9 years old; mean ± SD body weight, 544 ± 55 kg) with no history of recent antimicrobial treatment. PROCEDURES Horses were used in 2 experiments conducted 14 days apart. For each experiment, horses were housed individually in stables, and catheters were placed bilaterally in both jugular veins for drug administration by CRI (left catheter) and for intermittent...
Harrington JR, Wilkerson CP, Brake CN, Cohen ND.The innate immune system plays a critical role in protecting neonates against infections early in life and Toll-like receptors (TLRs) are key components of innate immune recognition of pathogens. This study examined the effects of age and stimulation with a TLR 7/8 agonist (R848) on TLR8 mRNA expression by foal neutrophils during the first month of life. We also examined the effects of R848 stimulation on mRNA expression of interleukin (IL)-6 and IL-8 at 1 and 14 days of life. We observed that TLR8 mRNA was constitutively expressed (P<0.05) at all ages examined, and its expression did not c...
