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Topic:Pathogens
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.
A study of the environmental survival of Streptococcus equi subspecies equi. Streptococcus equi represents a common hazard to equids worldwide. Environmental contamination with bacteria shed from an infected horse may represent a significant source of contagion and further knowledge of ex vivo bacterial survival under different conditions is important for disinfection and isolation protocols. Objective: To determine the potential duration of survival and vigour of growth of S. equi inoculated onto surfaces relevant to equine veterinary practice and stabling in summer and winter. Methods: Repeat sampling of environmental inocula of S. equi. Methods: Cultures of S. equi ...
B-Cell Epitope Mapping Using a Library of Overlapping Synthetic Peptides in an Enzyme-Linked Immunosorbent Assay. This chapter describes a strategy for mapping linear B-cell epitopes of proteins using synthetic biotinylated peptides in an ELISA.A set of overlapping peptides were designed based upon a known amino acid sequence of the target protein, VapA (Virulence-associated Protein A) of the bacterium Rhodococcus equi, an important pulmonary pathogen in foals. The peptides synthesized as biotinylated peptides were coated directly onto micro titer plates which had been pre-coated with NeutrAvidinâ„¢ and used to screen sera from foals confirmed to have R. equi disease. A linear B-cell epitope was identifie...
Towards European harmonisation of contagious equine metritis diagnosis through interlaboratory trials. 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...
Association of neutrophil morphology with bacterial isolates in equine tracheal wash samples. Tracheal wash sample neutrophilia is common in lower airway inflammation of various causes; however, relevance of cytomorphological features to culture of bacterial pathogens has not been established. Objective: To investigate whether the presence of nondegenerate or degenerate neutrophils in tracheal washes is associated with culture of bacteria and, if so, whether this is influenced by age or temporal factors. Methods: Cross-sectional study. Methods: Tracheal wash samples submitted to Rossdales LLP from 1/1/2013 to 31/7/2015 were evaluated using set criteria. Neutrophilia and degenerate neut...
Genomic diversity of Taylorella equigenitalis introduced into the United States from 1978 to 2012. Contagious equine metritis is a disease of worldwide concern in equids. The United States is considered to be free of the disease although sporadic outbreaks have occurred over the last few decades that were thought to be associated with the importation of horses. The objective of this study was to create finished, reference quality genomes that characterize the diversity of Taylorella equigenitalis isolates introduced into the USA, and identify their differences. Five isolates of T. equigenitalis associated with introductions into the USA from unique sources were sequenced using both short an...
Characterization of isolates of Bordetella bronchiseptica from horses. is a well-known Gram-negative bacterial pathogen causing a plethora of diseases in different animals. Although its infection has been reported from pigs and dogs in India, no report of B. bronchiseptica from horses is described. We report for the first time, isolation, identification and characterization of strains of B. bronchiseptica from respiratory infection in horses from different states in India. The antimicrobial susceptibility testing showed resistance to penicillins, ceftazidime, and chloramphanicol. The virulence capability of the strains was confirmed by sequencing genes such as a...
Streptococcus equi: breaking its strangles-hold. , head of bacteriology at the AHT, describes the causative agent of strangles in horses, and discusses progress with the latest research aimed at improving vaccines against this global disease.
Detection of Rickettsia spp. in ticks (Acari: Ixodidae) of domestic animals in Colombia. Rickettsiosis are emerging or re-emerging diseases, with a worldwide distribution associated to transmission by arthropod vectors. Rickettsia species belong to the spotted fever group (SFG) and are transmitted by hard ticks (Acari: Ixodidae) that may act as vectors and reservoirs. This study carried out a molecular detection of Rickettsia from 7 species of the family Ixodidae collected from domestic hosts by PCR amplification of fragments of the citrate synthase "gltA" gene and outer membrane protein "ompA" gene. Of the 204 samples analyzed, 11.3% (23) were positive for rickettsial infection. ...
Lipidomic analysis of immune activation in equine leptospirosis and Leptospira-vaccinated horses. Currently available diagnostic assays for leptospirosis cannot differentiate vaccine from infection serum antibody. Several leptospiral proteins that are upregulated during infection have been described, but their utility as a diagnostic marker is still unclear. In this study, we undertook a lipidomics approach to determine if there are any differences in the serum lipid profiles of horses naturally infected with pathogenic Leptospira spp. and horses vaccinated against a commercially available bacterin. Utilizing a high-resolution mass spectrometry serum lipidomics analytical platform, we demo...
Molecular Genetic Manipulation of Sarcocystis neurona. Sarcocystis neurona is a member of the important phylum Apicomplexa and the primary cause of equine protozoal myeloencephalitis (EPM). Moreover, S. neurona is the best-studied species in the genus Sarcocystis, one of the most successful parasite taxa, as virtually all vertebrate animals may be infected by at least one species. Consequently, scientific investigation of S. neurona will aid in the control of EPM and neurologic disease in sea mammals, while also improving our understanding of a prominent branch on the apicomplexan phylogenetic tree. These protocols describe methods that expand the...
Use of quantitative real-time PCR to determine viability of Streptococcus equi subspecies equi in respiratory secretions from horses with strangles. In recent years, molecular approaches have been able to characterise the viability of equine upper respiratory tract pathogens using absolute molecular quantitation as well as detection of transcripts for virulence genes. Objective: The objective of this study was to investigate molecular surrogates for S. equi subspecies equi (S. equi) viability in biological samples from horses with strangles. Methods: Retrospective cross-sectional study. Methods: S. equi culture-positive and culture-negative upper airway secretions were assessed by qPCR at the genomic (gDNA) and complimentary DNA (cDNA) ...
Protein profile of Brazilian Pythium insidiosum isolates. Pythium insidiosum is an important aquatic Oomycota that causes pythiosis in mammals, especially horses, dogs, and humans; these inhabit marshy environments in tropical and subtropical areas. The aim of this study was to determine the protein profile, as well as identify likely immunodominant proteins, of Brazilian P. insidiosum isolates from southern Brazil, an important equine pythiosis endemic area. P. insidiosum isolates (horses, n = 20 and dogs, n = 02) were analyzed by SDS-PAGE and Western blot techniques. Horse, cattle, dog, and rabbit sera of both diseased and healthy animals were used...
Identification of a staphylococcal complement inhibitor with broad host specificity in equid Staphylococcus aureus strains. Staphylococcus aureus is a versatile pathogen capable of causing a broad range of diseases in many different hosts. S. aureus can adapt to its host through modification of its genome (e.g. by acquisition and exchange of mobile genetic elements that encode host-specific virulence factors). Recently, the prophage φSaeq1 was discovered in S. aureus strains from six different clonal lineages almost exclusively isolated from equids. Within this phage, we discovered a novel variant of staphylococcal complement inhibitor (SCIN), a secreted protein that interferes with activation of the human complem...
Simultaneous determination of ibuprofen and its metabolites in complex equine urine matrices by GC-EI-MS in excretion study in view of doping control. A novel assay for the simultaneous determination of ibuprofen (IBU) and its four probable metabolites, 1-hydroxyibuprofen (1-OH IBU), 2-hydroxyibuprofen (2-OH IBU), 3-hydroxyibuprofen (3-OH IBU) and carboxyibuprofen (CBX IBU) in equine urine samples with the application of Gas Chromatography-Electron Ionization-Mass Spectrometry (GC-EI-MS) has been developed and elaborated. The new approach for sample preparation including minimizing matrix effects by the application of weak cation exchange solid-phase extraction together with strong cation exchange solid-phase extraction has been applied. The...
Toxic Causes of Intestinal Disease in Horses. Because most poisonings occur by toxin ingestion, the gastrointestinal system is the first exposed and, in most cases, it is exposed to the highest toxin concentrations. Consequently, enterocyte damage is common. However, because many toxins produce organ-specific damage, and enterocyte necrosis is easily confused with autolysis, many gastrointestinal lesions are overlooked or overshadowed by other clinical and pathologic changes. The objective of this work is to review several common toxins and poisonous plants that produce primarily gastrointestinal disease.
Extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli and Acinetobacter baumannii among horses entering a veterinary teaching hospital: The contemporary “Trojan Horse”. Pathogens frequently associated with multi-drug resistant (MDR) phenotypes, including extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae (ESBL-E) and Acinetobacter baumannii isolated from horses admitted to horse clinics, pose a risk for animal patients and personnel in horse clinics. To estimate current rates of colonization, a total of 341 equine patients were screened for carriage of zoonotic indicator pathogens at hospital admission. Horses showing clinical signs associated with colic (n = 233) or open wounds (n = 108) were selected for microbiological examination of nost...
Molecular evidence to suggest pigeon-type Chlamydia psittaci in association with an equine foal loss. Chlamydia psittaci is an important avian pathogen with spillover from infected wild and domesticated birds also posing a risk to human health. We recently reported a case of C. psittaci equine placentitis associated with further spillover to humans. Molecular typing of this case revealed it belonged to the 6BC clade of C. psittaci, a globally distributed highly virulent set of strains, typically linked to infection spillover from parrots. Equine chlamydiosis associated with C. psittaci infection has previously been reported elsewhere in countries where parrots are not endemic, however, rais...
Dispersal capacity of Haematopota spp. and Stomoxys calcitrans using a mark-release-recapture approach in Belgium. The dispersion potential of mechanical vectors is an important factor in the dissemination of pathogens. A mark-release-recapture experiment was implemented using two groups (unfed and partially fed) of the Tabanidae (Diptera) (Haematopota spp.) and biting Muscidae (Diptera) (Stomoxys calcitrans) most frequently collected in Belgium in order to evaluate their dispersion potential. In total, 2104 specimens of Haematopota spp. were collected directly from horses and 5396 S. calcitrans were collected in a cattle farm using hand-nets. Some of these insects were partially fed in vitro and all were ...
Heat shock stress: Profile of differential expression in Corynebacterium pseudotuberculosis biovar Equi. Transcriptome studies on Corynebacterium pseudotuberculosis have recently contributed to the understanding about this microorganism's survival mechanisms in various hostile conditions. The gene expression profile of the C. pseudotuberculosis strain 1002 (Ovis biovar), has revealed genes that are possible candidates responsible for its maintenance in adverse environments, such as those found in the host. In another strain of this bacterium, 258 (Equi biovar), a high temperature condition was simulated, in order to verify which genes are responsible for promoting the persistence of the bacterium...
[Antimicrobial susceptibility in isolates of Streptococcus equi subsp. equi from Buenos Aires province, Argentina]. Streptococcus equi subsp. equi is the etiologic agent of strangles, an infectious disease affecting the upper respiratory tract and head and neck lymph nodes of equines. Routine antimicrobial therapy includes penicillin (PEN) as antibiotic of first choice. Streptococci are usually susceptible to PEN and only a few antimicrobial studies had been performed. The aim of this work was to study the antimicrobial susceptibility profile of S. equi from Buenos Aires, Argentina. Ninety-two isolates were studied by the single disk method to PEN, cefotaxime, erythromycin (ERY), tetracycline, enrofloxacin ...
The possible role of Stomoxys calcitrans in equine sarcoid transmission. The association between bovine papillomavirus (BPV) and equine sarcoids is well established, but it is unclear how the virus spreads. Although evidence in support of viral spread through direct animal contact exists, this does not explain sarcoid development in isolated equids. BPV DNA has been detected in flies, which could indicate that these insects serve as a vector. This study aimed to investigate whether BPV-negative stable flies (Stomoxys calcitrans) become positive for BPV DNA after exposure to equine sarcoid or bovine papilloma tissue under experimental conditions and, if so, for how ...
Antimicrobial Resistance-Transducing Bacteriophages Isolated from Surfaces of Equine Surgery Clinics – A Pilot Study. In the past, the horizontal transfer of antimicrobial resistance genes was mainly associated with conjugative plasmids or transposons, whereas transduction by bacteriophages was thought to be a rare event. In order to analyze the likelihood of transduction of antimicrobial resistance in the field of clinical veterinary medicine, we isolated phages from from a surgery suite of an equine clinic. In a pilot study, the surgery suite of a horse clinic was sampled directly after surgery and subsequently sampled after cleaning and disinfection following a sampling plan based on hygiene, surgery, and...
First molecular characterisation of a Brazilian Burkholderia mallei strain isolated from a mule in 2016. We present the first molecular characterisation based on MLVA and SNP analysis of a strain of Burkholderia mallei isolated from a mule found dead in Brazil in 2016.
Characterization of respiratory dendritic cells from equine lung tissues. 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...
Corneal Response to Injury and Infection in the Horse. This article describes the natural responses of the immune system and the cornea to injury and infection. The process of reepithelialization and reformation of stromal collagen is discussed, as are the clinical signs and manifestations of the effects of the healing response when it is routine and when it is pathologic. Excessive inflammatory or immune responses by host tissues can cause further damage that may be present from the antecedent injury or the effect of a pathogen. The clinical signs and manifestations of wound healing as well as potential therapeutic interventions are described.
In vitro susceptibility of Borrelia burgdorferi isolates to three antibiotics commonly used for treating equine Lyme disease. Lyme disease in humans is predominantly treated with tetracycline, macrolides or beta lactam antibiotics that have low minimum inhibitory concentrations (MIC) against Borrelia burgdorferi. Horses with Lyme disease may require long-term treatment making frequent intravenous or intramuscular treatment difficult and when administered orally those drugs may have either a high incidence of side effects or have poor bioavailability. The aim of the present study was to determine the in vitro susceptibility of three B. burgdorferi isolates to three antibiotics of different classes that are commonly us...
Pharmacokinetics of ceftazidime after regional limb perfusion in standing horses. 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...
Quadruplex PCR assay for identification of Corynebacterium pseudotuberculosis differentiating biovar Ovis and Equi. Corynebacterium pseudotuberculosis is classified into two biovars, nitrate-negative biovar Ovis which is the etiologic agent of caseous lymphadenitis in small ruminants and nitrate-positive biovar Equi, which causes abscesses and ulcerative lymphangitis in equines. The aim of this study was to develop a quadruplex PCR assay that would allow simultaneous detection and biovar-typing of C. pseudotuberculosis. Methods: In the present study, genomes of C. pseudotuberculosis strains were used to identify the genes involved in the nitrate reduction pathway to improve a species identification three-pr...
Complete Genome Sequences of Getah Virus Strains Isolated from Horses in 2016 in Japan. Getah virus is mosquito-borne and causes disease in horses and pigs. We sequenced and analyzed the complete genomes of three strains isolated from horses in Ibaraki Prefecture, eastern Japan, in 2016. They were almost identical to the genomes of strains recently isolated from horses, pigs, and mosquitoes in Japan.
