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Gastrointestinal disease has been associated with shedding of Salmonella with previous studies demonstrating that horses with colic have a higher risk of acquiring and shedding Salmonella organisms.The purpose of this study was to determine the prevalence of and risk factors associated with Salmonella shedding in a colic population at a referral clinic.Retrospective case-control study.For each colic case that was positive for Salmonella (n = 56), two colic cases (n = 112) that tested negative for Salmonella, were enrolled as controls. Associations between variables and Salmonella shedding were identified using logistic regression. Univariate and multivariable models were developed pertaining to (1) presenting clinicopathological data and (2) clinical variables that developed during hospitalisation.Of the equids presenting with colic, 1585/1917 had a sample submitted for Salmonella testing. Of these, 56 were positive for Salmonella yielding a prevalence of 3.5%. Equids shedding Salmonella were more likely to present in July (odds ratio [OR] = 7.2; 95% confidence interval [CI] = 1.63-32.13; p = 0.009) and present with a history of fever (OR = 53.5; 95% CI = 2.57-1113.03; p = 0.01), increased lactate (OR = 1.6; 95% CI = 1.14-2.29; p = 0.007) and/or neutropenia (OR = 0.79; 95% CI = 0.65-0.97; p = 0.02). Hospitalised equids shedding Salmonella were more likely to be febrile (OR = 4.8; 95% CI = 1.47-15.8; p = 0.01) and 10 times more likely to develop reflux (OR = 10.1; 95% CI = 1.67-61.43; p = 0.01) compared to colic controls.Retrospective nature of the study and bias inherent to the retrieval of data from medical records cannot be discounted. Classifying Salmonella status based on a single sample may have resulted in misclassification bias.The prevalence of Salmonella shedding in this colic population was low compared to earlier reports. Certain predictors such as the development of a fever or reflux in hospitalised colic cases were associated with Salmonella shedding and may help the clinician to promptly identify horses likely to shed; thus, helping institute effective use of barrier nursing precautions.背景: 胃肠道疾病与沙门氏菌散播有关；先前的研究表明，有腹痛的马匹有更高罹患和散播沙门氏菌的风险。 目的: 本研究的目的是确定由于腹痛进入转诊医院马匹中，沙门氏菌散播的流行率和相关的危险因素。 研究设计: 回顾性病例对照研究 方法: 对每一例沙门氏菌阳性的腹痛病例(n = 56)，选两例沙门氏菌阴性的腹痛病例(n = 112)作为对照。各种变量与沙门氏菌散播之间的联系使用逻辑回归确定。建立单变量和多变量模型研究以下联系:(1)临床病理数据，(2)住院期间产生的临床变量。 结果: 在1917匹发生腹痛的马匹的样本中，1585匹完成了沙门氏菌检测。其中56例沙门氏菌阳性，患病率为3.5%。马属动物散播沙门氏菌常出现在7月份(OR = 7.2; 95% CI = 1.63-32.13; p = 0.009)。常伴随发热史(OR = 53.5；95% CI = 2.57-1113.03；p = 0.01)，乳酸升高(OR = 1.6；95% CI = 1.14-2.29；p = 0.007)和/或中性粒细胞减少(OR = 0.79；95% CI = 0.65 -0.97；p = 0.02)。住院马匹散播沙门氏菌的更可能发热(OR = 4.8；95% CI = 1.47 -15.8；p = 0.01)，和阴性腹痛对照组相比，发生胃返流的可能性增加10倍(OR = 10.1；95% CI = 1.67 -61.43；p = 0.01)。 主要限制: 回顾性研究的性质和从医疗记录中检索数据的固有主观性局限。基于单一样本对沙门氏菌状态进行分类可能会导致分类偏差和不合理。 结论: 与早期报道相比，该设计中马匹的沙门氏菌散播流行率较低。某些预测因素，如发烧或返流在住院腹痛病例中与沙门氏菌散播相关，可以帮助临床医生及时识别可能散毒的马匹，从而帮助建立有效的屏障以及护理预防措施。.

Castration is one of the most common surgical procedures performed in equine practice. Open, closed, and semiclosed techniques are described for castration of horses, and the procedure may be performed in a standing, sedated animal or in a recumbent animal under general anesthesia. Although a relatively routine procedure, complications can occur, with reported complication rates ranging from 10.2% to 60%. Most complications are mild and resolve rapidly with appropriate treatment, but more serious or life-threatening complications can also occur. A thorough knowledge of male reproductive anatomy and physiology combined with good surgical technique is imperative to help reduce the rate of complications.

Dietzia strains are widely distributed in the environment, presenting an opportunistic role, and some species have undetermined taxonomic characteristics. Here, we propose the existence of errors in the classification of species in this genus using comparative genomics. We performed ANI, dDDH, pangenome and genomic plasticity analyses better to elucidate the phylogenomic relationships between Dietzia strains. For this, we used 55 genomes of Dietzia downloaded from public databases that were combined with a newly sequenced. Sequence analysis of a phylogenetic tree based on genome similarity comparisons and dDDH, ANI analyses supported grouping different Dietzia species into four distinct groups. The pangenome analysis corroborated the classification of these groups, supporting the idea that some species of Dietzia could be reassigned in a possible classification into three distinct species, each containing less variability than that found within the global pangenome of all strains. Additionally, analysis of genomic plasticity based on groups containing Dietzia strains found differences in the presence and absence of symbiotic Islands and pathogenic islands related to their isolation site. We propose that the comparison of pangenome subsets together with phylogenomic approaches can be used as an alternative for the classification and differentiation of new species of the genus Dietzia.

Castration is one of the most common surgical procedures performed in equine practice. Open, closed, and semiclosed techniques are described for castration of horses, and the procedure may be performed in a standing, sedated animal or in a recumbent animal under general anesthesia. Although a relatively routine procedure, complications can occur, with reported complication rates ranging from 10.2% to 60%. Most complications are mild and resolve rapidly with appropriate treatment, but more serious or life-threatening complications can also occur. A thorough knowledge of male reproductive anatomy combined with good surgical technique is imperative to help reduce the rate of complications.

Infectious causes of myositis are reported relatively uncommonly in horses. Among them, bacterial causes include Streptococcus equi subsp. zooepidemicus, Actinobacillus equuli, Fusobacterium spp. Staphylococcus spp, and Corynebacterium pseudotuberculosis. Infection can be spread to muscles via haematogenous or extension from skin lesions. Parasitic myositis has also been documented. In this report, a 12 year-old Italian Quarter Horse mare presented with diffuse subcutaneous nodules and masses ranging from 2 × 3 to 5 × 20 cm in size, and adherent to subcutis and muscles that were first macroscopically and cytologically diagnosed as pyogranulomas. Subsequently, histological, molecular, bacteriological, and biochemical investigations were performed. All the data obtained allowed to diagnose a severe and diffuse multibacterial granulomatous myositis caused by Corynebacterium pseudotuberculosis and Corynebacterium amycolatum. Following the therapy and an initial disappearance of most of the lesions together with a general improvement of the mare, the clinical condition deteriorated, and new nodules appeared. Matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) and PCR techniques revealed the presence of bacteria as Glutamicibacter creatinolyticus and Dietzia spp. To the authors’ knowledge, this case report represents the first description of multibacterial granulomatous myositis due to Corynebacterium pseudotuberculosis, Corynebacterium amycolatum, Glutamicibacter creatinolyticus, and Dietzia spp. in a horse reared in Italy.

Objective To determine the influence of radiographic quantification of sand accumulation on the medical versus surgical management of large colon sand accumulations. To compare short- and long-term outcomes and complications associated with medical and surgical management of these horses. Study design Retrospective. Sample population A total of 153 horses. Methods Medical records and abdominal radiographs of horses presented for colic between 2004 and 2014 were reviewed. Severity of sand accumulation was quantified by tracing and measuring a region of interest with a commercial software program. Breed, weight, amount of sand, presence of diarrhea at presentation, treatment, and the development of complications were recorded. Results Records from 153 horses were reviewed. The mean cross-sectional area of sand accumulation was 692.9 cm2 (median = 658.7 cm2, 84.6-1780.7 cm2). Increased accumulation of gas on radiographs and abnormal transrectal examination findings were associated with an increased likelihood of surgery. The most common complication was the development of diarrhea (20.3%) with only 4 (2.6%) horses positive for Salmonella spp. Horses had a favorable prognosis, with 94.8% of horses treated medically and 94.7% of those treated surgically surviving to discharge. Conclusion Increased accumulation of gas on radiographs and transrectal palpation of impaction or intestinal gas distension increase the likelihood of surgery. Both medical and surgical treatments carry a good prognosis. Clinical relevance The sheer quantity of sand is not a factor when determining surgical intervention. Attention should be paid to the presence of increased gas accumulation on rectal or radiographic examination.

Corynebacterium pseudotuberculosis biovar Equi is an important pathogen of horses. It is increasing in frequency in the United States, and is responsible for various clinical forms of infection, including external abscesses, internal abscesses of the abdominal or thoracic cavities, and ulcerative lymphangitis. The host/pathogen factors dictating the form or severity of infection are currently unknown. Our recent investigations have shown that genotyping C. pseudotuberculosis isolates using enterobacterial repetitive intergenic consensus (ERIC)-PCR is useful for understanding the evolutionary genetics of the species as well for molecular epidemiology studies. The aims of the present study were to assess (i) the genetic diversity of C. pseudotuberculosis strains isolated from horses in California, United States and (ii) the epidemiologic relationships among isolates. One hundred and seven C. pseudotuberculosis biovar Equi isolates from ninety-five horses, and two C. pseudotuberculosis biovar Ovis strains, C. pseudotuberculosis ATCC 19410T type strain and C. pseudotuberculosis 1002 vaccine strain, were fingerprinted using the ERIC 1 + 2-PCR. C. pseudotuberculosis isolated from horses showed a high genetic diversity, clustering in twenty-seven genotypes with a diversity index of 0.91. Minimal spanning tree showed four major clonal complexes with a pattern of temporal clustering. Strains isolated from the same horse showed identical ERIC 1 + 2-PCR genotype, with the exception of two strains isolated from the same animal that showed distinct genotypes, suggesting a co-infection. We found no strong genetic signals related to clinical form (including internal versus external infections). However, temporal clustering of genotypes was observed.

Bacteria of the genusGlutamicibacterare considered ubiquitous because they can be found in soil, water and air. They have already been isolated from different habitats, including different types of soil, clinical samples, cheese and plants. Glutamicibacter creatinolyticus is a Gram-positive bacterium important to various biotechnological processes, however, as a pathogen it is associated to urinary tract infections and bacteremia. Recently,Glutamicibacter creatinolyticusLGCM 259 was isolated from a mare, which displayed several diffuse subcutaneous nodules with heavy vascularization. In this study, sequencing, genomic analysis ofG. creatinolyticusLGCM 259 and comparative analyseswere performedamong 4representatives of different members of genusfromdifferent habitats, available in the NCBI database. The LGCM 259 strain's genome carries important factors of bacterial virulence that are essential in cell viability, virulence, and pathogenicity. Genomic islands were predicted for 4 members of genusGlutamicibacter,showing ahigh number of GEIs,which may reflect a high interspecific diversity and a possible adaptive mechanism responsible for the survival of each species in its specific niche. Furthermore,G. creatinolyticusLGCM 259 sharessyntenicregions, albeit with a considerable loss of genes, in relation to the other species. In addition,G. creatinolyticusLGCM 259 presentsresistancegenes to 6 differentclasses ofantibiotics and heavy metals, such as: copper, arsenic, chromium and cobalt-zinc-cadmium.Comparative genomicsanalysescouldcontribute to the identification of mobile genetic elements particular to the speciesG. creatinolyticuscompared to other members of genus. The presence of specific regions inG. creatinolyticuscould be indicative of their rolesin host adaptation, virulence, and the characterization ofastrain that affects animals.

Author(s): Smith, Fauna Leah; Watson, Johanna L; Spier, Sharon J; Kilcoyne, Isabelle; Mapes, Samantha; Sonder, Claudia; Pusterla, Nicola | Abstract: BackgroundImported horses that have undergone recent long distance transport might represent a serious risk for spreading infectious respiratory pathogens into populations of horses.ObjectiveTo investigate the frequency of shedding of respiratory pathogens in recently imported horses.AnimalsAll imported horses with signed owner consent (n = 167) entering a USDA quarantine for contagious equine metritis from October 2014 to June 2016 were enrolled in the study.MethodsProspective observational study. Enrolled horses had a physical examination performed and nasal secretions collected at the time of entry and subsequently if any horse developed signs of respiratory disease during quarantine. Samples were assayed for equine influenza virus (EIV), equine herpesvirus type-1, -2, -4, and -5 (EHV-1, -2, -4, -5), equine rhinitis virus A (ERAV), and B (ERBV) and Streptococcus equi subspecies equi (S. equi) using quantitative PCR (qPCR).ResultsEquine herpesviruses were detected by qPCR in 52% of the study horses including EHV-2 (28.7%), EHV-5 (40.7%), EHV-1 (1.2%), and EHV-4 (3.0%). Clinical signs were not correlated with being qPCR-positive for EHV-4, EHV-2, or EHV-5. None of the samples were qPCR-positive for EIV, ERAV, ERBV, and S. equi. The qPCR assay failed quality control for RNA viruses in 25% (46/167) of samples.Conclusions and clinical importanceClinical signs of respiratory disease were poorly correlated with qPCR positive status for EHV-2, -4, and -5. The importance of γ-herpesviruses (EHV-2 and 5) in respiratory disease is poorly understood. Equine herpesvirus type-1 or 4 (EHV-1 or EHV-4) were detected in 4.2% of horses, which could have serious consequences if shedding animals entered a population of susceptible horses. Biosecurity measures are important when introducing recently imported horses into resident US populations of horses.

Summary Hereditary equine regional dermal asthenia (HERDA) results from a genetic mutation which affects the skin and other tissues of Quarter Horses and horses with Quarter Horse lineage. The disease HERDA has an autosomal recessive mode of inheritance and has become a significant concern in the Quarter Horse industry due to the high frequency of heterozygote carriers. Affected homozygous horses appear normal at birth; however, within the first 2 years of life they usually acquire loose, hyperextensible skin and wounds which result in disfiguring scars either spontaneously or from minor trauma. Some severely affected horses also develop haematomas and seromas. Consequently, most affected horses are subjected to euthanasia at an early age. No treatment options other than palliative therapy currently exist. As part of a five panel test (http://www.aqha.com/News/News-Articles/2013/April/04292013-Genetic-Testing.aspx) the American Quarter Horse Association presently requires DNA testing for HERDA on all breeding stallions. There are currently no restrictions on registration of horses heterozygous or homozygous for the HERDA mutation. Due to the autosomal recessive nature of the disease, Quarter Horse mares and horses of all breeds from HERDA-associated bloodlines should also be tested.

© 2015 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals, Inc. on behalf of American College of Veterinary Internal Medicine. Background: Few studies report the minimum inhibitory concentrations for antimicrobials against equine Corynebacterium pseudotuberculosis isolates. Hypothesis/Objectives: To evaluate trends in the in vitro activities of 20 antimicrobials against equine Corynebacterium pseudotuberculosis isolates from 1996 to 2012 and to determine if a relationship exists between the minimum inhibitory concentration (MIC) and location of the abscess. Animals: Corynebacterium pseudotuberculosis isolates from 196 horses with naturally occurring disease. Methods: Retrospective and cross-sectional design. Medical records were reviewed to obtain clinical and MIC data. Minimum inhibitory concentrations were determined by the microdilution technique. The MIC results over 3 periods were compared (1996-2001, 2002-2006, 2007-2012). Results: The MIC90values for clinically relevant antimicrobials were as follows: chloramphenicol ≤4 μg/mL, enrofloxacin ≤0.25 μg/mL, gentamicin ≤1 μg/mL, penicillin =0.25 μg/mL, rifampin ≤1 μg/mL, tetracycline ≤2 μg/mL, trimethoprim-sulfamethoxazole (TMS) ≤0.5 μg/mL, ceftiofur =2 μg/mL, and doxycycline ≤2 μg/mL. There were no significant changes in MIC results over the study period. There was no relationship between MIC patterns and abscess location. Conclusions and Clinical Importance: The MIC50and MIC90values of antimicrobials evaluated in this study for equine isolates of C. pseudotuberculosis did not vary over time. Abscess location was not associated with different MIC patterns in cultured isolates. Several commonly used antimicrobials are active in vitro against C. pseudotuberculosis in vitro.

Background 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-primer multiplex PCR assay. The nitrate reductase gene (narG) was included in the PCR assay along with the 16S, rpoB and pld genes to enhance the diagnosis of the multiplex PCR at biovar level. Results A novel quadruplex PCR assay for C. pseudotuberculosis species and biovar identification was developed. The results of the quadruplex PCR of 348 strains, 346 previously well-characterized clinical isolates of C. pseudotuberculosis from different hosts (goats, sheep, horse, cattle, buffalo, llamas and humans), the vaccine strain 1002 and the type strain ATCC 19410T, were compared to the results of nitrate reductase identification by biochemical test. The McNemar’s Chi-squared test used to compare the two methods used for C. pseudotuberculosis biovar identification showed no significant difference (P = 0.75) [95% CI for odds ratio (0.16–6.14)] between the quadruplex PCR and the nitrate biochemical test. Concordant results were observed for 97.13% (338 / 348) of the tested strains and the kappa value was 0.94 [95% CI (0.90–0.98)]. Conclusions The ability of the quadruplex assay to discriminate between C. pseudotuberculosis biovar Ovis and Equi strains enhances its usefulness in the clinical microbiology laboratory. Electronic supplementary material The online version of this article (10.1186/s12917-017-1210-5) contains supplementary material, which is available to authorized users.

The genomes of four strains (MB11, MB14, MB30, and MB66) of the species Corynebacterium pseudotuberculosis biovar equi were sequenced on the Ion Torrent PGM platform, completely assembled, and their gene content and structure were analyzed. The strains were isolated from horses with distinct signs of infection, including ulcerative lymphangitis, external abscesses on the chest, or internal abscesses on the liver, kidneys, and lungs. The average size of the genomes was 2.3 Mbp, with 2169 (Strain MB11) to 2235 (Strain MB14) predicted coding sequences (CDSs). An optical map of the MB11 strain generated using the KpnI restriction enzyme showed that the approach used to assemble the genome was satisfactory, producing good alignment between the sequence observed in vitro and that obtained in silico. In the resulting Neighbor-Joining dendrogram, the C. pseudotuberculosis strains sequenced in this study were clustered into a single clade supported by a high bootstrap value. The structural analysis showed that the genomes of the MB11 and MB14 strains were very similar, while the MB30 and MB66 strains had several inverted regions. The observed genomic characteristics were similar to those described for other strains of the same species, despite the number of inversions found. These genomes will serve as a basis for determining the relationship between the genotype of the pathogen and the type of infection that it causes.

Equine infection with Corynebacterium pseudotuberculosis can manifest in several forms, including external or internal abscesses. The objective of this study was to phenotype clinical isolates of C. pseudotuberculosis and to investigate the relationship between lesion location and extent of lesions in the animals from which they were collected. One hundred and seventy-one C. pseudotuberculosis biovar equi isolates were collected from horses presenting to the University of California Veterinary Medical Teaching Hospital and two other sources in the period between September 1996 and December 2011. Bacterial isolates were grouped on the bases of biochemical characteristics and growth on brain heart infusion agar. Six phenotypes were identified: (1) large colonies that metabolized sucrose (n = 81); (2) large sucrose-negative colonies (n = 47); (3) medium sucrose-positive (n = 20); (4) medium sucrose-negative (n = 11); (5) small sucrose-positive (n = 7), and (6) small sucrose-negative (n = 5). Medical records corresponding to each isolate were accessed from the University's administrative computer system or from the submitting source in order to determine the anatomical site from which the isolate was collected (n = 171), as well as the extent of lesions (n = 164) in the patient. The relationship between phenotype, lesion location and extent of lesions was then investigated statistically. No significant relationship between strain and lesion location or extent of lesions was found. This suggests that phenotypic differences during in vitro culture does not account for external versus internal disease in horses. Further work to characterize strains genotypically and to identify determinants for bacterial virulence should be performed. Importantly, host and environmental factors should also be further investigated.

Summary Reason for performing study Septic sialoadenitis, although uncommonly reported in equids, is a significant cause of pain, inappetence, dysphagia and discomfort. There are currently few reported cases possibly as a result of its infrequent occurrence. Objectives To review cases presenting with sialoadenitis and describe the presenting complaints, results of diagnostic tests, treatment and outcome. Study design Retrospective case series. Methods Records were reviewed for equids presenting to the UC Davis William R. Pritchard Veterinary Medical Teaching Hospital between 1998 and 2010 for salivary gland swelling. Equids were included if a diagnosis of septic sialoadenitis was made based on a combination of oral examination and/or ultrasonographic findings and/or microbial culture. Data collected included age, breed, presenting complaints, diagnostic results, treatment and outcome. Results Eighteen equids were diagnosed with septic sialoadenitis affecting the parotid gland (11) or the mandibular salivary gland (7). Ultrasound was useful to differentiate whether the mandibular or parotid salivary gland was involved. Affected equids ranged in age from 4 to 30 years (mean 17.7 years). Fourteen of 15 (93.3%) equids that underwent a complete oral examination had dental or other oral abnormalities. Six of 18 cases had evidence of sialolithiasis. Culture of the infected salivary gland or secretions was performed in 9 equids and all yielded growth of Fusobacterium sp. along with other aerobic and anaerobic bacteria. Infection resolved in 15/18 cases (83.3%) and 2/18 (11.1%) were subjected to euthanasia. Conclusions Dental disease and sialolith formation may play important roles in the development of septic sialoadenitis in equids. Anaerobic infection should be assumed in all cases and affected horses should be treated for this until culture and sensitivity results are available. Prognosis is favourable (83.3%) with appropriate treatment.

Weaning, particularly the widespread practice of abrupt separation of the mare and foal, has been shown to be a stressful event for horses. Physiological changes in foals measured after weaning include increased blood cortisol concentrations and a subsequent decrease in cell-mediated immune responses. In the randomized, double-blinded, placebo-controlled trial reported here, we assessed the effect of an equine appeasing pheromone (EAP; Modipher EQ, E.A.P. Mist [Pherosynthese s.n.c., LeRieu Neuf, Saint-Saturnin-les-Apt, France]) as an aid for reducing the behavioral and physiological signs of stress during weaning. Fourteen quarter horse foals were separated from their dam (equid mother) between 105 and 146 days of age, in age-matched pairs, and placed in 3.66×3.66m stalls (one treated and one control foal in each stall). Treated foals received the synthetic analogue of the EAP by intranasal wipe 30 minutes before separation and twice daily thereafter for 48 hours. Control foals received placebo by intranasal wipe on the same schedule. The foals were continuously videotaped for 48 hours postweaning to monitor behavioral responses. Blood samples were drawn 24 hours pretreatment and 24 and 48 hours postweaning for evaluation of physiological indicators of stress (serum cortisol) and cytokines as stress-related and immune-mediated response parameters. Interestingly, although behavioral and serum cortisol measures were similar between groups, treatment with EAP had a significant (P

Objective—To determine the incidence of complications and identify risk factors associated with development of complications following routine castration of equids. Design—Retrospective case series. Animals—311 horses, 10 mules, and 3 donkeys. Procedures—Medical records of equids undergoing routine castration were reviewed. Age, breed, surgical techniques (closed vs semiclosed castration and use of ligatures), anesthesia method (general IV anesthesia vs standing sedation with local anesthesia) and repeated administration of IV anesthetic agents, administration of antimicrobials and anti-inflammatory drugs, and details regarding development, management, and outcome of complications were recorded. Odds ratios and 95% confidence intervals were determined. Associations between additional doses of anesthetic agents during surgery and development of complications were analyzed with a Jonckheere-Terpstra test. Results—33 of 324 (10.2%) equids developed a complication after surgery; 32 recovered and 1 was euthanized because of eventration. Equids that underwent semiclosed castration had significantly higher odds of developing a complication (OR, 4.69; 95% confidence interval, 2.09 to 10.6) than did those that underwent closed castration. Equids that received additional doses of anesthetic agents to maintain adequate general anesthesia developed complications more frequently than those that did not require this treatment. Conclusions and Clinical Relevance—Incidence of complications was low, and most evaluated variables were not significantly associated with development of complications following castration in equids. However, findings suggested that the choice of surgical technique (closed vs semiclosed) is an important factor in this regard. Future studies should investigate whether duration of surgery is associated with complications following castration in equids.

© 2017 Baraúna et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Seven genomes of Corynebacterium pseudotuberculosis biovar equi were sequenced on the Ion Torrent PGM platform, generating high-quality scaffolds over 2.35 Mbp. This bacterium is the causative agent of disease known as "pigeon fever" which commonly affects horses worldwide. The pangenome of biovar equi was calculated and two phylogenomic approaches were used to identify clustering patterns within Corynebacterium genus. Furthermore, other comparative analyses were performed including the prediction of genomic islands and prophages, and SNP-based phylogeny. In the phylogenomic tree, C. pseudotuberculosis was divided into two distinct clades, one formed by nitrate non-reducing species (biovar ovis) and another formed by nitrate-reducing species (biovar equi). In the latter group, the strains isolated from California were more related to each other, while the strains CIP 52.97 and 1/06-A formed the outermost clade of the biovar equi. A total of 1,355 core genes were identified, corresponding to 42.5% of the pangenome. This pangenome has one of the smallest core genomes described in the literature, suggesting a high genetic variability of biovar equi of C. pseudotuberculosis. The analysis of the similarity between the resistance islands identified a higher proximity between the strains that caused more severe infectious conditions (infection in the internal organs). Pathogenicity islands were largely conserved between strains. Several genes that modulate the pathogenicity of C. pseudotuberculosis were described including peptidases, recombination enzymes, micoside synthesis enzymes, bacteriocins with antimicrobial activity and several others. Finally, no genotypic differences were observed between the strains that caused the three different types of infection (external abscess formation, infection with abscess formation in the internal organs, and ulcerative lymphangitis). Instead, it was noted that there is a higher phenetic correlation between strains isolated at California compared to the other strains. Additionally, high variability of resistance islands suggests gene acquisition through several events of horizontal gene transfer.

To determine the influence of radiographic quantification of sand accumulation on the medical versus surgical management of large colon sand accumulations. To compare short- and long-term outcomes and complications associated with medical and surgical management of these horses.Retrospective.A total of 153 horses.Medical records and abdominal radiographs of horses presented for colic between 2004 and 2014 were reviewed. Severity of sand accumulation was quantified by tracing and measuring a region of interest with a commercial software program. Breed, weight, amount of sand, presence of diarrhea at presentation, treatment, and the development of complications were recorded.Records from 153 horses were reviewed. The mean cross-sectional area of sand accumulation was 692.9 cmIncreased accumulation of gas on radiographs and transrectal palpation of impaction or intestinal gas distension increase the likelihood of surgery. Both medical and surgical treatments carry a good prognosis.The sheer quantity of sand is not a factor when determining surgical intervention. Attention should be paid to the presence of increased gas accumulation on rectal or radiographic examination.

Corynebacterium pseudotuberculosis is the etiological agent of a caseous lymphadenitis disease. Herein, we present the first complete genome sequencing of C. pseudotuberculosis strain 226, isolated from an abscess of the sub-iliac lymph node of a goat from California (USA). The genome contains 2,138 coding sequences (CDSs), 12 rRNAs, 49 tRNAs, and 72 pseudogenes.

Objective—To determine the outcome of penetrating injuries to the central region of the foot in equids and identify factors that may affect treatment and outcome. Design—Retrospective case series. Animals—63 equids (61 horses, 1 pony, and 1 mule). Procedures—Records of equids incurring puncture wounds through the frog (cuneus ungulae) or collateral sulci of the foot between 1998 and 2008 were reviewed. Evaluated factors that were hypothesized to affect outcome included signalment, degree of lameness, foot affected, duration between injury and admission, and treatment. Injuries were graded from 1 (< 1 inch; involving superficial corium only) to 4 (involving a synovial structure) on the basis of severity of penetration as determined by radiographic evidence or findings on synoviocentesis at the time of admission. Results—Overall, 60% (38/63) of equids returned to soundness. Thirteen equids were euthanized on the basis of synovial structure involvement and financial constraints. Of 35 equids that were treated conservatively, which may have included undergoing a surgical procedure with the horse standing, 32 (91.4%) returned to their previous level of soundness. Fifteen equids underwent surgical treatment under general anesthesia, of which 6 (40%) became sound for intended use. Ten of 34 (29%) equids with synovial structure involvement regained soundness. Equids treated earlier after injury had a better prognosis. Equids with a hind foot injury had a more favorable outcome than those with a forefoot injury. Conclusions and Clinical Relevance—Results suggested that penetrating injuries located centrally in the foot of equids without involvement of a synovial structure have a favorable prognosis, especially if managed early. Penetration of a synovial structure provided a poor prognosis.

Summary Reasons for performing study: Although crib-biting (cribbing)/windsucking has previously been associated with 2 types of colic, additional research into the possible role of other behaviours on incidence of colic by type and severity has not been undertaken. Objectives: To investigate: a relationship between cribbing/windsucking and colic; a relationship between cribbing/windsucking and different types of colic, both medical and surgical; and whether horses displaying specific behaviour traits were more likely to have had colic. Methods: A matched case-control retrospective study was conducted evaluating horses with various surgical and medical colic diagnoses, admitted to a referral hospital over a 3 year period. Computerised records and a validated internet questionnaire were used to obtain information on owner-perceived behavioural traits and repetitive behaviours. Results: Cribbing/windsucking was significantly associated with colic but was unassociated with one category or severity of colic over another. No other repetitive behaviour was associated with colic. Age (≥20 years) was significantly associated with colic. An anxious temperament was not associated with risk of colic. Conclusion: Animals at higher risk for colic may be identified based on history of cribbing/windsucking behaviour, but this behaviour was unassociated with increased risk for a particular category or severity of colic. Horses characterised as being more anxious were not at increased risk for colic. Potential relevance: There is a need to elucidate a causal relationship between cribbing/windsucking and gastrointestinal function as development of more effective and humane strategies to treat cribbing/windsucking behaviour may help to improve equine welfare and reduce the risk of colic.

The recent development of equine genome maps by the equine genome community and the complete sequencing of the horse genome performed at the Broad Institute have accelerated the pace of genetic discovery. This review focuses on genetic diseases in the horse for which a mutation is currently known, including hyperkalemic periodic paralysis, severe combined immunodeficiency, overo lethal white syndrome, junctional epidermolysis bullosa, glycogen branching enzyme deficiency, malignant hyperthermia, hereditary equine regional dermal asthenia, and polysaccharide storage myopathy. Emphasis is placed on the prevalence, clinical signs, etiology, diagnosis, treatment and prognosis for each disease.

Objective—To evaluate clinical, microbiologic, and pathologic outcomes in mice after inoculation with 4 equine-origin Corynebacterium pseudotuberculosis strains. Animals—15 C3H/HeJ mice. Procedures—In a preliminary study, the optimum route of inoculation was determined. In the main study, mice were allocated to 4 treatment groups (3 mice/group). One slow- or rapid-growing equine-origin C pseudotuberculosis strain was inoculated ID into the mice of each treatment group. Results—All 4 strains had distinct tropism for the liver. Histologic lesions associated with rapid-growing strains included focally extensive unencapsulated areas of acute, massive coagulative necrosis of hepatocytes with intralesional colonies of bacteria and variable portal hepatitis characterized by accumulations of mononuclear and polymorphonuclear inflammatory cells. In contrast, the livers of mice inoculated with slow-growing strains had multiple discrete, randomly distributed foci of hepatocellular necrosis and neutrophilic hepatitis that were considerably less severe than the lesions in the mice inoculated with the rapid-growing strains. Significantly more bacterial colonies were recovered from the organs of mice inoculated with rapid-growing than with slow-growing strains of bacteria. Bacteria were isolated from the liver, spleen, lungs, and mesenteric lymph nodes of mice inoculated with rapid-growing strains and from the liver and lymph nodes of mice inoculated with slow-growing strains. Conclusions and Clinical Relevance—Study of host-bacteria interactions in hosts that are naturally infected with C pseudotuberculosis is difficult because of underlying genetic variability among animals, expense, and requirements for multiple replicates and control animals. The C3H/HeJ mice may provide a useful means for studying virulence mechanisms of C pseudotuberculosis.

Corynebacterium pseudotuberculosis is a common cause of external abscesses in horses. Approximately 8% of affected horses develop internal infection, which is associated with increased mortality and expense. Respiratory disease caused by C. pseudotuberculosis occurs in approximately 40% of horses that develop internal C. pseudotuberculosis infection. The lower respiratory tract may be the only organ system affected and infection can manifest as pneumonia or pleuropneumonia. Approximately half of the horses that develop C. pseudotuberculosis lower respiratory tract infection have concurrent abdominal organ involvement. The liver is the site most commonly affected, although renal and splenic involvement also occurs. Abdominal ultrasound is an important diagnostic technique to specifically identify affected abdominal organs. With early diagnosis, a high proportion of horses with internal C. pseudotuberculosis infection respond well to long-term antimicrobial therapy; however, pregnant mares are at risk for fetal loss.

Behavioural reactions to selected handling procedures were compared between conditioned, or imprint-trained, and untrained foals raised on the same farm. Nineteen randomly chosen healthy foals were imprint trained at birth and 24 h later (Group A). Twenty-one similar foals that were not imprint-trained served as age-matched controls (Group B). Training began within 10 min of birth and consisted of touch desensitization by gentle rubbing. Each tactile stimulus was repeated 30-50 times over 45-60 min, until the foal no longer resisted the procedure and appeared relaxed. The procedure was then repeated at 24 h of age. At that time a physical examination and blood analysis were performed to assess the foals' health status. Group B animals were not handled except for a brief physical examination and blood analysis at 24 h of age. Thereafter all foals were kept on pastures with their dams with no further handling until they were three months of age. Any foals handled for other reasons before that time were excluded from the study. At three months, each of the 28 foals that completed the study experienced the following handling procedures: acceptance of restraint, haltering, complete physical examination, acceptance of a plastic rebreathing bag, touching the whole body, intramuscular vaccination in the neck, intranasal vaccination, and deworming with oral paste. Response to each procedure was scored (1=not resistant, 2=low resistance, 3=strong resistance, 4=not possible without major physical restraint). Conditioned foals (Group A) were significantly less resistant to touching the front and hind legs and picking up the hind feet (P < 0.05). The administration of vaccines and paste dewormer and the collection of blood were tolerated by the majority of the foals of both groups with no or low resistance. It appeared that neonatal imprint training resulted in a learned behaviour that resulted in decreased self-defence responses towards handling the limbs at three months of age.

Data on fifty horses with hereditary equine regional dermal asthenia (HERDA; "hyperelastosis cutis") were collected on clinical, histopathological, ultrastructural and immunohistological findings. All horses were Quarter horses or of Quarter horse ancestry. Pedigree evaluation strongly supported an autosomal recessive mode of inheritance. The most common lesions were seromas/haematomas, open wounds, sloughing skin, and loose, easily tented skin that did not return to its initial position. Definitive diagnosis could not be made via histopathology, although the presence of tightly grouped thin and shortened collagen fibres arranged in clusters in the deep dermis was suggestive of the disease. Trichrome, acid orcein-Giemsa and immunohistochemical stains for collagens I and III showed no consistent abnormalities compared to control horses; an increase in elastic fibres was not a consistent finding. Electron microscopy showed no abnormalities in the periodicity of the collagen bundles; neither orientation nor variation of cross-section diameter of the collagen fibrils differentiated control from affected horses. The diagnosis of HERDA relies on clinical presentation, but may be supported by suggestive (although not pathognomonic) histopathological lesions.

Objective—To develop and use a sensitive molecular assay for detecting the phospholipase D (PLD) exotoxin gene of Corynebacterium pseudotuberculosis in an attempt to identify insect vectors that may be important in transmission of clinical disease in horses. Sample Population—2,621 flies of various species. Procedure—A real-time polymerase chain reaction (PCR)-based fluorogenic 5' nuclease (TaqMan) system (ie, TaqMan PCR assay) was developed for the detection of the PLD gene in insects. Flies were collected monthly (May to November 2002) from 5 farms in northern California where C pseudotuberculosis infection in horses is endemic. Three of the 5 farms (which housed a total of 358 horses) had diseased horses during the study period. A total of 2,621 flies of various species were tested for the PLD gene of C pseudotuberculosis. Results—Evidence of bacterial DNA for the PLD gene was detected in skin biopsy specimens from clinically affected horses and from 3 fly species collected from farms where affected horses were housed. Farms with a high incidence of diseased horses had a high proportion of insects carrying the organism. High percentages of flies with positive results for the PLD gene were observed in October, when most clinically affected horses were observed. Conclusions and Clinical Relevance—Our results are consistent with the hypothesis that C pseudotuberculosis may be vectored to horses by flies. Three potential vectors were identified, including Haematobia irritans, Stomoxys calcitrans, and Musca domestica. The organism can be identified in up to 20% of house flies (Musca domestica) in the vicinity of diseased horses. (Am J Vet Res 2004;65:829–834)

Objective—To evaluate the efficacy of a customized solution to attenuate intestinal injury following 20% low-flow ischemia and reperfusion in the jejunum of horses.Animals—10 healthy adult horses.Procedure—Two 30.5-cm-long segments of jejunum were exteriorized through a ventral midline incision and the mesenteric artery and vein supplying that portion of the intestine were instrumented with flow probes. Blood flow was decreased to 20% of baseline for 90 minutes followed by 90 minutes of reperfusion. In 5 horses, 60 mL of the customized solution was placed in the lumen of each segment (treatment-group horses), and 60 mL of lactated Ringer's solution was placed in the lumen of 5 additional horses (control-group horses). Biopsy specimens were obtained from 1 segment in both groups for histologic evaluation. Aliquots of luminal fluid were obtained from the other segment in both groups for determination of albumin concentrations as an index of mucosal permeability.Results—Compared with control-group horses, treatment-group horses had a significant decrease in luminal albumin concentration following reperfusion. Although differences in mucosal grades were not significantly different between control- and treatment-group horses, treatment-group horses had significantly greater jejunal villous length and area, compared with that of control-group horses.Conclusions and Clinical Relevance—Intraluminal administration of the customized solution in the jejunum, compared with lactated Ringer's solution, results in an improvement in histologic findings and mucosal translocation of albumin in horses with mild intestinal injury. (Am J Vet Res2004;65:485–490)

Two horses were examined for large head wounds suspected to be the result of trauma and characterized by extensive necrosis of the skin and subcutaneous tissue, with abundant purulent exudate. Corynebacterium pseudotuberculosis was isolated from the facial wounds in both horses. Histopathologic examination revealed severe suppurative cellulitis and panniculitis with fistulous tracts and granulation tissue in 1 horse. Both horses were treated with local wound care, nonsteroidal anti-inflammatory drugs, and administration of antimicrobials. The concept of moist wound care was used in the second horse, with products that have recently become available for veterinary wound management. Outcome in both horses was good.

A 13-year-old Oldenburg mare was evaluated for lethargy and signs of mild colic. Pericardial tamponade caused by fibrinoeffusive pericarditis was diagnosed. Cytologic and biochemical evaluation of pericardial fluid was consistent with a septic effusion. Corynebacterium pseudotuberculosis, the cause of pigeon fever, was identified by bacteriologic culture of pericardial fluid. Drainage and lavage of the pericardial sac, local (intrapericardial) and systemic antimicrobial treatment, and subsequent corticosteroid treatment resulted in a successful outcome in this horse. To the authors' knowledge, this is the first report of pericarditis associated with C pseudotuberculosis in a horse.

Gastric endoscopy was performed at the end of a 50 or 80 km endurance ride. Gastric ulceration was evident in 67% of the horses with ulcers on the squamous region of the stomach found in 57% of the horses and active bleeding of the glandular mucosa in 27%. Three horses (10%) had lesions only on the glandular mucosa. Values of albumin, creatinine and glucose were higher in horses without gastric lesions. We conclude that horses from endurance competitions have a high prevalence of gastric ulceration that is similar to that observed in performance horses. However the severity of ulceration is less severe than has been reported in Thoroughbred race horses in active training. Owners should be aware of the high prevalence of gastric ulceration in horses that perform in endurance competitions. The high incidence of active bleeding from the glandular mucosa of the stomach in these horses requires further investigation.

Objective— To describe the insertion technique, efficacy, and complications associated with the use of an active (closed-suction) abdominal drain in horses. Study Design— Retrospective study. Animals— Sixty-seven horses with abdominal contamination treated by abdominal lavage and use of a closed-suction abdominal drain. Methods— Medical records of horses (1989–1996) that had a closed-suction abdominal drain were reviewed. Follow-up information was obtained by telephone interviews with owners. Results— Sixty-eight closed-suction abdominal drains were used in 67 horses that had abdominal contamination, peritonitis, or to prevent adhesion formation. The drain was placed under general anesthesia (62 horses) or in a standing position (6 horses). Abdominal lavage was performed every 4 to 12 hours and about 83% of the peritoneal lavage solution was retrieved. Minor complications associated with drain use occurred in 49% of the horses and included obstruction or slow passage of fluid through the drain in 18 horses (26%), leakage of fluid around the drain in 11 horses (16%), and subcutaneous fluid accumulation around the drain in 8 horses (12%). Incisional suppuration developed in 20 of 62 (32%) and incisional herniation in 5 of 46 (11%) horses. Conclusions— A closed-suction drain system was easily placed and was associated with only minor complications in most horses. Clinical Relevance— Active abdominal drainage and lavage is a useful adjunct in the treatment of peritonitis or as a prophylactic procedure in horses at risk of developing septic peritonitis and abdominal adhesions. Clinicians should be aware of the high incidence of minor complications.

To use an extracorporeal circuit to evaluate effects of intraluminal distention on the jejunum of healthy horses.2 jejunal segments from each of 5 horses.Jejunal segments were harvested and maintained in an extracorporeal circuit. One segment was subjected to distention (intraluminal pressure, 25 cm H2O) followed by decompression, and 1 segment was maintained without distention. The influence of distention-decompression on vascular resistance was calculated. Mucosal permeability was evaluated by measuring the clearance of albumin from blood to lumen. After distention and decompression, tissue specimens were collected for histomorphologic evaluation. In addition, the contractile response of the circular smooth muscle layer was determined following incubation with 3 prokinetic agents.Intestinal vascular resistance increased during intraluminal distention and returned to baseline values after decompression. Albumin clearance rate increased after distention, compared with baseline and control values. Histologic examination of the distended segments revealed grade-1 and -2 lesions of the mucosal villus. Edema and hemorrhage were evident in the submucosa and muscular layers. Mesothelial cell loss, edema, and hemorrhage were also evident in the serosa. Mucosal surface area and villus tip height decreased and submucosal volume increased in the distended tissue. Compared with responses in control specimens, distention decreased the contractile response induced by cisapride, erythromycin, and metoclopramide.Intraluminal distention of the jejunum followed by decompression increased mucosal permeability and injury and decreased responses to prokinetic agents. Horses with intraluminal intestinal distention may have a decreased response to prokinetic agents.

The genome of Corynebacterium pseudotuberculosis MB20 bv. equi was sequenced using the Ion Personal Genome Machine (PGM) platform, and showed a size of 2,363,089 bp, with 2,365 coding sequences and a GC content of 52.1%. These results will serve as a basis for further studies on the pathogenicity of C. pseudotuberculosis bv. equi.

Objective—To quantify the number of horses with Corynebacterium pseudotuberculosis infection identified in the United States from January 2003 through December 2012. Design—Cross-sectional study. Sample—State veterinary diagnostic laboratory records of 2,237 C pseudotuberculosis culture-positive samples from horses. Procedures—44 state veterinary diagnostic laboratories throughout the United States were invited by mail to participate in the study. Data requested included the number of C pseudotuberculosis culture-positive samples from horses identified per year, geographic location from which the C pseudotuberculosis culture-positive sample was submitted, month and year of sample submission, breed and age of horses, and category of clinical manifestation (ie, internal infection, external infection, or ulcerative lymphangitis). Results—Of the 44 invited laboratories, 15 agreed to participate and provided data on affected horses from 23 states. The proportion of C pseudotuberculosis culture-positive samples submitted during 2011 through 2012 (1,213/2,237 [54%]) was significantly greater than that for the period from 2003 through 2010 (1,024/2,237 [46%]). Corynebacterium pseudotuberculosis was recovered from horses in states where the disease has not been previously recognized as endemic. Affected horses were identified year-round. The greatest proportion of C pseudotuberculosis culture-positive samples was identified during November, December, and January (789/2,237 [35%]). No significant association between the clinical form of disease and age or breed of horse was observed. Conclusions and Clinical Relevance—The occurrence of C pseudotuberculosis infection in horses increased during the 10-year period, and affected horses were identified throughout the United States. Further studies to determine changes in annual incidence and to identify potential changing climatic conditions or vector populations associated with disease transmission are warranted to help control the occurrence and spread of C pseudotuberculosis infection in horses.