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Background: Respiratory diseases are the second most common cause of illnesses in horses, their etiology can be viral, bacterial, immune-mediated, or mechanical (Racklyeft and Love DN, Aust Vet J 78:549-59, 2000; Austin et al., J Am Vet Med Assoc 207:325-328, 1995; Arroyo et al., J Vet Intern Med 31:894-900, 2017). Klebsiella variicola is a Gram-negative bacterium that was initially identified as an endophyte in soil and plants such as bananas, rice, sugar cane and maize but recent studies have identified this microorganism as an emerging pathogen in humans (Rodríguez-Medina et al., Emerg Microbes Infect 8:973-988, 2019; Fontana et al., J Clin Microbiol 57:e00825-18, 2019; Rosenblueth et al., Syst Appl Microbiol 27:27-35, 2004). This paper describes, for the first time to our knowledge, the isolation of K. variicola from pleural effusion in a male adult horse., Case Presentation: 17-years Italian Saddle Horse with respiratory distress and fever was admitted to the Veterinary Teaching Hospital of the Department of Veterinary Medical Sciences, University of Bologna. At home, the patient had undergone antibiotic therapy without clinical improvement. Vital signs on admission revealed an increased respiratory rate, tachycardia, pyrexia and weight loss. The animal was submitted for collateral examination including thoracic radiology and ultrasound and thoracoscopy that showed bilateral pleural effusion associated with multifocal pulmonary atelectasis. During the thoracoscopic examination, that confirmed the presence of a seropurulent pleural effusion, a sample of pleural fluid was collected and Gram-negative bacteria were isolated and subjected to matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) that allowed the identification of K. variicola. The isolate was sensitive to amikacin, cefazolin, enrofloxacin, marbofloxacin, tetracycline, and trimethoprim-sulfamethoxazole;the horse was treated with Oxytetracycline and amikacin. Despite a general health improvement of the subject, the pleural effusion did not resolve after treatment., Conclusions: This paper describes, for the first time, the isolation of K. variicola in a horse with respiratory disease. The misidentification between K. variicola and K. pneumoniae has caused unawareness about significant aspects of this bacterial species. In fact, even though in animals the role of this bacterium is not clear, in humans it has been recognized as an emerging pathogen. The use of new methods for bacterial identification will probably lead to the isolation of a greater number of strains which will have to be studied to acquire knowledge that will be useful to clarify the clinical importance and relevance of K. variicola also in animals.

Background: In several species, paraoxonase-1 (PON-1) decreases during inflammation, because of the presence of oxidative stress; its measurement recently has been validated in horses, but its role as a clinical biomarker is unknown., Objectives: To evaluate sensitivity, specificity and likelihood ratio of PON-1 activity to identify systemic inflammatory response syndrome (SIRS)-positive horses or horses with a poor prognosis., Animals: One hundred seventy-two blood samples from 58 sick horses from 3 different veterinary hospitals., Methods: In a cross-sectional study, PON-1 activity was measured upon admission and at 24-hour intervals until discharge or death, and results were analyzed based on SIRS status and outcome., Results: No statistically significant difference was found in median PON-1 activity between SIRS and non-SIRS cases or between survivors and non-survivors except for mares, in which PON-1 activity was significantly lower in SIRS-positive horses (P = .05). The sensitivity of PON-1 activity in identifying horses with SIRS or negative outcome was low (0.0%-46.2% depending on the examined group) but its specificity was high (87.0%-100.0%). However, when PON-1 is low, the likelihood of death is 2.40-3.89 times higher than the likelihood of survival. Repeated measurement of PON-1 after treatment does not predict outcome., Conclusions and Clinical Importance: Evaluation of PON-1 activity in horses with inflammation might be advisable in the future, but only low activity at admission may be relevant in predicting SIRS or negative outcome., (© 2020 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals, Inc. on behalf of the American College of Veterinary Internal Medicine.)

Proteinase-activated receptor 2 (PAR 2 ) is a G-protein-coupled receptor for trypsin and mast cell tryptase; it is highly expressed at the intestinal level with multiple functions, such as epithelial permeability and intestinal motility. The aim of the study was to evaluate the distribution and expression of proteinase-activated receptor 2 in the small intestine during herniation through epiploic foramen. In this prospective clinical study, eight horses admitted for colic and which underwent exploratory laparotomy were considered. During surgery, the jejunum or the ileum was sampled by enterectomy. Morphological examination (histology, PAR 2 immunohistochemistry) and molecular biology analysis (western blot and quantitative polymerase chain reaction) were carried out on the resected intestinal samples. The Marginal Injured Tracts (MITs) and Central Injury Tracts (CITs) were defined as the oral and caudal marginal segments of the resected bowel tract and as the geometric centre of the intestinal ischaemic lesion length, respectively. The PAR 2 immunoreactivity was particularly evident in the epithelial cells, with higher immunoreactivity in the MIT rather than in the CIT. Moreover, a different immune localisation was observed in the MITs at the cell membrane level and in the CITs in the cytoplasm. No statistical difference was observed in PAR 2 mRNA and protein (44kDa) expression between the MIT and the CIT. The PAR 2 protein content in the intestinal tracts which were removed from horses with herniation was lower when compared with the control animals. This study provided data concerning the PAR 2 presence and distribution in horses with intestinal herniation through the epiploic foramen., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Strongyle infections have been traditionally regarded as a possible cause of colic in horses. Aim of the study was the comparison of parasitological status between subjects with or without colic syndrome, with particular attention to small strongyle infections. Coprological analyses were performed on 86 horses: 43 with colic and 43 controls. Strongyle eggs were found in 34/86 horses (prevalence 39.5%), the mean number of strongyles eggs per gram of faeces (EPG) 2 was 145.34 (standard deviation 398.28). All those 34 positive animals had small strongyles infections. Negative binomial multiple regression highlighted no influence of horse sex on strongyle EPG, while there was a negative relationship between age and EPG (p <0.05); the same analysis revealed a significant difference of EPG (p <0.05) between control horses (mean EPG=178.1; standard deviation: 411.4) and horses with surgical colic (mean EPG=68.6 standard deviation: 259.8) when controlling for S. vulgaris presence including it in the model. On the contrary, the intensity of infection in horses with non-surgical colic (mean EPG=154.5; standard deviation: 480.4) did not significantly differed from controls. Similar results were obtained having estimated cyathostomine EPGs as dependent variable. Multinomial logistic regression confirmed the negative relationship between cyathostonine presence and surgical colic occurrence. It is possible that (1) the presence of adult luminal parasites, would have a protective effect against the pathogenic action exerted by the development and emergence of small strongyles larvae from intestinal mucosa; (2) the management practices able to reduce the risk of colics are the same that cause higher exposure to strongyle infective larvae., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Equine colic may be associated with an acute phase response (APR). Measurement of acute phase proteins (APPs) allows the detection of an APR and may help clinicians in monitoring the disease; however, the role of APPs in colic is unclear. This study aimed to evaluate the clinical usefulness of serum amyloid A (SAA), haptoglobin and ferritin in combination with an extended clinicopathological profile in equine colic. The medical records of 54 horses were retrospectively selected. Horses were grouped based on outcome (survivors vs. non-survivors), diagnosis (ischaemic/strangulating vs. non-ischaemic/non-strangulating), and treatment (medical treatment vs. surgery). Laboratory data were compared, and a logistic regression analysis was performed for outcome prediction upon admission. A high percentage of horses had abnormal SAA (29/54), haptoglobin (20/54), and ferritin (31/54) concentrations. In particular, haptoglobin was below the reference interval in 13/54 horses. Non-survivors had significantly decreased haptoglobin and increased ferritin concentrations compared with survivors. The ischaemic/strangulating group had significantly increased creatinine and ferritin and decreased haptoglobin concentrations compared with the non-ischaemic/non-strangulating group. Creatinine was the only significant predictor of mortality in the regression analysis. In conclusion, APPs including SAA, haptoglobin, and ferritin combined with clinicopathological variables may help clinicians to understand the pathogenesis of APR and underline potential complications of equine colic. The reduction in haptoglobin concentration may suggest haemolysis or muscle fibre damage; ferritin may indicate alteration in iron metabolism and tissue damage. Further prospective studies are needed to assess diagnostic and prognostic values of APPs in colic horses., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Simple Summary: Severe equine asthma (EA) syndrome, formerly termed Recurrent Airway Obstruction (RAO) or heaves, is one of the most common respiratory diseases in adult horses and a frequent cause of poor equine performance. The affected animals may show periods of clinical remission followed by periods of exacerbation over months to years. Therefore, the aim of the present study was to investigate the histological features, and the Neurokinin-A (NKA) and Interleukin-8 (IL-8) immunoreactivity on bronchoscopic biopsies in horses, obtained during different phases of the disease (asymptomatic, exacerbation and remission). Histological samples of EA-affected horses appeared significantly different from those of non-EA-affected horses (control group) throughout the experimental phase, from inclusion to exacerbation and remission, and intensity of NKA immunopositivity of horses with severe EA was significantly higher than that of control horses in late exacerbation and in remission phase. No significant difference between horses with severe EA in each phase and control horses was noticed for IL-8 immunoreactivity. Moreover, no influence of bronchial sampling position on histological and immunohistochemistry results was found, and it suggests that bronchial structural and functional modification during severe equine asthma tends to be distributed homogeneously throughout the respiratory tree. Severe equine asthma (EA) syndrome is a chronic obstructive disease characterized by exaggerated contraction, inflammation, and structural alteration of the airways in adult horses, when exposed to airborne molds and particulate material. However, little is known about the relationship between the degree and type of inflammation on one hand, and the severity of the disease and the response to treatment on the other. Furthermore, to date, very few studies evaluate the diagnostic value of histology and immunohistochemical features of endoscopic biopsies on subjects with severe equine asthma. To investigate the expression of two inflammatory markers (NKA and IL-8) before, during, and after the exacerbation of severe EA, a histological and immunohistochemical study was carried out on a series of biopsy samples collected by bronchoscopy from six EA-affected horses subjected to process exacerbation through environmental stimuli and then to pharmacological treatment. The application of a histological biopsy scoring system revealed a significant difference between control cases and the EA-affected horses in all experimental phases (asymptomatic, early exacerbation phase, late exacerbation phase, and remission phase). For immunohistochemistry (IHC), only the intensity of NKA positivity increases significantly between control horses and the EA horses at late exacerbation and remission phases. In EA-affected horses, a difference was detected by comparing histology between asymptomatic and remission phase, meanwhile, NKA and IL-8 showed no differences between the experimental phases. Based on these results we can assert that: (1) The endoscopic biopsies generate reliable and homogeneous samples in the entire bronchial tree; (2) the clinical improvement associated with treatment is characterized by a significant worsening of the histological findings; and (3) the NKA immunopositivity seems to increase significantly rather than decrease, as one would have expected, after pharmacological treatment. Further studies are necessary both to implement the number of samples and to use other markers of inflammation to characterize the potential role of cytokines in the diagnosis and therapeutic approach of severe equine asthma. [ABSTRACT FROM AUTHOR]