N M Slovis

Lexington Equine Surgery and Sports Medicine, Lexington, Kentucky, United States

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Publications (41)67.62 Total impact

  • Allen E. Page, Nathan M. Slovis, David W. Horohov
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    ABSTRACT: Lawsonia intracellularis is the etiologic agent for equine proliferative enteropathy (EPE), which typically affects weanling and yearling horses. In North America, EPE cases often occur between August and January, although cases outside of this time frame have been reported. Clinical signs of EPE are usually nonspecific and include lethargy, pyrexia, anorexia, peripheral edema, weight loss, colic, and diarrhea. Diagnosis is based on the presence of hypoproteinemia and hypoalbuminemia along with clinical signs and positive commercial serologic and/or molecular testing. Treatment requires the use of antimicrobials with good intracellular penetration and supportive care to prevent or decrease secondary complications.
    Veterinary Clinics of North America Equine Practice 10/2014; · 1.05 Impact Factor
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    ABSTRACT: Background Bacterial sepsis remains a leading cause of morbidity and mortality in neonatal foals, but accurate diagnostic and prognostic markers are lacking. Adrenomedullin (AM) is a polypeptide with diverse biologic effects on the cardiovascular system that increases in septic humans and laboratory animals.HypothesesPlasma AM concentration (p[AM]) is increased in septic neonatal foals compared to sick nonseptic and healthy control foals, and p[AM] is predictive of survival in septic neonatal foals.AnimalsNinety critically ill (42 septic, 48 sick nonseptic) and 61 healthy foals <1 week of age.MethodsA prospective observational clinical study was performed. Venous blood was collected from critically ill foals at admission and from healthy foals at 24 hours of age. Critically ill foals were categorized as septic or sick nonseptic based on blood culture results and sepsis score. Plasma [AM] was measured by using a commercially available ELISA for horses. Data were analyzed by using the Mann-Whitney U-test and P < .05 was considered significant.ResultsPlasma [AM] was not significantly different between septic and sick nonseptic foals (P = .71), but critically ill foals had significantly increased p[AM] compared to healthy controls (P < .0001). In critically ill foals, p[AM] was not predictive of survival (P = .051). A p[AM] cutoff concentration of 0.041 ng/mL provided a test sensitivity of 91% and specificity of 54% to predict illness.Conclusions and Clinical RelevancePlasma [AM] shows promise as a marker of health in neonatal foals, but p[AM] increases nonspecifically during perinatal illnesses and is not necessarily associated with sepsis.
    Journal of Veterinary Internal Medicine 04/2014; · 2.06 Impact Factor
  • The Veterinary record. 02/2014;
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    ABSTRACT: The epidemiology of equine neorickettsiosis (EN) has been extensively studied but limited clinical and clinicopathological data are available concerning naturally infected horses. Factors predictive of survival will be identified in horses diagnosed with EN. Convenience sample of 44 horses with EN admitted to 2 referral institutions. A retrospective study was performed. A diagnosis of EN was based on the presence of positive blood or fecal PCR. The most common clinical signs included diarrhea (66%), fever (50%), anorexia (45%), depression (39%), colic (39%), and lameness (18%). The median duration of hospitalization was 6 days and 73% of horses survived to discharge. Laminitis was present in 36% of horses, 88% of which were affected in all 4 feet. Serum creatinine and urea nitrogen concentrations, as well as RBC count, blood hemoglobin concentration, hematocrit, band neutrophils, serum AST activity, serum CK activity, and anion gap, were significantly (P < .05) higher in nonsurvivors. Serum chloride and sodium, concentrations as well as duration of hospitalization were significantly lower in nonsurvivors. The results of forward stepwise logistic regression indicated that blood hemoglobin concentration on admission and antimicrobial treatment with oxytetracycline were independent factors associated with survival. Severity of colitis as reflected by electrolyte loss, hemoconcentration, and prerenal azotemia were predictors of survival in horses diagnosed with EN. Treatment with oxytetracycline was associated with increased survival.
    Journal of Veterinary Internal Medicine 10/2013; · 2.06 Impact Factor
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    ABSTRACT: REASONS FOR PERFORMING STUDY: Diarrhoea caused by infectious agents is common in foals but there is no comprehensive molecular workup of the relative prevalence of common agents and the appearance of coinfections. OBJECTIVES: To determine the prevalence of 9 infectious agents in GI diseased and healthy foals with ages ranging from one to 20 weeks of age, and to what degree co-infections are associated with clinical signs of GI disease. STUDY DESIGN: Retrospective controlled observational study. METHODS: The population consisted of 88 Thoroughbred foals ages 2 days to 17 weeks born on 32 different stud farms in Kentucky. Healthy (n = 37) and GI diseased (n = 51) foals were identified based on clinical presentation. Fecal samples were analysed for 9 infectious agents by real-time PCR: equine rotavirus, equine coronavirus, Clostridium difficile toxin A & B, Neorickettsia risticii, Clostridium perfringens alpha toxin, Lawsonia intracellularis, Rhodococcus equi, Cryptosporidium spp., and Salmonella spp. Salmonella was also cultured from overnight selenite enrichment broth. RESULTS: The prevalence of infectious pathogens under study was between 0% (Lawsonia intracellularis) and 34.6% (equine rotavirus). The overall prevalence for any infectious agent was 63.2% in the GI diseased group and 43.2% in the healthy group. Coinfections were significantly more frequent in the sick group (15 monoinfections versus 22 coinfections) than in the healthy group (12 versus 4, respectively, p = 0.0002). Six of the 8 infectious agents were associated with the GI diseased group, the other 2 were not (equine coronavirus and R. equi). CONCLUSIONS: The use of panels rather than individual tests in combination with quantitative toxin gene analysis enables the detection of co-infections that are significantly associated with risk of disease. Several infectious diseases previously not tested for or considered unimportant were found at high prevalence and require further investigation.
    Equine Veterinary Journal 06/2013; · 2.37 Impact Factor
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    ABSTRACT: REASONS FOR PERFORMING STUDY: Resistance to the somatotropic axis and increases in ghrelin concentrations have been documented in critically ill humans, but limited information exists in healthy or sick foals. OBJECTIVES: To investigate components of the somatotropic axis (ghrelin, growth hormone and insulin-like growth factor-1 [IGF-1]) in regard to energy metabolism (glucose and triglycerides), severity of disease and survival in critically ill equine neonates. We hypothesised that ghrelin and growth hormone would increase and IGF-1 would decrease in proportion to severity of disease, supporting somatotropic axis resistance, which would be associated with severity of disease and mortality in sick foals. STUDY DESIGN: Prospective multi-centre cross-sectional study. METHODS: Blood samples were collected at admission from 44 septic, 62 sick non-septic (SNS), and from 19 healthy foals, all <7 days of age. Foals with positive blood cultures or sepsis scores ≥12 were considered septic, foals with sepsis scores between 5 and 11 were classified as SNS. Data was analysed by nonparametric methods and multivariate logistic regression. RESULTS: Septic foals had higher ghrelin, growth hormone and triglyceride and lower IGF-1 and glucose concentrations than healthy foals (P<0.01). SNS foals had higher growth hormone and triglycerides and lower IGF-1 concentrations than healthy foals (P<0.05). Growth hormone:IGF-1 ratio was higher in septic and SNS foals than healthy foals (P<0.05). Hormone concentrations were not different between septic non-survivors (n = 14) and survivors (n = 30), but the growth hormone:IGF-1 ratio was lower in non-survivors (P = 0.043). CONCLUSIONS: Somatotropic axis resistance, characterised by a high growth hormone:IGF-1 ratio, was frequent in sick foals, associated with the energy status (hypoglycaemia, hypertriglyceridemia) and with mortality in septic foals. POTENTIAL RELEVANCE: A functional somatotropic axis appears to be important for foal survival during sepsis. Somatotropic resistance is likely to contribute to severity of disease, a catabolic state and likelihood of recovery.
    Equine Veterinary Journal 04/2013; · 2.37 Impact Factor
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    ABSTRACT: BACKGROUND: The renin-angiotensin-aldosterone system (RAAS) and hypothalamic-pituitary-adrenal axis (HPAA) and their interactions during illness and hypoperfusion are important to maintain organ function. HPAA dysfunction and relative adrenal insufficiency (RAI) are common in septic foals. Information is lacking on the RAAS and mineralocorticoid response in the context of RAI in newborn sick foals. OBJECTIVES/HYPOTHESIS: To investigate the RAAS, as well as HPAA factors that interact with the RAAS, in hospitalized foals, and to determine their association with clinical findings. We hypothesized that critical illness in newborn foals results in RAAS activation, and that inappropriately low aldosterone concentrations are part of the RAI syndrome of critically ill foals. ANIMALS: A total of 167 foals ≤3 days of age: 133 hospitalized (74 septic, 59 sick nonseptic) and 34 healthy foals. METHODS: Prospective, multicenter, cross-sectional study. Blood samples were collected on admission. Plasma renin activity (PRA) and angiotensin-II (ANG-II), aldosterone, ACTH, and cortisol concentrations were measured in all foals. RESULTS: ANG-II, aldosterone, ACTH, and cortisol concentrations as well as ACTH/aldosterone and ACTH/cortisol ratios were higher in septic foals compared with healthy foals (P < .05). No difference in PRA between groups was found. High serum potassium and low serum chloride concentrations were associated with hyperaldosteronemia in septic foals. CONCLUSIONS AND CLINICAL IMPORTANCE: RAAS activation in critically ill foals is characterized by increased ANG-II and aldosterone concentrations. Inappropriately low cortisol and aldosterone concentrations defined as high ACTH/cortisol and ACTH/aldosterone ratios in septic foals suggest that RAI is not restricted to the zona fasciculata in critically ill newborn foals.
    Journal of Veterinary Internal Medicine 02/2013; · 2.06 Impact Factor
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    ABSTRACT: Macrolide and rifampin resistance developed on a horse breeding farm after widespread use was instituted for treatment of subclinical pulmonary lesions in foals. Resistance occurred in 6 (24%) of 25 pretreatment and 8 (62%) of 13 (62%) posttreatment isolates from affected foals. Drug-resistant isolates formed 2 distinct genotypic clusters.
    Emerging Infectious Diseases 02/2013; 19(2):282-5. · 7.33 Impact Factor
  • S L Ness, L A Kennedy, N M Slovis
    Journal of Veterinary Internal Medicine 01/2013; · 2.06 Impact Factor
  • Journal of Veterinary Internal Medicine 10/2012; · 2.06 Impact Factor
  • Journal of Equine Veterinary Science 10/2012; 32(10):S37. · 0.62 Impact Factor
  • N.M. Slovis, J.P. Elam
    Journal of Equine Veterinary Science 10/2012; 32(10):S41–S42. · 0.62 Impact Factor
  • Journal of Equine Veterinary Science 10/2012; 32(10):S44–S45. · 0.62 Impact Factor
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    ABSTRACT: Objective-To determine whether the concentration of airborne virulent Rhodococcus equi varied by location (stall vs paddock) and month on horse farms. Sample-Air samples from stalls and paddocks used to house mares and foals on 30 horse breeding farms in central Kentucky. Procedures-Air samples from 1 stall and 1 paddock were obtained monthly from each farm from January through June 2009. Concentrations of airborne virulent R equi were determined via a modified colony immunoblot assay. Random-effects logistic regression was used to determine the association of the presence of airborne virulent R equi with location from which air samples were obtained and month during which samples were collected. Results-Of 180 air samples, virulent R equi was identified in 49 (27%) and 13 (7%) obtained from stalls and paddocks, respectively. The OR of detecting virulent R equi in air samples from stalls versus paddocks was 5.2 (95% confidence interval, 2.1 to 13.1). Of 60 air samples, virulent R equi was identified in 25 (42%), 18 (30%), and 6 (10%) obtained from stalls during January and February, March and April, and May and June, respectively. The OR of detecting virulent R equi from stall air samples collected during May and June versus January and February was 0.22 (95% confidence interval, 0.08 to 0.63). Conclusions and Clinical Relevance-Foals were more likely to be exposed to airborne virulent R equi when housed in stalls versus paddocks and earlier (January and February) versus later (May and June) during the foaling season.
    American Journal of Veterinary Research 10/2012; 73(10):1603-9. · 1.21 Impact Factor
  • Journal of Equine Veterinary Science 10/2012; 32(10):S94-S95. · 0.89 Impact Factor
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    ABSTRACT: Rhodococcus equi, a gram-positive facultative intracellular pathogen, is one of the most common causes of pneumonia in foals. Although R. equi can be cultured from the environment of virtually all horse farms, the clinical disease in foals is endemic at some farms, sporadic at others, and unrecognized at many. On farms where the disease is endemic, costs associated with morbidity and mortality attributable to R. equi may be very high. The purpose of this consensus statement is to provide recommendations regarding the diagnosis, treatment, control, and prevention of infections caused by R. equi in foals.
    Journal of Veterinary Internal Medicine 11/2011; 25(6):1209-20. · 2.06 Impact Factor
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    ABSTRACT: Pneumonia is a major cause of disease and death in foals. Rhodococcus equi, a Gram-positive facultative intracellular pathogen, is a common cause of pneumonia in foals. This article reviews the clinical manifestations of infection caused by R. equi in foals and summarizes current knowledge regarding mechanisms of virulence of, and immunity to, R. equi. A complementary consensus statement providing recommendations for the diagnosis, treatment, control, and prevention of infections caused by R. equi in foals can be found in the same issue of the Journal.
    Journal of Veterinary Internal Medicine 10/2011; 25(6):1221 - 1230. · 2.06 Impact Factor
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    ABSTRACT: Rhodococcus equi is a significant cause of pneumonia, resulting in disease and sometimes death of foals. It is believed that infection occurs by inhalation of dust contaminated with virulent R equi. Although association between the airborne concentration of virulent R equi and the incidence of foal pneumonia at breeding farms has been documented, studies at the level of individual foals have not been reported. Thus, the objective of this study was to determine whether the magnitude of airborne virulent R equi was significantly associated with risk of R equi pneumonia for individual foals. The concentration of virulent R equi was significantly (P < .001) greater in stalls than paddocks among samples collected from 47 foals at a breeding farm in central Kentucky. The presence of airborne virulent R equi in stalls was significantly (P = .045) more likely at 7 days of age for foals subsequently found to be affected by rhodococcal pneumonia. Additionally, airborne concentrations of virulent R equi in stalls were significantly greater at 7 and 14 days of age than at birth. Presence of the mare and foal at the time of sampling was significantly (P < .001) associated with increased airborne concentrations of virulent R equi in stalls. These findings suggest that environments containing airborne virulent R equi during the first week of life may influence the risk of subsequent disease for a foal.
    Journal of Equine Veterinary Science 08/2011; 31(8):463-469. · 0.89 Impact Factor
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    ABSTRACT: Equine proliferative enteropathy caused by Lawsonia intracellularis is an emerging disease with as yet unaddressed preventative measures. The hypothesis of this study was that vaccination will prevent clinical and sub-clinical disease. Weanling Thoroughbreds (n=202) from Central Kentucky were randomly assigned into two groups (vaccinated and non-vaccinated). Vaccinated foals received 30 mL of an avirulent, live L. intracellularis vaccine intra-rectally twice, 30 days apart. Foals were monitored for clinical disease, total solids and average weight gain until yearling age. There was an overall decreased disease incidence on the farms involved in the study that did not differ significantly between the groups. This decreased disease prevalence in the study population may be associated with the ongoing vaccine trial on these farms, as disease prevalence in Central Kentucky did not change in 2009 compared to 2008.
    The Veterinary Journal 07/2011; 192(3):511-3. · 2.17 Impact Factor
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    ABSTRACT: To assess the serial use of serum immunoperoxidase monolayer assays (IPMAs) and fecal PCR assays, combined with other diagnostic methods, to identify subclinical Lawsonia intracellularis infections for targeted treatment of Thoroughbred foals and weanlings at farms in which the pathogen was endemic or nonendemic. Evaluation study. 100 foals and weanlings (53 and 47 at farms in which L intracellularis was endemic and nonendemic, respectively). Serum was collected every 4 weeks and tested via IPMA, for antibodies against L intracellularis. Fecal samples were collected every 2 weeks and tested by use of an L intracellularis-specific PCR assay. When results for IPMAs or PCR assays were positive or clinical signs compatible with equine proliferative enteropathy (EPE) were detected, clinicopathologic testing was performed to determine treatment. No foals had positive results for the L intracellularis-specific IPMA until after weaning; 32 of 53 (60.4%) weanlings at the farm in which L intracellularis was endemic and 8 of 47 (170%) at the farm in which L intracellularis was nonendemic had positive IPMA results, whereas the number of weanlings that tested positive via fecal PCR assays at those farms was 6 and 0, respectively. Nineteen of 32 weanlings with positive IPMA results at the farm in which L intracellularis was endemic were treated for EPE; 5 of these had clinical signs of EPE. No weanlings at the nonendemic farm had clinical signs of or were treated for EPE. IPMA appeared to be a useful means of identifying weanlings exposed to L intracellularis.
    Journal of the American Veterinary Medical Association 06/2011; 238(11):1482-9. · 1.67 Impact Factor

Publication Stats

238 Citations
67.62 Total Impact Points

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Institutions

  • 2006–2014
    • Lexington Equine Surgery and Sports Medicine
      Lexington, Kentucky, United States
  • 2013
    • The Ohio State University
      • Department of Veterinary Clinical Sciences
      Columbus, OH, United States
  • 2011
    • Lexington Medical Center
      West Columbia, South Carolina, United States
  • 2007–2011
    • Texas A&M University
      • Department of Large Animal Clinical Sciences
      College Station, TX, United States
  • 2010
    • University of Georgia
      • Department of Large Animal Medicine
      Athens, GA, United States
    • University of Florida
      • Department of Large Animal Clinical Sciences
      Gainesville, Florida, United States
  • 2003
    • University of Kentucky
      Lexington, Kentucky, United States