Nine-year seroepidemiological study of severe fever with thrombocytopenia syndrome virus infection in feral horses in Cape Toi, Japan.

Severe fever with thrombocytopenia syndrome (SFTS) is a fatal zoonosis caused by ticks in East Asia. As SFTS virus (SFTSV) is maintained between wildlife and ticks, seroepidemiological studies in wildlife are important to understand the behavior of SFTSV in the environment. Miyazaki Prefecture, Japan, is an SFTS-endemic area, and approximately 100 feral horses, called Misaki horses (Equus caballus), inhabit Cape Toi in Miyazaki Prefecture. While these animals are managed in a wild-like manner, their ages are ascertainable due to individual identification. In the present study, we conducted a seroepidemiological survey of SFTSV in Misaki horses between 2015 and 2023. This study aimed to understand SFTSV infection in horses and its transmission to wildlife. A total of 707 samples from 180 feral horses were used to determine the seroprevalence of SFTSV using enzyme-linked immunosorbent assay (ELISA). Neutralization testing was performed on 118 samples. In addition, SFTS viral RNA was detected in ticks from Cape Toi and feral horses. The overall seroprevalence between 2015 and 2023 was 78.5% (555/707). The lowest seroprevalence was 55% (44/80) in 2016 and the highest was 92% (76/83) in 2018. Seroprevalence was significantly affected by age, with 11% (8/71) in those less than one year of age and 96.7% (435/450) in those four years of age and older (p < 0.0001). The concordance between ELISA and neutralization test results was 88.9% (105/118). SFTS viral RNA was not detected in ticks (n = 516) or feral horses. This study demonstrated that horses can be infected with SFTSV and that age is a significant factor in seroprevalence in wildlife. This study provides insights into SFTSV infection not only in horses but also in wildlife in SFTS-endemic areas.

Serum concentrations of selenium, copper, and zinc in neonatal foals: Influence of failure of passive transfer and age-related changes.

Background: An adequate supply of trace elements is very important for equine neonates, as deficiencies can lead to health problems and even death. Objective: This study investigated serum concentrations of selenium (Se), copper (Cu), and zinc (Zn) in neonatal foals up to the 8th day of life. The influences of disease, age, and failure of passive transfer (FPT) on these concentrations were analyzed. Animals and procedure: Serum concentrations of Se, Cu, and Zn were determined from blood samples of 93 foals by means of inductively coupled plasma mass spectrometry. The foals were divided into 2 groups based on health status: clinically sick (n = 51) and clinically healthy (n = 42). The latter group was further divided into foals with FPT (n = 20) and those without (n = 22). Results: Mean serum concentrations for Se, Cu, and Zn were 60 ± 40 µg/L, 0.25 ± 0.22 mg/L, and 605 ± 285 µg/L, respectively. A significant influence of age on serum Cu concentration was observed (P < 0.0001). No differences were observed between any of the serum concentrations in clinically sick and clinically healthy foals on the 1st day of life. The FPT status was not associated with reduced serum concentrations of Se, Cu, or Zn. Conclusion and clinical relevance: It is not necessary to supplement trace elements in all foals with FPT.

Concentrations sériques de sélénium, de cuivre et de zinc chez les poulains nouveau-nés : influence de l'échec du transfert passif et des changements liés à l'âge. Contexte: Un apport suffisant en oligo-éléments est très important pour les nouveau-nés équins, car des carences peuvent entraîner des problèmes de santé, voire la mort. Objectif: Cette étude a examiné les concentrations sériques de sélénium (Se), de cuivre (Cu) et de zinc (Zn) chez les poulains nouveau-nés jusqu'au 8ème jour de vie. Les influences de maladies, de l'âge et de l'échec du transfert passif (FPT) sur ces concentrations ont été analysées. Animaux et procédure: Les concentrations sériques de Se, Cu et Zn ont été déterminées à partir d'échantillons de sang de 93 poulains au moyen d'une spectrométrie de masse à plasma à couplage inductif. Les poulains ont été divisés en 2 groupes en fonction de leur état de santé: cliniquement malades (n = 51) et cliniquement sains (n = 42). Ce dernier groupe a été divisé en poulains avec FPT (n = 20) et ceux sans (n = 22). Résultats: Les concentrations sériques moyennes de Se, Cu et Zn étaient respectivement de 60 ± 40 µg/L, 0,25 ± 0,22 mg/L et 605 ± 285 µg/L. Une influence significative de l'âge sur la concentration sérique de Cu a été observée (P < 0,0001). Aucune différence n'a été observée entre les concentrations sériques chez les poulains cliniquement malades et cliniquement sains au premier jour de leur vie. Le statut FPT n'était pas associé à une réduction des concentrations sériques de Se, Cu ou Zn. Conclusion et pertinence clinique: Il n'est pas nécessaire de supplémenter tous les poulains en oligo-éléments avec FPT.(Traduit par Dr Serge Messier).

IgE-Binding Monocytes Have an Enhanced Ability to Produce IL-8 (CXCL8) in Animals with Naturally Occurring Allergy.

IL-8 is a potent chemokine that recruits neutrophils and basophils to promote inflammation in many species. IL-8 is produced by many cell types, including monocytes. In this study, we report a novel role for IgE-binding monocytes, a rare peripheral immune cell type, to promote allergic inflammation through IL-8 production in a horse model of natural IgE-mediated allergy. We developed a mAb with confirmed specificity for both recombinant and native equine IL-8 for flow cytometric analysis. Equine IL-8 was produced by CD14+/MHC class II+/CD16- monocytes, including a subpopulation of IgE-binding monocytes, following stimulation with LPS. In addition, IgE cross-linking induced IL-8 production by both peripheral blood basophils and IgE-binding monocytes. IL-8 production was compared between healthy horses and those with a naturally occurring IgE-mediated skin allergy, Culicoides hypersensitivity. Allergic horses had significantly higher percentages of IL-8+ IgE-binding monocytes after IgE cross-linking. In contrast, frequencies of IL-8+ basophils after IgE cross-linking were similar in all horses, regardless of allergic disease, highlighting IgE-binding monocytes as a novel source of IL-8 during allergy. We concluded that IgE-binding monocytes from allergic individuals have an increased capacity for IL-8 production and likely contribute to the recruitment of innate immune cells during IgE-mediated allergy and promotion of inflammation during repeated allergen contact.

A pilot study evaluating the Calibrated Automated Thrombogram assay and application of plasma-thromboelastography for detection of hemostatic aberrations in horses with gastrointestinal disease.

BACKGROUND: Critically ill horses, such as horses with gastrointestinal (GI) disease, often suffer from hemostatic aberrations. Global hemostatic tests examining the initiation of coagulation, clot strength and fibrinolysis, such as the Calibrated Automated Thrombogram (CAT) and plasma-thromboelastography (TEG) have not been evaluated in horses. This study aimed to evaluate CAT and apply plasma-TEG in horses. Test performance of CAT was evaluated on equine platelet poor plasma with intra- and inter-assay variability (CV) and a heparin dilution curve. To examine clinical performance of both tests, group comparisons were assessed comparing healthy horses, horses with mild and severe GI disease with both CAT and plasma-TEG. RESULTS: For CAT, intra- and inter-assay CVs were established for lag-time (1.7, 4.7%), endogenous thrombin potential (1.6, 4.6%), peak (2.6, 3.9%) and time to peak (ttPeak) (1.9, 3.4%). Increasing heparin concentrations led to the expected decrease in thrombin generation. In the group comparison analysis, CAT showed significant higher peak (p = 0.04) and ttPeak (p = 0.008) in the severe GI disease group compared to horses with mild GI disease and healthy horses, respectively. Plasma-TEG showed an increased angle (p = 0.032), maximum amplitude (p = 0.017) and shear elastic force (G) (p = 0.017) in the severe GI disease group compared to healthy horses. CONCLUSIONS: CAT performed well in horses. Both CAT and plasma-TEG identified hemostatic aberrations in horses with severe GI disease compared to healthy horses. Further studies including more horses, are needed to fully appreciate the use of CAT and plasma-TEG in this species.

Evaluation of fasting plasma insulin and proxy measurements to assess insulin sensitivity in horses.

BACKGROUND: Proxies are mathematical calculations based on fasting glucose and/or insulin concentrations developed to allow prediction of insulin sensitivity (IS) and ß-cell response. These proxies have not been evaluated in horses with insulin dysregulation. The first objective of this study was to evaluate how fasting insulin (FI) and proxies for IS (1/Insulin, reciprocal of the square root of insulin (RISQI) and the quantitative insulin sensitivity check index (QUICKI)) and ß-cell response (the modified insulin-to-glucose ratio (MIRG) and the homeostatic model assessment of ß-cell function (HOMA-ß)) were correlated to measures of IS (M index) using the euglycemic hyperinsulinemic clamp (EHC) in horses with insulin resistance (IR) and normal IS. A second objective was to evaluate the repeatability of FI and proxies in horses based on sampling on consecutive days. The last objective was to investigate the most appropriate cut-off value for the proxies and FI. RESULTS: Thirty-four horses were categorized as IR and 26 as IS based on the M index. The proxies and FI had coefficients of variation (CVs) ≤ 25.3 % and very good reliability (intraclass correlation coefficients ≥ 0.89). All proxies and FI were good predictors of the M index (r = 0.76-0.85; P < 0.001). The proxies for IS had a positive linear relationship with the M index whereas proxies for ß-cell response and FI had an inverse relationship with the M index. Cut-off values to distinguish horses with IR from horses with normal IS based on the M index were established for all proxies and FI using receiver operating characteristic curves, with sensitivity between 79 % and 91 % and specificity between 85 % and 96 %. The cut-off values to predict IR were < 0.32 (RISQI), < 0.33 (QUICKI) and > 9.5 µIU/mL for FI. CONCLUSIONS: All proxies and FI provided repeatable estimates of horses' IS. However, there is no advantage of using proxies instead of FI to estimate IR in the horse. Due to the heteroscedasticity of the data, proxies and FI in general are more suitable for epidemiological studies and larger clinical studies than as a diagnostic tool for measurement of IR in individual horses.

Serum albumin and total protein concentration in the tear film of horses with healthy or diseased eyes.

OBJECTIVE: To determine total protein content (TPC) and serum albumin levels in the tears of horses with healthy or diseased eyes. ANIMALS STUDIED: Forty-two horses with healthy eyes and 11 horses with unilateral (n = 10) or bilateral (n = 1) ocular disease. PROCEDURE: Each eye underwent an ophthalmic examination including detailed conjunctivitis scoring and tear collection with Schirmer strips. TPC and serum albumin levels were quantified in tear samples and compared among healthy eyes, affected eyes, and contralateral unaffected eyes. The impact of the following variables on lacrimal protein levels were assessed: age, breed, and sex (healthy eyes), as well as conjunctivitis score (diseased eyes). RESULTS: Lacrimal TPC ranged from 7.0 to 19.5 mg/mL in healthy eyes, while serum albumin ranged from 71.1 to 711.3 µg/mL (~1.6% of TPC) and was higher in tears of aged and female horses (P ≤ .033). Eyes with ocular disease had significantly greater (P ≤ .001) serum albumin in tears (median 679.6 µg/mL) compared to contralateral unaffected eyes (130.0 µg/mL) and eyes of the reference population (200.7 µg/mL). However, lacrimal TPC did not differ significantly among the 3 groups. Scoring of palpebral conjunctival hyperemia trended toward a positive association with serum albumin in tears (r = 0.49, P = .062). CONCLUSIONS: The protein profile in equine tears differs in health and disease. Serum albumin in tears increases with ocular disease and, similar to other species, might serve as a biomarker for ocular insult in horses. Future studies could investigate the protein levels in horses with specific ocular conditions and help determine the biological importance of albumin on the equine ocular surface.

Metabogenomics reveals four candidate regions involved in the pathophysiology of Equine Metabolic Syndrome.

An analogous condition to human metabolic syndrome, Equine Metabolic Syndrome (EMS) is defined by several clinical signs including obesity, hyperinsulinemia, and peripheral insulin dysregulation (ID). Affected horses may also exhibit hypertension, hyperlipemia and systemic inflammation. Measures of ID typically comprise the gold-standard for diagnosis in veterinary care. Yet, the dynamic nature of insulin homeostasis and complex procedures of typical assays make accurate quantification of ID and EMS challenging. This work aimed to investigate new strategies for identification of biochemical markers and correlated genes in EMS. To quantify EMS risk within this population, we utilized a composite score derived from nine common diagnostic variables. We applied a global liquid chromatography/mass spectroscopy approach (HPLC/MS) to whole plasma collected from 49 Arabian horses, resulting in 3392 high-confidence features and identification of putative metabolites in public databases. We performed a genome wide association analysis with genotypes from the 670k Affymetrix Equine SNP array utilizing EMS-correlated metabolites as phenotypes. We discovered four metabolite features significantly correlated with EMS score (P < 1.474 × 10-5). GWAs for these features results (P = 6.787 × 10-7, Bonferroni) identified four unique candidate regions (r2 > 0.4) containing 63 genes. Significant genomic markers capture 43.52% of the variation in the original EMS score phenotype. The identified genomic loci provide insight into the pathways controlling variation in EMS and the origin of genetic predisposition to the condition. Rapid, feasible and accurate diagnostic tools derived from metabogenomics can be translated into measurable benefits in the timeline and quality of preventative management practices to preserve health in horses.

Serial measurements of Paraoxonase-1 (PON-1) activity in horses with experimentally induced endotoxemia.

BACKGROUND: Paraoxonase-1 (PON-1) is an antioxidant enzyme, whose activity decreases during the acute phase response in many species. Little is known about PON-1 and its role as a negative acute phase protein during septic inflammation in horses, but promising findings about its utility in diagnosing SIRS and predicting the outcome in diseased horses, were recently highlighted. The objective of the study was to investigate the behaviour of PON-1 in horses after experimentally induced endotoxemia. To this aim, PON-1 activity was measured on 66 plasma samples collected from six clinically healthy mares, previously included in another study, before and at multiple time points between 12 and 240 h after intravenous infusion of Escherichia coli O55:B5 lipopolysaccharide (LPS). RESULTS: Compared with baseline values, a progressive transient decrease of PON-1 activity was observed starting from 24 h post-infusion, with lowest values observed between 3 to 7 days post-infusion, followed by a normalisation to pre-infusion levels the tenth day. CONCLUSIONS: The results of this study suggest that measurement and monitoring of PON-1 activity might be useful to evaluate progression and recovery from endotoxemia in horses. Further studies in horses with naturally occurring sepsis are warranted.

Weight loss is linearly associated with a reduction of the insulin response to an oral glucose test in Icelandic horses.

BACKGROUND: Insulin dysregulation (ID) goes along with lasting or transient hyperinsulinemia able to trigger equine laminitis, a painful and crippling foot condition. Promoting weight loss through dietary changes and physical activity is currently the main option to prevent this disease. This study aimed at describing the relationship between weight variations and the level of ID as determined by oral glucose tests (OGT). Therefore, the insulin response of 19 Icelandic horses to repeated OGTs was retrospectively analysed considering the variations in their body weight. RESULTS: There was a strong linear relationship between variations in body weight and variations in the total insulin response to OGT as approximated by the area under the curve of insulin (p < 0.001). As indicated by a weighted least squares model, the insulin response decreased by 22% for 5% weight loss on average. However some horses did not respond to weight loss with a reduction of their insulin response to OGT. Additionally, a high correlation between 120 min serum insulin concentration and total insulin response was observed (r = 0.96, p < 0.001). CONCLUSIONS: The results corroborate that weight loss is effective against ID and allow for a better quantification of the expected improvement of the insulin response after weight loss. However, it is unclear why some horses did not respond as expected. The high correlation between the 120 min insulin concentration and total insulin response suggests that insulin status can be accurately determined and monitored with only few samples in a practical setting.

Serum symmetric dimethylarginine concentration in healthy horses and horses with acute kidney injury.

BACKGROUND: There are limited options to diagnose acute kidney injury (AKI) in horses. Symmetric dimethylarginine (SDMA) is routinely used in human and small animal medicine. The aim of this study was to assess serum SDMA concentrations in healthy horses and horses with AKI. The objective of this study was to evaluate the association of: 1) age, 2) sex, 3) body weight and 4) serum creatinine and urea levels on serum SDMA concentrations. Fifty-three healthy horses, including 17 foals (2-6 months of age) and 36 adult horses (3-29 years of age), and 23 horses with AKI were included in the study based on history, physical examination, blood analysis, urinalysis and an ultrasonographic examination of the urinary tract. Serum SDMA concentrations were measured using a non-species specific commercial ELISA test. RESULTS: In healthy adult horses, the value of SDMA was 0.53 ± 0.14 µmol/L. The value was higher in foals (1.5 ± 0.4 µmol/L, P < 0.001). Horses with AKI had significantly higher concentrations of SDMA compared to healthy horses (1.76 ± 1.05 µmol/L, P < 0.001). In the healthy adult horses, there was no association of sex, age or body weight on SDMA. However, a significant positive relationship was found between serum creatinine and SDMA concentrations. CONCLUSIONS: Healthy adult horses had SDMA values similar to those of other species. Foals had higher SDMA values. Therefore, different reference values should be created for them. The study confirmed an increased SDMA in horses with AKI. This, as well as the low influence of extrarenal factors on the SDMA values, may confirm its usefulness in the diagnosis of kidney dysfunction. Higher SDMA values may also indicate a more advanced degree of kidney dysfunction. Further research is required to determine whether SDMA could be used to detect kidney dysfunction in the asymptomatic stage of AKI.

Utility of systemic voriconazole in equine keratomycosis based on pharmacokinetic-pharmacodynamic analysis of tear fluid following oral administration.

OBJECTIVE: To clarify the detailed pharmacokinetics (PK) of orally administered voriconazole in tear fluid (TF) of horses for evaluating the efficacy of voriconazole secreted into TF against equine keratomycosis. ANIMALS STUDIED: Five healthy Thoroughbred horses. PROCEDURES: Voriconazole was administrated through a nasogastric tube to each horse at a single dose of 4.0 mg/kg. TF and blood samples were collected before and periodically throughout the 24 hours after administration. Voriconazole concentrations in plasma and TF samples were analyzed using liquid chromatography-electrospray tandem-mass spectrometry. The predicted voriconazole concentration in both samples following multiple dosing every 24 hours was simulated by the superposition principle. RESULTS: The mean maximum voriconazole concentrations in plasma and TF were 3.3 µg/mL at 1.5 h and 1.9 µg/mL at 1.6 h, respectively. Mean half-life in both samples were 16.4 and 25.2 h, respectively. The ratio of predicted AUC0-24 at steady state in TF (51.3 µg∙h/mL) to previously published minimum inhibitory concentration (MIC) of Aspergillus and Fusarium species was >100 and 25.7, respectively. CONCLUSIONS: This study demonstrated the detailed single-dose PK of voriconazole in TF after oral administration and simulated the predicted concentration curves in a multiple oral dosing. Based on the analyses of PK-PD, the simulation results indicated that repeated oral administration of voriconazole at 4.0 mg/kg/d achieves the ratio of AUC to MIC associated with treatment efficacy against Aspergillus species. The detailed PK-PD analyses against pathogenic fungi in TF can be used to provide evidence-based medicine for equine keratomycosis.

Chitosan-based agent use for hemostasis after cryptorchidectomy in a horse.

OBJECTIVE: To document marked hemorrhage as a complication of inguinal cryptorchidectomy and its successful treatment with a novel chitosan-based hemostatic agent. STUDY DESIGN: Case report. ANIMALS: One healthy 5-year old quarter horse cryptorchid. METHODS: The horse was presented for routine unilateral cryptorchidectomy after prior hemicastration. An inguinal approach was made to the abdomen, and the right external pudendal artery was lacerated at the level of the internal inguinal ring, requiring multiple anesthetic events over a 2-week period in attempts to control hemorrhage. A chitosan-based hemostatic agent was packed into the wound to gain control. RESULTS: Chitosan granules placed in the wound successfully controlled the hemorrhage, whereas the use of gauze packing alone failed. There were no immediate or long-term complications to the chitosan granules; the horse was doing well 18 months postoperatively, and the client was satisfied with the outcome. CONCLUSION: Major hemorrhage was demonstrated from the external pudendal artery and caused difficulties because it occurred deep within the inguinal canal during an inguinal cryptorchidectomy. A chitosan-based hemostatic agent was successfully used to achieve hemostasis. CLINICAL SIGNIFICANCE: The external pudendal artery should be avoided in the medial commissure of the inguinal canal. The use of chitosan-based hemostatic agents warrants further investigation in horses because these products may be useful for controlling major hemorrhage from various causes in equine practice.

Prognostic value of colonic and peripheral venous lactate measurements in horses with large colon volvulus.

OBJECTIVE: To determine the prognostic value of (1) colonic venous lactate or peripheral lactate values obtained before and after manual correction of a large colon volvulus and (2) a combination of variables including pelvic flexure biopsy. STUDY DESIGN: Prospective clinical study. ANIMALS: Forty adult horses in which large colon volvulus was diagnosed intraoperatively. METHODS: Colonic venous, peripheral venous, and arterial blood samples were collected to measure lactate values before and after manual correction. Mucosal biopsy samples were obtained in cases that underwent enterotomy or colonic resection and anastomosis. Interstitium to crypt (I:C) ratio and hemorrhage scores were measured. Optimal cutoff values were determined by receiver operator curve analysis, and associations between variables and short-term outcome were determined by univariable regression. Short-term survival was defined as horses being discharged from the hospital. P ≤ .05 was considered significant. RESULTS: No association was found between colonic venous lactate values before (P = .011) or after (P = .201) manual correction of large colon volvulus and determination of short-term outcome. Peripheral venous lactate at admission ≥3.2 mmol/L and after manual correction ≥5 mmol/L, arterial lactate postmanual correction ≥3.53 mmol/L, and histomorphometric measurements of mucosal hemorrhage ≥3 and I:C ratio > 1 were associated with poor short-term outcome. CONCLUSION: Peripheral lactate values, histomorphometric measures of I:C ratio, and hemorrhage score provided prognostic information that could help guide recommendations made to owners. CLINICAL SIGNIFICANCE: Peripheral lactate values after manual correction provide important intraoperative diagnostic information to assist in predicting case outcome in the operative and immediately postoperative period.

Alterations of serum vitamin E and vitamin A concentrations of ponies and horses during experimentally induced obesity.

Vitamin A, vitamin E and retinol-binding protein 4 (RBP4) are a focus of current obesity research in humans. The impact of body weight (BW) gain on fat-soluble vitamins and its associated parameters in equines has not been previously reported. Ten Shetland ponies and 9 Warmblood horses, all adult geldings, non-obese and healthy, were fed an excessive energy diet for 20 months to induce BW gain. Serum α-tocopherol (vitamin E), retinol (vitamin A), retinol-binding protein 4 (RBP4) and retinol/RBP4 ratio were analysed before BW gain induction and at six timepoints during the BW gaining period. The mean (±SD) % BW gain achieved during two years of excess energy intake was 29.9 ± 19.4% for ponies and 17 ± 6.74% for horses. Serum α-tocopherol increased significantly in ponies and horses during excess energy intake and circulating α-tocopherol levels correlated positively with α-tocopherol intake (r = .6; p < .001). Serum retinol concentrations showed variations during the study but without relation to intake. Serum RBP4 decreased at the end of the study. The retinol/RBP4 ratio increased with BW gain without differences between ponies and horses. In comparison with human research, the increase in the retinol/RBP4 ratio was unexpected and needs further elucidation.

Point-of-Care Diagnostics in Equine Practice.

Point-of-care testing (POCT) refers to benchtop diagnostic modalities that have been translated into portable and easy-to-use formats suitable for patient-side use. Recent advances in diagnostic technology have allowed the development of a growing collection of POCT assays available to equine practitioners. Advantages include rapid results that reduce initial guesswork and promote diagnosis-targeted patient care, which may ultimately provide better clinical outcomes. Small handheld devices comprise most POCT technologies, providing qualitative or quantitative determination of an increasing range of analytes, including critical care analyzers and, more recently, hematology and immunology analyzers. This article discusses commercially available equine POCT.

Hematology Red Flags: The Value of Blood Smear Examination in Horses.

This article uses a case-based approach, complemented with diagnostic algorithms and images, to highlight hematologic changes of pathologic relevance in horses, namely, marked erythrocytosis, anemia or leukocytosis, inflammatory leukograms, lymphocytosis in adult horses, thrombocytopenia, and pancytopenia. These hematologic abnormalities occur with certain diseases and their identification can help clinicians narrow to down differential diagnostic lists. This article highlights the importance of blood smear examination, particularly, but not only, when numerical red flags are identified on automated blood counts.

Coagulation Assessment in the Equine Patient.

Horses with clinical signs of unprovoked or excessive hemorrhage should be evaluated for underlying platelet defects or coagulopathies. This article provides an overview of preliminary screening and definitive tests to assess coagulation and identify hemostatic defects in horses, as well as a review of the hemostatic disorders most frequently encountered in clinical practice.

Equine Inflammatory Markers in the Twenty-First Century: A Focus on Serum Amyloid A.

Serum amyloid A (SAA) is a marker of inflammation and infection in the horse that can be assessed in the field, with rapid and marked changes seen following initiation of an inflammatory stimulus. This quality of SAA also makes its clinical use challenging, because even small inflammatory conditions can cause large changes in SAA levels. Review of the current literature provides guidelines for responses of SAA to various conditions, which can be applied to specific clinical cases. The practitioner is encouraged to use SAA in conjunction with physical examination and other diagnostic modalities to guide treatment and monitor case progression.

Bone Marrow Examination: Why, How, and What to Expect from the Pathologist.

This article describes the indications for sampling of bone marrow, the technical aspects of obtaining marrow core biopsies and aspirates, and the preparation of marrow smears. All aspects are illustrated with clinical cases. The information that can be expected from the pathologist's report of marrow samples is outlined, and the clinical features and prognosis of different types of leukemia are detailed.

The Sick Adult Horse: Renal Clinical Pathologic Testing and Urinalysis.

Clinicopathologic evaluation of renal function and renal disease in sick adult horses remains grounded in detection of azotemia, assessment of serum and urine electrolyte concentrations, and evaluation of urinalysis findings, including specific gravity, reagent strip analysis, and sediment examination. Because increases in serum or plasma urea nitrogen and creatinine concentrations are insensitive indicators of a decreased glomerular filtration rate, there is considerable interest in identifying novel biomarkers of renal function or injury in blood and urine, with serum symmetric dimethylarginine concentration being the most recent addition to the commercial market.