Absence of equid herpesvirus-1 reactivation and viremia in hospitalized critically ill horses

Background: Equid herpesvirus‐1 (EHV‐1) reactivation and shedding can occur in latently infected, asymptomatic animals. Risk factors for reactivation include stress and illness. The risk of asymptomatic shedding in hospitalized, critically ill horses with acute abdominal disease is unknown. This information is important to assess the need for additional biosecurity protocols to prevent spread of EHV‐1 in hospitalized critically ill horses with acute abdominal disorders. Objectives: To determine the frequency of reactivation and nasal shedding of EHV‐1 in hospitalized critically ill horses. Animals: One hundred twenty‐four client‐owned horses admitted to the Veterinary Teaching Hospital with acute abdominal disorders were included in the study. Methods: Cross‐sectional study examining the risk of reactivation of EHV‐1 in horses admitted with acute, severe, gastrointestinal disease. Whole blood and nasal secretions were collected throughout hospitalization. In addition, mandibular lymph nodes were collected from 9 study horses and 26 other Michigan horses. All samples were tested for the presence of EHV‐1 nucleic acid by real‐time PCR assays targeting the glycoprotein B gene and the polymerase (ORF 30) gene. Results: One hundred and twenty‐four horses met the inclusion criteria. None of the samples were positive for EHV‐1 DNA. Conclusion and Clinical Importance: These results suggest that nasal shedding and viremia of EHV‐1 in hospitalized critically ill horses with acute abdominal disorder is extremely rare. Implementation of additional biosecurity protocols to limit aerosol spread of EHV‐1 among horses with acute abdominal disease and other hospitalized horses is not necessary.     

Renal amyloidosis in cattle with inflammatory diseases

BACKGROUND: The association of inflammatory diseases such as traumatic reticuloperitonitis (TRP), mastitis, metritis, and pododermatitis with renal amyloidosis in cattle is poorly described. HYPOTHESIS: Serum amyloid A (SAA) levels are elevated during inflammatory diseases, and renal amyloidosis is formed as a complication. ANIMALS: This study was conducted with 82 crossbred cattle with mastitis (n = 18 cows), metritis (n = 11 cows), TRP (n = 30 cows), and pododermatitis (n = 23 : 15 cows and 8 beef cattle). Ten clinically healthy cows served as controls. Methods: Hematological, urinary, and blood parameters, including SAA, were measured by an automated procedure provided with trade kits. Determination of amyloidal structures was made by histopathological examination of renal biopsy specimens. RESULTS: At the end of this trial, amyloidosis was detected in 5 cows displaying typical nephrotic syndrome, with hypoproteinemia and proteinuria in combination with polyuria and weight loss. Furthermore, it was observed that cows with renal amyloidosis had significantly higher (P < .01) total leukocyte counts, serum and urine enzyme activities, and urea and creatinine concentrations, with lower serum total protein concentrations, when compared with animals without renal amyloidosis. CONCLUSIONS AND CLINICAL IMPORTANCE: The incidence of AA amyloidosis in cattle in this study suggests that cattle with mastitis, metritis, and pododermatitis have a high prevalence of systemic amyloidosis in response to inflammation.     

Selected Biochemical Indicators of Equine Rhabdomyolysis in Arabian Horses: Acute Phase Proteins and Trace Elements

Although creatine kinase (CK), aspartate transaminase (AST), cytokines, and oxidative stress parameters were shown to be useful biomarkers for diagnosis of equine rhabdomyolysis, additional biomarkers of the disease may be of interest to indicate prognosis of the disease. Therefore, the present study investigated acute phase proteins and trace elements as additional biomarkers of ER. Sixty male horses (4-6 years old) of 2 equal groups were used. Horses of the first group were clinically healthy and served as a control group, whereas horses of the second group were ER-diseased animals. Harvested sera were used for estimation of the activities of CK, AST, lactate dehydrogenase (LDH), serum amyloid A (SAA), haptoglobin (Hp), ceruloplasmin (Cp), copper, iron, and zinc, whereas plasma samples were used for determination of fibrinogen. The present findings revealed a significant (P ≤ .05) increase in values of CK, AST, and LDH in diseased horses compared to those in control values. In addition, a significant (P ≤ .05) increase in SAA (162.6 ± 5.32 mg/L), Hp (3.6 ± 0.54 g/L), Cp (39.32 ± 2.31 mg/L), and copper (28.36 ± 1.23 μmol/L) along with a significant (P ≤ .05) reduction in levels of iron (9.32 ± 0.23 μmol/L) and zinc (8.65 ± 1.02 μmol/L) was recorded in diseased horses compare to that in controls (11.3 ± 2.2 mg/L, 0.8 ± 0.2 g/L, 24.23 ± 1.32 mg/L, 18.41 ± 1.03 μmol/L, and 14.2 ± 0.42 μmol/L, respectively). In conclusion, SAA, Hp, Cp, copper, and zinc were useful prognostic biomarkers for the diagnosis of ER in Arabian horses.     

A Comparison of Elevated Blood Parameter Values in a Population of Thoroughbred Racehorses

In racing Thoroughbred horses, blood cell counts and key biochemistry parameters are used to monitor horse health during training. The most common measure is total white blood cell (WBC) count, usually coupled with estimates of the relative abundance of the five main types of WBC. However, WBC can go down and up when challenged, making interpretation difficult. In contrast, a large majority of health issues that impact training should trigger an inflammatory response. In this study, we test the potential for two inflammatory biomarkers, fibrinogen and serum amyloid A (SAA), to provide more reliable indicators of health issues across a large sample of horses in training. We find that although WBC and other cell counts are generally correlated with each other and other biochemistry parameters across their full range of values, fibrinogen and SAA exhibit the greatest concordance among the top 15% of values. Moreover, horses with the top WBC values do not overlap significantly with those having the top fibrinogen and SAA values. Because most horses are healthy, these patterns suggest that natural variation in cell counts and biochemistry largely occlude values that might indicate health issues. In contrast, the subset of unusual horses with elevated levels of both fibrinogen and SAA are strongly suggestive of the expected handful of animals with minor, undetected issues. We conclude that fibrinogen and SAA have excellent potential as biomarkers and are likely to be more informative about conditions relevant to horses in training compared with the widely used WBC.     

Comparison of paired serum and lithium heparin plasma samples for the measurement of serum amyloid A in horses using an automated turbidimetric immunoassay

This study aimed to evaluate whether equine serum amyloid A (SAA) concentrations could be reliably measured in plasma with a turbidimetric immunoassay previously validated for equine SAA concentrations in serum. Paired serum and lithium-heparin samples obtained from 40 horses were evaluated. No difference was found in SAA concentrations between serum and plasma using a paired t test (P = 0.48). The correlation between paired samples was 0.97 (Spearman’s rank P < 0.0001; 95% confidence interval 0.95–0.99). Passing-Bablok regression analyses revealed no differences between paired samples. Bland–Altman plots revealed a positive bias in plasma compared to serum but the difference was not considered clinically significant. The results indicate that lithium-heparin plasma samples are suitable for measurement of equine SAA using this method. Use of either serum or plasma allows for greater flexibility when it comes to sample collection although care should be taken when comparing data between measurements from different sample types.     

Serum amyloid A isoforms in serum and synovial fluid in horses with lipopolysaccharide-induced arthritis

The aim of the study was to determine the intraarticular serum amyloid A (SAA) response pattern in horses with inflammatory arthritis. Inflammatory arthritis was induced by injection of lipopolysaccharide (LPS) into the radiocarpal joint of four horses. Serum and synovial fluid (SF) samples were collected before and at 4, 8, 12, 24, 48, 72, 96, and 144 h after injection. Concentrations of SAA were measured by immunoturbidometry, and expression of SAA isoforms was visualized by denaturing isoelectric focusing and Western blotting. The LPS injection caused systemic and local clinical signs of inflammation. Serum amyloid A appeared in serum and SF within 8 h after LPS injection. Isoelectric focusing showed three major SAA bands with apparent isoelectric points (pI) of 7.9, 8.6, and >9.3 in serum and SF. Synovial fluid contained two additional isoforms with highly alkaline apparent pI values (apparent pI value extrapolated from standard curve = 10.0 and 10.2), which were not present in any of the serum samples. In conclusion, intraarticular injection of LPS induced systemic and local inflammatory responses in the horses. By demonstrating SF-specific SAA isoforms the results of the present study suggest that SAA is synthesized locally in the equine inflamed joint, similar to what has been demonstrated in humans previously. The marked local SAA synthesis suggests an important pathophysiological role in inflammatory arthritis.     

Use of Infrared Thermography to Detect Intrasynovial Injections in Horses

Athletic horses often experience painful conditions of the musculoskeletal system, but their ability to compete can be prolonged using certain anesthetic agents. The present study investigated the ability of thermography to detect fetlock and middle carpal intrasynovial injections of bupivacaine hydrochloride in five mares. Saline injections were performed in the contralateral limbs. Thermographic evaluation was conducted at the dorsal and palmar aspects before (basal) and 15, 30, 60, 90, 120, and 1440 minutes after injection. The intrasynovial treatments resulted in increased limb temperature, with fetlock temperatures higher on the dorsal aspect at 15, 30, and 60 minutes and on the palmar aspect from 15 to 1440 minutes (P < .05) after the bupivacaine and saline injections. Increased carpal temperature was detected on the dorsal aspect at 60 and 90 minutes (P < .05). The present study demonstrates that thermography can be used to detect intrasynovial injections in horses.