Hematological and clinical biochemistry profiles in Canindé goats infected by Corynebacterium pseudotuberculosis and bred in a tropical semi-arid region.

Caseous lymphadenitis (CLA), an infectious disease caused by Corynebacterium pseudotuberculosis in goats and sheep, is highly prevalent worldwide and is characterized by economic losses in small ruminant production. Currently available techniques for clinical and laboratory diagnosis of the disease lack market availability and/or sensitivity, and therefore, infected animals can remain in the herd, serving as a source of infection for other animals. The present study aimed to verify hematological and clinical biochemistry changes in goats naturally infected by C. pseudotuberculosis. One hundred seventy-three Canindé goats were included in this study, from which blood samples and caseous lesions were collected. The animals were classified as uninfected, asymptomatic, and symptomatic according to microbiological isolation and serological assays. A high dissemination of the infection was observed in the herd, with 86.13% of positive animals, being 74.57% asymptomatic and 11.56% symptomatic. In the hemogram and clinical biochemistry analyses, the only statistical difference found was a higher level of serum urea in asymptomatic individuals than in non-infected animals. In addition, this study points to the possibility of chronic CLA being potentially reflected in hepatic and renal biochemical markers.

Diagnostic Validation of a Whole-Slide Imaging Scanner in Cytological Samples: Diagnostic Accuracy and Comparison With Light Microscopy.

Digital slides created by whole-slide imaging scanners can be evaluated by pathologists located in remote sites, but the process must be validated before this technology can be applied to routine cytological diagnosis. The aim of this study was to validate a whole-slide imaging scanner for cytological samples. Sixty cytological samples, whose diagnoses were confirmed by gold-standard examinations (histology or flow cytometry), were digitalized using a whole-slide imaging scanner. Digital slides and glass slides were examined by 3 observers with different levels of cytopathological expertise. No significant differences were noted between digital and glass slides in regard to the number of cases correctly diagnosed, or the sensitivity, specificity, or diagnostic accuracy, irrespective of the observers' expertise. The agreements between the digital slides and the gold-standard examinations were moderate to substantial, while the agreements between the glass slides and the gold-standard examinations were substantial for all 3 observers. The intraobserver agreements between digital and glass slides were substantial to almost perfect. The interobserver agreements when evaluating digital slides were moderate between observers 1 and 2 and between observers 1 and 3 while they were substantial between observers 2 and 3. In conclusion, our study demonstrated that the digital slides produced by the whole-slide imaging scanner are adequate to diagnose cytological samples and are similar among clinical pathologists with differing levels of expertise.

Sample Collection.

Results may be changed with suboptimal sample collection and transport, which then result in incorrect diagnoses. Quality management of samples must start in the patient, extend through sampling itself, include appropriate short transport, and then be correctly accessioned at the referral laboratory or in-house station to ensure accurate diagnosis of disease. A quality assurance plan at the laboratory chosen is mandatory under American Society for Veterinary Clinical Pathology guidelines.

Changes in Student Perceptions and Study Strategies Over Time in a Veterinary Clinical Pathology Course Using Case-Based Instruction.

Veterinary students are challenged to develop new, nonlinear ways of thinking as they learn diagnostic reasoning skills. To support this process, we use real-life cases in our clinical pathology course. Changes in student perceptions regarding the use of cases and changes in study strategies over time have not been previously investigated or compared to student grades. Students participated in three voluntary online surveys that included 4-point Likert scale questions and open-ended questions on the helpfulness of cases for learning and study strategies used during the course. We used Friedman tests to detect any differences in perceptions over time; McNemar's test and Wilcoxon signed-rank tests were used to detect any differences in study strategies over time. Fisher's exact tests were used to examine the association between the Likert scale responses and grades in quartiles. Before beginning the course, 29% of students responded that cases were very helpful to their learning, with similar responses for helpfulness in applying course material and grasping important concepts. There was a significant trend of increasing positivity over the duration of the course, with 74% responding that cases were very helpful at the end of the course. The most-reported study strategy was working individually on cases before the midterm (74% of students), and the most helpful study strategy was attending class regularly (88% reported it as very helpful). Study strategies did not change significantly over time. Overall, perceptions and study strategies did not vary significantly with grades.

Diagnostic yield and accuracy of postmortem cytological sampling from the brain surface of animals with neurological abnormalities.

Clarification of central nervous system (CNS) disorders frequently requires pathological investigation via brain biopsy or postmortem examination. The use of cytology is usually restricted to diagnosis of mass lesions and septic meningitis. The value of brain cytology at postmortem examination has not been explored sufficiently. This study aimed to clarify the diagnostic value of meningeal imprint cytology at postmortem brain examination. Samples were taken from cerebrum and cerebellum and stained with the modified Wright stain and with haematoxylin-eosin. The slides were evaluated and findings were compared to brain histopathology with respect to resemblance, discrepancy and diagnostic validity. The study included 169 cases involving multiple animal species. Histopathology identified inflammatory disorders in 60/135 (44.4%) cases, neoplasia in 19/135 (14.1%) and non-infiltrative diseases in 56/135 (41.5%). Cytology revealed pathological changes in 79/135 (58.5%) of these cases. The histopathological diagnosis was reproduced in 57/135 (42.2%) cases, 43/57 (75.4%) of which were inflammatory. Non-diagnostic cases included 16/135 (11.9%) with sub-diagnostic cytological features and 3/135 (2.2%) with unclear phenomena. In 55/135 (40.7%) of brains with histological lesions, cytology proved inferior, providing negative results, including 40/55 (72.7%) cases with non-infiltrative diseases, 12/55 (21.8%) with inflammation and 3/55 (5.5%) with neoplasia. Conversely, 3/34 (8.8%) of controls showed cytological abnormalities. Cytological sampling from CNS adds to the sensitivity of neuropathological investigations, even if restricted to non-invasive surface imprints. The diagnostic accuracy exceeds 40%, with infiltrative diseases being five times more likely to be detected than non-infiltrative diseases.

Metals in obex and retropharyngeal lymph nodes of Illinois white-tailed deer and their variations associated with CWD status.

Prion proteins (PrP(C)) are cell membrane glycoproteins that can be found in many cell types, but specially in neurons. Many studies have suggested PrP(C)'s participation in metal transport and cellular protection against stress in the central nervous system (CNS). On the other hand PrP(Sc), the misfolded isoform of PrP(C) and the pathogenic agent in transmissible spongiform encephalopathies (TSE), has been associated with brain metal dyshomeostasis in prion diseases. Thus, changes in metal concentration associated with protein misfolding and aggregation have been reported for human and animal prion diseases, as well as for other neurodegenerative disorders, such as Parkinson's and Alzheimer's disease. The use of metal concentrations in tissues as surrogate markers for early detection of TSEs has been suggested. Studies on the accumulation of metals in free-ranging white-tailed deer have not been conducted. This study established concentrations of copper, iron, manganese, and magnesium in 2 diagnostic tissues used for CWD testing (obex and retropharyngeal lymph nodes (RLN)). We compared these concentrations between tissues and in relation to CWD status. We established reference intervals (RIs) for these metals and explored their ability to discriminate between CWD-positive and CWD-negative animals. Our results indicate that independent of CWD status, white-tailed deer accumulate higher concentrations of Fe, Mn and Mg in RLN than in obex. White-tailed deer infected with CWD accumulated significantly lower concentrations of Mn and Fe than CWD-negative deer. These patterns differed from other species infected with prion diseases. Overlapping values between CWD positive and negative groups indicate that evaluation of these metals in obex and RLN may not be appropriate as a diagnostic tool for CWD infection in white-tailed deer. Because the CWD-negative deer were included in constructing the RIs, high specificities were expected and should be interpreted with caution. Due to the low sensitivity derived from the RIs, we do not recommend using metal concentrations for disease discrimination.