Yasamin Vali

The avian spleen, as a major secondary lymphoid organ, plays a key role in immune regulation in chickens lacking structured encapsulated lymph nodes. As a secondary lymphoid organ, it provides microenvironment for immune interactions, antigen recognition, and cytokine signaling. Despite its importance, in vivo and in ovo assessments remain limited, with most data derived from postmortem studies. Magnetic resonance imaging (MRI) offers a non-invasive, high-resolution method for evaluating organ morphology and volume, enabling assessment of morphological changes intra vitam . This study evaluated in ovo MRI for spleen visualization and volumetry in chicken embryos as a potential tool for immunological and developmental research. Ten SPF chicken eggs were incubated under standardized conditions and imaged on day 18 using a 3 T MRI scanner. Volumetric analysis was conducted on T2W-CISS images using Amira software following manual segmentation of spleen and embryo. Mean spleen volume was 17.72 mm ³ (SD 1.78; range 14.20–19.37) and mean embryo volume 21,439.27 mm ³ (SD 944.16; range 19,823.24–23,127.17). Spleen-to-embryo volume ratio was 0.0825 ± 0.0060%. Mean spleen weight was 0.0154 g (SD 0.0046; range 0.008–0.022) and embryo weight 23.5 g (SD 3.37; range 15–25), with weight ratio 0.068 ± 0.025%. MRI volumetry strongly correlated with weight measurements ( r = 0.96, p < 0.01). These findings demonstrate in ovo MRI as a feasible, non-invasive tool for splenic morphology and volumetry. It could support studies on infection dynamics, inflammation, and disease processes in avian models, and enable longitudinal evaluation beyond hatching, tracking splenic development and disease progression from embryo to postnatal life in the same individuals over time.

Pegiviruses are generally regarded as non-pathogenic viruses with controversial clinical significance. Here, we describe an avian pegivirus (partridge pegivirus, ParPgV) associated with field outbreaks of encephalitis in red-legged partridges ( Alectoris rufa ). Next-generation sequencing identified ParPgV in brain tissues, revealing two distinct avian-origin pegiviruses. Histopathology and electron microscopy revealed encephalitic lesions, neuronal degeneration, and viral particles within neurons. Field surveillance demonstrated widespread vertical transmission across multiple partridge flocks. Experimental inoculation of red-legged partridges, grey partridges, and specific-pathogen-free chickens demonstrated viral neurotropism and systemic distribution with differences in humoral immune response. Infected red-legged partridges developed cerebellar atrophy detectable by MRI. Detection of negative-strand RNA replication intermediates confirmed active viral replication across different experimental hosts, and RNAscope in situ hybridization and immunohistochemistry further confirmed viral RNA and antigen in neural and lymphoid tissues. Here, we show experimental evidence supporting an association between a pegivirus and encephalitis, and suggest underappreciated neuropathogenic potential.

Accurate interpretation of intradiskal signal voids on magnetic resonance imaging (MRI) is essential to avoid misdiagnosis and improve diagnostic decision‐making in canine spinal imaging. Gas accumulation within the degenerated canine intervertebral disk (IVD), known as vacuum phenomenon (VP), and IVD mineralization are common findings in computed tomography (CT), with distinctly different x‐ray attenuation characteristics. In MRI, both appear as a signal void, which can complicate interpretation. We hypothesized that gas and mineralization would not differ in intensity values on MRI but would differ in location and shape when compared to CT. This exploratory retrospective multicenter study aims to assess the characteristics of VPs and mineralization in MRI, using CT as the gold standard. Imaging archives were searched for matching canine spinal CT and MRI performed within 48 h. Inclusion criteria included mineralization or gas in the IVD on CT images and available sagittal T2W‐sequence MRI images of the same vertebral segment. Twenty‐six studies were included, contributing 32 IVD spaces. The presence of IVD mineralization and gas in CT, along with the location, shape, and pixel‐value of MRI signal intensity in IVD spaces, was recorded. No statistical differences were identified in pixel values between the groups ( p  = 0.5). However, there were significant changes in the location of the signal void compared to the recorded location in CT, particularly in VP ( p  = 0.03). These results emphasize that MRI T2 signal voids in canine IVDs may represent gas. No specific MRI characteristics allowed reliable prioritization of VP versus mineralization; therefore, both should be considered differential diagnoses when encountering intradiskal signal voids on MRI.

Introduction: The subchondral bone plate plays a critical role in load transfer across joints. Its density distribution reflects the joint’s loading history, and variations in density are likely associated with changes in the material properties of the subchondral bone. This study aimed to evaluate the mechanical strength of the subchondral bone plate of the canine talus and correlate it with the subchondral bone density. Methods: Twenty paired cadaveric tali from large breed dogs were included in the present study. Test points were selected and marked on the subchondral bone plate, where mechanical strength was assessed using indentation testing to record the maximum penetration force. The density at these test points was measured using computed tomographic osteoabsorptiometry (CT-OAM). Results: The result revealed that density and strength of the subchondral bone plate were not uniformly distributed across its surface. A strong correlation was observed between subchondral bone density and mechanical strength across all specimens, with the areas of highest density corresponding to the areas of greatest mechanical strength. Discussion: The present study’s key finding—a strong correlation between subchondral bone density and mechanical strength—highlights the potential of using subchondral bone density as a reliable indicator of mechanical strength. This relationship offers important insights for clinical assessments and research on joint biomechanics. Furthermore, the use of CT-OAM provides a non-invasive method to evaluate both the density and mechanical strength of the subchondral bone plate, enabling valuable longitudinal studies on subchondral bone properties in dogs.

Diagnostic imaging is a crucial non-invasive tool for evaluating canine elbow joints, particularly for screening and treatment planning of medial coronoid disease (MCD). Radiography remains the most accessible and widely used screening modality, but its diagnostic accuracy varies significantly. Sensitivity values reported in previous studies vary depending on factors such as study population, imaging technique, and interpretation criteria. This study compared four measures (sensitivity, specificity, positive and negative predictive value) of radiography with a more advanced imaging method, computed tomography (CT), which provides more detailed images of bones. The results showed that radiography correctly identified 65% of the cases (17/26), while missing some of the affected joints. Furthermore, 7% of the healthy joints (29/398) were misdiagnosed as diseased, leading to a specificity of 93% (369/398). For a disease prevalence of 6% (26/424), the positive and negative predictive value of radiography were 37% (17/46) and 98% (369/378), respectively. Overall, when CT is available, it is the preferred technique for screening. In cases where it is not available, it is important to have an idea of the sensitivity and specificity, but also of the positive and negative predictive value, especially at low prevalences. These results help veterinarians make better decisions when screening for elbow problems in dogs.

Background: Osteochondritis dissecans (OCD) and osteochondrosis (OC) are multifactorial developmental joint diseases that can occur in various anatomical locations, including the tarsus of immature, rapidly growing large breed dogs. The pathogenesis of canine OCD and OC involves a disruption in endochondral ossification, resulting in a failure of matrix calcification and vascular invasion. This study aimed to investigate the subchondral bone density changes in Labrador Retrievers with tarsocrural OCD/ OC. Results: A total of 8 dogs with unilateral tarsocrural OCD/ OC were included in the study and density was evaluated with Computed Tomography osteoabsorptiometry (CTOAM ). The findings revealed a significant decrease in subchondral bone density at the location of the OCD/ OC lesion, particularly at the medial trochlear ridge. This area of low density was surrounded by a higher density rim. Furthermore, the contralateral joint showed a significantly higher overall mineral density. Conclusion: These results highlight the significant changes in bone mineral density associated with tarsocrural OCD/ OC. The lower density in the affected joint suggests pathological alterations in the subchondral bone, which may impact the bone turnover and contribute to the development of secondary osteoarthrosis, subsequently. The higher density observed in the contralateral joint emphasizes the role of altered joint loading and adaptation in the subchondral bone.

Objective: To investigate the utility of the neutrophil‐to‐lymphocyte ratio (NLR) as a prognostic marker in cats with blunt trauma.Design: Retrospective study from January 2018 to December 2021.Setting: University teaching hospital.Animals: Medical records of 177 cats admitted with blunt trauma were evaluated. History, clinical findings, blood cell count‐based ratios, thoracic radiographs on presentation, and outcome were reviewed. The Animal Trauma Triage (ATT) score was assessed in each cat and classified as mild (1–3), moderate (4–7), and severe trauma (≥8). Forty‐eight healthy blood donor cats served as the control population. NLR, neutrophil counts, and lymphocyte counts were compared between cats with blunt trauma and controls, and among trauma patients.Interventions: NoneMeasurements and Main Results: NLR, neutrophil counts, and lymphocyte counts significantly differ in cats with blunt trauma compared to controls (p < 0.001), and NLR was higher in patients with thoracic trauma (p = 0.044). Nonsurvivors had lower lymphocyte counts (p = 0.041), although those values do not appear to be clinically relevant. A significant increase in NLR was observed with increasing severity of trauma (p < 0.001). The NLR was not associated with the length of hospitalization, intensive care assistance, or mortality.Conclusion: NLR is a widely available diagnostic tool, which can be used in addition to ATT to assess trauma severity, although in our study it was not predictive of the outcome.

Right ventricular structural and functional changes result from many cardiovascular disorders in cats. Accordingly, echocardiographic evaluation of the size and function of the right ventricle (RV) provides important prognostic information in many conditions affecting the right heart. Therefore, detection of these changes is clinically important and needs reference values to ease the diagnosis. The present study was designed to calculate structural and functional right ventricular variables in 10 apparently healthy cats (six males and four females, average age 1 year old and body weight 2.70 -4.80 kg) with no sedation. For this purpose, The minimum, maximum, mean +/- standard error of the mean of right ventricle internal dimension in systole and diastole (cm), right ventricle free wall thickness in systole and diastole (cm), fractional shortening (%), right ventricle volume in systole and diastole (mL), right ventricle area in systole and diastole (cm2), ejection fraction (%) and fractional area change (%) were measured and reported. Descriptive statistics were provided for all calculated variables. Statistical correlation of the collected variables with body weight, gender and heart rate were analyzed. Results showed that there is a significant correlation between heart rate with body weight and between systolic and diastolic RV volumes with gender. The results of the present study would help clinicians in the diagnosis of the right heart changes in DSH cats.(c) 2023 Urmia University. All rights reserved.

A 4-year-old chicken was presented with a history of anorexia, depression, and blindness. An ultrasound examination of the coelomic cavity was performed that revealed splenomegaly, hepatic nodules, and hypoechoic thickening of the intestinal wall. Ultrasonography of the coelomic cavity was done and revealed splenomegaly, nodular hepatic changes, and hypoechoic thickening of the intestinal wall. A diagnosis of Marek's disease was made based on the history and extension of the abdominal organ changes and confirmed by histopathology. This study describes an ultrasonographic appearance of Marek's disease in a chicken and emphasizes the importance and benefits of ultrasonography in staging the progression of Marek's disease.