Veterinary Pathology最新文献

Porcine circovirus 3 (PCV3) is a recently identified pathogen in swine populations. It is considered a ubiquitous virus and is frequently associated with subclinical infections throughout various stages of production. PCV3 is detectable in diverse tissues, blood, and secretions, indicating systemic dissemination and potential for both vertical and horizontal transmission. PCV3 has been implicated in reproductive and postnatal diseases collectively named as PCV3-associated diseases (PCV3-AD). Clinically, PCV3-AD encompasses reproductive disorders such as mummified fetuses, stillbirths, and weak neonates, alongside postnatal manifestations including anorexia, weight loss, and progressive wasting. Histopathologically, PCV3-AD is primarily defined by systemic nonsuppurative periarteritis and arteritis that are observed across multiple tissues, particularly within the heart, mesenteric arterial plexus, and kidneys. Despite the broad tissue tropism and frequent detection of viral nucleic acids within affected vascular and parenchymal structures, the precise mechanisms underpinning PCV3 pathogenesis remain poorly understood. Diagnosis of PCV3-AD relies on the confluence of characteristic clinical signs, compatible histopathological findings, and the in situ detection of the virus within lesions. However, the true prevalence of PCV3-AD under field conditions is likely underestimated due to the limited availability and high costs associated with laboratory techniques for definitive viral detection. This review seeks to consolidate and interpret clinical and pathological evidence indicative of PCV3-AD while addressing the critical diagnostic challenges faced by veterinary pathologists. Enhanced understanding of the disease's clinical-pathological correlations and diagnostic approaches is essential to accurately assess its impact on swine health and production.

To understand diseases of wild urban jackrabbits (Lepus townsendii), we autopsied 130 individuals that died near roadways in Calgary, Alberta, Canada. Renal hamartomas were present in 8 of 130 hares (6.2%; 95% confidence interval: 3.2%-11.7%). Most were unilateral (7/8); one case had bilateral lesions. Hamartomas are benign, tumor-like lesions comprised of normal tissue elements in abnormal amounts and arrangements. Macroscopically, hamartomas were white, tan, or pink-red, well-circumscribed, singular or multilobular, expansile nodules in the cortex or corticomedullary junction. Histologically, renal hamartomas consisted of well-demarcated mature stromal tissue with fibrous tissue and occasionally, adipocyte differentiation. These results represent a unique temporal and geographical cluster of a renal anomaly in an urban wildlife population. Renal hamartomas were not identified in other large studies of diseases in free-ranging leporids including hares. Contributing factors to this cluster remain unknown.

Chronic inflammatory rhinitis (CIR) is among the most common causes of chronic nasal signs in dogs. Despite research efforts, the etiology of CIR remains mostly undiscovered. The aim of our study was to describe the histological findings in nasal biopsies of control dogs without signs of nasal disease compared to dogs with CIR. The study groups were control dogs euthanized for reasons unrelated to this study (n = 20) and previously collected, archived nasal biopsies from dogs diagnosed with CIR (n = 20). A CIR diagnosis was based on clinical presentation, computed tomography, rhinoscopy, and histopathological findings indicative of CIR. Inflammatory cell counts and changes in the mucosal epithelium and associated lamina propria were evaluated from nasal biopsy specimens. The numbers of lymphocytes and plasma cells (P < .0001), neutrophils (P < .0001), and eosinophils (P = .0016) in the lamina propria, and mucosal intraepithelial leukocytes (P < .0001) were significantly higher in dogs with CIR compared to control dogs. A small population of leukocytes was also observed in control dogs, likely representing a physiological immune cell population. The type of inflammation in CIR is not purely lymphoplasmacytic, as both neutrophils and eosinophils were also detected in CIR dogs. The mucosal epithelium was thicker (P = .006), and visible goblet cells (P < .001) were decreased, in dogs with CIR, with a multifocal loss of cilia in some dogs, which may represent a form of respiratory epithelial metaplasia. Epithelial alterations likely play a role in the pathophysiology of CIR and contribute to the clinical signs.

Diagnosing early nodal metastases in canine malignant melanoma is challenging due to the morphological similarities between nodal melanophages and neoplastic melanocytes, and the limitations of conventional immunohistochemical markers like melan-A, which only labels a subset of tumor cells and requires tissue bleaching. This retrospective study investigated the utility of the immunohistochemical marker SOX-10, a nuclear transcription factor, in identifying metastatic cells in lymph nodes (LNs) from dogs with oral, labial, or digital malignant melanoma undergoing regional or sentinel lymphadenectomy. The analysis included 49 LNs from 27 dogs with oral (n = 10), labial (n = 9), and digital (n = 8) melanoma. Primary tumors were highly melanotic in 7 (26%) dogs, sparsely melanotic in 15 (56%), and amelanotic in 5 (19%). SOX-10 immunohistochemistry increased the detection rate of nodal metastasis from 29% (14/49 nodes) with hematoxylin and eosin staining alone and 31% (15/49 nodes) with melan-A immunohistochemistry to 33% (16/49 nodes), allowing the identification of 12 LNs with macrometastases, 2 with micrometastases, and 2 with isolated tumor cells. Compared with melan-A, SOX-10 exhibited a more uniform labeling pattern, enhancing the identification of micrometastases and isolated tumor cells. It also facilitated the distinction between neoplastic cells and melanophages, even in heavily pigmented samples, without the need for bleaching, thereby preserving tissue integrity. These findings suggest that SOX-10 is a promising diagnostic marker for canine melanoma, offering improved detection of early melanocytic metastatic lesions.

Here we assess the diagnostic features of 73 canine extramedullary plasmacytomas (EMPs) and their differentiation from canine cutaneous histiocytomas (CHs) using histology and immunohistochemistry for MUM1, CD3, CD79a, immunoglobulin (Ig) light chains (λ and κ), and IBA1. Most EMPs were classified as cleaved and mature subtypes. Almost 92% of EMPs were positive for MUM1, whereas 77% were positive for CD79a and 74% for Ig light chains λ and κ. The use of MUM1 and Ig light chains resulted in a sensitivity of 100% in diagnosing EMPs, surpassing the combination of MUM1 and CD79a (94%). In 8% of the EMPs, there was pseudofollicular arrangement of neoplastic cells, whereas 7% had amyloid deposition and 3% had mineralization. CHs were positive for IBA1 but negative for all other IHCs.

Intracellular inclusions are singular structures that may occur secondary to viral infection, cytoplasmic invagination, and organelle entrapment, or due to abnormal accumulation of biological material, such as proteins. Determining the exact nature of an inclusion is crucial in diagnostic pathology, especially in the context of colony management and toxicity studies. In this case series, we identified pancreatic islet intranuclear (IN) and intracytoplasmic (IC) eosinophilic inclusions in 13 out of 21 southern giant pouched rats (Cricetomys ansorgei), a species studied for its outstanding olfactory capacities. Intranuclear inclusions were smooth, globular, and marginated the chromatin. Intracytoplasmic inclusions were either single or multiple, and polygonal to globular. Females and males were both affected, regardless of their wild-caught or inhouse-bred status. Immunohistochemistry labeling for p62 in some IN inclusions suggested a correlation with autophagy. Okajima's stain for hemoglobin positively stained all inclusions. Periodic acid-Schiff reaction, Masson's trichrome, Congo red, and Prussian blue were all negative, ruling out polysaccharides, β-pleated sheets, fibrin, and free iron. Ultrastructural evaluation further revealed that IN inclusions consisted of aggregated fibrillar to microtubular material and excluded a viral infection. By contrast, IC inclusions were identified as giant mitochondria with crystalline deposits and abnormal cristae. In conclusion, the frequent occurrence of either type of inclusion, irrespective of clinical health status, suggests that they are likely incidental although possibly related to autophagy. Importantly, the natural occurrence of giant mitochondria in seemingly healthy individuals is unusual. Giant pouched rats may thus represent a suitable species to deepen our understanding of these peculiar organelles.

Immunodeficient mouse strains are widely used in several fields of biomedical research. Despite that, no standardized system for evaluating immunodeficiency in mice currently exists, and an unbiased comparison of various immunodeficient mouse strains is difficult. The aim of our study was to develop a standardized multi-disciplinary protocol for the morpho-phenotypical assessment of immunodeficient mouse models. We selected 4 immunodeficient strains of mice (Cd40l^-/-, Was^-/-, Rag1^R972Q/R972Q, and Rag1^-/-) on a C57BL/6J genetic background and a group of control C57BL/6J wild-type mice. The lymphoid organs were harvested, weighed, and analyzed by histology, immunohistochemistry, and flow cytometry. Hematology and bone marrow cytology were also performed. The main immune cell populations were investigated, including lymphocytes, monocytes/macrophages, neutrophils, and natural killer cells. Relative organ weights were lower in the strains with the highest level of immunodeficiency (Rag1^R972Q/R972Q and Rag1^-/-). Histology revealed overall lower cellularity in the same strains, particularly in Rag1^-/- mice. Tissue spatial distributions of the immune cell populations were confirmed by immunohistochemistry, while flow cytometry allowed for their relative quantification. Likewise, hematology detected moderate lymphopenia in the Rag1^R972Q/R972Q mice and more severe lymphopenia in Rag1^-/- mice. Our protocol has proven itself effective for the morpho-phenotypical assessment of the immunodeficient mouse models under investigation and was useful in characterizing the type and severity of the defects. The different laboratory techniques were consistent in the characterization and confirmation of immunodeficiency in the different strains, providing different complementary insights.

Although rare, tick-borne encephalitis (TBE) is one of the most important and commonly fatal viral diseases affecting the central nervous system (CNS). This arboviral disease is transmitted by ticks and prevalent in widespread parts of Eurasia. Besides humans, several domestic animals such as dogs, horses, and ruminants can also be infected. To our knowledge, there have been no reports of TBE in South American camelids, so far. Here, we present 2 cases of Huacaya alpacas with progressive, therapy-resistant neurologic signs, which were euthanized and submitted for necropsy. Histologic examination of the CNS revealed a moderate lymphohistiocytic meningoencephalomyelitis characterized by perivascular cuffing, glial cell proliferation, neuronal degeneration, and neuronophagia. Tick-borne encephalitis virus (TBEV) infection was confirmed by polymerase chain reaction (PCR), sequencing, immunohistochemistry, and RNAscope in situ hybridization. TBEV should be included as a differential diagnosis in alpacas from endemic regions presenting with neurologic signs.

Silica is a well-known stimulus of granulomatous inflammation in the lungs of humans and other animals. However, it has been poorly studied as a cause of cutaneous inflammation in domestic animals, despite the predominance of silica in traditional (clay-based) cat litter substrates. Here we characterize the clinical and pathologic findings of 13 surgical biopsies from the paws or paw pads of domestic cats submitted to 2 veterinary institutions between 2005 and 2023. Gross lesions often included chronic or intermittent paw pad swelling, ulceration and bleeding, or draining tracts, particularly in the front paws. All biopsies consisted of granulomatous to pyogranulomatous inflammation with birefringent, amorphous to granular, blue-gray, intrahistiocytic material consistent with silica. Raman spectra were collected from 3 biopsy samples at 45 different locations. Using multivariate analysis, the foreign material in the biopsies had similar Raman spectra to multiple brands of silica-based cat litter. Ten of 13 biopsies also contained evidence of plasma cell pododermatitis, suggesting that underlying paw pad disease may predispose some cats to cutaneous cat litter implantation. In these cats, subsequent granulomatous inflammation may obscure the underlying condition and exacerbate clinical disease. Routine polarization of feline paw or paw pad biopsies is recommended to aid in recognition of cat litter granulomas. Careful examination for a predisposing condition is also warranted when cat litter granulomas are identified. Recurrence is common following surgery; affected cats, and predisposed cats with paw pad disease, may benefit from the use of alternate litter substrates to prevent this lesion or its recurrence.

Cutaneous lesions due to papillomavirus (PV) infection are well described in cats. However, there are few reports of similar lesions in the oral cavity. In this case series, 7 cats with in situ carcinomas of the oral mucosa are reported. Lesions appeared histologically like cutaneous Bowenoid in situ carcinomas, and PV-induced cell changes were visible within lesions from 6 cats. A PV etiology was further supported by intense p16^CDKN2A protein immunolabeling within all lesions. Five lesions contained Felis catus papillomavirus (FcaPV) type 3 DNA, while 2 contained FcaPV1 DNA. Cats had clinical signs of drooling and oral pain for over 6 months prior to diagnosis, and the dorsal surface of the tongue was most often affected. Four cats had multiple oral lesions, and 2 cats had oral and skin lesions. Of the 6 cats for which clinical outcome was known, 3 are still alive at least 6 months after diagnosis, 2 died of unrelated causes 7 and 14 months after diagnosis, and 1 cat was euthanatized due to oral pain 18 months after diagnosis. Results suggest PV-associated oral in situ carcinoma is a specific disease entity of cats. Lesions are slowly progressive with pain management allowing long survival times. No cases were known to progress to invasive squamous cell carcinoma, and feline oral squamous cell carcinomas appear to infrequently develop as a progression from these lesions. Due to the marked difference in biological behavior, diagnosticians should differentiate PV-associated oral in situ carcinomas and oral squamous cell carcinomas in cats.