Neospora caninum is an apicomplexan protozoan that is considered one of the main agents responsible for abortion in ruminants. The lesions found in the central nervous system (CNS) of aborted fetuses show multifocal necrosis, gliosis, and perivascular cuffs of mononuclear cells, but the inflammatory and glial cells have not been immunophenotypically characterized. The lesions in the CNS of infected adult animals have rarely been described. Therefore, in this study, we characterized the lesions, the immunophenotypes of the inflammatory and glial cells and the expression of MHC-II and PCNA in the CNS of goats infected with N. caninum. The CNS of eight aborted fetuses and six adult male goats naturally infected with N. caninum were analyzed with lectin histochemistry (RCA1) and immunohistochemistry (with anti-CD3, −CD79α, −GFAP, −MHC-II, and -PCNA antibodies). All animals were the offspring of dams naturally infected with N. caninum. The microscopic lesions in the CNS of the aborted fetuses consisted of perivascular cuffs composed mainly of macrophages (RCA1+), rare T lymphocytes (CD3+), and rare B lymphocytes (CD79α+). Multifocal necrosis surrounded by astrocytes (GFAP+), gliosis composed predominantly of monocytic-lineage cells (macrophages and microglia, RCA1+), and the cysts of N. caninum, related (or not) to the lesions were present. Similar lesions were found in four of the six male goats, and multinucleate giant cells related to focal gliosis were also found in three adult goats. Anti-GFAP immunostaining showed astrocytes characterizing areas of glial scarring. Cysts of N. caninum were found in three adult male goats. The presence of N. caninum was evaluated with histopathology, immunohistochemistry, and PCR. Immunohistochemistry demonstrated anti-PCNA labeling of macrophages and microglia in the perivascular cuffs and the expression of MHC-II by microglia and endothelial cells in the CNS of the aborted fetuses and adult male goats. Macrophages and microglia were the predominant inflammatory cells in the CNS of aborted fetuses and healthy adult male goats infected with N. caninum. Activated astrocytes were mainly associated with inflamed areas, suggesting that astrocytes were involved in the resolution of the lesions.

Most lesions found in the mammary glands of cats are malignant, with aggressive behavior and unfavorable prognosis. Studies on the epidemiologic and clinicopathological characteristics of mammary lesions in cats are scarce. The present study aimed to evaluate those characteristics and to correlate them with survival in cats. Mammary specimens were selected from 418 domestic cats that underwent surgical removal with or without lymphadenectomy. The cats and mammary lesions were evaluated for epidemiologic, clinical, and pathologic characteristics. Cats with malignant neoplasms were older than cats with benign neoplasms and non-neoplastic lesions; 858 lesions were identified, including sporotrichosis, basaloid carcinoma, and benign phyllodes, described for the first time in cats. Tubulopapillary and cribriform carcinomas were the most common malignant tumors found and were very similar in characteristics such as marked anisocytosis/anisokaryosis, high mitotic count (score 3) (p < 0.001), and presence of necrosis (p = 0.005). The association between advanced age and malignancy, as well as the description of new lesions, emphasizes the importance of population studies in cats to understand the behavior of the disease and to draw attention to diagnoses that should be considered in routine care.

Neurocysticercosis (NCC) is a parasitic disease of the central nervous system in humans caused by Taenia solium metacestodes, also known as Cysticercus cellulosae. However, cerebral infections caused by metacestodes in companion animals are rare. This study described the pathological and parasitological aspects of NCC in one dog. An 8-year-old female Boxer dog from Lavras City, Minas Gerais State, Brazil, with a history of access to rural areas on weekends and acute clinical signs of generalized tonic-clonic seizures, including limb stiffness (spasticity), labored breathing, consciousness, and progression to rhythmic jerking of the limbs, was submitted for necropsy at the Veterinary Pathology Sector of the Universidade Federal de Lavras (UFLA). At necropsy, three parasitic cysts were found in the cortical region of the cerebral hemispheres, and calcified cysts were found in the myocardium. The diagnosis was based on parasite morphology after cyst dissection and scanning electron microscopy. The T solium metacestoda appears as a semi-translucent vesicle with a protoscolex containing a rostellum with hooks arranged in two rows, forming a double crown and four suckers. These findings demonstrated that; although rare, NCC should be considered in dogs with clinical signs of seizures, especially in geographical areas with a high prevalence of parasitism and warrants surveillance for this disease.

Canine melanoma is a relatively common and clinically significant neoplasm in veterinary oncology, with important prognostic implications. Epithelial–mesenchymal transition (EMT), associated with changes in cell adhesion and increased metastatic potential, remains poorly characterized in this tumor type. We evaluated E-cadherin and N-cadherin expression in 32 primary canine melanomas and their regional lymph nodes, assessing associations with tumor progression and survival. Regional lymph node metastases were observed in 53% of cases. High N-cadherin expression in primary tumors correlated with metastasis and reduced survival, while E-cadherin expression showed no difference between metastatic and non-metastatic tumors. Notably, metastatic primary tumors exhibited a positive correlation between E- and N-cadherin expression. These results indicate that N-cadherin is a potential prognostic marker; and highlight the need for further studies on EMT as a therapeutic target to control metastasis.