Systemic reactive angioendotheliomatosis-like syndrome in a steer presumed to be persistently infected with bovine viral diarrhea virus

Epigenomic and Proteomic Changes in Fetal Spleens Persistently Infected with Bovine Viral Diarrhea Virus: Repercussions for the Developing Immune System, Bone, Brain, and Heart

Bovine viral diarrhea virus (BVDV) infection during early gestation results in persistently infected (PI) immunotolerant calves that are the primary reservoirs of the virus. Pathologies observed in PI cattle include congenital defects of the brain, heart, and bone as well as marked functional defects in their immune system. It was hypothesized that fetal BVDV infection alters T cell activation and signaling genes by epigenetic mechanisms. To test this, PI and control fetal splenic tissues were collected on day 245 of gestation, 170 days post maternal infection. DNA was isolated for reduced representation bisulfite sequencing, protein was isolated for proteomics, both were analyzed with appropriate bioinformatic methods. Within set parameters, 1951 hypermethylated and 691 hypomethylated DNA regions were identified in PI compared to control fetuses. Pathways associated with immune system, neural, cardiac, and bone development were associated with heavily methylated DNA. The proteomic analysis revealed 12 differentially expressed proteins in PI vs. control animals. Upregulated proteins were associated with protein processing, whereas downregulated proteins were associated with lymphocyte migration and development in PI compared to control fetal spleens. The epigenetic changes in DNA may explain the immune dysfunctions, abnormal bone formation, and brain and heart defects observed in PI animals.

A Review of Proliferative Vascular Disorders of the Central Nervous System of Animals

In disease, blood vessel proliferation has many salient roles including in inflammation, when granulation tissue fills superficial defects, or in the recanalization of an occluded blood vessel. Sometimes angiogenesis goes awry-granulation can be exuberant, and plexiform proliferation of vascular components can contribute to pulmonary hypertension. This review focuses on the diverse manifestations of pathologic vascular overgrowth that occur in the brain, spinal cord, and meninges of animals from birth until old age. Entities discussed include systemic reactive angioendotheliomatosis in which glomeruloid vascular proliferations are encountered in various organs including the central nervous system (CNS). The triad of CNS vascular malformations, hamartomas, and benign vascular proliferations are an especially fraught category in which terminology overlap and the microscopic similarity of various disorders makes diagnostic classification incredibly challenging. Pathologists commonly take refuge in "CNS vascular hamartoma" despite the lack of any unique histopathologic features and we recommend that this diagnostic category be abandoned. Malformative lesions that are often confusing and have similar features; the conditions include arteriovenous malformation, cavernous angioma, venous angioma, and capillary telangiectases. Meningioangiomatosis, a benign meningovascular proliferation with dual components, is a unique entity seen most commonly in young dogs. Last, accepted neoplastic conditions range from lower-grade locally acquired growths like hemangioblastoma (a tumor of mysterious interstitial stromal cells encountered in the setting of abundant capillary vasculature proliferation), the rare hemangioendothelioma, and the highly malignant and invariably multifocal metastatic hemangiosarcoma. Additionally, this review draws on the comparative medical literature for further insights into this problematic topic in pathology.

Characterization of vascular lesions in pigs affected by porcine circovirus type 2-systemic disease

Vascular lesions and their association with porcine circovirus type 2 (PCV2) were evaluated in multiple organs from 10 pigs affected with PCV2-systemic disease (PCV2-SD). Animals had vascular lesions in multiple organs, consisting of lymphohistiocytic lymphangitis and/or phlebitis, mild to severe necrotizing arteritis, and thrombosis within splenic arterioles and choroid plexus capillaries. Variable amounts of PCV2 nucleic acid detected by in situ hybridization were present within endothelial cells, tunica media myocytes, and perivascular and/or intralesional inflammatory cell infiltrates. PCV2 nucleic acid was detected within endothelial cells of both lymphatic and blood vessels without lesions in the associated tissues. Necrotizing arteritis was principally present in lymph nodes and kidney and consisted of degeneration, necrosis, and pyknosis of myocytes, often with intracytoplasmic, brightly eosinophilic inclusion bodies that were strongly positive for PCV2 nucleic acid. Segmental or circumferential fibrinoid necrosis was mainly present in vessels of the lymph node, spleen, and choroid plexus and was variably associated with PCV2 nucleic acid. Severe lymphangitis associated with strong intralesional PCV2 labeling was frequently detected within the mesenteric and mediastinal lymph nodes and the lamina propria of the ileum. In most tissues, medium and large lymphatics and/or veins often had disruption of the intima and mild mononuclear inflammatory cell infiltration that was variably associated with PCV2 nucleic acid. The present study indicates that vasculitis is a frequent finding in natural cases of PCV2-SD and that PCV2 may have a direct cytopathic effect on tunica media myocytes of small- and medium-sized arteries as well as endothelium.

Koch's postulates and the pathogenesis of comparative infectious disease causation associated with Bartonella species

In his homage to Lucretius (‘Georgica’), Vergil is credited with stating: ‘Felix qui potuit rerum cognoscere causas’ (‘Fortunate is he who knows the causes of things’). Based on numerous commentaries and publications it is obvious that clinicians, diagnosticians and biomedical research scientists continue to struggle with disease causation, particularly in the assessment of the pathogenic role of ‘stealth pathogens’ that produce persistent infections in the host. Bartonella species, because of their evolutionary ability to induce persistent intravascular infections, present substantial challenges for researchers attempting to clarify the ability of these stealth bacteria to cause disease. By studying the comparative biological and pathological behaviour of microbes across mammalian genera, researchers might be able more rapidly to advance medical science and, subsequently, patient care by undertaking focused research efforts involving a single mammalian species or by attempting to recapitulate a complex disease in an rodent model. Therefore, in an effort to further assist in the establishment of disease causation by stealth pathogens, we use recent research observations involving the genus Bartonella to propose an additional postulate of comparative infectious disease causation to Koch's postulates.