Fine structure of secondary granule inclusions in fowl heterophils after ruthenium tetroxide fixation

Bone marrow from domestic fowls was initially fixed for electron microscopy in glutaraldehyde and post-fixed with either ruthenium tetroxide or osmium tetroxide. Inclusions with distinct outlines were revealed in the secondary granules of heterophil leucocytes after ruthenium tetroxide but not with osmium tetroxide fixation. In longitudinal orientation, these inclusions were rod-shaped and composed of microfilaments measuring 3.7 nm in diameter. In transverse section, the outline of some of these inclusions was hexagonal and therefore the inclusions may be crystalline in nature.     

Noncrystalline inclusions in erythrocytes of a rhinoceros iguana

In the following case, intracytoplasmic and intranuclear noncrystalline inclusions are found in the erythrocytes of a male Rhinoceros Iguana. Ultrastructurally, cytoplasmic inclusions are hexagonal with sharp borders not bound by a membrane. Similar to surrounding hemoglobin in that they are amorphous, homogenous and composed of finely textured material, the inclusions are easily differentiated by their symmetry and weak electron density. Nuclear inclusions are observed causing margination of chromatin and nucleoplasm. They are also easily distinguished by their hexagonal shape, weak electron density and the greater granularity of the surrounding nucleoplasm. The case is unusual because noncrystalline inclusions other than Heinz bodies have not yet been described in the erythrocytes of animals with nucleated red cells.     

Canine adenovirus type 1 infection of a Eurasian river otter (Lutra lutra)

A 10-year-old female Eurasian river otter (Lutra lutra) died after prolonged anorexia and weight loss in the Seoul Grand Park Zoo, Seoul, Republic of Korea. On necropsy, the liver was found to be swollen and friable with 1 lobe enlarged and necrotic. The other organs showed no significant alterations except for mild atrophy of the right kidney. Microscopically, there was multifocal hepatic necrosis. The hepatocytes around the necrotic areas were swollen and contained large basophilic intranuclear inclusions. Periportal infiltration by plasma cells and lymphocytes was also evident. Transmission electron microscopy revealed characteristic hexagonal virus particles sized approximately 70 nm in diameter in the nuclei of the hepatocytes, which were consistent with an adenovirus. Polymerase chain reaction of the formalin-fixed, paraffin-embedded liver sections was used to determine whether the virus was either the canine adenovirus type 1 (CAV-1), canine adenovirus type 2 (CAV-2), or some other viral agent. The results of these tests showed that the virus was CAV-1. To our knowledge, this is the first report on a CAV-1 infection in an otter.     

Parvovirus-like enteropathy in Missouri turkeys

A viral enteric disease of young turkeys characterized by stunting of affected birds, diarrhea, and increased mortality is described. Eosinophilic intranuclear inclusion bodies were found in the absorptive epithelial cells of the ileum. Electron microscopy of formalin-fixed tissue revealed that the intestinal inclusions contained numerous loosely packed 15-to 20-nm hexagonal particles. The size, shape, and intranuclear location have been used to tentatively identify these particles as parvoviruses.     

Systemic glycoproteinosis resembling Lafora's disease in a cow

A 6-year-old, Hereford/Angus crossbred cow which died acutely was submitted for necropsy and diagnostic evaluation. A toxicity was suspected by the owner who had noticed incoordination of one week's duration. The animal was last observed 24 hours prior to death. Toxicology screens for alkaloids, heavy metals, pesticides and nitrates were negative. The significant histologic abnormalities were confined to the thalamic nuclei, periventricular neurons and the liver. Neurons and hepatocytes contained 1 to 2 intracytoplasmic inclusions which stained faintly eosinophilic to slightly basophilic with H&E. The inclusions frequently had dense central cores and a fibrillar to homogeneous periphery. Based on a battery of histochemical stains for carbohydrates, and other mucosubstances and the morphology and location of the inclusions, a diagnosis of systemic glycoproteinosis consistent with Lafora's disease was made. This case represents the first report of lesions consistent with Lafora's disease in the bovine species.     

Proliferative dermatitis in a loggerhead turtle, Caretta caretta, and a green turtle, Chelonia mydas, associated with novel papillomaviruses

A subadult loggerhead turtle, Caretta caretta, presented with generalized small, white, raised lesions over its neck, shoulders, and all four flippers. A juvenile green turtle, Chelonia mydas, recently treated for fibropapillomatosis, presented with four similar localized lesions on one flipper. To diagnose the conditions, biopsies of the lesions were taken for histopathology, electron microscopy, and molecular diagnostics. Histopathologic findings were similar in the two turtles and skin lesions were characterized by multifocal areas of epidermal hyperplasia accompanied by variation and abnormalities in the nuclear morphology of keratinocytes and a few intranuclear inclusions in some cells. Transmission electron microscopy revealed multiple epithelial cells with large intranuclear aggregates of virions consistent in morphology with papillomavirus. Papillomavirus was detected in samples from both turtles by polymerase chain reaction (PCR). Sequence analysis of the partial sequence of the papillomavirus E1 gene revealed two viruses (CcPV and CmPV) that were distinct from each other and from other species in Papillomaviridae, and likely represent two novel species and perhaps a new genus.     

Age-related histological changes in the canine substantia nigra

Age-related changes in the canine substantia nigra, were examined using immunostaining for tyrosine hydroxylase (TH), glial fibrillary acidic protein (GFAP), neurofilament (NF), ubiquitin, single stranded DNA (ssDNA), and alpha-synuclein (alphaSN). Brain sections from 34 necropsied dogs, ranging from 2 months to 18 years old, were used for this study. On general histological examinations, several age-related changes, including lipofuscin deposition, polyglucosan bodies, amorphous basophilic inclusions and eosinophilic crystal inclusions, were found in the aged dogs. Immunohistochemically, TH-positive neurons were located only in the substantia nigra. The number of TH-positive neurons was well preserved in all dogs examined, however, the ratio of TH-positive neurons to GFAP-positive glial cells tended to show slight decrease in aged dogs. By ssDNA immunostaining for apoptotic cells, there were no significant results in the number of ssDNA-positive neurons. The number of ubiquitin- and NF-positive swollen neurites was increased markedly in aged dogs. Ubiquitin immunostaining revealed a small number of basophilic and eosinophilic inclusions, although both types of inclusions were negative for NF. By alphaSN immunostaining, no neurons were immunoreactive and no basophilic or eosinophilic intracytoplasmic inclusions were revealed. These results indicate that in the substantia nigra of aged dogs the dopaminergic neurons are well preserved, but intracytoplasmic inclusions and ubiquitin-positive degenerative neurites are commonly found.     

An outbreak of fatal herpesvirus infection in domestic rabbits in Alaska

A herpesvirus infection affecting mini Rex and crossbred meat rabbits was identified in a rabbitry in Alaska. Illness affected over half of the 55 rabbits on the premises, and 16 rabbits died or were euthanatized because of illness. Disease affected all ages from adults to nursing young and occurred over an approximately 2-month period. Clinical signs included conjunctivitis and periocular swelling, ulcerative dermatitis, progressive weakness, anorexia, respiratory distress, and abortion. Hemorrhagic dermatitis and panniculitis were associated with epidermal microvesicular degeneration, dermal and subcutaneous vascular necrosis, and thrombosis. Eosinophilic intranuclear inclusions consistent with herpesvirus were found within the epidermis and superficial follicular epithelium and within mesenchymal cells within the dermis and subcutis. Syncytial cells containing viral inclusions occurred within the epidermal and superficial follicular epithelium. Other findings were hemorrhagic necrosis of the myocardium with rare intranuclear inclusions within stromal cells, multifocal pulmonary hemorrhage, hemorrhage with sinus erythrophagocytosis in lymph nodes, and massive necrosis and fibrin deposition within red pulp of the spleen. A virus isolated from the skin produced syncytia, intranuclear inclusions, and cell lysis typical of herpesvirus in rabbit kidney cells in vitro. The viral isolate was characterized ultrastructurally as an enveloped virus with icosahedral nucleocapsids 100 nm diameter, consistent with a herpesvirus.     

Feline anaemia associated with Ehrlichia-like bodies in three domestic short-haired cats

Three domestic short-haired cats with a history of anorexia and loss of body condition had high rectal temperatures, and a normocytic, normochromic anaemia. Two of them were also dyspnoeic, and thoracic radiographs revealed a diffuse, unstructured increase in radio-opacity involving all the lung lobes. Examination of Giemsa-stained blood smears and culture of blood monocytes revealed purplish-staining intracytoplasmic inclusions, in monocytes and lymphocytes, which occurred either singly or in aggregates. Electron micrographs of a buffy coat smear from one of the cats revealed round intracytoplasmic inclusions, with electron dense and lucid areas morphometrically similar to those found in other members of the genus Ehrlichia. An attempt to culture chlamydia from one of the cats was unsuccessful. The cats were treated successfully, one with tetracycline hydrochloride and the other two with imidocarb dipropionate.     

Characterization of cytoplasmic hyaline bodies in a hepatocellular carcinoma of a dog

This report describes the morphological and immunohistochemical features of intracytoplasmic inclusion bodies found in a 13-year-old Yorkshire dog with a hepatocellular carcinoma and referred for anorexia, lethargy and mild polydipsia. Fine-needle aspirates of the large abdominal mass revealed high number of pleomorphic neoplastic hepatocytes, containing round to polygonal, well-demarcated, hyaline bodies. Same findings were histologically confirmed on multiple biopsies. Immunohistochemically, the inclusion bodies were negative for alpha-1-antitrypsin, carcinoembryonary antigen, fibrinogen, IgG, IgM, cytokeratins 7, 8, 18, 19, 20. By transmission electron microscopy, the cytoplasmic inclusions were composed of granular homogeneous or reticulated electrondense matrix, enclosed within dilated rough endoplasmic reticulum or remnants of its membranes, consistent with proteinaceous material accumulated within neoplastic hepatocytes due to aberrant protein secretion or transport. This is the first detailed characterization of hyaline cytoplasmic inclusion bodies in canine hepatocellular carcinoma.     

鱼类细胞肿大虹彩病毒病研究进展

鱼类细胞肿大虹彩病毒病在东亚和东南亚的真鲷、石斑鱼、大菱鲆、大黄鱼、鳜鱼等多种养殖鱼类中的频繁流行,致使感染鱼类出现大面积死亡,已成为危害养殖鱼类最严重的病毒病之一.文章综述了近年来鱼类细胞肿大虹彩病毒病的研究现状,重点介绍了该类疾病的流行病学、临床症状、组织病理学、分子生物学检测技术、病毒的传播途径、致病机制以及病毒的免疫防控等方面的研究进展,并对当前鱼类细胞肿大虹彩病毒研究中存在的问题进行了分析和展望.     

Sphingomyelin lipidosis in a cat

A 7-month-old Balinese cat with progressive neurological dysfunction had histopathological lesions of brain, liver, kidney, spleen, and lung consistent with a lysosomal storage disease. Ultrastructural examination revealed lysosomal hypertrophy with membranous inclusions. Hepatic sphingomyelin and cholesterol were elevated 10 times normal, and total phospholipids were increased 3.6 fold. Sphingomyelinase activity measured with 14C labeled sphingomyelin at pH 5.0 was virtually absent in brain and liver. Other lysosomal hydrolase activities were normal or elevated. Clinical, morphological, and biochemical findings suggest that this cat had sphingomyelin lipidosis similar to human Niemann-Pick disease type A, and that feline sphingomyelin lipidosis provides another model of human lysosomal storage disease.     

Babesiosis in free-ranging chamois (Rupicapra r. rupicapra) from Switzerland

Pathological examination of five adult chamois (Rupicapra r. rupicapra) found dead in two different regions from the Swiss Alps revealed pale mucous membranes and musculature, swollen spleen and haemoglobinuria. Histologically, haemosiderosis in the spleen and centrilobular hepatic necrosis were the predominant findings. On blood smears, small (approximately 0.84-1.47 microm), round to pyriform, peripherally located inclusions were present in the erythrocytes. PCR followed by sequencing of DNA extracted from blood or spleen of the infected animals revealed 99-100% identity of the amplified part of the 18S rRNA gene with GenBank entries attributed to Babesia divergens/Babesia capreoli. This is the first report of fatal Babesia infections in chamois raising the question of an emerging disease in this species.     

Cytoplasmic blood plasma inclusions of canine hepatocytes demonstration by immunoperoxidase-labeling method

Cytoplasmic inclusions in canine hepatocytes were scattered abundantly throughout hepatic lobules. They were mainly round, measured 3 microns to 20 microns in diameter, stained eosinophilic with hematoxylin and eosin stain, and were positive for diastase-resistant periodic acid-Schiff and phosphotungstic acid hematoxylin stains. Immunoperoxidase staining revealed that most of the inclusions were positive for such blood plasma components as albumin, immunoglobulins G, M, A, and transferrin. Ultrastructurally, the inclusions were granular, floccular, fibrillar, or homogeneous with a low or high electron density. Fibrin fibers and erythrocytes were occasionally recognized in the inclusions. These inclusions were considered to have derived from engulfment of blood elements into hepatocytes, probably as a result of increase of the intrasinusoidal blood pressure.     

Pigeon herpesvirus: inclusion body hepatitis in a free-ranging pigeon

An adult male pigeon (Columba livia) was presented to the Wildlife Service at the University of Pennsylvania School of Veterinary Medicine for depression, cachexia, and diarrhea. Five days after the initial presentation, the bird died and was necropsied. Gross lesions included opaque air sacs and multiple 1-mm yellow-white foci on the epicardial surface of the heart. Histopathologic lesions included a pericarditis, epicarditis, and multifocal hepatic necrosis accompanied by eosinophilic inclusion bodies. Ultrastructural examination of the hepatic inclusions revealed viral particles consistent with a herpesvirus. The gross, light microscopic, and electron microscopic findings are consistent with pigeon herpesvirus infection.     

Experimental oral administration of canine adenovirus (type 2) to raccoons (Procyon lotor).

Canine adenovirus type 2 (CAV2) has been proposed for recombinant vaccines to control rabies in wild animals. To evaluate the suitability of CAV2 as a safe vector for the genetically engineered vaccines, seven wild-caught raccoons (three males and four females) were administered CAV2 per os. Two of the animals were euthanatized on each of post-infection days 3, 6, and 14, and one was euthanatized on day 21. Two other control raccoons (a male and a female) were also euthanatized on day 21. Microscopic pulmonary lesions of multifocal necrotizing bronchiolitis with basophilic intranuclear inclusions were seen in 3/4 raccoons euthanatized on post-infection days 3 and 6. Ultrastructural examination of lungs with pulmonary lesions revealed hexagonal viral particles characteristic of adenoviruses. CAV2 is potentially pathogenic for raccoons, and this susceptibility should be of concern to developers of recombinant vaccines who intend to use CAV2 as a vaccine vector.     

Piscine orthoreovirus (PRV) infects Atlantic salmon erythrocytes

Piscine orthoreovirus (PRV) belongs to the Reoviridae family and is the only known fish virus related to the Orthoreovirus genus. The virus is the causative agent of heart and skeletal muscle inflammation (HSMI), an emerging disease in farmed Atlantic salmon (Salmo salar L.). PRV is ubiquitous in farmed Atlantic salmon and high loads of PRV in the heart are consistent findings in HSMI. The mechanism by which PRV infection causes disease remains largely unknown. In this study we investigated the presence of PRV in blood and erythrocytes using an experimental cohabitation challenge model. We found that in the early phases of infection, the PRV loads in blood were significantly higher than in any other organ. Most virus was found in the erythrocyte fraction, and in individual fish more than 50% of erythrocytes were PRV-positive, as determined by flow cytometry. PRV was condensed into large cytoplasmic inclusions resembling viral factories, as demonstrated by immunofluorescence and confocal microscopy. By electron microscopy we showed that these inclusions contained reovirus-like particles. The PRV particles and inclusions also had a striking resemblance to previously reported viral inclusions described as Erythrocytic inclusion body syndrome (EIBS). We conclude that the erythrocyte is a major target cell for PRV infection. These findings provide new information about HSMI pathogenesis, and show that PRV is an important factor of viral erythrocytic inclusions.     

Studies on the multiplication of a porcine parvovirus

A porcine parvovirus has been characterized with regard to its replication in foetal porcine kidney cells and certain biophysical properties. Electron microscopy of infected cells at selected times postinfection revealed that porcine parvovirus replication took place within or near a series of granular intranuclear inclusions which may be contiguous with cellular heterochromatin. Developing virions were observed to aggregate into a nuclear-like amorphous mass which gradually disrupted as cellular integrity was lost. Purified virions were found to have a buoyant density in CsCl of 1.38 g/ml, while ‘empty’ particles has a buoyant density of 1.29 g/ml. The particle diameter was calculated to be approximately 22 nm.     

Ovine pulmonary cytomegalovirus.

Cytomegalic cells with intranuclear inclusions were identified in lung tissue from one of two weanling Western lambs with pneumonia and Mycoplasma ovipneumoniae infection. On the basis of light and electron microscopy, cytomegalovirus infection was diagnosed. Arrays of viral particles whose morphology was consistent with that of viruses of the herpes group were in the intranuclear inclusions of cytomegalic cells.     

Morphological studies of esophageal papilloma naturally occurring in cattle

Esophageal papillomas naturally occurring in 35 cattle were examined by light and electron microscopy. The characteristic histological lesions noted were acanthosis and parakeratosis of the mucous membrane with formation of basophilic intranuclear inclusion bodies in cells of the stratum corneum. Electron microscopically, viral particles were observed in the strata spinosum and corneum, and larger aggregations of viral particles appeared to correspond to the histological inclusions. The virus particles had a hexagonal profile, measured 35-40 nm in diameter and were arranged in crystalline arrays in some nuclei. The viral particles had morphologic characteristics indistinguishable from those of other papilloma viruses. The inclusions were stained positively by immunohistochemical methods using anti-bovine papilloma virus serum.