Immunohistochemical Detection of Intralesional Antigens of Ovine Gammaherpesvirus-2 in Cattle with Sheep-associated Malignant Catarrhal Fever

Sheep-associated malignant catarrhal fever (SA-MCF) is a severe lymphoproliferative disease of ruminants caused by ovine gammaherpesvirus-2 (OvHV-2). Since the initial identification of SA-MCF there has been extensive research related to the pathogenesis of OvHV-2, based primarily on serological and molecular assays associated with typical histopathological findings. The monoclonal antibody (MAb-15A) binds to a common epitope in MCF viruses and is used frequently in serological investigations. However, the utilization of this antibody to detect antigens of OvHV-2 in tissues has not been examined. Accordingly, this study standardized an immunohistochemical assay using MAb-15A to identify antigens of OvHV-2 in tissues of cattle (n = 5) with SA-MCF. All animals developed acute neurological signs, without ocular and nasal manifestations, and had nucleic acids of OvHV-2 in brain tissue detected by polymerase chain reaction. The principal histopathological findings were lymphocytic nephritis (n = 5), widespread arterial proliferation and vasculitis (n = 5), lymphocytic portal hepatitis (n = 3), non-suppurative meningoencephalitis (n = 2) and atrophic enteritis with cryptal necrosis and dilation (n = 2). Intralesional intracytoplasmic antigens of OvHV-2 were identified within multiple epithelial cells of the kidneys of all animals, the intestines of animals with and without atrophic enteritis, and within epithelial cells of bile ducts in animals with lymphocytic hepatitis. Additionally, there was positive intracytoplasmic immunoreactivity within histiocytes and lymphocytes in several tissues. These findings suggest that the MAb-15A detects antigens of OvHV-2 within epithelial cells and leucocytes in several organs. Moreover, this assay would contribute significantly towards understanding of the pathogenesis of SA-MCF and may be used for retrospective studies. Additionally, angiopathy in SA-MCF may be a progressive lesion, which may terminate in luminal occlusion and probably occurs irrespectively of the eye and head form of MCF.

Viruses associated with congenital tremor and high lethality in piglets

The recently described atypical porcine pestivirus (APPV) has been associated with congenital tremor (CT) type A-II in piglets in different countries. Another important neurological pathogen of pigs is porcine teschovirus (PTV), which has been associated with non-suppurative encephalomyelitis in pigs with severe or mild neurological disorders. There have been no reports of APPV and/or PTV coinfection associated with CT or encephalomyelitis in Brazilian pig herds. The aim of this study was to describe the pathological and molecular findings associated with simultaneous infection of APPV and PTV in piglets with clinical manifestations of CT that were derived from a herd with high rates of CT-associated lethality. In 2017, three piglets from the same litter with CT died spontaneously. The principal pathological alterations in all piglets were secondary demyelination and hypomyelination at the cerebellum, brainstem and spinal cord confirmed by histopathology and luxol fast blue-cresyl violet stain. Additional significant pathological findings included multifocal neuronal necrosis, neuronophagia and gliosis found in the cerebral cortex and spinal cord of all piglets, while atrophic enteritis and mesocolonic oedema were observed in some of them. APPV and PTV RNA were detected in the central nervous system of affected piglets, and PTV was also detected in the intestine and faeces. The pathological alterations and molecular findings together suggest a dual infection due to APPV and PTV at this farm. Moreover, the combined effects of these pathogens can be attributed to the elevated piglet mortality, as coinfections involving PTV have a synergistic effect on the affected animals.

Pneumonia due to Talaromyces marneffei in a Dog from Southern Brazil with Concomitant Canine Distemper Virus Infection

The pathological and molecular findings associated with Talaromyces marneffei-induced pneumonia with concomitant infection by canine distemper virus (CDV) are described in a dog. The principal pathological alteration occurred in the lungs. Histopathology confirmed multifocal granulomatous pneumonia associated with numerous intralesional and intracellular septate fission cells consistent with T. marneffei. A molecular assay designed to amplify a partial fragment of the 18S rRNA gene of T. marneffei provided positive results from two fungal cultures derived from the lung. Sequencing and phylogenetic analyses confirmed the results of polymerase chain reaction (PCR). Furthermore, antigens of the CDV N protein were identified within the bronchial epithelium by immunohistochemistry and a PCR assay amplified the CDV N gene from hepatic and pulmonary fragments. Collectively, the pathological and molecular techniques confirmed a diagnosis of T. marneffei-induced pneumonia with concomitant infection by CDV. These findings represent the first description of pulmonary penicilliosis in the dog and extend the geographical niche of this emerging infectious pathogen. In this case, infection by CDV may have induced immunosuppression, which facilitated the development of pulmonary penicilliosis.

Concomitant Malignant Pulmonary Peripheral Nerve Sheath Tumour and Benign Cutaneous Peripheral Nerve Sheath Tumour in a Dog

Peripheral nerve sheath tumours (PNSTs) are neoplastic growths derived from Schwann cells, perineural cells or both. Malignant PNSTs (MPNSTs) are uncommon in domestic animals. This report describes the concomitant occurrence of PNSTs in a 10-year-old female cocker spaniel with a clinical history of respiratory impairment. Grossly, there was a large infiltrative mass in the caudal lobe of the right lung; smaller nodules were observed in the other lobes of the right lung. Furthermore, a small encapsulated cutaneous nodule was observed on the left hindlimb. Histopathology of the pulmonary tumours revealed the proliferation of pleomorphic spindle-shaped cells with moderate mitotic index arranged in interwoven bundles and concentric Antoni A and Antoni B patterns; invasion of the adjacent pulmonary tissue was observed. The cutaneous nodule consisted of neoplastic mesenchymal cells in interwoven bundles with concentric whorls, but without the marked anisokaryosis, binucleation and infiltrative growth seen in the pulmonary tumour. Immunohistochemistry revealed that both tumours were immunoreactive for vimentin, glial fibrillary acidic protein and S100 protein, but were negative for factor VIII. These findings are indicative of a MPNST in the lung with a concomitant benign PNST in the limb. This case represents the first report of a primary MPNST in the lung of a dog. This neoplastic growth should be included in the differential diagnosis of primary malignant pulmonary tumours of dogs.

Brazilian strain of bovine respiratory coronavirus is derived from dual enteric and respiratory tropism

Bovine coronavirus (BCoV) is a pathogen related to enteric and respiratory diseases in cattle worldwide. Enteric (BECoV) strains of BCoV are predominant in South America, and genetic investigations have been conducted to identify its relationship with isolates of respiratory origin (BRCoV). In this study, we used a BRCoV strain (BR-UEL11) derived from an outbreak of respiratory disease in feedlot cattle in southern Brazil, and compared the partial sequence of the polymorphic region of Spike (which was detected and sequenced by two distinct reverse transcription-polymerase chain reactions) with those of other BCoV strains. The phylogenetic relationship of BR-UEL11 with Brazilian BCoV, which is associated with calf diarrhea and winter dysentery (enteric, BECoV; respiratory, BRCoV), and classical reference prototypes was analyzed. The analysis showed that the BRCoV strains from Brazil clustered with a clade that was distinct from most isolates associated with calf diarrhea (BECoV) and ancestral prototype strains such as Mebus, Nebraska, and LYVB. Furthermore, the BRCoV strains from Brazil clustered with a clade that contained recent strains associated with winter dysentery, showing 98-99% nucleotide identity with those strains. These results suggested that the Brazilian BCoV evolved from being solely enteric to a dual enteric and respiratory tropic virus.

Morphology and muscle gene expression in GIFT and Supreme Nile tilapia varieties reared in two cultivation systems

Tissue growth in most fishes occurs by muscular hyperplasia and hypertrophy, which are influenced by different regulatory factors, such as myostatin. The current study evaluated the influence of cultivation in hapas and earthen ponds on the diameter of white muscle fibers and on the myostatin (MSTN-1) gene in GIFT and Supreme varieties of tilapia. Fish of both varieties were reared for 204 days and then divided into four developmental stages. White muscle samples, corresponding to 100 fibers per slide, were collected from the middle region of fish of each variety and cultivation system, and were measured and divided into two classes representing hyperplasia and hypertrophy. Samples were subjected to real-time PCR to analyze gene expression. Hyperplasia decreased during the developing stages, coupled with increased hypertrophy. There was a higher rate of hypertrophy in fish raised in earthen ponds when compared to those raised in hapas, during juvenile and developing phases, and greater hypertrophic growth was observed in GIFT specimens when compared to Supreme specimens in earthen ponds. Since increased MSTN-1 gene expression was observed in GIFT specimens during the developing phase in pond cultivations, and in Supreme tilapia in hapas, MSTN-1 expression is related to greater hypertrophy. These results demonstrate the capacity for increased muscle growth in earthen pond cultivation in which the GIFT variety developed best. How the environment affects the growth of different tilapia varieties may be employed to optimize culture management and genetic improvement programs. Further investigations should aim to describe mechanisms affecting muscle growth and development.

Phylogenetic analyses of the hemagglutinin gene of wild-type strains of canine distemper virus in southern Brazil

This study examined the phylogenetic relationship of strains of canine distemper virus (CDV) collected from Paraná State, Brazil, based on the hemagglutinin gene. Urine samples were collected from 4 dogs from northern Paraná State that demonstrated clinical manifestations of canine distemper. The participation of CDV was initially confirmed by RT-PCR targeting the nucleocapsid protein, after which the complete hemagglutinin gene was sequenced from each sample. Sequences were deposited in and compared with those already in GenBank. Phylogenetic analyses, using amino acid and nucleotide sequences based on the hemagglutinin gene, demonstrated that these strains of CDV are closely related to those from the Europe 1 lineage of CDV, with marked differences from other recognized geographical clusters of CDV isolates and from the vaccine strains. The strains of CDV from this region of southern Brazil appear to be related to those from Europe 1.

First description of group A rotavirus from fecal samples of ostriches (Struthio camelus)

This study investigated the occurrence of rotavirus infections in ostriches (Struthio camelus) reared in Northern Paraná, Brazil. Fecal (n=66) and serum (n=182) samples from nine farms located in four different cities were analyzed by silver stained-polyacrylamide gel electrophoresis (ss-PAGE), RT-PCR assay, virus isolation, and counterimmunoelectroosmophoresis (CIE). Rotavirus group A seropositivity occurred in 5.49% (10/182) of serum samples of ostriches originated from two farms. Only 9.09% (6/66) of fecal samples from ostriches with diarrhea maintained in one farm were positive by ss-PAGE, RT-PCR, and virus isolation. The G (VP7) and P (VP4) genotypes of rotavirus wild strains isolated in cell culture were determined by multiplex-nested PCR. The genotyping identified two rotavirus strains: G6P[1] and G10P[1]. In three rotavirus strains it was only possible to identify the P type; one strain being P[1] and two strains that presented the combination of P[1]+P[7]. These findings might represent the first characterization of rotavirus in ostriches, and the finding of porcine and bovine-like rotavirus genotypes in ostriches might suggest virus reassortment and possible interspecies transmission.

Cutaneous myxosarcoma with pulmonary metastases in a dog

The pathological findings in a 13-year-old dog with cutaneous myxosarcoma with pulmonary metastases are described. Grossly, there was a large subcutaneous mass in the right scapular region, a smaller nodule in the caudal abdominal region and a fibrotic mass at a fracture site in the right hindlimb. Radiographic examination revealed several pulmonary nodules. Microscopical evaluation revealed a myxosarcoma characterized by the proliferation of spindle to stellate cells with multiple prominent nucleoli and vascular invasion. The neoplastic cells were haphazardly arranged in a mucopolysaccharide matrix. Immunohistochemically, the neoplastic cells expressed vimentin, but not cytokeratin or glial fibrillary acidic protein. There was restricted expression of desmin, smooth muscle actin and S-100 protein.

Diagnostic exercise: intraosseous epidermoid cysts in the third phalanx of a dressage mare

An 11-yr-old Dressage mare had abnormal gait, and an abscess of the left hoof was suspected but not observed. Radiographic and computerized tomographic evaluations showed a large cystic lesion near the apex of the pedal bone, and a smaller, similar lesion at the lateral wing. Sagittal sections through the affected member revealed two intraosseous cysts at the third phalanx. Histologic and histochemical results characterized the lesions as intraosseous epidermoid cysts of the third phalanx.

Diagnostic exercise: Tyzzer's disease, distemper, and coccidiosis in a pup

A 2-month-old mongrel dog had multifocal necrotizing hepatitis, interstitial pneumonia, and hemorrhagic enteritis. Immunohistochemistry detected antigens of Clostridium piliforme in the intestine and liver, and antigens of canine distemper virus within the lung, urinary bladder, brain, spleen, and liver. Furthermore, uncharacterized intralesional coccidian protozoa were observed within the intestine.

Central primitive neuroectodermal tumour with ependymal differentiation in a dog

A central primitive neuroectodermal tumour (PNET) with ependymal differentiation was identified in an 18-month-old female Australian terrier dog that died following signs of central nervous system disease. A large space-occupying haemorrhagic mass replaced the thalamus and part of the hypothalamus of the brain. Microscopical examination revealed a tumour formed by a compact sheet of small cells that contained ependymal and perivascular pseudorosettes. Immunohistochemically, the neoplastic cells variably expressed glial fibrillary acidic protein, neuron-specific enolase, vimentin and cytokeratin, consistent with divergent differentiation of the tumour. This case is thought to represent the first description of PNET with ependymal differentiation in a dog.

Phylogenetic analysis of Anaplasma marginale strains from Paraná State, Brazil, using the msp1alpha and msp4 genes

Anaplasma marginale is an obligate intraerythrocytic rickettsial pathogen (order, Rickettsiales: family, Anaplasmataceae) that causes bovine anaplasmosis. This disease is widely distributed in tropical and sub-tropical regions of the world and causes important economic losses to cattle production. Major surface protein (MSP)1a (msp1alpha gene) is one of the six MSPs identified on A. marginale from cattle, whose sequence and size vary according to the number of tandem 28- to 29-amino acid repeats. This study characterized the msp1alpha and msp4 genes obtained from three distinct Brazilian herds from the State of Paraná. Three strains of the msp1alpha and one strain of the msp4 gene were sequenced. The strains evaluated revealed PCR products of different size, representing three, five and six internal repeats. Sequence analyses confirmed the number of tandem sequence copies and revealed a high degree of sequence identity with strains from other Brazilian States, as well as strains from the USA, Europe and Israel. The msp1alpha DNA and amino acid sequences from A. marginale and DNA sequences of msp4 strains did not reveal distinct phylogeographical segregation. However, the amino acid sequences of msp4 demonstrated definite phylogeographical relationship. These results suggest that the amino acid sequences of msp4 should be used for phylogenetic identification of A. marginale strains and may be an important tool for the epidemiology and control of anaplasmosis. Additionally, the close similarity of the Paraná strains of A. marginale with strains from USA, Europe and Asia may reflect the introduction of these genes during the development of the Brazilian bovine herd.

Ocorrência simultânea de adenocarcinoma das glândulas ceruminosas e otite externa em um cão

O artigo não apresenta resumo.

Glial fibrillary acidic protein (GFAP)-immunoreactive astrocytes in dogs infected with canine distemper virus

An experiment based on astrocyte immunoreactivity to glial fibrillary acidic protein (GFAP) was designed to determine whether the astrocyte response in canine distemper encephalitis (CDE) was associated with the age of the animal, type of lesion and the cerebellar region affected. Four histopathological types of CDE lesion were examined, namely acute (11 dogs), acute with necrosis (four dogs), subacute (22 dogs) and chronic (six dogs). The animals were divided into three age groups, namely, 0-2 years (27 dogs), 2.1-4 years (12 dogs), and 4.1-12 years (four dogs). Three different cerebellar regions were evaluated. Cerebellar sections from three healthy dogs were used for control purposes. The highest number of astrocytes occurred in the cerebellar white matter and in dogs with acute distemper encephalopathy. In animals with subacute distemper encephalitis, the numbers of astrocytes appeared to increase with age, but the opposite effect occurred in dogs with acute or chronic encephalitis; age appeared not to influence the astrocyte numbers in dogs suffering from acute encephalitis with necrosis.

Renin and hemodynamic responses to exercise in borderline hypertensives

OBJECTIVE

In this study, we examined the relationship between baseline plasma renin (REN) and hemodynamic variables during recovery from aerobic exercise in 10 Caucasian (C) and 10 African-American (AA) borderline hypertensive females.

METHODS

Subjects attended three preliminary sessions and an experimental session in which treadmill walking was performed for 40 minutes at a moderate intensity. During this session, blood was drawn at baseline prior to exercise and immediately following. Blood pressure and other hemodynamic variables were recorded at rest before exercise and for 2 hours afterwards. The average difference from baseline during the two hour recovery period was calculated for each variable and used as the dependent variable in a multiple regression analysis.

RESULTS

For mean arterial pressure and cardiac output, the regression slopes did not differ between AA and C. However, during recovery, the average difference from baseline for systemic vascular resistance (SVR) increased in AA but decreased in C.

CONCLUSION

In conclusion, REN had a significant effect on SVR but no effect on the other hemodynamic variables during recovery from aerobic exercise. It appears as if the peripheral vasculature in AA may be more sensitive than in C to the vasoconstrictive effects of the renin angiotensin system.

Cardiovascular responses to beta-blockade and 5 degrees C cold air stress

To determine the cardiovascular responses to beta-blockade and cold air stress, six males were randomly exposed at rest to three drug conditions (placebo, nonselective beta-blockade (propranolol), and selective beta-blockade (atenolol)) in each of two environments (5 and 25 degrees C) for 1 h. Cardiac output was lower on beta-blockade than on the placebo in both the 25 and 5 degrees C environments. Cardiac output on propranolol (4.2 +/- 0.3 L.min-1) at 5 degrees C was lower than on atenolol (4.7 +/- 0.4 L.min-1, p < 0.05). Mean arterial pressure was greater (p < 0.05) at 5 than 25 degrees C for each drug condition. There was no drug effect on total peripheral resistance at 25 degrees C. At 5 degrees C, total peripheral resistance on both beta-blockers (propranolol 1942.7 +/- 169.9 dyn.s.cm-5 (1 dyn = 10 microN); atenolol 1706.7 +/- 160.0 dyn.s.cm-5) was higher (p < 0.05) than on the placebo (1485.3 +/- 111.8 dyn.s.cm-5). Total peripheral resistance was also higher on propranolol than atenolol (p < 0.05). In conclusion, cold air stress interacts with beta-blockade to elevate total peripheral resistance by decreasing cardiac output while having little effect on mean arterial pressure. These effects are greater on nonselective than on selective blockade.

Periodic carbohydrate replacement during 50 min of high-intensity cycling improves subsequent sprint performance

The purpose of this study was to investigate the effect of 7% carbohydrate-electrolyte (CE) drink on sprint capacity immediately following 50 min of high-intensity cycling. After an overnight 12-hr fast, 8 trained male cyclists performed two 50-min simulated time trials on a Monark stationary cycle ergometer. Subjects consumed either the CE or a flavored water placebo (PL) at 10, 20, 30, and 40 min during the time trial. At the conclusion of each 50-min time trial, subjects immediately performed a Wingate Anaerobic Power Test. Peak power, mean power, and minimum power were significantly higher for the CE trials, whereas mean RPE was significantly lower. Mean heart rate and fatigue index were not different between trials. These results suggest that sprint performance following a high-intensity simulated time trial of only 50 min can be improved with periodic consumption of CE during the ride, particularly following an overnight fast, when liver glycogen is likely to be low. These findings have implications for competitive cycling, where sprint capacity at the conclusion of a race is an important determinant of success.