Neuronal and astrocytic involvement in striped dolphins (Stenella coeruleoalba) with morbilliviral encephalitis

Dolphin morbillivirus (DMV), a highly pathogenic agent, may cause peculiar, "brain-only" forms of infection (BOFDI), in which viral antigen and/or genome is found exclusively in the brain from striped dolphins (Stenella coeruleoalba). These BOFDIs show morphopathological similarities with subacute sclerosing panencephalitis and old dog encephalitis (ODE) in measles virus-infected patients and in canine distemper virus-infected dogs, respectively. The brain tissue from 3 BOFDI-affected striped dolphins was investigated by means of double labelling-indirect immunofluorescence (DL-IIF) and ultrastructurally, in order to characterize the DMV-targeted neuronal and non-neuronal cell populations, along with the associated submicroscopic findings. Viral colonization of calbindin-immunoreactive (IR) and nitric oxide synthase-IR neurons was detected in the cerebral parenchyma from the 3 DMV-infected dolphins under study, associated with nuclear (chromatin) and cytoplasmic (mitochondrial) ultrastructural changes. Furthermore, a limited viral targeting of brain astrocytes was found in these animals, all of which exhibited a prominent astrogliosis/astrocytosis. To the best of our knowledge, those herein reported should be the first submicroscopic pathology and neuropathogenetic data about BOFDI in striped dolphins. In this respect, the marked astrogliosis/astrocytosis and the low viral colonization of brain astrocytes in the 3 DMV-infected dolphins under investigation are of interest from the comparative pathology and viral neuropathogenesis standpoints, when compared with ODE-affected dogs, in whose brain a non-cytolytic, astrocyte-to-astrocyte infectious spread has been recently documented. Further studies aimed at characterizing the complex DMV-host interactions in BOFDI-affected striped dolphins are needed.

Detection of bovine Deltapapillomavirus DNA in peripheral blood of healthy sheep (Ovis aries)

Blood samples from 65 sheep were tested for the presence of bovine Deltapapillomavirus (δPVs) DNA. The sheep were divided into three groups. Sheep in groups 1 and 2 were from Sardinia and Campania, respectively, and were in contact with cattle and grazed on lands contaminated with bracken fern. Sheep in Group 3 lived in closed pens and had no contact with cattle. These sheep were fed hay that did not contain bracken fern. Bovine δPV E5 DNA was detected in blood from 24 of 27 (89%) sheep in Group 1. A single bovine δPV type was detected in the blood from nine (33%) sheep, including the detection of bovine δPV-1 DNA in four sheep, bovine δPV-2 in four and δPV-13 in one sheep. Two δPV types were detected in 33% of the sheep, and three bovine δPV types were detected in 22% of the sheep. Bovine δPVs were detected in 17 of 20 (85%) sheep from Group 2. The detection rate by a single δPV type was 40% with just δPV-1 DNA amplified from two, just δPV-2 DNA from four, and just δPV-13 DNA from two sheep. Two and three δPVs were detected in 30% and 15%, respectively. All sequenced amplicons showed a 100% identity with papillomaviral E5 DNA deposited in GenBank. Bovine δPV-14 DNA sequences were not detected from any sheep. No bovine δPV DNA was revealed in blood samples from sheep in Group 3. The detection of bovine δPV DNA in the blood of sheep means that sheep may be able to be infected by these PVs. This suggests that bovine δPVs could potentially be a previously unrecognized cause of disease in sheep. Furthermore, it is possible that sheep could act as a reservoir for these viruses.

Bovine Papillomavirus Type 13 Expression in the Urothelial Bladder Tumours of Cattle

Bovine papillomavirus type 13 (BPV-13), a novel Deltapapillomavirus, has been found associated with urothelial tumours of the urinary bladder of cattle grazing on lands infested with bracken fern. BPV-13 was detected in 28 of 39 urothelial tumours. Diagnosis was based on sequencing of L1 and E5 amplicons from tumour samples. The nucleotide sequences generated from these amplicons showed a 100% homology with the sequences of BPV-13 L1 and E5 DNA found in Brazil from a fibropapilloma of the ear in a cow and from equine sarcoids in two horses. GenBank accession number of our representative BPV-13 sequences is JQ798171.1. Furthermore, mRNA encoding BPV-13 E5 oncoprotein was also documented, and its expression was also shown by immunohistochemistry and immunofluorescence in the basal and suprabasal urothelial tumour cells. In twenty-three tumours, BPV-13 was simultaneously found with BPV-2, a Deltapapillomavirus genus, species 4. The latter virus was detected by amplifying and sequencing a 154-bp-sized DNA fragment of BPV-2 E5. In addition, BPV-13 by itself was seen to be expressed in five BPV-2-negative urothelial tumours. This study shows that BPV-13 is present in urothelial tumour cells thus sharing biological properties with BPV-1 and BPV-2. Although further studies are needed, BPV-13 appears to be another worldwide infectious agent responsible for a distressing disease causing severe economic losses in cattle industry.

Phosphatidylinositol-3-kinase-AKT pathway, phospho-JUN and phospho-JNK expression in spontaneously arising bovine urinary bladder tumours

The aetiopathogenesis of urinary bladder tumours in cattle involves prolonged ingestion of bracken fern and infection by bovine papillomavirus types 1 or 2 (BPV-1/2). E5, the major BPV-1/2 oncoprotein, binds to the activated platelet-derived growth factor beta receptor (pPDGF-betaR), inducing cell transformation in vitro and spontaneously arising urinary bladder tumours. The aim of this study was to assess whether the 85 kDa regulatory subunit (p85) of the phosphatidylinositol-3-kinase (PI3K)-AKT pathway and other transforming signals phospho-JUN (pJUN) and phospho-JUN N-terminal kinases (pJNK) may be important in the development of BPV-associated urothelial carcinomas. A physical interaction between the pPDGF-betaR and PI3K was shown in four tumours and two samples of normal bladder tissue by co-immunoprecipitation and western blotting. There was greater expression of the PI3K-AKT-cyclin D3 molecular pathway downstream to the activation of pPDGF-betaR in neoplastic compared with normal tissue. pJNK and pJUN were overexpressed in samples of tumour compared with normal mucosal tissue. These findings provide new insights into the aetiopathogenic mechanisms underlying naturally occurring bovine urothelial carcinogenesis and contribute to understanding of the role of E5 oncoprotein in naturally occurring tumorigenesis.

Sigma-2 receptor expression in bovine papillomavirus-associated urinary bladder tumours

The expression of sigma-2 receptors was investigated in nine urothelial tumours of the urinary bladder of cattle. Each tumour was associated with the presence of DNA of bovine papillomavirus type-2 (BPV-2) and expression of the E5 viral oncoprotein. Five tumours were classified as low-grade carcinoma on the basis of morphological criteria and calculation of mean nuclear area (MNA) and mean nuclear perimeter (MNP). Four tumours were classified as high-grade carcinoma. Sigma-2 receptors were overexpressed in both types of carcinoma. In control normal bovine bladder tissue the density of receptors (expressed as the B(max)) was 0.37 pmol/mg of protein. Low-grade carcinomas had a mean B(max) of 1.37+/-0.32 pmol/mg of protein (range 1.03-1.86) and in high-grade carcinomas the mean B(max) was 10.9+/-2.8 pmol/mg of protein (range 8.2-14). The difference in B(max) between low- and high-grade carcinomas was statistically significant (P=0.0001).

Activated platelet-derived growth factor beta receptor expression, PI3K-AKT pathway molecular analysis, and transforming signals in equine sarcoids

The equine sarcoid is the most common dermatologic neoplasm reported in horses. Bovine papillomavirus (BPV) types 1 and 2 are associated with sarcoids, in which the expression of the major transforming oncoprotein (E5) is often recorded. The transformation activity of the virus is due to the binding of the E5 to the platelet-derived growth factor beta receptor (PDGFbeta-r). In the present study, we show by Western blot in 4 sarcoid samples and 3 normal equine skin samples that the PDGFbeta-r is more phosphorylated in sarcoid tissue than in normal skin (P < .001). Furthermore, the physical interaction between the activated receptor and the 85-kDa regulatory subunit (p85) of phosphatidylinositol-3-kinase (PI3K) is shown by coimmunoprecipitation. The PI3K-AKT-cyclin D3 molecular pathway downstream to the activation of the PDGFbeta-r is shown to be expressed, and the amount of the investigated molecules is higher than normal (P < .001), suggesting an activation of these effectors in sarcoids. Further, we demonstrate that phospho-JNK and phospho-JUN are more expressed in sarcoids than in normal skin. Our results provide new insights into the pathogenesis of equine sarcoids and support the validity of this in-vivo model to further characterize the molecular pathways underlying BPV E5-induced carcinogenesis.

Heterogeneous shedding of Brucella abortus in milk and its effect on the control of animal brucellosis

AIMS

To ascertain whether in Brucella abortus-infected water buffalo herds, the number of newly infected animals could be reduced by culling superspreaders (the animals secreting > or =10(4) CFU per ml of milk).

METHODS AND RESULTS

The number of B. abortus present in the milk (CFU per ml) from 500 water buffaloes was measured by the culture. Each animal was tested three times, at one month intervals. The presence or the absence of B. abortus in each milk sample was confirmed by PCR. A majority of infected animals shed the pathogen at a low level (< or =10(3) CFU ml(-1)). However, a few infected individuals (superspreaders) shed large numbers of B. abortus (> or =10(4) CFU ml(-1)). Quantitative PCR of B. abortus positive milk samples gave comparable results to culture. Culling of the superspreaders was sufficient to arrest the spread of infection.

SIGNIFICANCE AND IMPACT OF THE STUDY

The approach described here can reduce significantly the cost of controlling brucellosis. Culture and quantitative PCR tests identify superspreaders and, compared with the serological tests in use to detect brucellosis, provide also a more accurate estimate of the disease incidence.

Lymphoepithelioma-like carcinoma of the urinary bladder in a cow associated with bovine papillomavirus type-2

Lymphoepithelioma-like carcinoma (LELCA) of the urinary bladder is reported in a 7-year-old cow that had grazed pasture rich in bracken fern and had suffered from severe intermittent haematuria from 3 to 4 years of age. On necropsy examination there were multiple haemorrhagic foci scattered over the mucosal surface of the urinary bladder. Microscopically there were nests, cords and sheets of neoplastic cells infiltrating the lamina propria and muscularis propria. These had a syncytial appearance with ill-defined cytoplasmic borders, large nuclei and prominent nucleoli. There was a prominent associated inflammatory infiltrate comprising lymphocytes and plasma cells with sparse histiocytes and granulocytes. Immunohistochemically, LELCA cells expressed cytokeratin but not vimentin. The LELCA was focally admixed with a concomitant papillary high-grade carcinoma that also infiltrated the lamina propria. A diffuse carcinoma in situ was also present. Bovine papillomavirus type-2 (BPV-2) DNA was amplified from frozen neoplastic tissue and from selected areas of formalin-fixed, paraffin wax-embedded tissue obtained by laser capture microdissection. Microbiological culture of a urine sample resulted in isolation of Weeksella virosa, Rhizobium radiobacter and Staphylococcus warneri. Flow cytometric analysis performed on blood mononuclear cells revealed down-regulation of a panel of markers including CD3, CD4, CD8alpha, CD45, MHC class I and MHC class II (HLA-DRalpha, HLA-DQ, HLA-DP). This report extends the spectrum of neoplastic urothelial lesions described in cattle and provides further evidence that some features of these tumours are similar to human counterparts.

Mannose-binding lectin haplotypes influence Brucella abortus infection in the water buffalo (Bubalus bubalis)

A case-control study established that the haplotype pair HYA/HYA at the MBL (mannose binding lectin) locus of water buffalo is associated with resistance to Brucella abortus infection (P < 10(-7)) and the haplotype pairs LYD/LYD with susceptibility to the same pathogen (P < 10(-7)). The subjects included in the present study were tested twice-at a 1-month interval-for the presence of anti-B. abortus antibodies in the serum by agglutination, complement fixation and flow cytometry. Cases (335 subjects) included animals consistently positive to all these tests; controls (335 subjects) comprised animals exposed yet negative by the same tests. The serum from genetically resistant subjects displayed in vitro significantly higher antibacterial activity compared to the serum from genetically susceptible subjects, lending biological significance to the results from the association study. Inhibition of the antibacterial activity following heat treatment of the serum, addition of specific MBL inhibitors (EDTA, mannose, N-acetyl-D: -glucosamine) or anti-human MBL antiserum provide convincing evidence that the antibacterial activity present in the serum results from the interaction between MBL and B. abortus. A replication study (comprising 100 cases and 100 controls) confirmed the results from the original study.

Melanosis of the Urinary Bladder in a Cow

Melanosis of the urinary bladder is a very rare condition characterized by an abnormal black or brownish-black pigmentation of the organ. The pigmentary disorder can involve both the urothelial cell layers and/or the submucosa. The biologic potential of the melanosis of urinary bladder remains unknown because only a few cases have been reported in medical literature. So far melanosis of the urinary bladder is not known to occur in cattle. Here we describe the first case of melanosis of the urinary bladder in an inbred red-spotted, 7-year-old cow. Light, ultrastructural, and immunohistochemic investigations demonstrated melanin pigment in the submucosa and lamina propria but not the urothelium of the bladder. In addition, biochemical characterization of the pigment-laden cells demonstrated that the pigment of this disorder consisted mainly of eumelanin, thus corroborating the morphologic studies. Finally, virologic examination revealed the presence of bovine papillomavirus type 2.

Multiple Glomus Tumors of the Urinary Bladder in a Cow Associated with Bovine Papillomavirus Type 2 (BPV-2) Infection

We report a case of multiple glomus tumors associated with bovine papillomavirus type 2 (BPV-2) infection in the urinary bladder of a 13-year-old cow suffering from severe chronic enzootic hematuria. Macroscopically, multiple submucosal reddish nodules were seen swelling the vesical mucosa. Histologically, neoplastic proliferation was characterized by the presence of numerous blood vessels. These were lined by normal endothelial cells surrounded by round epithelioid cells with central nuclei, prominent nucleoli, acidophilic cytoplasm, and well-defined cytoplasmic borders. Tumor cells were distributed around open vascular lumina and in perivascular spaces. They were immunohistochemically positive for actin and vimentin and negative for cytokeratins, desmin, and factor VIII-related antigen. On the basis of these findings, this tumor was diagnosed as glomus tumor, a neoplasm not previously reported in cattle and exceedingly rare in animals. BPV-2 DNA was amplified from the formalin-fixed, paraffin-processed tissue specimens obtained by laser capture microdissection. This report widens the spectrum of mesenchymal tumors of the bovine urinary bladder. Finally, the microscopic pattern of tumor described here shares striking morphologic and immunohistochemical similarities with the angiomatous form of glomus tumor known to occur in man.

Sialic Acid and GM3 Ganglioside Expression in Papillomavirus-associated Urinary Bladder Tumours of Cattle with Chronic Enzootic Haematuria

This study was based on 30 papillomavirus-associated urinary bladder tumours from cattle with chronic haematuria, the animals having been kept since birth on pasture rich in bracken fern. The ganglioside content was assessed and compared with that of normal bovine urinary bladders, which was shown to be 28.6+/-3.3 (mean+/-SD) microg of lipid-bound sialic acid per gram of fresh tissue. In neoplastic bladder samples this value was higher but variable (120.9+/-80.6 in benign tumours, and 94.7+/-45.7 in malignant tumours). The main ganglioside, GM3, represented ca 75% of the total ganglioside mixture in normal tissues and 50-80% in tumour samples. GM1, GM2, GD1a, GD3 and FucGM1 were found as minor components. The study suggested that GM3 ganglioside may have a crucial role in "downregulation" of the metastatic potential of bovine urothelial cancers.

Bovine papillomavirus type-2 (BPV-2) infection and expression of uroplakin IIIb, a novel urothelial cell marker, in urinary bladder tumors of cows

Several immunohistochemical markers have been used to define the differentiation pattern of urothelial cell tumors of the urinary bladder. We investigated the expression of the recently characterized uroplakin (UP) IIIb, an urothelium-specific and differentiation-dependent protein, in 39 urothelial tumors of the urinary bladder in cows that had suffered from chronic enzootic hematuria for several years. Bovine papillomavirus type 2 DNA was amplified and UP IIIb protein was detected in all these tumors. In papillomas and papillary carcinomas, UP IIIb expression was mostly seen as superficial staining; luminal and peripheral patterns were also observed. In nonpapillary carcinomas, UP IIIb appeared to define clearly the cell membrane lining intercellular and intracellular lumina as well as the cell borders in deeper cell layers. In benign and malignant lesions, an intracytoplasmic immunoreactivity was also detected. Coarse intracytoplasmic UP IIIb-positive material close to the nucleus occurred in some malignant cells. Focally strong membraneous immunostaining that marked single cells with complete ringlike peripheral pattern was seen. Although UP IIIb expression does not seem to correlate with the biological behavior of urothelial tumors, it appears to be a highly sensitive marker for bovine urothelial tumors.

Selection of an Escherichia coli O157:H7 bacteriophage for persistence in the circulatory system of mice infected experimentally

A bacteriophage lytic for Escherichia coli O157:H7 was isolated from bovine manure. Following in-vivo selection, the phage acquired the capacity to persist in the circulatory system of mice for at least 38 days. When mice were infected experimentally with E. coli O157:H7 (10(7) CFU/mouse), simultaneous injection of the mice with phage (10(8) PFU/mouse) cleared E. coli O157:H7 from the mice within 48 h.

Bovine papillomavirus E5 oncoprotein binds to the activated form of the platelet-derived growth factor beta receptor in naturally occurring bovine urinary bladder tumours

Studies regarding the functions of the bovine papillomavirus (BPV) E5 oncoprotein in vivo are lacking and no E5-mediated mechanism underlying epithelial carcinogenesis is known. We have shown that BPV-2 DNA is present in the majority of naturally occurring urinary bladder tumours of cattle and that E5 is expressed in the cancer cells. Here we show that the interaction between the platelet-derived growth factor (PDGF) beta receptor and BPV E5, described in vitro in cultured cells, takes place in vivo in bovine urinary bladder cancers. In these cancers, E5 and PDGF beta receptor colocalize, as shown by confocal microscopy, and physically interact, as shown by coimmunoprecipitation. Furthermore, the PDGF beta receptor associated with E5 is highly phosphorylated, suggesting the functional activation of the receptor upon E5 interaction. Our results demonstrate, for the first time, that E5-PDGF beta receptor interaction occurs during the natural history of bovine urinary bladder tumours, suggesting an important role for E5 in carcinogenesis. Finally, the system provides a suitable animal model of papillomavirus-associated cancer to test therapeutic vaccination against E5. Successful bladder tumour regression would provide a valuable model for therapeutic vaccination against papillomavirus-associated tumours.

Caprine herpesvirus-1 (CapHV-1) induces apoptosis in goat peripheral blood mononuclear cells

Programmed cell death (PCD), or apoptosis, is initiated in response to various stimuli, including virus infection. A number of studies have shown that deregulation of apoptosis is an important feature of virus-induced immunosuppression for various viral diseases. In the present study, CapHV-1 was found to cause apoptosis in mitogen-stimulated as well as nonstimulated caprine peripheral blood mononuclear cells (PBMC). Apoptotic index, as quantified by fluorescent dyes, revealed a significant increase in the percentage of apoptotic cells at 24 and 48 h postinfection as compared to their respective noninfected controls. Apoptosis specific internucleosomal laddering in DNA from CapHV-1 infected PBMC was seen in agarose gel electrophoresis. No DNA fragmentation was observed in control noninfected PBMC. Virus-induced apoptosis was reduced by Z-VAD-FMK, an aspecific caspase inhibitor, by AC-DEVD-CHO (caspase-3-specific) and AC-VEID-CHO (caspase-6-specific) treatment. PCD in CapHV-1 infected peripheral blood mononuclear cells occurs at the G0/G1 phase of the cell cycle. However, penetration of virus particles and infection was not required for PCD, as UV-inactivated CapHV-1 induced apoptosis of mitogen-stimulated bovine peripheral blood mononuclear cells in vitro.

Chromosome Aberrations in Cattle with Chronic Enzootic Haematuria

Chromosomal aberrations were investigated in 56 cattle with chronic enzootic haematuria (CEH) raised on pastures giving access to bracken fern. Of these animals, 27 were slaughtered and showed neoplastic lesions of the urinary bladder. Tumour tissue from 11 of the 27 cattle contained bovine papillomavirus type 2 (BPV-2) DNA. Increased numbers of chromosomal aberrations were seen in all animals with CEH, as compared with 30 control cattle that had had no access to bracken fern. The highest clastogenic effect was observed in cattle with urinary bladder cancer and evidence of BPV-2 DNA, suggesting that BPV-2 and bracken fern act synergistically in the production of chromosomal instability. In 19 of 20 animals with CEH, two bracken fern toxic compounds (quercitin and ptaquiloside) were demonstrated in urine, serum and milk.

Efficacy of an inactivated canine coronavirus vaccine in pups

The efficacy of an inactivated CCoV vaccine (Duramune PC) was evaluated in four pups. Two dogs were maintained non-vaccinated. Ten days after the booster shot all the pups were challenged with a field CCoV strain administered by oro-nasal route. The vaccinated pups did not display clinical signs and shed the challenge-virus for 11.25 days, evaluated by virus isolation, and 13.5 days, evaluated by PCR assay. The two non vaccinated pups displayed mild diarrhoea at day post-challenge 4 and shed the challenge-virus for 14 and 15 days respectively, by virus isolation, and for 22 and 24 days respectively, by PCR assay.

Bovine papillomavirus type 4 in oesophageal papillomas of cattle from the south of Italy

Oesophageal papillomas are known to occur in cattle infected with bovine papillomavirus type 4 (BPV-4), and BPV-4 papillomas may undergo malignant progression in cattle that feed on bracken fern. In the south of Italy, where bracken fern is common, examination of 1133 slaughterhouse cattle aged 4-12 years revealed oesophageal lesions (single or multiple peduncuolated proliferations, or mucosal thickening) in 147 (13%). These two types of lesion were consistent with exophytic and inverted papilloma, respectively. BPV-4 was detected by polymerase chain reaction (PCR) analysis in >60% of the samples in which oesophageal papilloma was diagnosed histopathologically. Nucleotide sequencing of the PCR amplicons confirmed the presence of BPV-4 in the papillomas. This is the first report of such infections in a European country other than Britain.