Production, characterisation and applications of monoclonal antibodies to two novel porcine bocaviruses from swine in Northern Ireland.

The production, preliminary characterisation and applications of monoclonal antibodies (mAbs) against two novel swine bocaviruses isolated in cell culture from swine in Northern Ireland are described. Of the 17 stable final clones produced, four were characterised. All were of the IgG2a isotype and showed no cross-reactivity with either bocavirus strain. Partial neutralisation was observed with PBoV4 mAbs and homologous virus. The two mAbs selected for use in antigen-detecting ELISAs were successful in highlighting those fractions containing infectious virus within sucrose gradients. This is the first report of the production of specific reagents that will prove useful in the study of the biology of these viruses and swine bocavirus-associated diseases.

Simultaneous detection of three porcine viruses by multiplex PCR.

Specific oligonucleotide primers were selected and combined in a multiplex arrangement, in order to detect simultaneously three economically important porcine viruses by polymerase chain reaction (PCR). The pathogen panel was comprised of viruses that cause reproductive failure in infected herds: Aujeszky's disease virus (ADV), porcine parvovirus (PPV) and porcine respiratory and reproductive syndrome virus (PRRSV). In order to reduce the time required for the detection of the pathogens, the assay was optimised to a RapidCycler PCR instrument. The multiplex PCR assay was shown to be specific, sensitive and rapid, because the results were read in less than 60 min after sample preparation. Due to its speed, efficiency and sensitivity, the described rapid multiplex PCR assay serves as a useful novel tool in the veterinary diagnostic laboratories for the quick and complex detection of these important porcine pathogens.

PCR detection of porcine circovirus type 2 (PCV2) DNA in blood, tonsillar and faecal swabs from experimentally infected pigs.

PCV2 infection is now recognized as the major factor in the development of post-weaning multisystemic wasting syndrome (PMWS). In this study we evaluated the use of PCR to detect the presence of PCV2 DNA in blood, faecal and tonsillar swabs collected from 12 pigs experimentally infected with PCV2 and sampled at selected time points post-infection. The PCR results were evaluated together with the presence of PMWS typical histopathological lesions and the presence of PCV2 antigen. PCV2 DNA was present in the blood of all 12 infected pigs at the end of the experiment and faecal and tonsillar swabs of 11 of the 12 pigs. The rate of PCR-positive serum and plasma samples was significantly higher in four pigs that showed virological and pathological evidence of PMWS, than in infected pigs without evidence of disease. In conclusion this study confirms that PCR cannot substitute for the traditional methods used for diagnosis of PMWS, however, PCR amplification of PCV2 DNA from serum or plasma could be a useful tool to support an early diagnosis of PMWS in live animals.

House fly vector for porcine circovirus 2b on commercial pig farms.

We investigated the on-farm potential of common farm invertebrates to transmit porcine circovirus genotype 2 (PCV2) and other non-enveloped viruses. In 2007 (pre-PCV2 vaccination) and 2008 (post-PCV2 vaccination), invertebrate communities were trap-collected (8 trap-dates per year), counted and sorted into genus and species groups on 5 farm study sites within England. Total DNA was extracted from feces of representational cross-sections of pigs on each farm in each year and also from intact samples of Diptera flies (ca. 20 flies per trap) and dissected viscera of any cockroaches (ca. 5 per trap). Each DNA sample was tested for the presence of PCV2 DNA by separate PCRs for ORF1 and ORF2. Positive samples were sub-typed via DNA sequencing of PCR products. The pig-associated Diptera fly community was dominated by Musca domestica (house fly) in both years on all 5 farms; numerous Blatta orientalis cockroaches were only noted on 1 farm throughout. Specific PCV2b DNA elements were routinely detected (25-60% of samples) in weaner/nursery pig feces in 2007, but not in other age groups. Musca collected on 4 of the 5 farms in 2007 was also positive for PCV2b DNA elements. Comparison of ORF2 sequences indicated that ORF2 sequences indicating PCV2b genotype were identical in pigs and flies. Minor changes were noted in ORF1 sequences from different samples. Flies collected in the weaner/nursery area were most likely to be positive (22-50% of fly-trap samples). DNA extracted from all cockroaches (2007 and 2008) and all flies and pig feces in 2008 were also negative throughout. We suggest that Musca flies have the most likely on-farm potential to carry and transmit PCV2b due to their life cycle incorporating stages in close association with pigs and their habitat. Vaccination appeared to reduce environmental load of PCV2b.

Development of a minor groove binder assay for real-time one-step RT-PCR detection of swine vesicular disease virus.

The design and development of a 5' conjugated minor groove binder (MGB) probe real-time RT-PCR assay are described for rapid, sensitive and specific detection of swine vesicular disease virus (SVDV) RNA. The assay is designed to target the 2C gene of the SVDV genome and is capable of detecting 2×10(2) copies of an RNA standard per reaction. It does not detect any of the other RNA viruses that cause vesicular disease in pigs, or the human enterovirus, Coxsackie B5 virus (CVB5) which is closely related antigenically to SVDV. The linear range of this test was from 2×10(2) to 2×10(8) copies/µl. The assay is rapid and can detect SVDV RNA in just over 3.5 h including the time required for nucleic acid extraction. The development of this assay provides a useful tool for the differential diagnosis of SVD or for the detection of SVDV in research applications. This study demonstrates the suitability of MGB probes as a real-time PCR chemistry for the diagnosis of swine vesicular disease.

Development and comparison of a Primer-Probe Energy Transfer based assay and a 5' conjugated Minor Groove Binder assay for sensitive real-time PCR detection of infectious laryngotracheitis virus.

In this study the design and development of two real-time PCR assays for the rapid, sensitive and specific detection of infectious laryngotracheitis virus (ILTV) DNA is described. A Primer-Probe Energy Transfer (PriProET) assay and 5' conjugated Minor Groove Binder (MGB) method are compared and contrasted. Both have been designed to target the thymidine kinase gene of the ILTV genome. Both PriProET and MGB assays are capable of detecting 20 copies of a DNA standard per reaction and are linear from 2×10(8) to 2×10(2)copies/µl. Neither PriProET, nor MGB reacted with heterologous herpesviruses, indicating a high specificity of the two methods as novel tools for virus detection and identification. This study demonstrates the suitability of PriProET and 5' conjugated MGB probes as real-time PCR chemistries for the diagnosis of respiratory diseases caused by ILTV.

The value of axillary ultrasound with fine needle aspiration as a pre-operative staging procedure in breast cancer: Northern Irish experience.

INTRODUCTION: In our unit sentinel lymph node biopsy (SLNB) is performed without intra-operative pathological nodal assessment. If node biopsies are positive the patients have to return at a later date for a complete axillary node clearance (ANC). METHODS: We conducted a retrospective study to ascertain if the use of pre-operative ultrasound assessment of the axilla with fine needle aspiration (FNA) sampling could identify patients with nodal metastases and therefore identify patients who should proceed primarily to ANC. RESULTS: Our study showed that 40 patients out of 119 had nodal metastases, and ultrasound correctly identified 19 of those patients.

Initial incursion of pandemic (H1N1) 2009 influenza A virus into European pigs.

The initial incursion of pandemic (H1N1) 2009 influenza A virus (pH1N1) into a European pig population is reported. Diagnosis of swine influenza caused by pandemic virus was made during September 2009 following routine submission of samples for differential diagnosis of causative agents of respiratory disease, including influenza A virus. All four pigs (aged six weeks) submitted for investigation from a pig herd of approximately 5000 animals in Northern Ireland, experiencing acute-onset respiratory signs in finishing and growing pigs, were positive by immunofluorescence for influenza A. Follow-up analysis of lung tissue homogenates by real-time RT-PCR confirmed the presence of pH1N1. The virus was subsequently detected on two other premises in Northern Ireland; on one premises, detection followed the pre-export health certification testing of samples from pigs presumed to be subclinically infected as no clinical signs were apparent. None of the premises was linked to another epidemiologically. Sequencing of the haemagglutinin and neuraminidase genes revealed high nucleotide identity (>99.4 per cent) with other pH1N1s isolated from human beings. Genotypic analyses revealed all gene segments to be most closely related to those of contemporary pH1N1 viruses in human beings. It is concluded that all three outbreaks occurred independently, potentially as a result of transmission of the virus from human beings to pigs.

Improved diagnosis for nine viral diseases considered as notifiable by the world organization for animal health.

Nine viral diseases included in the World Organization for Animal Health list of notifiable diseases (former list A) were chosen for their contagiousness and high capacity of spreading to improve their diagnosis using new and emerging technologies. All the selected diseases--foot-and-mouth disease, swine vesicular disease, vesicular stomatitis, classical swine fever, African swine fever, bluetongue, African horse sickness, Newcastle disease and highly pathogenic avian influenza--are considered as transboundary diseases, which detection causes the prohibition of livestock exportation, and, thus, it leads to high economical losses. The applied diagnostic techniques can fall into two categories: (i) nucleic-acid detection, including padlock probes, real-time PCR with TaqMan, minor groove binding probes and fluorescence energy transfer reaction probes, isothermal amplification like the Cleavase/Invader assay or the loop-mediated amplification technology and the development of rapid kits for 'mobile' PCR and (ii) antigen-antibody detection systems like simplified and more sensitive ELISA tests. Besides, internal controls have been improved for nucleic acid-detecting methods by using an RNA plant virus--Cowpea Mosaic Virus--to ensure the stability of the RNA used as a positive control in diagnostic real-time RT-PCR assays. The development of these diagnosis techniques has required the joint efforts of a European consortium in which nine diagnostic laboratories and an SME who have collaborated since 2004 within the European Union-funded Lab-on-site project. The results obtained are shown in this paper.

Porcine circovirus 2 replication in colostrum-deprived piglets following experimental infection and immune stimulation using a modified live vaccine against porcine respiratory and reproductive syndrome virus.

Porcine circovirus type 2 (PCV2) infection is now recognized as the major factor in the development of post-weaning multisystemic wasting syndrome (PMWS). Although Koch's postulates have been fulfilled for PCV2 and PMWS, the severe clinical expression of the disease observed in field cases has been difficult to reproduce experimentally. Some studies have demonstrated that immune stimulation associated with the use of some commercially available swine vaccines may trigger progression of PCV2 infection to disease and lesions characteristic of PMWS. Here we describe the effects on PCV2 infection in an experimental model following the use of a commercially available modified live vaccine to porcine respiratory and reproductive syndrome virus (PRRSV). Although none of the piglets infected with PCV2 developed clinical PMWS, the severity of microscopical lesions and the PCV2 antigen load associated with these lesions were higher in the PRRSV-vaccinated piglets compared with those detected in the PCV2 only infected animals.

Diagnosis of duck circovirus infections by conventional and real-time polymerase chain reaction tests.

Development of the first conventional and real-time polymerase chain reaction (PCR) tests for the diagnoses of duck circovirus (DuCV) infections is described. Both tests amplified a 230 bp fragment specific to the DuCV Rep gene. Although both tests had the same detection limit (13 x 10(3) target DNA/ml) when the target DNA was diluted in water, the detection limit of the real-time test (13 x 10(4) target DNA/ml) was 10-fold less than the conventional test (13 x 10(5) target DNA/ml) when the amplifications were performed in the presence of cellular DNA. Using the conventional PCR test, DuCV DNA was detected in 85 (84%) of 101 bursa of Fabricius samples from dead or sick ducks, aged between 1 and 12 weeks, and in samples from 35 (94%) of 37 flocks. Application of the SYBR Green-based real-time PCR test to 54 selected bursa of Fabricius samples indicated that more samples were positive by real-time PCR than by conventional PCR, allowed the numbers of genome copies to be estimated and showed that some bursa of Fabricius samples contained over 10(13) genome copies/g tissue. Although DuCV infections were detected in birds aged from 1 to 12 weeks, higher virus DNA levels were detected in ducks aged older than 5 weeks than in ducks younger than 5 weeks. An in situ hybridization method for the detection of DuCV in histological samples was also developed. Additional work is required to determine the clinicopathological significance of DuCV infections.

Expression of receptors for epidermal growth factor and insulin-like growth factor I by ZR-75-1 human breast cancer cell variants is inversely related: the effect of steroid hormones on insulin-like growth factor I receptor expression.

We have investigated the expression of insulin-like growth factor I receptors (IGFR) by the ZR-75-1 human breast cancer cell line and tamoxifen-resistant (ZR-75-9a1) and oestrogen-independent (ZR-PR-LT) variants. ZR-75-1 cells expressed 6633+/-953 receptors per cell,(K(d) 0.24+/-0.06 nM). IGFR expression was reduced in ZR-75-9a1 cells (1180+/-614 receptors per cell, K(d) 0.13+/-0.05) and increased in the ZR-PR-LT cell line (18 430+/-3210 receptors per cell, K(d) 0.24+/-17). A comparison of these data with previously published findings for epidermal growth factor receptor (EGFR) expression by these cell lines revealed that IGFR and EGFR expression are inversely related in the variant lines whereas ZR-75-1 cells express similar numbers of both receptors. Since the changes in IGFR expression observed are associated with changes in steroid hormone receptor status, we also investigated the effects of oestradiol, the synthetic progestin ORG 2058 and dexamethasone on IGFR expression. Oestradiol increased IGFR expression only in the ZR-75-1 cell line. Low concentrations of ORG 2058 increased IGFR levels in the two cell lines positive for progesterone receptor (ZR-75-1 and ZR-PR-LT). High concentrations of ORG 2058 increased IGFR expression in all cell lines, as did dexamethasone. These data suggest that EGFR and IGFR expression may be linked in breast cancer, and that EGFR/IGFR ratios in breast cancer may be a more sensitive prognostic indicator than EGFR expression alone. Regardless of basal IGFR expression by the cell studied, ORG 2058 increased IGFR expression, possibly via both the progesterone and glucocorticoid receptors.