Virulence factors of Mycoplasma synoviae: Three genes influencing colonization, immunogenicity, and transmissibility

Infections caused by Mycoplasma synoviae are major welfare and economic concerns in poultry industries worldwide. These infections cause chronic respiratory disease and/or synovitis in chickens and turkeys leading to reduced production and increased mortality rates. The live attenuated vaccine strain MS-H (Vaxsafe® MS), commonly used for protection against M. synoviae infection in many countries, contains 32 single nucleotide variations compared to its wildtype parent strain, 86079/7NS. Genomic analysis of vaccine strains reisolated from flocks following the administration of MS-H has identified reversions to the original 86079/7NS sequence in the obgE, oppF and gapdh genes. Here, three MS-H field reisolates containing the 86079/7NS genotype in obgE (AS2), obgE and oppF (AB1), and obgE, oppF and gapdh (TS4), as well as the vaccine MS-H and the parental strain 86079/7NS were experimentally inoculated to chickens. The strains were assessed for their ability to infect and elicit immune responses in the recipient chickens, as well as in naïve in-contact chickens. Despite the loss of temperature sensitivity phenotype and colonization of the reisolates in the lower respiratory tract, there was no significant differences detected in the microscopic mucosal thickness of the middle or lower trachea of the inoculated chickens. Concurrent reversions in ObgE, OppF and GAPDH proteins were associated with higher gross air sac lesion scores and increased microscopic upper-tracheal mucosal thickness in chickens directly inoculated with the reisolates following intratracheal administration of a virulent strain of infectious bronchitis virus. The gross air sac lesions of the chickens in-contact with those inoculated with reisolates were not significantly different to those of chickens in-contact with MS-H inoculated chickens, suggesting that horizontal transmission of the reisolates in the poultry flock will not lead to higher pathogenicity or clinical signs. These results suggest a significant role of GAPDH and/or cumulative effect of ObgE, OppF and GAPDH on M. synoviae pathogenicity. Future experiments will be required to investigate the effect of single mutations in gapdh or oppF gene on pathogenicity of M. synoviae.

JS07.5.A 18F-fluciclovine PET and multi-parametric MRI to distinguish pseudoprogression from tumor progression in post-treatment glioblastoma

Background

Differentiation of tumor progression (TP) from pseudoprogression (PsP) is a major unmet need in glioblastoma (GBM). 18F-Fluciclovine is a synthetic amino acid PET radiotracer with higher uptake in tumor tissue vs. areas of treatment-related change. We aimed to assess the combined value of 18F-Fluciclovine PET and multi-parametric MRI for differentiating PsP from TP.

Material and Methods

We enrolled 30 patients with GBM with a new or enlarging contrast-enhancing lesion on MRI after chemoradiotherapy who were planned for surgical resection of the lesion. Patients underwent pre-operative 18F-Fluciclovine PET and multi-parametric MRI. Following surgery, the relative percentages of viable tumor and therapy-related changes observed on histopathology were quantified. Patients were categorized as TP if viable tumor represented ≥ 50% of the specimen, mixed TP if < 50% and > 10%, and PsP if ≤ 10%. SUVmax, SUVpeak, and 50% threshold SUVmean were calculated and normalized to contralateral brain, pituitary gland, and superior sagittal sinus (SSS). The least absolute shrinkage and selection operator (LASSO) was used to determine the variables most predictive of tumor percentage. The strength of association between the primary outcome and selected variables was assessed by Pearson’s or Point-biserial correlation.

Results

18 patients with TP, 4 with mixed TP-PsP, and 8 with PsP were included. There was a positive correlation between 50% threshold SUV mean measured from PET images acquired 50-60 minutes post-injection and rCBVmax by MRI and tumor percentage by histology (r= 0.56; p= 0.004 and r=0.50; p=0.012 respectively). 40-50 minutes SUVmax (OR=1.78 rpb=0.51) and rCBVmax (OR=1.64, rpb=0.48) were positively correlated with tumor TP/mixed TP group. Patients who demonstrated TP/mixed TP-PsP had significantly higher 40-50 minutes SUVmax compared to patients with histological PsP (6.71±2.03 vs 3.93±1.63; p=0.012). 40-50 minutes SUVmax cut-off of 4.46 provided 90% sensitivity and 80% specificity for differentiation of TP/mixed TP-PsP from PsP (AUC=0.88). Combining a 40-50 minutes SUVmax cut-off of 4.46 and an rCBVmax cut-off of 3.67 provided 100% sensitivity and 100% specificity for differentiating TP/mixed TP-PsP from PsP (AUC=1). Patients who demonstrated TP had a significantly higher 40-50 minutes SUVmax compared to patients with histological PsP (6.99±2.06 vs 3.93±1.63; p=0.008). A 40-50 minutes SUVmax cut-off of 4.66 provided 94% sensitivity and 80% specificity for differentiation of TP from PsP (AUC=0.89).

Conclusion

18F-Fluciclovine PET uptake is positively correlated with viable tumor quantification on histology and can accurately differentiate PsP from TP in patients with GBM. Further independent studies are required to cross-validate these promising early results.

Characterisation of the whole genome sequence of an avian hepatitis E virus directly from clinical specimens reveals possible recombination events between European and USA strains

Avian hepatitis E virus (aHEV) is the causative agent of an important disease of broiler breeders and layers. aHEV cannot be readily propagated in cell culture and is characterised primarily by sequencing of amplicons generated through several RT-PCRs that target individual genes. This study aims to uncover the origin of current Australian aHEV isolates based on whole genome sequencing using clinical liver tissues. Complete genome sequences of the two aHEV isolates were assembled using Nanopore and Illumina reads. The two isolates possessed only four single nucleotide polymorphisms to each other. Comparison of the sequences with aHEV genome sequences available in the GenBank showed the highest nucleotide sequence identity of 88% with the prototype USA strain (AY535004), 82% with the European (AM943647) and genotype 1 Australian strains (AM943647). Recombination analysis suggested that aHEV isolates characterised in this study are progeny of a cross between a US and a Hungarian strain. Phylogenetic tree and phylogenetic networks constructed using complete genome and individual coding sequences revealed that Australian aHEV isolates formed a distinct clade closer to the USA strains and classified as genotype 2 whereas genotype 1 Australian strain clustered together with South Korean strains.

Tubulointerstitial nephritis and uveitis in Northern Ireland

Objectives

This paper looks at patients with a diagnosis of tubulointerstitial nephritis and uveitis (TINU) presenting to the Northern Ireland regional adult and paediatric uveitis service in the Belfast Health and Social Care Trust. The demographic distribution, treatment required and the visual and renal outcomes of these patients are documented.

Methods

Data were collected retrospectively on 24 patients with TINU using the Northern Ireland Electronic Care Record, central pathology records alongside the adult and paediatric uveitis databases from 2011 to 2021. Patients were categorised into two groups using the Mandeville classification system. Standard Uveitis Nomenclature (SUN) was used to classify the uveitis.

Results

The population prevalence is at least 12.6 cases per million based on a population of 1.9 million. Nineteen of 24 cases were definite TINU and five of 24 probable. Seventeen out of 24 had biopsy-positive TIN, all of which met all of the Mandeville clinical diagnostic features required for a definite diagnosis. All but one presented with acute bilateral anterior uveitis. The paediatric cases ranged from age 12 to 18 at age of onset with a mean age of 14. Of the 18 adult onset cases, the age ranged from 20 to 76 years. The mean age of onset for the adult cases was 53 years. Of these patients 71% were female; 42% required second-line immunosuppression for ocular disease. Visual acuity was maintained. Follow-up time ranged from 3 months to 16 years. No patient developed long-term renal impairment.

Conclusions

TINU is a cause of uveitis in both the paediatric and adult populations. In Northern Ireland average age with TINU was older than much of the published literature. Long-term immunosuppression for uveitis may be required as ongoing ocular, rather than renal inflammation seemed to require treatment.

Diagnostic Limitations in Congenital Zika Virus Infection

This is the first documented case of an infant with congenital Zika virus infection (ZVI) born in Ireland. A term infant was delivered with an antenatal diagnosis of severe microcephaly. First trimester bloods confirmed maternal ZVI and although the infant did not have Zika virus RNA or Zika-specific IgM in her blood or urine, she had multiple clinical features of congenital ZVI and Zika virus RNA was present in the placenta.

Development of a rapid technique for extraction of viral DNA/RNA for whole genome sequencing directly from clinical liver tissues

Characterisation of the entire genome of Fowl aviadenoviruses (FAdV) requires isolation and propagation of the virus in chicken embryo liver or kidney cells, a process which is not only time consuming but may occasionally fail to result in viral growth. Furthermore, in a mixed infection, isolation in cell culture may result in the loss of viral strains. In this study, we optimised a FAdV DNA extraction technique directly from affected liver tissues using kaolin hydrated aluminium silicate treatment. The whole genome of FAdV was sequenced directly from extracted DNA without any targetted PCR based enrichment. The extraction method was also tested on avian liver tissues affected with the RNA virus Avian hepatitis E virus and demonstrated to yield sequencing grade RNA. Therefore, the method described here is a simple technique which is potentially useful for the extraction of sequencing grade DNA/RNA from tissues with high fat content.

Chronologic Analysis of Gross and Histologic Lesions Induced by Field Strains of FAdV-1, FAdV-8b, and FAdV-11 in Six-Week-Old Chickens

Inclusion body hepatitis (IBH) is a disease affecting broiler chicken flocks worldwide. Several serotypes of fowl adenovirus (FAdV) have been implicated in disease outbreaks, with and without immunosuppression as a predisposing factor. IBH usually occurs in flocks up to 30 days of age; it is seldom seen in older birds. The objective of this study was to determine whether the pathogenicity for older birds of three FAdV field strains, belonging to serotypes 1, 8b, and 11, in the absence of immunosuppressive factors, was akin to that for younger birds, and to establish an effective and economical disease model for assessing cross-protection between serotypes. To achieve this objective, the gross pathology, histopathology, and dissemination of virus were examined at multiple time points after inoculation of 6-wk-old, specific-pathogen-free chickens via intraperitoneal injection. Both FAdV-8b and FAdV-11 generated lesions typical of those associated with outbreaks of IBH, and they were shown to be primary pathogens. The presence and severity of hepatic lesions were used to define two disease stages: degeneration (1-5 days postinoculation) and convalescence (6-14 days postinoculation). During the degenerative stage, FAdV-8b was detected in the liver, kidney, and gizzard of most birds, whereas FAdV-11 was predominantly detected in the liver, and both viruses persisted in the gizzard into convalescence. The pathogenesis of two IBH-associated FAdV strains in 6-wk-old chickens confirms their high level of virulence and also provides an effective experimental model for investigation of cross-protection between FAdVs. It also demonstrates persistence of the virus in the gizzard long after infection, supporting the notion that it is a site of viral shedding.

Vaccination with FAdV-8a induces protection against inclusion body hepatitis caused by homologous and heterologous strains

Fowl aviadenoviruses (FAdV) are important avian pathogens, responsible for several poultry diseases prevalent worldwide, including inclusion body hepatitis (IBH). FAdV intraspecies cross-protection has been clearly demonstrated, but there is little evidence that any interspecies cross-protection exists. The present study aimed to assess the inter- and intraspecies protection between three FAdV field isolates (FAdV-8a, FAdV-8b, FAdV-11) identified in association with severe IBH outbreaks. Inocula prepared using inactivated plaque-purified virus with adjuvant Montanide™ ISA 71VG, were injected intramuscularly into 3-week-old SPF chickens. At 6-weeks of age, the birds were challenged with 10⁶ TCID₅₀ of homologous or heterologous virus intraperitoneally, and full post mortem examination performed at 4 days post-challenge. Various tissues were examined for gross and histological lesions and assessed for the presence of virus by PCR-HRM. All homologous-type vaccine/challenge groups exhibited protection against IBH lesions with no virus detected in the tissues. Unvaccinated groups challenged with virus showed evidence of FAdV-induced lesions; however, FAdV-8a demonstrated lower pathogenicity compared with FAdV-8b and FAdV-11. In the heterologous-type vaccine/challenge groups, FAdV-8a vaccine was shown to protect against challenge with both FAdV-8b and FAdV-11. FAdV-8a and 8b belong to species E and were therefore anticipated to cross-protect. However, FAdV-11 belongs to species D and therefore cross-protection by FAdV-8a was an uncharacteristic and unique finding of this study. Further research is required to disseminate the molecular basis for the interspecies cross-protection between FAdV-8a and FAdV-11. Nonetheless, the FAdV-8a isolate was shown to have substantial potential as a vaccine candidate in countries where FAdV-8a, 8b or 11 are prevalent.

Validation of a Metastatic Assay using biopsies to improve risk stratification in patients with prostate cancer treated with radical radiation therapy

Background

Radiotherapy is an effective treatment of intermediate/high-risk locally advanced prostate cancer, however, >30% of patients relapse within 5 years. Clinicopathological parameters currently fail to identify patients prone to systemic relapse and those whom treatment intensification may be beneficial. The purpose of this study was to independently validate the performance of a 70-gene Metastatic Assay in a cohort of diagnostic biopsies from patients treated with radical radiotherapy and androgen deprivation therapy.

Patients and methods

A bridging cohort of prostate cancer diagnostic biopsy specimens was profiled to enable optimization of the Metastatic Assay threshold before further independent clinical validation in a cohort of diagnostic biopsies from patients treated with radical radiotherapy and androgen deprivation therapy. Multivariable Cox proportional hazard regression analysis was used to assess assay performance in predicting biochemical failure-free survival (BFFS) and metastasis-free survival (MFS).

Results

Gene expression analysis was carried out in 248 patients from the independent validation cohort and the Metastatic Assay applied. Ten-year MFS was 72% for Metastatic Assay positive patients and 94% for Metastatic Assay negative patients [HR = 3.21 (1.35–7.67); P = 0.003]. On multivariable analysis the Metastatic Assay remained predictive for development of distant metastases [HR = 2.71 (1.11–6.63); P = 0.030]. The assay retained independent prognostic performance for MFS when assessed with the Cancer of the Prostate Assessment Score (CAPRA) [HR = 3.23 (1.22–8.59); P = 0.019] whilst CAPRA itself was not significant [HR = 1.88, (0.52–6.77); P = 0.332]. A high concordance [100% (61.5–100)] for the assay result was noted between two separate foci taken from 11 tumours, whilst Gleason score had low concordance.

Conclusions

The Metastatic Assay demonstrated significant prognostic performance in patients treated with radical radiotherapy both alone and independent of standard clinical and pathological variables. The Metastatic Assay could have clinical utility when deciding upon treatment intensification in high-risk patients. Genomic and clinical data are available as a public resource.

Mutation of oppF gene in the Mycoplasma synoviae MS-H vaccine strain and its implication for differential serological responses to vaccination versus field challenge

Mycoplasma synoviae (MS) is a major pathogen of poultry globally, causing chronic respiratory disease and arthritis. Vaccination is an effective means for the control of the disease. The MS-H vaccine is an attenuated strain developed through chemical mutagenesis of an Australian field strain, 86079/7NS. Analysis of whole genome of MS-H and its comparison with that of 86079/7NS has revealed a frameshift mutation early in a gene (oppF) that codes for an oligopeptide transporter permease, OppF. Monospecific antibodies raised against peptides upstream and downstream of the mutation in OppF revealed that only N-terminus of the OppF was expressed in MS-H while the full version was expressed in 86079/7NS. Also, examination of the recombinant N- (OppF-N) and C termini (OppF-C) of OppF, upstream and downstream of the mutation site respectively, as well as the full length OppF in Western immunoblotting experiments showed that serum from MS-H vaccinated chicken strongly bound OppF-N while serum from 86079/7NS challenged chicken detected OppF, OppF-N and OppF-C. The potential of the recombinant OppF, OppF-N and OppF-C to discriminate antibody responses to MS-H reisolates with wild or vaccine type OppF was assessed against 88 chicken sera in indirect ELISA and ratios were calculated between optical densities (OD) over those obtained in MS major membrane protein MSPB ELISA. Comparison of the OD ratios revealed that the MSPB/OppF and MSPB/OppF-C OD ratios of the sera against isolates with vaccine type OppF were significantly higher than those against isolates with wild type OppF. These results are in accordance with oppF gene mutation in MS-H and confirms that MS-H does not express OppF beyond the frame shift mutation found in its oppF gene. Also, the indirect ELISA based on OppF-C in combination with the MSPB has the potential to differentiate between MS-H and field strain antibody responses.

Investigation onto the correlation between systemic antibodies to surface glycoproteins of infectious laryngotracheitis virus (ILTV) and protective immunity

Infectious laryngotracheitis virus (ILTV) is an alphaherpesvirus that causes upper respiratory tract disease in chickens and significant losses to the poultry industry worldwide. Both antibody and cell-mediated responses are generated against ILTV infection; however, the correlation of humoral immune response with protection against ILTV infection is debatable. To examine if whether antibody responses to individual ILTV glycoproteins are correlated with disease and protection, four ILTV glycoproteins (gD, gE, gG and gJ) were expressed as recombinant proteins and used in conjunction with commercially available recombinant gC and gI in indirect ELISAs to measure post-vaccination and/or post-challenge chicken serum antibodies. Serum optical density (OD) values detected by the whole virus, gC, gI and gJ were significantly higher in birds vaccinated with the Serva vaccine strain compared to the SA2 vaccine strain. However, the mean ODs detected by gD, gE and gG were not significantly different between the vaccine strains. Examination of post-ILTV vaccination sera found that gE was the most antigenic glycoprotein and that gC ODs were strongly correlated with those of gI and gJ, while ODs to gG had a relatively poor correlation with those of other glycoproteins. Moderate to poor correlations were found between microscopic tracheal lesion scores and ODs to individual glycoproteins. Examination of post-vaccination pre-challenge antibodies to individual glycoproteins did not find a strong correlation with protective immunity as measured by the severity of clinical signs, gross lesions, and tracheal viral load. Results from this study demonstrated that systemic antibody titers to individual ILTV glycoproteins C, D, E, G, I and J had a relatively poor correlation to protective immunity.

High-resolution melt curve analysis to confirm the presence of co-circulating isolates of avian nephritis virus in commercial chicken flocks

Avian Nephritis Virus (ANV) has been implicated in poor growth and renal disease of young chickens. This paper describes the development of a reverse-transcriptase polymerase chain reaction for the detection of ANV in commercial meat chickens and the use of high-resolution melt curves to detect the presence of genetically different ANVs. Pooled cloacal swabs from both healthy and ill commercial chicken broiler flocks were tested for the presence of ANV using a combination of polymerase chain reaction, molecular cloning, high-resolution melt curve analysis and sequencing. Except for one, all specimens were found to contain two genetically different ANVs. Phylogenetic analysis of the capsid amino acid sequences revealed the presence of four of six groups of ANV identified previously in other countries as well as in two novel groups of ANV. Phylogenetic analysis of nucleotide sequences of partial polymerase, capsid and 3' untranslated regions reveal that the genes of individual ANV virus isolates have different ancestors. This was shown to be due to a template-switching event in the capsid gene that resulted in the 3' end of the capsid gene and the 3' untranslated region of one ANV isolate being transferred to another ANV. These results reveal that infection of chicken flocks with multiple ANV isolates is common and this needs to be taken into consideration in diagnosis of ANV using molecular techniques and in future epidemiological investigations.

Chronological analysis of gross and histological lesions induced by field strains of fowl adenovirus serotypes 1, 8b and 11 in one-day-old chickens

Fowl adenoviruses (FAdVs) cause diseases in domestic chickens, including inclusion body hepatitis (IBH), with immunosuppression believed to play a role in their pathogenesis. To gain a better understanding of the pathogenesis and chronology of disease caused by FAdVs, the gross pathology, histopathology and dissemination of virus were examined at several different time points, after inoculation of one-day-old specific pathogen-free chickens with FAdV-1, FAdV-8b or FAdV-11 via the ocular route. FAdV-8b had a slightly greater virulence than FAdV-11, but both were primary pathogens. The presence and severity of hepatic lesions were used to define the three stages of the disease: incubation (1-3 days post-inoculation, PI), degeneration (4-7 days PI) and convalescence (14 days PI). Both viruses were detected in the liver, kidney, bursa, thymus and gizzard of most birds during the degenerative stage, and persisted in the gizzard into convalescence. The FAdV-1 isolate was found to be apathogenic, but virus was detected in the bursa and/or gizzard of several birds between 2 and 7 days PI. This is the first study examining the chronology of gross and microscopic lesions of pathogenic and apathogenic FAdVs in association with viral presence in multiple tissues. It was concluded that both FAdV-8b and FAdV-11 are primary pathogens, and that these strains may play a role in immunosuppression.

Management of maple syrup urine disease in the peri-operative period

Maple syrup urine disease (MSUD) has an incidence of 1:125,000 newborns in Ireland. Patients, when fasting, or in a catabolic state build up toxic metabolites leading to progressive neurological dysfunction. We describe the necessary peri-operative management of a patient with MSUD who developed symptomatic gallstones requiring a laparoscopic cholecystectomy.

Safety and vaccine efficacy of a glycoprotein G deficient strain of infectious laryngotracheitis virus delivered in ovo

Infectious laryngotracheitis virus (ILTV), an alphaherpesvirus, causes respiratory disease in chickens and is commonly controlled by vaccination with conventionally attenuated vaccines. Glycoprotein G (gG) is a virulence factor in ILTV and a gG deficient strain of ILTV (ΔgG-ILTV) has shown potential for use as a vaccine. In the poultry industry vaccination via drinking water is common, but technology is now available to allow quicker and more accurate in ovo vaccination of embryos at 18 days of incubation. In this study ΔgG-ILTV was delivered to chicken embryos at three different doses (10(2), 10(3) and 10(4) plaque forming units per egg) using manual in ovo vaccination. At 20 days after hatching, birds were challenged intra-tracheally with wild type ILTV and protection was measured. In ovo vaccination was shown to be safe, as there were no developmental differences between birds from hatching up to 20 days of age, as measured by weight gain. The highest dose of vaccine was the most efficacious, resulting in a weight gain not significantly different from unvaccinated/unchallenged birds seven days after challenge. In contrast, birds vaccinated with the lowest dose showed weight gains not significantly different from unvaccinated/challenged birds. Gross pathology and histopathology of the trachea reflected these observations, with birds vaccinated with the highest dose having less severe lesions. However, qPCR results suggested the vaccine did not prevent the challenge virus replicating in the trachea. This study is the first to assess in ovo delivery of a live attenuated ILTV vaccine and shows that in ovo vaccination with ΔgG-ILTV can be both safe and efficacious.

Application of high-resolution melting curve analysis for typing of fowl adenoviruses in field cases of inclusion body hepatitis

OBJECTIVE

Fowl adenoviruses (FAdVs) cause inclusion body hepatitis (IBH) in chickens. In this study, clinical cases of IBH from Australian broiler flocks were screened for the presence and genotype of FAdVs.

METHODS

Twenty-six IBH cases from commercial poultry farms were screened. Polymerase chain reaction (PCR) coupled with high-resolution melt (HRM) curve analysis (PCR/HRM genotyping) was used to determine the presence and genotype of FAdVs. For comparison, field isolates were also assessed by virus microneutralisation and nucleotide sequence analysis of the hexon loop 1 (Hex L1) gene. PCR detection of chicken anaemia virus (CAV) and infectious bursal disease virus (IBDV) was also employed.

RESULTS

FAdV-8b and FAdV-11 were identified in 13 cases each. In one case, FAdV-1 was also identified. Cross-neutralisation was observed between the FAdV-11 field strain and the reference FAdV-2 and 11 antisera, a result also seen with the type 2 and 11 reference FAdVs. Field strains 1 and 8b were neutralised only by their respective type antisera. The FAdV-8b field strain was identical to the Australian FAdV vaccine strain (type 8b) in the Hex L1 region. The Hex L1 sequence of the FAdV-11 field strain had the highest identity to FAdV-11 (93.2%) and FAdV-2 (92.7%) reference strains. In the five cases tested for CAV and IBDV, neither virus was detected. The evidence suggested the presence of sufficient antibodies against CAV and IBD in the parent flocks and there was no indication of immunosuppression caused by these viruses.

CONCLUSION

These results indicate that PCR/HRM genotyping is a reliable diagnostic method for FAdV identification and is more rapid than virus neutralisation and direct sequence analysis. Furthermore, they suggest that IBH in Australian broiler flocks is a primary disease resulting from two alternative FAdV strains from different species.

Epidemiology of recent outbreaks of infectious laryngotracheitis in poultry in Australia

OBJECTIVE

Over the past 3 years, numerous outbreaks of infectious laryngotracheitis (ILT) have occurred in poultry in Australia. The objectives of this study were to identify the viral strains involved in the recent outbreaks and to determine possible epidemiological links between these outbreaks.

PROCEDURE

A combination of polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) analyses of several genes of the ILT virus was used to identify genetic differences in field/vaccine ILT virus isolates. In a previous study, these procedures had demonstrated five classes (1-5) in Australia.

RESULTS

Analysis of 92 field ILT viruses demonstrated four new classes: 6, 7, 8 and 9. Class 6 was responsible for four outbreaks in one Victorian broiler company and demonstrated to be distinct from other Australian strains of ILT. Class 7 was the Nobilis ILT vaccine (Intervet Pty Ltd). Class 8 was responsible for the majority of the outbreaks in New South Wales and was phylogenetically close to class 7. On one occasion, classes 7 and 8 were identified in an outbreak on a Victorian farm that had used the Nobilis ILT vaccine. Class 9, also phylogenetically close to classes 7 and 8, was found only in New South Wales. The previously identified class 2 was also found to be responsible for a large number of outbreaks, mainly in Victoria.

CONCLUSION

The results demonstrate that, epidemiologically, most outbreaks of ILT in New South Wales are unrelated to those in Victoria and suggest a link between classes 8 and 9 and the Nobilis ILT vaccine (class 7).

Differentiation of infectious bursal disease virus strains using real-time RT-PCR and high resolution melt curve analysis

Differentiation of infectious bursal disease virus (IBDV) strains is crucial for effective vaccination programs and epidemiological investigations. In this study, a combination of real-time RT-PCR and high resolution melt (HRM) curve analysis was developed for simultaneous detection and differentiation of IBDV strains/isolates. The hypervariable region of VP2 gene was amplified from several IBDV strains and subjected to HRM curve analysis. The method could readily differentiate between classical vaccines/isolates and variants. Analysis of the nucleotide sequence of the amplicons from each strain revealed that each melt curve profile was related to a unique DNA sequence. The real-time RT-PCR HRM curve analysis was also able to differentiate IBDV strains/isolates directly in bursal tissues from field submissions and from vaccinated commercial flocks. The differences between melting peaks generated from IBDV strains were significantly different (P<0.0001) demonstrating the high discriminatory power of this technique. The results presented in this study indicated that real-time RT-PCR followed by HRM curve analysis provides a rapid and robust technique for genotyping IBDV isolates/strains and can contribute to effective control of IBDV outbreaks.

Detection of avian nephritis virus in Australian chicken flocks

Avian nephritis virus (ANV) is thought to infect poultry flocks worldwide, but no confirmed case has been reported in Australia. The first such case is described in this study. Cases of young chickens with clinical signs of dehydration and diarrhea were submitted to our laboratory and histopathology detected interstitial nephritis. Vaccine strains of infectious bronchitis virus were detected in some of these cases but were not considered to be the causative agent. A total of seven fresh submissions from broiler chicken flocks were collected at 8-11 days of age. Degenerate PCR primers were designed based on published ANV polymerase gene sequences and used to analyze historic cases as well as the fresh submissions. Six of the seven fresh submissions, and one historic case, were positive for ANV with nucleotide sequencing confirming these results. These results establish ANV as an infectious pathogen circulating in Australian poultry.

Characterization of Chlamydiaceae species using PCR and high resolution melt curve analysis of the 16S rRNA gene

AIM

To design a rapid diagnostic test to differentiate species belonging to the family Chlamydiaceae.

METHODS AND RESULTS

Five oligonucleotide sets each targeting various conserved regions of the genome of six species (Chlamydia muridarum, C. suis, C. trachomatis, Chlamydophila felis, Cp. pneumoniae and Cp. psittaci) belonging to the family Chlamydiaceae were tested for their suitability for polymerase chain reaction (PCR) and high resolution melt (HRM) curve analysis to differentiate Chlamydiaceae species. Three of the oligonucleotide sets were able to detect all six reference species used in this study, but only one set (16SG) could clearly differentiate between them by HRM curve analysis. The PCR-HRM curve analysis confidence percentages correlated strongly with the nucleotide sequence identities. Clinical specimens from a number of animal species suspected of chlamydiosis were tested with the newly developed 16SG PCR-HRM curve analysis and sequenced to confirm the infecting species. It was demonstrated that PCR-HRM using the 16SG oligonucleotide set could relate the infecting Chlamydiaceae species to the most similar (based on 16S rRNA gene nucleotide sequence) reference species tested. Although Cp. pecorum was not included initially as a reference species in this assay, inclusion of a field isolate of Cp. pecorum as a reference allowed two koala specimens to be correctly identified.

CONCLUSION

PCR-HRM analysis using the oligonucleotide set 16SG is a robust, simple and rapid technique for differentiation of at least the Chlamydiaceae species used in this study.

SIGNIFICANCE AND IMPACT OF THE STUDY

This technique allowed for the rapid detection and identification of the six Chlamydiaceae reference species and may be useful for identification of uncharacterized Chlamydiaceae species or for use in animal species where occurrence of the disease has not been fully investigated.

Nutrition and udder health in dairy cows: a review

Mastitis is still one of the three main diseases that affects the profitability of dairy farmers. Despite the implementation of the five-point mastitis control programme in the early 1970 s, the incidence in the UK has not reduced dramatically over the past 10 years. A review of the scientific literature indicates that there is a link between nutrition and mastitis in the dairy cow. The major impact of nutrition on udder health is via suppression of the immune system. Cows in negative energy balance are at a higher risk of ketosis and clinical ketosis is associated with a two-fold increase in the risk of clinical mastitis. Trace minerals and vitamins that can affect udder health are selenium and vitamin E, copper, zinc, and vitamin A and β-carotene.

Dexamethasone potentiates the antiangiogenic activity of docetaxel in castration-resistant prostate cancer

We sought to characterise whether dexamethasone (DEX) may enhance tumour response to docetaxel in in vitro and in vivo models of metastatic prostate cancer (CaP). In vitro experiments conducted on PC3 and human bone marrow endothelial cells (hBMECs) determined that administration of DEX (10 nM) reduced constitutive nuclear factor-kappaB (NF-kappaB) activity, decreasing interleukin (IL)-8, CXCL1 and VEGF gene expression in PC3 cells. Dexamethasone also attenuated docetaxel-induced NF-kappaB and activator protein-1 transcription and reduced docetaxel-promoted expression/secretion of IL-8 and CXCL1 in PC3 and hBMECs. Although DEX failed to enhance docetaxel cytotoxicity on PC3 cells, DEX potentiated the antiangiogenic activity of docetaxel in vitro, further reducing vessel area and vessel length in developing endothelial tubes (P<0.05). Docetaxel had a potent antiangiogenic activity in the dorsal skin flap-implanted PC3 tumours in vivo. Small blood vessel formation was further suppressed in tumours co-treated with docetaxel and DEX, substantiated by an increased average vessel diameter and segment length and a decreased number of branch points in the residual tumour vasculature (P<0.001). Our data show that DEX potentiates the antiangiogenic activity of docetaxel, suggesting a putative mechanism for the palliative and survival benefits of these agents in metastatic CaP.

Potential efficacy of zonisamide in refractory juvenile myoclonic epilepsy: retrospective evidence from an Irish compassionate-use case series

To retrospectively evaluate the efficacy of zonisamide as adjunctive therapy in the treatment of refractory juvenile myoclonic epilepsy. We retrospectively reviewed the records of seven patients with refractory juvenile myoclonic epilepsy, commenced on a compassionate-use basis on zonisamide as adjunctive treatment between October 2001 and September 2004. We found significant response rates (>50% reduction in seizure frequency) of 83.3%, 100% and 100% for generalised convulsions, myoclonus, and absence seizures respectively. These results were sustained over more prolonged follow-up in five of seven patients, with one patient improving further over time. Two patients became seizure free with the introduction of zonisamide. Two patients were able to reduce the number of anti-epileptic medications and maintain >75% and 100% reduction in seizure frequency respectively. Four patients initially had minor side-effects that resolved during the maintenance period. In this retrospective study, zonisamide was effective and well-tolerated as adjunctive therapy in patients with refractory juvenile myoclonic epilepsy.

Differentiation of infectious laryngotracheitis virus isolates by restriction fragment length polymorphic analysis of polymerase chain reaction products amplified from multiple genes

Infectious laryngotracheitis (ILT) has been identified in most countries around the world and remains a threat to the intensive poultry industry. Outbreaks of mild to moderate forms of ILT are common in commercial layer flocks, while sporadic outbreaks of ILT in broiler flocks have also been recognized as an emerging problem in several countries. Examination of viral isolates using restriction fragment length polymorphism of polymerase chain reaction (PCR-RFLP) from individual ILTV genes has suggested that some of these outbreaks were caused by vaccine strains. In this study, PCR-RFLP of a number of ILTV genes/genomic regions including gE, gG, TK, ICP4, ICP18.5, and open reading frame (ORF) B-TK was used to examine a number of historical and contemporary Australian ILTV isolates and vaccine strains. PCR-RFLP of gE using restriction endonuclease EaeI failed to distinguish between any of the isolates including the vaccine strains. PCR-RFLP of gG, TK, and ORFB-TK using restriction endonucleases MspI and FokI, respectively, divided all the isolates into two groups. PCR-RFLP of ICP18.5 and ICP4 using restriction endonuclease HaeIII separated the isolates into three different groups with some field isolates only able to be distinguished from vaccine strains by PCR-RFLP of ICP18.5. A combination of groupings including gG, TK, ICP4, ICP18.5, and ORFB-TK PCR-RFLP classified the ILTV isolates under investigation into five different groups with most isolates distinguishable from vaccine strains. Results from this study reveal that to achieve reliable identification of strains of ILTV, the examination of multiple gene regions will be required, and that most of the recent ILT outbreaks in Australia are not being caused by vaccine strains.