Veterinary Biosciences - Research Publications
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ItemNo Preview AvailableMapping B lymphocytes as major reservoirs of naturally occurring latent equine herpesvirus 5 infection(MICROBIOLOGY SOC, 2017-03)Equine herpesvirus 5 (EHV5) is a commonly detected gammaherpesvirus, which, along with the closely related EHV2, constitute the only two known percaviruses that infect horses. Apart from detection in horse populations worldwide and the recent publication of the whole genome, there is little known about the biology and pathogenesis of this virus, with many assumptions made by parallels with EHV2. The long-term survival of gammaherpesviruses within infected hosts involves the establishment and maintenance of latency in selected cell and tissues types, particularly lymphocytes. A latent gammaherpesvirus infection is characterized by a limited number of genes expressing in a particular cell or tissue type. In this study, we have used in vitro co-culturing to detect EHV5 in equine PBMCs and characterize the predominant cellular site for the establishment and maintenance of a latent infection. These experiments were conducted by isolating PBMCs from 10 horses and sorting subpopulations into two T lymphocyte (CD4 and CD8), B lymphocyte and macrophage enriched or depleted fractions. These lymphocyte and macrophage fractions were examined for the presence of latent EHV5 by in vitro co-culturing with equine foetal kidney cells. The lymphocyte fraction enriched with B lymphocytes had a significantly increased (P=0.005) number of plaques formed during co-culturing, whereas the B lymphocyte depleted fraction had a significant reduction in the number of plaques formed after co-culturing. Taken together, these results demonstrate that equine gammaherpesviruses establish latency in the equine PBMCs, with the predominant site for maintenance of latent virus being B lymphocytes.
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ItemNo Preview AvailablePicornaviridae(ACADEMIC PRESS LTD-ELSEVIER SCIENCE LTD, 2017)
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ItemImpairment of infectious laryngotracheitis virus replication by deletion of the UL[-1] gene(SPRINGER WIEN, 2017-06)Infectious laryngotracheitis virus (ILTV) encodes several unique genes, including a pair of unique nuclear proteins UL0 and UL[-1] that are expressed during replication in cell culture. Although the UL0 gene has been shown to be dispensable for replication, the role of UL[-1] has not been elucidated. In this study a deletion mutant of ILTV lacking the UL[-1] gene was constructed using homologous recombination. The coding sequences of the gene were replaced with the gene for enhanced green fluorescent protein and the cytomegalovirus major immediate early promoter element. The progeny virus carrying the reporter gene was readily identified using fluorescent microscopy, but was unable to propagate in the permissive cells in the absence of wild type ILTV. Even after plaque purification and fluorescent associated cell sorting the recombinant virus deficient in UL[-1] gene could not be successfully isolated. Our findings suggest that the UL[-1] gene has an important role in ILTV replication.
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ItemNo Preview AvailableEquine rotaviruses-Current understanding and continuing challenges(ELSEVIER, 2013-11-29)Equine rotaviruses were first detected in foals over 30 years ago and remain a major cause of infectious diarrhoea in foals. During this time, there has been substantial progress in the development of sensitive methods to detect rotaviruses in foals, enabling surveillance of the genotypes present in various horse populations. However, there has been limited epidemiological investigation into the significance of these circulating genotypes, their correlation with disease and the use of vaccination in these animal populations. Our knowledge of the pathogenesis of rotavirus infection in foals is based on a limited number of studies on a small number of foals and, therefore, most of our understanding in this area has been extrapolated from studies in other species. Questions such as the concentrations of rotavirus particles shed in the faeces of infected foals, both with and without diarrhoea, and factors determining the presence or absence of clinical disease remain to be investigated, as does the relative and absolute efficacy of currently available vaccines. The answer to these questions may help direct research into the development of more effective control measures.
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ItemNo Preview AvailableUpdate on Viral Diseases of the Equine Respiratory Tract(Elsevier, 2015)Many viral agents have been associated with respiratory disease of the horse. The most important viral causes of respiratory disease in horses are equine influenza and the equine alphaherpesviruses. Agents such as equine viral arteritis virus, African horse sickness virus, and Hendra virus establish systemic infections. Clinical signs of disease resulting from infection with these agents can manifest as respiratory disease, but the respiratory tract is not the major body system affected by these viruses. Treatment of viral respiratory disease is generally limited to supportive therapies, whereas targeted antimicrobial therapy is effective in cases of bacterial infection.
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ItemCharacterisation of the canine faecal virome in healthy dogs and dogs with acute diarrhoea using shotgun metagenomics(PUBLIC LIBRARY SCIENCE, 2017-06-01)The virome has been increasingly investigated in numerous animal species and in different sites of the body, facilitating the identification and discovery of a variety of viruses. In spite of this, the faecal virome of healthy dogs has not been investigated. In this study we describe the faecal virome of healthy dogs and dogs with acute diarrhoea in Australia, using a shotgun metagenomic approach. Viral sequences from a range of different virus families, including both RNA and DNA families, and known pathogens implicated in enteric disease were documented. Twelve viral families were identified, of which four were bacteriophages. Eight eukaryotic viral families were detected: Astroviridae, Coronaviridae, Reoviridae, Picornaviridae, Caliciviridae, Parvoviridae, Adenoviridae and Papillomaviridae. Families Astroviridae, Picornaviridae and Caliciviridae were found only in dogs with acute diarrhoea, with Astroviridae being the most common family identified in this group. Due to its prevalence, characterisation the complete genome of a canine astrovirus was performed. These studies indicate that metagenomic analyses are useful for the investigation of viral populations in the faeces of dogs. Further studies to elucidate the epidemiological and biological relevance of these findings are warranted.
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ItemVetCompass Australia: A National Big Data Collection System for Veterinary Science(MDPI, 2017-10)VetCompass Australia is veterinary medical records-based research coordinated with the global VetCompass endeavor to maximize its quality and effectiveness for Australian companion animals (cats, dogs, and horses). Bringing together all seven Australian veterinary schools, it is the first nationwide surveillance system collating clinical records on companion-animal diseases and treatments. VetCompass data service collects and aggregates real-time, clinical records for researchers to interrogate, delivering sustainable and cost-effective access to data from hundreds of veterinary practitioners nationwide. Analysis of these clinical records will reveal geographical and temporal trends in the prevalence of inherited and acquired diseases, identify frequently prescribed treatments, revolutionize clinical auditing, help the veterinary profession to rank research priorities, and assure evidence-based companion-animal curricula in veterinary schools. VetCompass Australia will progress in three phases: (1) roll-out of the VetCompass platform to harvest Australian veterinary clinical record data; (2) development and enrichment of the coding (data-presentation) platform; and (3) creation of a world-first, real-time surveillance interface with natural language processing (NLP) technology. The first of these three phases is described in the current article. Advances in the collection and sharing of records from numerous practices will enable veterinary professionals to deliver a vastly improved level of care for companion animals that will improve their quality of life.
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ItemCross-sectional study of antimicrobials used for surgical prophylaxis by bovine veterinary practitioners in Australia(BMJ PUBLISHING GROUP, 2017-10)Antimicrobials are widely used in veterinary practices, but there has been no investigation of antimicrobial classes used or the appropriateness of their use in bovine practice. This study investigated antimicrobial use for surgical prophylaxis in bovine practice in Australia. A cross-sectional study of veterinarian antimicrobial usage patterns was conducted using an online questionnaire. Information solicited included respondent's details, the frequency with which antimicrobials were used for specific surgical conditions (including the dose, timing and duration of therapy) and details of practice antimicrobial use policies and sources of information about antimicrobials. In total, 212 members of the Australian veterinary profession working in bovine practice completed the survey. Antimicrobials were always or frequently used by more than 75 per cent of respondents in all scenarios. Generally, antimicrobial drug choice was appropriate for the reported surgical conditions. Procaine penicillin and oxytetracycline accounted for 93 per cent of use. However, there was a wide range of doses used, with underdosing and inappropriate timing of administration being common reasons for inappropriate prophylactic treatment. There was very low use of critically important antimicrobials (3.3 per cent of antimicrobials reported). Antimicrobial use guidelines need to be developed and promoted to improve the responsible use of antimicrobials in bovine practice.
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ItemNo Preview AvailableAntimicrobials used for surgical prophylaxis by companion animal veterinarians in Australia(ELSEVIER SCIENCE BV, 2017-05)Antimicrobials are widely used in veterinary practices, but there has been no investigation into the classes of antimicrobials used or the appropriateness of their use in surgical prophylaxis. Antimicrobial usage guidelines were published by the Australian Infectious Disease Advisory Panel (AIDAP) in 2013, but there has been no investigation of compliance with them. This study aimed to investigate antimicrobial use for surgical prophylaxis in companion animal practice and assess compliance with AIDAP guidelines for selected conditions by conducting a cross-sectional study of antimicrobial usage patterns of Australian veterinarians using an online questionnaire. Information solicited included: details of the respondent, the frequency with which antimicrobials were used for specific surgical conditions (including dose and duration) and practice antimicrobial use policies and sources of information about antimicrobial drugs and their uses. A total of 886 members of the Australian veterinary profession completed the survey. Few (22%) reported that their practice that had an antimicrobial use policy. Generally, the choice of antimicrobial drug was appropriate for the given surgical conditions. There was poor compliance with AIDAP guidelines for non-use of antimicrobials for routine neutering. Veterinarians caring solely for companion animals had higher odds of optimal compliance with guidelines than veterinarians in mixed species practices (OR 1.4, 95%CI 1.1-1.9). Recent graduates (>2011) had lower odds of compliance than older graduates (OR 0.8, 95%CI 0.6-0.9). The findings suggest that antimicrobial use guidelines need to be expanded and promoted to improve the responsible use of antimicrobials in small animal practice in Australia.
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ItemLow genetic diversity among historical and contemporary clinical isolates of felid herpesvirus 1(BIOMED CENTRAL LTD, 2016-09-02)BACKGROUND: Felid herpesvirus 1 (FHV-1) causes upper respiratory tract diseases in cats worldwide, including nasal and ocular discharge, conjunctivitis and oral ulceration. The nature and severity of disease can vary between clinical cases. Genetic determinants of virulence are likely to contribute to differences in the in vivo phenotype of FHV-1 isolates, but to date there have been limited studies investigating FHV-1 genetic diversity. This study used next generation sequencing to compare the genomes of contemporary Australian clinical isolates of FHV-1, vaccine isolates and historical clinical isolates, including isolates that predated the introduction of live attenuated vaccines into Australia. Analysis of the genome sequences aimed to assess the level of genetic diversity, identify potential genetic markers that could influence the in vivo phenotype of the isolates and examine the sequences for evidence of recombination. RESULTS: The full genome sequences of 26 isolates of FHV-1 were determined, including two vaccine isolates and 24 clinical isolates that were collected over a period of approximately 40 years. Analysis of the genome sequences revealed a remarkably low level of diversity (0.0-0.01 %) between the isolates. No potential genetic determinants of virulence were identified, but unique single nucleotide polymorphisms (SNPs) in the UL28 and UL44 genes were detected in the vaccine isolates that were not present in the clinical isolates. No evidence of FHV-1 recombination was detected using multiple methods of recombination detection, even though many of the isolates originated from cats housed in a shelter environment where high infective pressures were likely to exist. Evidence of displacement of dominant FHV-1 isolates with other (genetically distinct) FHV-1 isolates over time was observed amongst the isolates obtained from the shelter-housed animals. CONCLUSIONS: The results show that FHV-1 genomes are highly conserved. The lack of recombination detected in the FHV-1 genomes suggests that the risk of attenuated vaccines recombining to generate virulent field viruses is lower than has been suggested for some other herpesviruses. The SNPs detected only in the vaccine isolates offer the potential to develop PCR-based methods of differentiating vaccine and clinical isolates of FHV-1 in order to facilitate future epidemiological studies.