Veterinary Health Research Pty Ltd.

Armidale, Australia

Veterinary Health Research Pty Ltd.

Armidale, Australia
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Cliffe K.M.,PIC Research Laboratory | Cliffe K.M.,University of Cambridge | Day A.E.,PIC Research Laboratory | Day A.E.,Abcam | And 14 more authors.
Animal Genetics | Year: 2010

Sequences from 20 amplicons representing nine different loci and 11369bp from the short arm of the pig Y chromosome were compared using pools of DNA from different European and Chinese breeds. A total of 33 polymorphic sites were identified, including five indels and 28 single nucleotide polymorphisms (SNPs). Three high frequency SNPs within the coding regions of SRY were further analysed across 889 males representing 25 European and 25 Asian breeds or Lines, plus a European Line of Meishan. Two haplotypes seen to be associated with European or Chinese origin in the initial SNP discovery phase were found to be the most common in their respective groups of breeds in a more detailed genotyping study. Two further SRY haplotypes are relatively rare. One was found exclusively within Tamworth, at low frequency in Retinto, and in three Chinese breeds (Huai, Sahwutou and Xiaomeishan). The other uncommon haplotype is found exclusively in Bamajiang, two further Chinese breeds (Hangjiang Black and Longling) and two European rare breeds (Mangalica and Linderödssvin), but appears based on comparison with other suids to represent an ancestral sequence. © 2010 Stichting International Foundation for Animal Genetics.

Pearson G.T.,University of Edinburgh | Mayhew I.G.,Massey University | Stewart Lowden C.,Veterinary Health Research Pty. Ltd | Hopwood P.A.,University of Edinburgh | And 5 more authors.
Veterinary Journal | Year: 2010

Previous immunohistochemical studies targeting the receptor tyrosine kinase (c-Kit) have demonstrated an apparent reduction in the number of gastrointestinal pacemaker cells - the interstitial cells of Cajal (ICC) - in horses with intestinal motility disorders. This study compared the level of transcription of the c- kit gene encoding this receptor in horses with and without such motility disorders. Transcription levels of this gene were also compared to the density of ICC immunohistochemically positive for the c-Kit antigen. Intestinal samples were collected from 18 horses with intestinal disease and from 15 control animals. Following gene extraction and identification, real-time quantitative analysis of c. -kit and a control gene, ACTB (β-actin), was carried out on all samples and the density of the c-Kit-positive ICC compared. There was a significant reduction in c-Kit immunoreactivity in the ICC of horses with large intestinal obstructive disorders relative to controls but no significant difference in the transcription of the c- kit gene between normal and affected animals. Further studies will be required to elucidate the mechanisms regulating c-Kit expression and to assess the pathophysiological significance of these findings. © 2009 Elsevier Ltd.

Gongora J.,University of Sydney | Cuddahee R.E.,Duke University | Nascimento F.F.D.,University of Sydney | Palgrave C.J.,Roslin Institute | And 12 more authors.
Zoologica Scripta | Year: 2011

Although African suids have been of scientific interest for over two centuries, their origin, evolution, phylogeography and phylogenetic relationships remain contentious. There has been a long-running debate concerning the evolution of pigs and hogs (Suidae), particularly regarding the phylogenetic relationships among extant Eurasian and African species of the subfamily Suinae. To investigate these issues, we analysed the mitochondrial and nuclear DNA sequences of extant genera of Suidae from Eurasia and Africa. Molecular phylogenetic analyses revealed that all extant sub-Saharan African genera form a monophyletic clade separate from Eurasian suid genera, contradicting previous attempts to resolve the Suidae phylogeny. Two major sub-Saharan African clades were identified, with Hylochoerus and Phacochoerus grouping together as a sister clade to Potamochoerus. In addition, we find that the ancestors of extant African suids may have evolved separately from the ancestors of modern day Sus and Porcula in Eurasia before they colonised Africa. Our results provide a revision of the intergeneric relationships within the family Suidae. © 2011 The Authors. Zoologica Scripta © 2011 The Norwegian Academy of Science and Letters.

Lees P.,The Royal Veterinary College | Cheng Z.,The Royal Veterinary College | Chambers M.,Veterinary Health Research PTY Ltd | Speirs G.,Eco Animal Health | And 2 more authors.
Journal of Veterinary Pharmacology and Therapeutics | Year: 2013

Two premix products containing the endectocide ivermectin were compared for pharmacokinetic profiles and bioequivalence in young pigs. Test and reference articles were administered to individual pigs in-feed at 12-h intervals for a total of 14 doses. Plasma concentration-time profiles were compared after provision of the final doses of medicated feed, by which time steady-state concentrations of ivermectin had been achieved. The pharmacokinetic variables monitored were peak concentration (Cmax), area under the curve (AUC)0-last, elimination half-life of the terminal phase (T1/2 λz) and average steady-state concentration (Css), determined by noncompartmental analysis. Logarithmic transformation of the variables was carried out when appropriate. Analysis of data by the Classic Method yielded confidence intervals of 80.59-114.47 (for AUC0-last), 90.38-119.68 (for Cmax) and 84.70-111.96 (for Css). It was concluded that the two articles were bioequivalent for ivermectin. © 2012 John Wiley & Sons Ltd.

Nascimento F.F.,University of Sydney | Nascimento F.F.,Federal University of Rio de Janeiro | Gongora J.,University of Sydney | Charleston M.,University of Sydney | And 3 more authors.
BMC Evolutionary Biology | Year: 2011

Background: Porcine endogenous retroviruses (PERVs) represent remnants of an exogenous form that have become integrated in the domestic pig (Sus scrofa) genome. Although they are usually inactive, the capacity of 1 ERVs to infect human cells in vitro has raised concerns about xenotransplantation because the viruses could cross the species barrier to humans. Here we have analyzed the evolution of 1 ERVs in ten species of Suidae (suids, pigs and hogs) from Eurasia and Africa using DNA sequences for their coding domains (gag, pro/pol and env genes). For comparison with 1 PERVs, we have also analysed 2 ERVs which in domestic pigs are known to be inactive and do not pose a risk to xenotransplantation. Results: Phylogenetic analysis using Bayesian inference showed that 1 and 2 ERVs have distinctive evolutionary histories. Firstly, two different viral lineages of 1 ERVs were found and a coevolutionary analysis demonstrated that they correspond broadly to their host phylogeny, one of Eurasian and another of African species, and show no evidence of horizontal transmission. 2 ERVs, however, show a bush-like evolution, suggesting a rapid viral radiation from a single common ancestor with no correspondence between host and viral evolutionary trees. Furthermore, though 1 ERV env genes do not possess frequent stop codons, 2 env genes do. To understand whether 1 suid ERVs may be still replicating, we have also evaluated their likely mechanism of proliferation by statistically testing internal to terminal branches using nonsynonymous versus synonymous substitution ratios. Our results suggest that 1 ERVs are increasing in copy number by reinfection, which requires the translocation of the virus from one cell to another. Conclusions: Evidence of at least two viral subpopulations was observed in 1 ERVs from Eurasian and African host species. These results should be taken into account in xenotransplantation since 1 ERVs appear to be codiverging with their host and maintaining ongoing capacity to infect somatic and germ cells. © 2011 Nascimento et al; licensee BioMed Central Ltd.

do Nascimento F.F.,University of Sydney | do Nascimento F.F.,Federal University of Rio de Janeiro | Gongora J.,University of Sydney | Tristem M.,Imperial College London | And 2 more authors.
Infection, Genetics and Evolution | Year: 2011

Diversity of long terminal repeats (LTRs) from γ1 endogenous retroviruses (ERVs) was analysed by DNA sequencing in 10 species of the family Suidae (suids, pigs and hogs). Phylogenetic analysis separated LTR sequences into two groups which correlated approximately with either the previously described cluster I and III, or the clusters II, IV and V. Interestingly, a specific LTR exhibiting a novel molecular rearrangement was identified exclusively within African host species when compared to LTRs previously reported from known ERVs in the domestic pig (Sus scrofa). Furthermore, other sections of LTRs appear to be unique to African suids as suggested by phylogenetic analysis. These differences between African and Eurasian ERV lineages show that these ERVs belong to different viral sub-populations, implying coevolution of endogenous viral sequences with their host species and providing no evidence of transfer of viral sequences between African and Eurasian suids. © 2011 Elsevier B.V.

PubMed | University of Queensland, Veterinary Health Research Pty Ltd. and CSIRO
Type: | Journal: Veterinary parasitology | Year: 2016

Resistance to the amino-acetonitrile derivative monepantel has been reported in several species of gastrointestinal nematodes over recent years. We were interested in the use of in vitro assays with free-living worm life-stages to detect resistance to this drug. We therefore used larval development and larval migration assays to examine dose response relationships for the drug against two susceptible and one resistant isolate of Haemonchus contortus. The resistant isolate was established by laboratory propagation of the survivors of a field treatment with Zolvix() that had originally resulted in a drug efficacy of over 99%. Drug efficacy against this field-derived laboratory-propagated resistant isolate in vivo was approximately 15%. The larval development assay proved able to discriminate between the susceptible and resistant isolates, with larvae of the resistant isolate showing an ability to develop at higher drug concentrations than the two susceptible isolates. The resistant isolate showed the presence of two distinct subpopulations, separated by a plateau in the dose-response curve. Sub-population 1 (approximately 40% of the total population) showed a low level of resistance with an IC50 increased approximately 7-fold compared to the baseline susceptible isolate, while sub-population 2 (the remaining 60% of the total population) showed an IC50 increased over 1000-fold compared to the baseline susceptible isolate. This level of resistance is unusually high for any gastrointestinal nematode species in drug dose-response in vitro assays. In contrast, the migration assay could not discriminate between the three isolates, with migration not reduced to zero at any of the drug concentrations tested. This study demonstrates that a larval development assay is able to detect resistance to monepantel in H. contortus, and that resistance can exist in two distinct forms. This suggests that at least two separate monepantel resistance mechanisms are acting within the worm isolate studied here, with one or more mechanisms conferring a much higher level of resistance than the other(s).

Roeber F.,University of Melbourne | Jex A.R.,University of Melbourne | Campbell A.J.D.,University of Melbourne | Nielsen R.,Veterinary Health Research Pty. Ltd. | And 3 more authors.
International Journal for Parasitology | Year: 2012

The accurate diagnosis of strongylid nematode infections is central to investigating their epidemiology and for parasite control. To overcome major limitations in sensitivity or specificity of traditional methods, including faecal egg count (FEC) and/or larval culture (LC), we evaluated and established a semi-automated, high throughput multiplexed-tandem PCR (MT-PCR) platform for the diagnosis of gastrointestinal strongylid nematode infections in sheep, and established its diagnostic sensitivity (100%) and specificity (87.5%) based on the testing of 100 faecal DNA samples from helminth-free sheep and 30 samples from sheep with infections confirmed by necropsy. Subsequently, the platform was employed to test 219 faecal samples from sheep with naturally acquired infections from various geographical localities within Australia and the results compared with those from conventional LC using 139 of the 219 samples. The results obtained using both MT-PCR and LC correlated significantly for most nematodes examined, but revealed that Oesophagostomum venulosum and Chabertia ovina (parasites of the large intestine) were significantly under-represented in the LC results. The results showed that Trichostrongylus spp. (87%), Teladorsagia circumcincta (80%) and Haemonchus contortus (67%) had the highest prevalences, followed by O. venulosum (51%) and C. ovina (12%). The molecular-diagnostic platform established can be used for species- or genus-specific diagnosis of patent nematode infections within 24. h (compared with 7-10. days for LC), and is a sensitive and cost effective tool for routine application in research and service laboratories. © 2012.

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