ORCID Profile
0000-0002-8892-5600
Current Organisations
Southern Cross University
,
Murdoch University School of Veterinary and Life Sciences
,
Murdoch University
,
Edith Cowan University - Mount Lawley Campus
,
Charles Sturt University - Wagga Wagga Campus
,
Charles Sturt University
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Publications
Airsac cystadenocarcinomas in cockatoos.
Publisher: Wiley
Date: 06-2006
DOI: 10.1111/J.1751-0813.2006.TB12803.X
Abstract: The clinical signs, radiographic and pathological findings of four histologically similar neoplasms that occurred as unilateral tumours projecting from the left axilla in three galahs ( Eolophus roseicapillus ) and one sulphur‐crested cockatoo ( Cacatua galerita ) are described. In each case, the main reason for clinical presentation was respiratory distress. All cases were eventually fatal due to airway obstruction with evidence of extensive neoplastic invasion of the lungs, major airways and or humerus in all cases. A diagnosis of airsac cystadenocarcinoma was made in each bird on the basis of gross and histological appearance. The neoplasms were composed of fluid or air‐filled sacs of proliferative cuboidal to squamous epithelial cells that stained positively with cytokeratin and negatively with vimentin. This was supported by a thin fibrovascular network although at least some areas in all four birds resembled airsac tissue. In some cases areas of haemorrhage, erythrophagocytosis, haemosiderosis and nodules of haemosiderophage infiltration with acicular cholesterol clefts were present in some parts of the sectioned tissue.
Equine alopecia areata
Publisher: Wiley
Date: 22-02-2013
DOI: 10.1111/VDE.12013
Abstract: Alopecia areata (AA) causes hair loss due to inflammatory changes within and around hair bulbs and lower portions of the hair follicles. Documentation of AA in horses is limited to a few case reports. The aim of this retrospective study was to characterize equine AA by describing patterns in age, sex, breed and lesion distribution in a series of cases. An attempt was made to characterize the long-term course of the disease by surveying owners of affected horses. Computerized records from 1 January 1980 to 1 July 2011 yielded 15 horses. Descriptive statistics were calculated for age at presentation, breed, sex, dermatological signs, season when diagnosed and any recurrence of AA. The breed and sex distribution of horses with AA was compared with the equine hospital population during the study period. The prevalence of AA was 0.017%. Appaloosas and quarter horses were the most commonly recorded breeds. The median age was 9 years, with an age range from 3 to 15 years. Alopecia was the primary dermatological abnormality in all horses and commonly affected the mane, tail and face. More than half of the horses presented for other medical conditions. Five of seven (71.4%) owners who returned completed surveys reported a seasonal pattern to the disease, which usually worsened in spring and summer. Alopecia areata is a rare disease in horses, and is typically cosmetic in nature. To the authors' knowledge, this is the first study investigating the epidemiology of equine AA.
A blocking ELISA for the detection of antibodies to psittacine beak and feather disease virus (BFDV)
Publisher: Elsevier BV
Date: 06-2009
DOI: 10.1016/J.JVIROMET.2009.02.009
Abstract: Currently, the only diagnostic test available routinely for the sero-diagnosis of BFDV is the haemagglutination-inhibition (HI) assay. This test, whilst useful and applicable to s les from a wide range of psittacine birds, is not an ideal assay it requires erythrocytes from live animals, virus purified from the feathers of infected birds and polyclonal antibody preparations in order to perform the assay. Variations in these reagents make consistency between tests difficult to achieve, underscoring the need for a new test with standardised reagents for the sero-diagnosis of BFDV infection which has led to the development of an antibody response. The methods used to develop a novel "blocking" (or "competitive") ELISA (bELISA) for the detection of anti-BFDV antibodies in psittacine sera are presented in this paper. The assay was developed using a baculovirus-expressed recombinant BFDV capsid protein and a newly developed monoclonal antibody raised against this protein. The assay was then validated with 160 s les from eastern long-billed corellas (Cacatua tenuiostris) vaccinated with the recombinant capsid protein and challenged with live virus and s les from 82 cockatiels known to be HI negative. The bELISA described in this study is a sensitive and specific diagnostic test and should have wide application for the sero-diagnosis of BFDV.
A Scoping Review of the Global Distribution of Causes and Syndromes Associated with Mid-to Late-Term Pregnancy Loss in Horses between 1960 and 2020
Publisher: MDPI AG
Date: 13-04-2022
Abstract: Equine pregnancy loss is frustrating and costly for horse breeders. The reproductive efficiency of mares has significant implications for a breeding operation’s economic success, and widespread losses can have a trickle-down effect on those communities that rely on equine breeding operations. Understanding the causes and risks of equine pregnancy loss is essential for developing prevention and management strategies to reduce the occurrence and impact on the horse breeding industry. This PRISMA-guided scoping review identified 514 records on equine pregnancy loss and described the global spatiotemporal distribution of reported causes and syndromes. The multiple correspondence analysis identified seven clusters that grouped causes, syndromes, locations and pathology. Reasons for clustering should be the focus of future research as they might indicate undescribed risk factors associated with equine pregnancy loss. People engaged in the equine breeding industry work closely with horses and encounter equine bodily fluids, placental membranes, aborted foetuses, and stillborn foals. This close contact increases the risk of zoonotic disease transmission. Based on this review, research is required on equine abortion caused by zoonotic bacteria, including Chlamydia psittaci, Coxiella burnetii and Leptospira spp., because of the severe illness that can occur in people who become infected.
Assessment of recombinant beak and feather disease virus capsid protein as a vaccine for psittacine beak and feather disease
Publisher: Microbiology Society
Date: 03-2009
Abstract: Beak and feather disease virus (BFDV) is a significant pathogen of wild Australasian and African psittacine birds. We assessed the immunogenicity of recombinant BFDV capsid (recBFDVcap) to protect against the development of psittacine beak and feather disease (PBFD). Long-billed corellas ( Cacatua tenuirostris ) ( n =13) received (by injection) 1 ml vaccine containing 10 μg recBFDVcap on day 0 and 0.4 ml vaccine containing 66.8 μg recBFDVcap on day 11. All vaccinated corellas and five non-vaccinated control corellas were given 0.4 ml BFDV suspension [titre=log 2 12 haemagglutination units (HAU) 50 μl −1 ] intramuscularly and 0.1 ml orally 16 days after booster vaccination. Blood was collected during the vaccination period and blood and feathers were collected after BFDV administration. Testing of blood s les included BFDV DNA detection by PCR and quantitative PCR (qPCR) as well as antibody detection by haemagglutination inhibition (HI) and on feather s les, BFDV DNA and antigen was detected by haemagglutination (HA) and qPCR. Four of 97 blood s les collected from vaccinated birds after virus challenge tested positive by PCR, whereas 17 of 35 s les taken from non-vaccinated control corellas tested positive. Vaccinated birds did not develop feather lesions, had only transient PCR-detectable viraemia and had no evidence of persistent infection 270 days post-challenge using PCR, histopathology and immunohistochemistry. Non-vaccinated control corellas developed transient feather lesions and had PCR, HI and HA test results consistent with PBFD. They were BFDV PCR-positive for up to 41 days post-challenge and qPCR demonstrated reduced virus replication in vaccinated birds compared with non-vaccinated control birds.
Atypical scrapie in Australia
Publisher: Wiley
Date: 03-11-2016
DOI: 10.1111/AVJ.12529
Abstract: Since its initial detection in Norway in 1998, atypical scrapie ('atypical/Nor98 scrapie') has been reported in sheep in the majority of European countries (including in regions free of classical scrapie) and in the Falkland Islands, the USA, Canada, New Zealand and Australia. The diagnosis in Australia of atypical scrapie in four Merino and one Merino-cross sheep showing clinical signs of neurological disease was based on the detection of grey matter neuropil vacuolation (spongiform change) in the brain (particularly in the molecular layer of the cerebellar cortex) and associated abnormal prion protein (PrP The distinctive lesion profile of atypical scrapie in these five sheep highlights the diagnostic importance of routine histological evaluation of the cerebellum for evidence of neuropil vacuolation and associated PrP
Hydroureteronephrosis and fetal mummification secondary to uterine torsion in a Merino ewe
Publisher: Wiley
Date: 02-08-2020
DOI: 10.1111/AVJ.12999
Elimination of False-Positive Polymerase Chain Reaction Results Resulting from Hole Punch Carryover Contamination
Publisher: SAGE Publications
Date: 2008
DOI: 10.1177/104063870802000111
Abstract: The collection of biological material (e.g., blood) directly onto filter paper for subsequent use in laboratory assays such as polymerase chain reaction (PCR), has become a common practice. Dried cells or fluid on the paper can be readily rehydrated and retrieved into a standard volume of an appropriate elution buffer but introduces a dilution factor to the s le. The use of a common cutting instrument for excising a standard-sized piece of paper that contains the material also introduces the potential for transferring biological material from one s le to subsequent s les, causing false-positive results by PCR. In the present study, filter-paper-collected blood that contained beak and feather disease virus was used to determine if viral DNA could be transferred between s les by a hole punch used to excise sequential filter papers. It was determined that false-positive results could be obtained at least 13 times after a positive s le. Subsequently, the efficacy of 4 methods of hole punch disinfection, flaming, VirkonS, bleach, and a bleach-ethanol combination, was assessed. The only effective and practical method to destroy DNA was a method where the hole punch was agitated in commercial bleach, rinsed in water, the water was displaced with 100% ethanol and air-dried. This method was simple, cheap, and relatively rapid, and allowed for the use of a single hole punch for a series of s les, without carryover contamination and consequent false-positive results.
Development and applications of a monoclonal antibody to a recombinant beak and feather disease virus (BFDV) capsid protein
Publisher: Elsevier BV
Date: 02-2008
DOI: 10.1016/J.JVIROMET.2007.08.029
Abstract: The development of diagnostic assays for detecting beak and feather disease virus (BFDV) has traditionally been h ered by the difficulty associated with producing suitable reagents, namely purified virus and polyclonal antibodies. In an effort to develop a consistent and standardised source of antibody, a monoclonal antibody to a recombinant BFDV capsid protein has been developed and its use in western blotting, immunohistochemistry (IHC), ELISA and haemagglutination-inhibition (HI) assays characterised. The antibody was specific for both the recombinant BFDV capsid protein and the whole virus and had similar optimal titres when used in western blotting and IHC. The antibody also had HI activity and detected BFDV virus from three genera of psittacine birds, including the recently described cockatiel BFDV isolate. The monoclonal antibody should have widespread application in both research and the development of diagnostic assays for BFDV.
Ichthyosis fetalis in Polled Hereford and Shorthorn calves
Publisher: SAGE Publications
Date: 06-08-2017
Abstract: Inherited forms of ichthyosis, or generalized scaling of the skin, have been reported in many animal species, including cattle, and are characterized by an autosomal recessive mode of inheritance. We investigated 2 calves affected with ichthyosis fetalis, a Polled Hereford and a Shorthorn. Both cases had hard white plaques on the skin consistent with excessive keratinization. This was confirmed by histopathology, which showed severe diffuse epidermal and follicular orthokeratotic hyperkeratosis. The known mutation (H1935R) in gene ABCA12, responsible for ichthyosis fetalis in Chianina cattle, was shown to be absent in both affected calves and their obligate heterozygous parents. These molecular findings indicate that allelic heterogeneity exists for this condition in cattle.
A quantitative, real-time polymerase chain reaction assay for beak and feather disease virus
Publisher: Elsevier BV
Date: 07-2009
DOI: 10.1016/J.JVIROMET.2009.03.009
Abstract: PCR-based assays for the detection of BFDV DNA are in widespread use throughout the world. Quantitative real-time PCR assays are extremely sensitive and have the advantages over standard PCR assays that they do not require post-reaction processing to visualise PCR products and can quantify the amount of DNA present in a s le. This study describes a quantitative real-time PCR assay for the detection of BFDV DNA, using primers designed to lify a conserved 81 bp fragment of ORFV1 and SYTO9, a fluorescent intercalating dye. A synthetic oligonucleotide was used to make standard curves for the quantitation of viral load in blood and feather preparations. The assay was very sensitive, with a detection limit of 50 copies/microL. The assay was developed using DNA extracts from the feathers of 10 different species of birds which had tested BFDV-positive previously and was validated with blood and feather s les from corellas vaccinated with an experimental BFDV vaccine, then challenged with live virus. Viral DNA was detected consistently in the blood of all control (non-vaccinated) birds and in some vaccinated birds. Contamination of the environment with feather dander from BFDV-infected birds meant that feather preparations used for the haemagglutination assay were unreliable for the detection and quantitation of viral excretion. Nonetheless, the assay should prove to be a useful and sensitive test for the detection of viral DNA in a range of s les.
Beak and feather disease virus infection in cockatiels (Nymphicus hollandicus)
Publisher: Informa UK Limited
Date: 16-01-2008
DOI: 10.1080/03079450701802206
Abstract: Psittacine beak and feather disease is known to occur in a wide range of psittacine species however, there are no scientific or credible anecdotal reports of psittacine beak and feather disease occurring in the cockatiel (Nymphicus hollandicus) despite it being one of the world's most commonly kept companion bird species. Consequently, this has resulted in speculation that the species may have some innate resistance to beak and feather disease virus (BFDV) infection. To investigate this hypothesis we conducted a survey of cockatiels (n=88) at commercial aviaries to investigate whether BFDV infection occurs in cockatiels, and found that all birds were virus-free by polymerase chain reaction and haemagglutination assay and had no detectable antibody titre by haemagglutination-inhibition assay. In addition to this, we sequenced the genome of two BFDV isolates obtained from diseased cockatiel feathers and performed cross-reactivity assays using virus eluted from these feathers and sera from naturally immune psittacine birds. Serological cross-reactivity results and phylogenetic analysis of the nucleotide sequences indicated that the cockatiel virus isolates were serologically and genetically different to other BFDV isolates. This is the first paper to report evidence of an antigenically distinct BFDV in psittacine birds.
Surgical removal of an ovarian tumour in a koi carp (Cyprinus carpio).
Publisher: Wiley
Date: 05-2006
DOI: 10.1111/J.1751-0813.2006.TB12776.X
Abstract: Ultrasonography, radiography and exploratory coeliotomy were used to diagnose and treat a large intracoelomic neoplasm from a female koi carp (Cyprinus carpio) presented for abdominal enlargement of several months duration. Feed was withheld for 1 week immediately prior to surgery and the fish was sedated with isoeugenol (AQUI-S) at a dose rate of 10 mL/L to facilitate diagnostic imaging techniques. Surgical anaesthesia was induced by adding tricaine (MS-222) 50 mg/L to the water and an exploratory coeliotomy and tumour removal was performed. The fish was allowed to recover in fresh water at 18 degrees C and salt was added slowly to the water over a period of 1 hour to a concentration of 5 g/L This concentration was maintained in a recovery pond for 1 week postoperatively. Enrofloxacin was administered intramuscularly (10 mg/kg) immediately, 3 days and 1 week postoperatively. A diagnosis of undifferentiated ovarian carcinoma was made on the basis of the histological appearance of the neoplasm and immunohistochemical staining.
A tumour of vascular origin in a horse
Publisher: Wiley
Date: 26-11-2020
DOI: 10.1111/EVE.13407
Abstract: Tumours of vascular origin are uncommon in horses. This report describes the surgical treatment of a large subcutaneous tumour in a Quarter Horse colt. The histopathological appearance of the mass was most consistent with a haemangioma. While these neoplasms of vascular origin are often difficult to characterise, it has been suggested that there is a continuum of types with some cases falling between the categories. Further classification of vascular tumours requires special stains and immunohistochemical techniques.
Hematology of vaccinated and non-vaccinated long-billed corellas following infection with beak and feather disease virus (BFDV)
Publisher: Springer Science and Business Media LLC
Date: 31-01-2009
Chronic shoulder osteoarthritis in a loggerhead turtle (Caretta caretta)
Publisher: Wiley
Date: 07-2006
DOI: 10.1111/J.1751-0813.2006.00003.X
Abstract: This report describes the lesions seen in an extremely weak and emaciated adult male loggerhead turtle (Caretta caretta) found stranded near Perth, Western Australia. Blood collected from a dorsal cervical sinus immediately prior to euthanasia demonstrated severe anaemia, markedly elevated plasma concentrations of creatinine kinase (2263 U/L), alkaline phosphatase (58 U/L), urea (18.1 mmol/L) and hypoglycaemia (glucose 0.7 mmol/L). Necropsy examination demonstrated a severe chronic osteoarthritis of the right shoulder joint with marked remodelling of the glenoid fossa, coracoid, scapula and humerus. There was marked synovial effusion and periarticular fibrosis. Cytological examination and culture of synovial fluid failed to demonstrate an infectious agent. Other findings were low numbers of trypanorhynch cysts present on the surface of the liver and numerous spirorchid eggs in the attached mesentery. Several large and small spirorchid flukes were present in the heart and there was a localised endarteritis in the left aortic arch associated with this infection. Numerous nematode eggs and at least three species of spirorchid eggs were seen microscopically in faeces collected from the terminal colon. The pathogenesis and significance of these lesions is discussed.
Baculovirus expression of beak and feather disease virus (BFDV) capsid protein capable of self-assembly and haemagglutination.
Publisher: Elsevier BV
Date: 05-2007
DOI: 10.1016/J.JVIROMET.2006.12.011
Abstract: Beak and feather disease virus (BFDV) is a common avian circovirus infection of wild Psittaciformes and is a recognised threat to endangered psittacine species. Currently, there is a requirement to develop BFDV antigen for diagnostic purposes and since efforts to propagate BFDV in vitro have so far been unsuccessful the entire coding region of BFDV ORF C1 was expressed in Sf9 insect cells using a baculovirus expression system. The entire coding region of BFDV ORF C1, the presumptive capsid, was expressed in Sf9 insect cells using baculovirus expression system. Electron microscopic examination of negatively stained material demonstrated that the recombinant protein self-assembled to produce virus-like particles (VLPs) thus confirming that ORF C1 is likely to be the sole determinant for capsid construction in vivo. BFDV VLPs also possessed haemagglutinating activity which provides further evidence that self-assembled BFDV VLPs retain receptor mediated biological activity and that the determinants for BFDV haemagglutination activity rely solely on the capsid protein. The recombinant protein reacted with anti-BFDV sera from naturally immune parrots and cockatoo and from chickens experimentally inoculated with native BFDV in both Western blots and haemagglutination inhibition (HI) assay. BFDV VLPs were also a suitable replacement antigen for serological detection of BFDV antibody by HI.
Related Organisations
Murdoch University School Of Veterinary And Life Sciences
Location: Australia
Related Funding Activities
No related grants have been discovered for Patrick Shearer.