Melbourne Veterinary School - Research Publications
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ItemNo Preview AvailableASPECTS OF THE DIAGNOSIS, PATHOGENESIS AND EPIDEMIOLOGY OF CANINE PARVOVIRUS(AUSTRALIAN VETERINARY ASSN, 1983)Between 18 July 1980 and 2 January 1981, 188 samples (145 faeces and 43 intestinal contents) were submitted from dogs with suspected canine parvovirus (CPV) enteritis. CPV was demonstrated in 56 (30%) of these samples; the weekly rate of positive CPV identification was remarkably constant at approximately 30% even though clinical and often post-mortem findings strongly supported a diagnosis of CPV enteritis. The simplest, most sensitive and most rapid method for detection of virus was haemagglutination (HA) which was twice as sensitive as isolation of virus and 8 times as sensitive as electron microscopy (EM). Forty nine of 56 (88%) samples positive for CPV were from dogs less than 1 year old and 44 (79%) CPV-positive samples were from pups less than 6 months old; only one sample from a pup less than 2 months old (pup was 7 weeks old) was positive. An additional 68 samples (53 faeces and 15 intestinal contents) were submitted from Beagle dogs that were part of a colony of approximately 1200 dogs. Epidemiological data pinpoints the entry of CPV into the colony in November 1978 at which time most dogs including pups less than 6 months of age developed antibody to CPV without developing clinical disease. From these data an overview of some aspects of the pathogenesis and epidemiology of CPV is constructed.
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ItemNo Preview AvailableVIRUSES AND VIRUS-LIKE PARTICLES IN THE FECES OF DOGS WITH AND WITHOUT DIARRHEA(AUSTRALIAN VETERINARY ASSN, 1984)Negative staining electron microscopy was used to identify viruses in 157 normal and 29 diarrhoeal faecal samples collected from 156 dogs admitted to an animal shelter during an 8 month period (March to October) in 1982. Seven distinct viral types were detected: 21-26 nm parvovirus-like particles, 28-31 nm astrovirus-like particles, a previously undescribed 34-35 nm "round" virus particle, coronavirus, coronavirus-like particles ( CVLP ), rotavirus and papova-like virus. Parvovirus-like particles alone were detected in 14 diarrhoeal and 50 normal faeces, astrovirus-like particles in 3 normal faeces, "round" viruses in 4 normal faeces, coronavirus in 2 diarrhoeal and 5 normal faeces, CVLP in one diarrhoeal and one normal faeces, rotavirus in 2 normal faeces, papova-like virus in one normal faeces, both parvovirus-like particles and coronavirus in 2 diarrhoeal and 2 normal faeces, parvovirus-like particles and rotavirus in one normal faeces and parvovirus-like and papova-like virus in one normal faeces. The significance of these findings in canine and human disease is discussed.
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ItemNo Preview AvailableVIRUS AND VIRUS-LIKE PARTICLES IN THE FECES OF CATS WITH AND WITHOUT DIARRHEA(WILEY, 1987-04)Negative staining electron microscopy was used to identify viruses in 166 normal and 62 diarrhoeal faecal samples from 208 cats admitted to an animal shelter during a 16-month period (March 1984 to June 1985). On the basis of size and shape 7 distinct viral types were detected: 24 nm parvovirus-like particles, 30 nm astrovirus, 30 nm picornavirus-like particles, reovirus, rotavirus, coronavirus and a 75 nm "togavirus-like" particle. The incidence of these particles in the 208 cats was 11%, 7%, 6%, 0.4%, 5%, 1% and 1% respectively. Virus isolation studies using 40 of the faecal samples succeeded in isolating reovirus 1 in 2 cases. Immune electron microscope studies demonstrated the presence of antibody in a human serum to cat astrovirus, but failed to clarify the identity of the parvovirus-like particles and picornavirus-like particles, other than showing that some of the parvovirus-like particles were not related to feline panleukopenia virus. It was found that parvovirus-like particles, astrovirus, picornavirus-like particles, reovirus and rotavirus could be excreted by cats with normal faeces as well as cats with diarrhoeal faeces. Parvovirus-like particles, astrovirus, picornavirus-like particles and rotavirus could be excreted in high concentration in normal faeces. There was no simple relationship between age and diarrhoea in the population of cats studied. Age was not a critical factor in the excretion of parvovirus-like particles, astrovirus, picornavirus-like particles and rotavirus. The incidence of diarrhoea was not clearly associated with the seasons.
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ItemNo Preview AvailableReverse transcriptase-polymerase chain reaction for the detection equine rhinitis B viruses and cell culture isolation of the virus(SPRINGER WIEN, 2007-01)Equine rhinitis B virus (ERBV), genus Erbovirus, family Picornaviridae occurs as two serotypes, ERBV1 and ERBV2. An ERBV-specific nested reverse transcriptase-polymerase chain reaction (RT-PCR) that amplified a product within the 3D(pol) and 3' non-translated region of the viral genome was developed. The RT-PCR detected all 24 available ERBV1 isolates and one available ERBV2 isolate. The limit of detection for the prototype strain ERBV1.1436/71 was 0.1 50% tissue culture infectious doses. The RT-PCR was used to detect viral RNA in six of 17 nasopharyngeal swab samples from horses that had clinical signs of acute febrile respiratory disease but from which ERBV was not initially isolated in cell culture. The sequences of these six ERBV RT-PCR positive samples had 93-96% nucleotide identity with six other partially sequenced ERBV1 isolates and one ERBV2. ERBV was isolated from one of the six samples at fourth cell culture passage when it was shown that the addition of 20 mg/mL MgCl(2) to the cell culture medium enhanced the growth of the virus. This isolated virus was antigenically similar to ERBV2.313/75. Determination of the nucleotide sequence of the P1 region of the genome also indicated that the isolate was ERBV2, and it was therefore designated ERBV2.1576/99. This is the first reported isolation of ERBV in Australia. The study highlights the utility of PCR for the identification of viruses in clinical samples that may initially be considered negative by conventional cell culture isolation.
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ItemGenome Sequences of Equid Herpesviruses 2 and 5(AMER SOC MICROBIOLOGY, 2015-03-12)We resequenced the genome of equid herpesvirus 2 (EHV2) strain 86/67 and sequenced the genomes of EHV2 strain G9/92 and equid herpesvirus 5 (EHV5) strain 2-141/67. The most prominent genetic differences are the dissimilar locations of the interleukin-10 (IL-10)-like genes and the presence of an OX-2-like gene in EHV5 only.
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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.
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ItemNo Preview AvailableEvidence of widespread natural recombination among field isolates of equine herpesvirus 4 but not among field isolates of equine herpesvirus 1(SOC GENERAL MICROBIOLOGY, 2016-03)Recombination in alphaherpesviruses allows evolution to occur in viruses that have an otherwise stable DNA genome with a low rate of nucleotide substitution. High-throughput sequencing of complete viral genomes has recently allowed natural (field) recombination to be studied in a number of different alphaherpesviruses, however, such studies have not been applied to equine herpesvirus 1 (EHV-1) or equine herpesvirus 4 (EHV-4). These two equine alphaherpesviruses are genetically similar, but differ in their pathogenesis and epidemiology. Both cause economically significant disease in horse populations worldwide. This study used high-throughput sequencing to determine the full genome sequences of EHV-1 and EHV-4 isolates (11 and 14 isolates, respectively) from Australian or New Zealand horses. These sequences were then analysed and examined for evidence of recombination. Evidence of widespread recombination was detected in the genomes of the EHV-4 isolates. Only one potential recombination event was detected in the genomes of the EHV-1 isolates, even when the genomes from an additional 11 international EHV-1 isolates were analysed. The results from this study reveal another fundamental difference between the biology of EHV-1 and EHV-4. The results may also be used to help inform the future safe use of attenuated equine herpesvirus vaccines.