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Grant K.A.,Epidemiology Unit | Fielding J.E.,Epidemiology Unit | Fielding J.E.,Australian National University | Mercer G.N.,Australian National University | And 8 more authors.
Australian and New Zealand Journal of Public Health

Objective: To describe the epidemiological characteristics of the 2009 H1N1 pandemic virus (pH1N1) over the 2009 and 2010 influenza seasons in Australia and New Zealand (NZ) and compare them with expectations based on previous pandemics. Methods: Laboratory-confirmed influenza and influenza-like illness (ILI) data were collected from established general practitioner sentinel surveillance schemes in NZ, Victoria and Western Australia (WA) throughout the 2009 and 2010 winter influenza seasons. Respiratory swabs from a sample of ILI patients were tested for influenza type and subtype. ILI rates and laboratory-confirmed influenza data were analysed by age group and over time. Morbidity, mortality and reproductive number data were collated from the published literature. Results: Peak ILI rates and the percentage of influenza-positive swabs from ILI patients from all sentinel surveillance schemes were considerably lower in 2010 than 2009. Compared to the population, cases of ILI were over-represented in the young. While the age distributions in NZ and WA remained consistent, ILI cases were significantly younger in Victoria in 2009 compared to 2010. In Victoria, laboratory-confirmed pH1N1 comprised up to 97% of influenza-positive swabs in 2009 but only 56-87% in 2010. Mortality and hospitalisations were lower in 2010. The effective reproduction number (R) for pH1N1 was estimated to be 1.2-1.5 in NZ and WA, similar to estimated R values for seasonal influenza. Data from the surveillance systems indicated differences in the epidemiology of pH1N1 compared to expectations based on previous pandemics. In particular, there was no evidence of a second pandemic wave associated with increased mortality, and complete influenza strain replacement did not occur. Implications: Pandemic planning needs to accommodate the potential for influenza viruses to produce pandemics of various infectiousness and degrees of severity. © 2012 Public Health Association of Australia. Source

Bradbury R.S.,University of Tasmania | Tristram S.G.,University of Tasmania | Roddam L.F.,Menzies Research Institute | Reid D.W.,Menzies Research Institute | And 2 more authors.
British Journal of Biomedical Science

Pseudomonas aeruginosa is an important pathogen in humans, particularly in the context of nosocomial infection and infections of the cystic fibrosis (CF) lung. In order to provide clinicians with information about the likely effectiveness of specific antimicrobial treatment for P. aeruginosa infections, clinical laboratories employ in vitro antimicrobial susceptibility testing. Two commonly employed methods are the CLSI disc-diffusion and Etest methods. The purpose of this study is to compare the accuracy of susceptibility results generated by these two methods against agar dilution as the reference method. Susceptible or non-susceptible (resistant and intermediate) results of the Etest and CLSI disc-diffusion methods are compared with CLSI agar dilution results for a large cohort of clinical cystic fibrosis (n=71) and non-cystic fibrosis (n=83) isolates using CLSI interpretive criteria. An unacceptable number of major and very major errors were observed for various antimicrobials tested against both CF and non-CF isolates when using the Etest and CLSI disc-diffusion methods. The potential for error in standard laboratory antimicrobial susceptibility testing should be considered by clinicians when being guided by the results of such tests in the prescription of antimicrobial agents for P. aeruginosa infection. Source

Warrilow D.,Public Health Virology Laboratory | Watterson D.,University of Queensland | Hall R.A.,University of Queensland | Davis S.S.,Australian Department of Primary Industries and Fisheries | And 8 more authors.

Here we describe Casuarina virus (CASV), a new virus in the family Mesoniviridae. This is the first report of a mesonivirus in Australia, which extends the geographical range of this virus family to 3 continents. The virus was isolated in 2010 from Coquillettidia xanthogaster mosquitoes during surveillance in the suburbs of Darwin, the capital of the Northern Territory. Cryo-electron microscopy of the CASV virions revealed spherical particles of 65 nm in size with large club-shaped projections of approximately 15 nm in length. The new virus was most closely related to Alphamesonivirus 1, the only currently recognized species in the family. In 2013 a further 5 putative new mesonivirus species were described: Hana, Méno, Nsé, Moumo and Dak Nong viruses. The evolutionary distance between CASV and two of its closest relatives, Cavally and Hana viruses (Jones-Taylor-Thornton distance of 0.151 and 0.224, respectively), along with its isolation from a different genus of mosquitoes captured on a separate continent indicate that CASV is a new species. © 2014 Warrilow et al. Source

Hobson-Peters J.,University of Queensland | Warrilow D.,Queensland Government | McLean B.J.,University of Queensland | Watterson D.,University of Queensland | And 12 more authors.

Insect-specific viruses belonging to significant arboviral families have recently been discovered. These viruses appear to be maintained within the insect population without the requirement for replication in a vertebrate host. Mosquitoes collected from Badu Island in the Torres Strait in 2003 were analysed for insect-specific viruses. A novel bunyavirus was isolated in high prevalence from Culex spp. The new virus, provisionally called Badu virus (BADUV), replicated in mosquito cells of both Culex and Aedes origin, but failed to replicate in vertebrate cells. Genomic sequencing revealed that the virus was distinct from sequenced bunyavirus isolates reported to date, but phylogenetically clustered most closely with recently discovered mosquito-borne, insect-specific bunyaviruses in the newly proposed Goukovirus genus. The detection of a functional furin cleavage motif upstream of the two glycoproteins in the M segment-encoded polyprotein suggests that BADUV may employ a unique strategy to process the virion glycoproteins. © 2016 Elsevier Inc. Source

Italiano C.M.,Royal Perth Hospital | Speers D.J.,Nedlands | Chidlow G.R.,Queen Elizabeth Medical Center | Dowse G.K.,Communicable Disease Control Directorate | And 3 more authors.
Journal of Infectious Diseases

On 16 April 2009, a boat carrying 47 Afghan asylum seekers and 2 Indonesian crew exploded in Australian waters, resulting in mass casualties. Of these casualties, 23 persons who suffered significant burns were transferred to Royal Perth Hospital, Perth, Western Australia. One patient was subsequently shown to be a hepatitis B virus (HBV) carrier at the time of the explosion. Over the following months, 3 other patients received a diagnosis of acute hepatitis B, and an additional 4 patients showed serological evidence of recent HBV infection, including 1 patient who was transferred to another Australian city. Molecular typing determined that the strains from the HBV carrier and the acute and recent case patients formed a closely related cluster, and the investigation suggested that transmission occurred at or around the time of the boat explosion. This is the first report of confirmed transmission of HBV following a disaster, and it reinforces the importance of postexposure prophylaxis for HBV in mass casualty situations. © The Author 2011. Published by Oxford University Press on behalf of the Infectious Diseases Society of America. All rights reserved. Source

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