Epidemiologic, Entomologic, and Virologic Factors of the 2014-15 Ross River Virus Outbreak, Queensland, Australia.

Australia experienced its largest recorded outbreak of Ross River virus (RRV) during the 2014-15 reporting year, comprising >10,000 reported cases. We investigated epidemiologic, entomologic, and virologic factors that potentially contributed to the scale of the outbreak in Queensland, the state with the highest number of notifications (6,371). Spatial analysis of human cases showed that notifications were geographically widespread.

The effects of culture independent diagnostic testing on the diagnosis and reporting of enteric bacterial pathogens in Queensland, 2010 to 2014.

Changes in diagnostic laboratory testing procedures can impact on the number of cases notified and the public health surveillance of enteric pathogens. Culture independent diagnostic testing using a multiplex polymerase chain reaction (PCR) test was introduced for the rapid detection of bacterial enteric pathogens in pathology laboratories in Queensland, Australia, from late 2013 onwards. We conducted a retrospective descriptive study using laboratory data to assess the impact of the introduction of PCR testing on four common enteric pathogens, Salmonella, Campylobacter, Shigella and Yersinia, in Queensland between 2010 and 2014.

Epidemiology of bacterial toxin-mediated foodborne gastroenteritis outbreaks in Australia, 2001 to 2013.

Bacterial toxin-mediated foodborne outbreaks, such as those caused by Clostridium perfringens, Staphylococcus aureus and Bacillus cereus, are an important and preventable cause of morbidity and mortality. Due to the short incubation period and duration of illness, these outbreaks are often under-reported. This is the first study to describe the epidemiology of bacterial toxin-mediated outbreaks in Australia.

A new insect-specific flavivirus from northern Australia suppresses replication of West Nile virus and Murray Valley encephalitis virus in co-infected mosquito cells.

Recent reports of a novel group of flaviviruses that replicate only in mosquitoes and appear to spread through insect populations via vertical transmission have emerged from around the globe. To date, there is no information on the presence or prevalence of these insect-specific flaviviruses (ISFs) in Australian mosquito species. To assess whether such viruses occur locally, we used reverse transcription-polymerase chain reaction (RT-PCR) and flavivirus universal primers that are specific to the NS5 gene to detect these viruses in mosquito pools collected from the Northern Territory.

Genetic divergence among members of the Kokobera group of flaviviruses supports their separation into distinct species.

The Kokobera virus group comprises mosquito-borne flaviviruses that cluster together phylogenetically. These viruses are unique to Australia and Papua New Guinea, and have been associated with a mild polyarticular disease in humans. Recent isolation of genetically diverse viruses within this group has prompted analysis of their genetic and phenotypic relationships.

Molecular evolution of lineage 2 West Nile virus.

Since the 1990s West Nile virus (WNV) has become an increasingly important public health problem and the cause of outbreaks of neurological disease. Genetic analyses have identified multiple lineages with many studies focusing on lineage 1 due to its emergence in New York in 1999 and its neuroinvasive phenotype. Until recently, viruses in lineage 2 were not thought to be of public health importance due to few outbreaks of disease being associated with viruses in this lineage.

Characterization of virulent West Nile virus Kunjin strain, Australia, 2011.

To determine the cause of an unprecedented outbreak of encephalitis among horses in New South Wales, Australia, in 2011, we performed genomic sequencing of viruses isolated from affected horses and mosquitoes. Results showed that most of the cases were caused by a variant West Nile virus (WNV) strain, WNV(NSW2011), that is most closely related to WNV Kunjin (WNV(KUN)), the indigenous WNV strain in Australia. Studies in mouse models for WNV pathogenesis showed that WNV(NSW2011) is substantially more neuroinvasive than the prototype WNV(KUN) strain.

Determinants of attenuation in the envelope protein of the flavivirus Alfuy.

Murray Valley encephalitis virus (MVEV) is a mosquito-borne flavivirus endemic to Australia and Papua New Guinea. Most strains of MVEV cause potentially fatal cases of encephalitis in humans and horses, and have been shown to be highly neuroinvasive in weanling mice. In contrast, the naturally occurring subtype Alfuy virus (ALFV) has never been associated with human disease, nor is it neuroinvasive in weanling mice, even at high doses.

Evolution of new genotype of West Nile virus in North America.

Previous studies of North American isolates of West Nile virus (WNV) during 1999-2005 suggested that the virus had reached genetic homeostasis in North America. However, genomic sequencing of WNV isolates from Harris County, Texas, during 2002-2009 suggests that this is not the case. Three new genetic groups have been identified in Texas since 2005.

Phylogeography of West Nile virus: from the cradle of evolution in Africa to Eurasia, Australia, and the Americas.

West Nile virus (WNV) is the most widely distributed of the encephalitic flaviviruses and is a major cause of encephalitis, with isolates obtained from all continents, apart from Antarctica. Subsequent to its divergence from the other members of the Japanese encephalitis virus complex, presumably in Africa, WNV has diverged into individual lineages that mostly correspond with geographic distribution. Here we elucidate the phylogeography and evolutionary history of isolates from lineage 1 of WNV.

Multiple pathways to the attenuation of West Nile virus in south-east Texas in 2003.

West Nile virus (WNV) was first detected in Texas in 2002. During 2003, several isolates exhibiting significant attenuation of mouse neuroinvasiveness, and in some cases a small plaque and temperature sensitive phenotype when compared to other North American WNV isolates, were obtained from birds and mosquitoes in South-East Texas. To determine the attenuation markers of WNV, we have sequenced the genomes of three attenuated isolates and four temporally related virulent isolates and compared the amino acid substitutions in a total of 101 isolates, including three previously published genomes of attenuated strains, to identify mutations that are potentially involved in attenuation.

Structure of yellow fever virus envelope protein domain III.

The structure of recombinant domain III of the envelope protein (rED3) of yellow fever virus (YFV), containing the major neutralization site, was determined using NMR spectroscopy. The amino acid sequence and structure of the YFV-rED3 shows differences from ED3s of other mosquito-borne flaviviruses; in particular, the partially surface-exposed BC loop where methionine-304 and valine-324 were identified as being critical for the structure of the loop. Variations in the structure and surface chemistry of ED3 between flaviviruses affect neutralization sites and may affect host cell receptor interactions and play a role in the observed variations in viral pathogenesis and tissue tropism.

NMR assignments of the sylvatic dengue 1 virus envelope protein domain III.

Nearly complete backbone and side chain resonance assignments have been obtained for the third domain, residues M289-K400, of the envelope protein from the sylvatic strain (P72-1244) of the dengue 1 virus, containing mutations N336S and E370K, using double- and triple-resonance spectroscopy.

Genetic variation of St. Louis encephalitis virus.

St. Louis encephalitis virus (SLEV) has been regularly isolated throughout the Americas since 1933. Previous phylogenetic studies involving 62 isolates have defined seven major lineages (I-VII), further divided into 14 clades.

NMR assignments of the yellow fever virus envelope protein domain III.

Nearly complete backbone and sidechain resonance assignments have been obtained for the third domain, residues S288-K398, of the envelope protein from the Asibi strain of yellow fever virus using double- and triple-resonance spectroscopy.

Genetic stasis of dominant West Nile virus genotype, Houston, Texas.

The accumulation and fixation of mutations in West Nile virus (WNV) led to the emergence of a dominant genotype throughout North America. Subsequent analysis of 44 isolates, including 19 new sequences, from Houston, Texas, suggests that WNV has reached relative genetic stasis at the local level in recent years.

Genetic and phenotypic differences between isolates of Murray Valley encephalitis virus in Western Australia, 1972-2003.

Murray Valley encephalitis virus (MVEV) is a medically important mosquito-borne flavivirus found in Australia and Papua New Guinea (PNG). Partial envelope gene nucleotide sequences of 28 isolates of MVEV from Western Australia (WA) between 1972 and 2003 were aligned and compared phylogenetically with the prototype MVE-1-51 from Victoria in 1951 and isolates from northern Queensland and PNG. Monoclonal antibody-binding patterns were also investigated.

Biological, antigenic and phylogenetic characterization of the flavivirus Alfuy.

Alfuy virus (ALFV) is classified as a subtype of the flavivirus Murray Valley encephalitis virus (MVEV); however, despite preliminary reports of antigenic and ecological similarities with MVEV, ALFV has not been associated with human disease. Here, it was shown that ALFV is at least 10(4)-fold less neuroinvasive than MVEV after peripheral inoculation of 3-week-old Swiss outbred mice, but ALFV demonstrates similar neurovirulence. In addition, it was shown that ALFV is partially attenuated in mice that are deficient in alpha/beta interferon responses, in contrast to MVEV which is uniformly lethal in these mice.

Effect of the peroxisome proliferator-activated receptor beta activator GW0742 in rat cultured cerebellar granule neurons.

The ligand-activated transcription factor peroxisome proliferator-activated receptor beta (PPARbeta) is present in the brain and is implicated in the regulation of genes with potential roles in neurotoxicity. We sought to examine the role of PPARbeta in neuronal cell death by using the PPARbeta ligand GW0742. Primary cultures of rat cerebellar granule neurons were prepared from 7-day-old pups.

Effects of peroxisome proliferator-activated receptor gamma ligands ciglitazone and 15-deoxy-delta 12,14-prostaglandin J2 on rat cultured cerebellar granule neuronal viability.

Peroxisome proliferator-activated receptor gamma (PPARgamma) has been the focus of studies assessing its potential neuroprotective role. These studies have shown either neuroprotection or neurotoxicity by PPARgamma ligands. Comparison of these studies is complicated by the use of different PPARgamma ligands, mechanisms of neurotoxicity induction, and neuronal cell type.

Expression of plasma membrane calcium pump isoform mRNAs in breast cancer cell lines.

The plasma membrane Ca(2+) ATPase (PMCA) is an important regulator of free intracellular calcium, with dynamic regulation in the rat mammary gland during lactation. Recent studies suggest that Ca(2+) plays a role in cellular proliferation. To determine if PMCA expression is altered in tumorigenesis, we compared relative levels of PMCA1 mRNA.

Peroxisome proliferator-activated receptor alpha in the human breast cancer cell lines MCF-7 and MDA-MB-231.

Peroxisome proliferator-activated receptor (PPAR) alpha is a ligand-activated transcription factor that has been linked with rodent hepatocarcinogenesis. It has been suggested that PPARalpha mRNA expression levels are an important determinant of rodent hepatic tumorigenicity. Previous work in rat mammary gland epithelial cells showed significantly increased PPARalpha mRNA expression in carcinomas, suggesting the possible role of this isoform in rodent mammary gland carcinogenesis.

Peroxisome proliferator-activated receptor beta expression in human breast epithelial cell lines of tumorigenic and non-tumorigenic origin.

Peroxisome proliferator-activated receptor beta (PPARbeta) is a member of the nuclear hormone receptor superfamily and is a ligand activated transcription factor, although the precise genes that it regulates and its physiological and pathophysiological role remain unclear. In view of the association of PPARbeta with colon cancer and increased mRNA levels of PPARbeta in colon tumours we sought in this study to examine the expression of PPARbeta in human breast epithelial cells of tumorigenic (MCF-7 and MDA-MB-231) and non-tumorigenic origin (MCF-10A). Using quantitative RT-PCR we measured PPARbeta mRNA levels in MCF-7, MDA-MB-231 and MCF-10A cells at various stages in culture.