303 research outputs found

    Discovery of Aspergillus frankstonensis sp. nov. during environmental sampling for animal and human fungal pathogens

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    Invasive fungal infections, IFI, due to species in Aspergillus section Fumigati, ASF, including the Aspergillus viridinutans species complex, AVSC, are increasingly reported in humans and cats. The risk of exposure to these medically important fungi in Australia is unknown. Air and soil was sampled from the domiciles of pet cats diagnosed with these IFI and from a nature reserve in Frankston, Victoria, where Aspergillus viridinutans sensu stricto was discovered in, . Of, ASF species isolated, were A. fumigatus sensu stricto, were AVSC, A. felis-clade and A. frankstonensis sp. nov., and, were other species, . Seven pathogenic ASF species known to cause disease in humans and animals, A. felis-clade, A. fischeri, A. thermomutatus, A. lentulus, A. laciniosus A. fumisynnematus, A. hiratsukae, comprised, of isolates overall. AVSC species were only isolated from Frankston soil where they were abundant, suggesting a particular ecological niche. Phylogenetic, morphological and metabolomic analyses of these isolates identified a new species, A. frankstonensis that is phylogenetically distinct from other AVSC species, heterothallic and produces a unique array of extrolites, including the UV spectrum characterized compounds DOLD, RAIMO and CALBO. Shared morphological and physiological characteristics with other AVSC species include slow sporulation, optimal growth at, ÊC, no growth at, ÊC, and viriditoxin production. Overall, the risk of environmental exposure to pathogenic species in ASF in Australia appears to be high, but there was no evidence of direct environmental exposure to AVSC species in areas where humans and cats cohabitate.Jessica J. Talbot, Jos Houbraken, Jens C. Frisvad, Robert A. Samson, Sarah E. Kidd, John Pitt, Sue Lindsay, Julia A. Beatty, Vanessa R. Barr

    Computed tomographic features of feline sino-nasal and sino-orbital aspergillosis

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    Feline upper respiratory tract aspergillosis (URTA) occurs as two distinct anatomic forms, sinonasal aspergillosis (SNA) and sino-orbital aspergillosis (SOA). An emerging pathogen, Aspergillus felis is frequently involved. The pathogenesis of URTA, in particular, the relationship between the infecting isolate and outcome, is poorly understood. Computed tomography was used to investigate the route of fungal infection and extension in 16 cases (SNA n=7, SOA n=9) where the infecting isolate had been identified by molecular testing. All cases had nasal cavity involvement except one cat with SNA that had unilateral frontal sinus changes. A strong association between the infecting species and anatomic form was identified. A. fumigatus infections remained within the sino-nasal cavity. Cryptic species infections were associated with orbital and paranasal soft-tissue involvement and with orbital lysis. These species were further associated with a mass in the nasal cavity, paranasal sinuses or nasopharynx. Orbital masses showed heterogeneous contrast enhancement, with central coalescing hypoattenuating foci and peripheral rim enhancement. Severe, cavitated turbinate lysis, typical of canine SNA, was present only in cats with SNA. These findings support that the nasal cavity is the portal of entry for fungal spores in feline URTA and that the route of extension to involve the orbit is via direct naso-orbital communication from bone lysis. Additionally, a pathogenic role for A. wyomingensis and a sinolith in a cat with A. udagawae infection are reported for the first time. Keywords: Aspergillus felis; Aspergillosis; Cats; Sino-nasal; Sino-orbita

    Computed tomographic features of feline sino-nasal and sino-orbital aspergillosis

    Get PDF
    Feline upper respiratory tract aspergillosis (URTA) occurs as two distinct anatomic forms, sinonasal aspergillosis (SNA) and sino-orbital aspergillosis (SOA). An emerging pathogen, Aspergillus felis is frequently involved. The pathogenesis of URTA, in particular, the relationship between the infecting isolate and outcome, is poorly understood. Computed tomography was used to investigate the route of fungal infection and extension in 16 cases (SNA n=7, SOA n=9) where the infecting isolate had been identified by molecular testing. All cases had nasal cavity involvement except one cat with SNA that had unilateral frontal sinus changes. A strong association between the infecting species and anatomic form was identified. A. fumigatus infections remained within the sino-nasal cavity. Cryptic species infections were associated with orbital and paranasal soft-tissue involvement and with orbital lysis. These species were further associated with a mass in the nasal cavity, paranasal sinuses or nasopharynx. Orbital masses showed heterogeneous contrast enhancement, with central coalescing hypoattenuating foci and peripheral rim enhancement. Severe, cavitated turbinate lysis, typical of canine SNA, was present only in cats with SNA. These findings support that the nasal cavity is the portal of entry for fungal spores in feline URTA and that the route of extension to involve the orbit is via direct naso-orbital communication from bone lysis. Additionally, a pathogenic role for A. wyomingensis and a sinolith in a cat with A. udagawae infection are reported for the first time. Keywords: Aspergillus felis; Aspergillosis; Cats; Sino-nasal; Sino-orbita

    Feline parvovirus seroprevalence is high in domestic cats from disease outbreak and non-outbreak regions in Australia

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    Multiple, epizootic outbreaks of feline panleukopenia (FPL) caused by feline parvovirus (FPV) occurred in eastern Australia between 2014 and 2018. Most affected cats were unvaccinated. We hypothesised that low population immunity was a major driver of re-emergent FPL. The aim of this study was to (i) determine the prevalence and predictors of seroprotective titres to FPV among shelter-housed and owned cats, and (ii) compare the prevalence of seroprotection between a region affected and unaffected by FPL outbreaks. FPV antibodies were detected by haemagglutination inhibition assay on sera from 523 cats and titres ≄1:40 were considered protective. Socioeconomic indices based on postcode and census data were included in the risk factor analysis. The prevalence of protective FPV antibody titres was high overall (94.3%), even though only 42% of cats were known to be vaccinated, and was not significantly different between outbreak and non-outbreak regions. On multivariable logistic regression analysis vaccinated cats were 29.94 times more likely to have protective FPV titres than cats not known to be vaccinated. Cats from postcodes of relatively less socioeconomic disadvantage were 5.93 times more likely to have protective FPV titres. The predictors identified for FPV seroprotective titres indicate targeted vaccination strategies in regions of socioeconomic disadvantage would be beneficial to increase population immunity. The critical level of vaccine coverage required to halt FPV transmission and prevent FPL outbreaks should be determined

    Detecting a stochastic gravitational wave background with the Laser Interferometer Space Antenna

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    The random superposition of many weak sources will produce a stochastic background of gravitational waves that may dominate the response of the LISA (Laser Interferometer Space Antenna) gravitational wave observatory. Unless something can be done to distinguish between a stochastic background and detector noise, the two will combine to form an effective noise floor for the detector. Two methods have been proposed to solve this problem. The first is to cross-correlate the output of two independent interferometers. The second is an ingenious scheme for monitoring the instrument noise by operating LISA as a Sagnac interferometer. Here we derive the optimal orbital alignment for cross-correlating a pair of LISA detectors, and provide the first analytic derivation of the Sagnac sensitivity curve.Comment: 9 pages, 11 figures. Significant changes to the noise estimate

    Influence of thermally induced chemorheological changes on the torsion of elastomeric circular cylinders

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    When an elastomeric material is deformed and subjected to temperatures above some characteristic value T cr (near 100 ∘ C for natural rubber), its macromolecular structure undergoes time and temperature-dependent chemical changes. The process continues until the temperature decreases below T cr . Compared to the virgin material, the new material system has modified properties (reduced stiffness) and permanent set on removal of the applied load.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46097/1/161_2006_Article_9.pd

    An improved method for measuring muon energy using the truncated mean of dE/dx

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    The measurement of muon energy is critical for many analyses in large Cherenkov detectors, particularly those that involve separating extraterrestrial neutrinos from the atmospheric neutrino background. Muon energy has traditionally been determined by measuring the specific energy loss (dE/dx) along the muon's path and relating the dE/dx to the muon energy. Because high-energy muons (E_mu > 1 TeV) lose energy randomly, the spread in dE/dx values is quite large, leading to a typical energy resolution of 0.29 in log10(E_mu) for a muon observed over a 1 km path length in the IceCube detector. In this paper, we present an improved method that uses a truncated mean and other techniques to determine the muon energy. The muon track is divided into separate segments with individual dE/dx values. The elimination of segments with the highest dE/dx results in an overall dE/dx that is more closely correlated to the muon energy. This method results in an energy resolution of 0.22 in log10(E_mu), which gives a 26% improvement. This technique is applicable to any large water or ice detector and potentially to large scintillator or liquid argon detectors.Comment: 12 pages, 16 figure
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