66 research outputs found

    Knock-on community impacts of a novel vector: spillover of emerging DWV-B from Varroa-infested honeybees to wild bumblebees.

    Get PDF
    This is the final version. Available from the publisher via the DOI in this record.The Sanger sequences that support the findings of this study have been deposited in GenBank with virus accession codes MG264907‐MG265503 and Nosema accession codes MK942707‐MK942712; SMRT reads have been archived in NCBI's Sequence Read Archive with BioProject accession number PRJNA542789. Prevalence and qPCR data that support the findings will be available from the Dryad Digital Repository: https://doi.org/10.5061/dryad.70jt240.Novel transmission routes can directly impact the evolutionary ecology of infectious diseases, with potentially dramatic effect on host populations and knock-on effects on the wider host community. The invasion of Varroa destructor, an ectoparasitic viral vector in Western honeybees, provides a unique opportunity to examine how a novel vector affects disease epidemiology in a host community. This specialist honeybee mite vectors deformed wing virus (DWV), an important re-emerging honeybee pathogen that also infects wild bumblebees. Comparing island honeybee and wild bumblebee populations with and without V. destructor, we show that V. destructor drives DWV prevalence and titre in honeybees and sympatric bumblebees. Viral genotypes are shared across hosts, with the potentially more virulent DWV-B overtaking DWV-A in prevalence in a current epidemic. This demonstrates disease emergence across a host community driven by the acquisition of a specialist novel transmission route in one host, with dramatic community level knock-on effects

    Thermally activated composite with two-way and multi-shape memory effects

    Get PDF
    The use of shape memory polymer composites is growing rapidly in smart structure applications. In this work, an active asymmetric composite called “controlled behavior composite material (CBCM)” is used as shape memory polymer composite. The programming and the corresponding initial fixity of the composite structure is obtained during a bending test, by heating CBCM above thermal glass transition temperature of the used Epoxy polymer. The shape memory properties of these composites are investigated by a bending test. Three types of recoveries are conducted, two classical recovery tests: unconstrained recovery and constrained recovery, and a new test of partial recovery under load. During recovery, high recovery displacement and force are produced that enables the composite to perform strong two-way actuations along with multi-shape memory effect. The recovery force confirms full recovery with two-way actuation even under a high load. This unique property of CBCM is characterized by the recovered mechanical wor

    Influence du mode de polymérisation de composites verre/polyester sur leur comportement mécanique

    Get PDF
    L’objet de cette communication est d’analyser les propriĂ©tĂ©s mĂ©caniques de composites unidirectionnels verre/polyester obtenus par deux procĂ©dĂ©s diffĂ©rents de polymĂ©risation : un procĂ©dĂ© conventionnel thermique et un procĂ©dĂ© photochimique. Les propriĂ©tĂ©s mĂ©caniques de surface ont Ă©tĂ© Ă©tudiĂ©es par micro-indentation afin d’observer l’influence des conditions d’élaboration sur la rĂ©ponse du composite Ă  une pĂ©nĂ©tration. Il apparait que la duretĂ© d’indentation HIT et le taux de conversion de la rĂ©sine ne sont pas suffisants pour discriminer les Ă©chantillons. Les propriĂ©tĂ©s d’élasticitĂ© et de fluage sont Ă©galement nĂ©cessaires pour comparer et comprendre le comportement des diffĂ©rents composites. Le procĂ©dĂ© de photopolymĂ©risation de la rĂ©sine amĂ©liore les propriĂ©tĂ©s mĂ©caniques du composite ainsi Ă©laborĂ©

    Digital behavioural signatures reveal trans-diagnostic clusters of schizophrenia and Alzheimer's disease patients

    Get PDF
    The current neuropsychiatric nosological categories underlie pragmatic treatment choice, regulation and clinical research but does not encompass biological rationale. However, subgroups of patients suffering from schizophrenia or Alzheimer's disease have more in common than the neuropsychiatric nature of their condition, such as the expression of social dysfunction. The PRISM project presents here initial quantitative biological insights allowing the first steps toward a novel trans-diagnostic classification of psychiatric and neurological symptomatology intended to reinvigorate drug discovery in this area. In this study, we applied spectral clustering on digital behavioural endpoints derived from passive smartphone monitoring data in a subgroup of Schizophrenia and Alzheimer's disease patients, as well as age matched healthy controls, as part of the PRISM clinical study. This analysis provided an objective social functioning characterization with three differential clusters that transcended initial diagnostic classification and was shown to be linked to quantitative neurobiological parameters assessed. This emerging quantitative framework will both offer new ways to classify individuals in biologically homogenous clusters irrespective of their initial diagnosis, and also offer insights into the pathophysiological mechanisms underlying these clusters.</p

    Nodular Worm Infection in Wild Chimpanzees in Western Uganda: A Risk for Human Health?

    Get PDF
    This study focused on Oeosophagostomum sp., and more especially on O. bifurcum, as a parasite that can be lethal to humans and is widespread among humans and monkeys in endemic regions, but has not yet been documented in apes. Its epidemiology and the role played by non-human primates in its transmission are still poorly understood. O. stephanostomum was the only species diagnosed so far in chimpanzees. Until recently, O. bifurcum was assumed to have a high zoonotic potential, but recent findings tend to demonstrate that O. bifurcum of non-human primates and humans might be genetically distinct. As the closest relative to human beings, and a species living in spatial proximity to humans in the field site studied, Pan troglodytes is thus an interesting host to investigate. Recently, a role for chimpanzees in the emergence of HIV and malaria in humans has been documented. In the framework of our long-term health monitoring of wild chimpanzees from Kibale National Park in Western Uganda, we analysed 311 samples of faeces. Coproscopy revealed that high-ranking males are more infected than other individuals. These chimpanzees are also the more frequent crop-raiders. Results from PCR assays conducted on larvae and dried faeces also revealed that O. stephanostomum as well as O. bifurcum are infecting chimpanzees, both species co-existing in the same individuals. Because contacts between humans and great apes are increasing with ecotourism and forest fragmentation in areas of high population density, this paper emphasizes that the presence of potential zoonotic parasites should be viewed as a major concern for public health. Investigations of the parasite status of people living around the park or working inside as well as sympatric non-human primates should be planned, and further research might reveal this as a promising aspect of efforts to reinforce measures against crop-raiding

    Detection of Babesia divergens in southern Norway by using an immunofluorescence antibody test in cow sera

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>The incidence of bovine babesiosis, caused by <it>Babesia divergens </it>(Apicomplexa: Piroplasmida) has decreased markedly since the 1930 s, but may re-emerge as a consequence of climate change and changes in legislation and pasturing practices. This is a potentially serious disease, with both economical and animal welfare consequences. Therefore, there is a need to survey the distribution of <it>B. divergens</it>.</p> <p>Methods</p> <p>We tested sera from 306 healthy pastured cows from 24 farms along the southern Norwegian coast by using an indirect immunofluorescence IgG antibody test (IFAT). Fractions of seropositive cows were compared by calculating 95% CI.</p> <p>Results</p> <p>The results of this test showed that 27% of the sera were positive for <it>B. divergens </it>antibodies. The fraction of antibody-positive sera that we detected showed a two-humped distribution, with a high fraction of positives being found in municipalities in the western and eastern parts of the study area, while the municipalities between these areas had few or no positive serum samples.</p> <p>Conclusions</p> <p>Neither the farmers' observations nor the Norwegian Dairy Herd Recording System give an adequate picture of the distribution of bovine babesiosis. Serological testing of cows by using IFAT is a convenient way of screening for the presence of <it>B. divergens </it>in an area.</p
    • 

    corecore