Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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    Early pathogenesis of wesselsbron disease in pregnant ewes
    Oymans, Judith ; Keulen, Lucien van; Wichgers Schreur, Paul J. ; Kortekaas, Jeroen - \ 2020
    Pathogens 9 (2020)5. - ISSN 2076-0817
    Flavivirus - Immunohistochemistry - Neuroinvasion - Pregnant ewes - Vertical transmission - Wesselsbron virus

    Wesselsbron virus (WSLV) is a neglected, mosquito-borne flavivirus that is endemic to the African continent. The virus is teratogenic to ruminants and causes a self-limiting febrile illness in humans. Wesselsbron disease manifests with similar clinical signs and occurs in the same areas under the same climatic conditions as Rift Valley fever, which is therefore included in the differential diagnosis. Although the gross pathology of WSLV infection in pregnant ewes is reported in literature, the pathogenesis that leads to stillbirths, congenital malformations and abortion has remained undescribed. In the present study, pregnant ewes were inoculated with WSLV and subjected to detailed clinical- and histopathology 8 days later. The virus was mainly detected in foetal trophoblasts of the placenta and in neural progenitor cells, differentiated neurons, oligodendrocytes, microglia and astrocytes. Our study demonstrates that WSLV efficiently crosses the maternal–foetal interface and is highly neuroinvasive in the ovine foetus.

    The vertical transmission of antibiotic residues from parent hens to broilers
    Jansen, Larissa J.M. ; Berentsen, Ron J. ; Arends, Maura ; Berendsen, Bjorn J.A. - \ 2020
    Food Additives & Contaminants. Pt. A, Chemistry, Analysis, Control, Exposure & Risk Assessment 37 (2020)5. - ISSN 1944-0049 - p. 783 - 792.
    antibiotics - egg - feather - LC-MS - Vertical transmission

    Imprudent and superfluous use of antibiotics contributes to the selection of resistant bacteria, which is a large threat to human health. Therefore analytical procedures have been implemented in the poultry production sector to check if antibiotic treatments are registered, aiming to achieve more prudent use of antibiotics. These methods rely on the analysis of feathers, a matrix in which antibiotic residues persist. However, other routes besides direct administration, through which poultry feathers could contain antibiotic residues, should also be taken into account. In this research the vertical transmission from parent hen to broiler was investigated through a controlled animal study for the antibiotics enrofloxacin, doxycycline and sulfachlorpyridazine. Vertical transmission was observed for all antibiotics to both egg and egg shell. Also it is demonstrated that the transferred antibiotics from parent hen to chick are subsequently excreted via the chick’s droppings. Through this route, the broilers’ environment is contaminated. If eggs are hatched that were taken during treatment of the parent hen, this indirect route and/or the direct vertical transmission can eventually result in the detection of low concentrations of antibiotic residues in the broilers’ feathers at greater age: <50 µg kg−1 for freely extractable residues and <10 µg kg−1 for non-freely extractable residues. No antibiotics were detected in the broilers’ muscle or kidney from 4 weeks of age. This research provides relevant information regarding the possible amount of residues originating from vertical transmission when monitoring matrices such as feathers and broiler droppings in order to stimulate correct use and registration of antibiotics in the poultry sector.

    Elucidating transmission patterns of endemic Mycobacterium avium subsp. paratuberculosis using molecular epidemiology
    Mitchell, Rebecca M. ; Beaver, Annabelle ; Knupfer, Elena ; Pradhan, Abani K. ; Fyock, Terry ; Whitlock, Robert H. ; Schukken, Ynte H. - \ 2019
    Veterinary Sciences 6 (2019)1. - ISSN 2306-7381
    MLSSR typing - Mutation rate - Mycobacterial co-infections - Mycobacterium avium subsp. paratuberculosis (MAP) - Vertical transmission - Within-host evolution

    Mycobacterial diseases are persistent and characterized by lengthy latent periods. Thus, epidemiological models require careful delineation of transmission routes. Understanding transmission routes will improve the quality and success of control programs. We aimed to study the infection dynamics of Mycobacterium avium subsp. paratuberculosis (MAP), the causal agent of ruminant Johne's disease, and to distinguish within-host mutation from individual transmission events in a longitudinally MAP-defined dairy herd in upstate New York. To this end, semi-annual fecal samples were obtained from a single dairy herd over the course of seven years, in addition to tissue samples from a selection of culled animals. All samples were cultured for MAP, and multi-locus short-sequence repeat (MLSSR) typing was used to determine MAP SSR types. We concluded from these precise MAP infection data that, when the tissue burden remains low, the majority of MAP infections are not detectable by routine fecal culture but will be identified when tissue culture is performed after slaughter. Additionally, we determined that in this herd vertical infection played only a minor role in MAP transmission. By means of extensive and precise longitudinal data from a single dairy herd, we have come to new insights regarding MAP co-infections and within-host evolution.

    Low intraspecific genetic diversity indicates asexuality and vertical transmission in the fungal cultivars of ambrosia beetles
    Peppel, L.J.J. van de; Aanen, D.K. ; Biedermann, P.H.W. - \ 2018
    Fungal Ecology 32 (2018). - ISSN 1754-5048 - p. 57 - 64.
    Ambrosia fungus - Ambrosiella - Anisandrus - Asexuality - Clonal fungiculture - Genetic diversity - Symbiosis - Vertical transmission - Xylosandrus
    Ambrosia beetles farm ascomycetous fungi in tunnels within wood. These ambrosia fungi are regarded asexual, although population genetic proof is missing. Here we explored the intraspecific genetic diversity of Ambrosiella grosmanniae and Ambrosiella hartigii (Ascomycota: Microascales), the mutualists of the beetles Xylosandrus germanus and Anisandrus dispar. By sequencing five markers (ITS, LSU, TEF1α RPB2, β-tubulin) from several fungal strains, we show that X. germanus cultivates the same two clones of A. grosmanniae in the USA and in Europe, whereas A. dispar is associated with a single A. hartigii clone across Europe. This low genetic diversity is consistent with predominantly asexual vertical transmission of Ambrosiella cultivars between beetle generations. This clonal agriculture is a remarkable case of convergence with fungus-farming ants, given that both groups have a completely different ecology and evolutionary history.
    Dispersion and colonization by fungus-growing termites : Vertical transmission of the symbiont helps, but then...?
    Nobre, Tânia ; Aanen, Durr K. - \ 2010
    Communicative and Integrative Biology 3 (2010)3. - p. 248 - 250.
    Long-distance dispersal - Microtermes - Mutualism - Symbiont transmission mode - Termitomyces - Vertical transmission

    The fungus-growing termites (Macrotermitinae) have developed an obligate mutualistic symbiosis with fungi (Termitomyces) and, in most cases, the symbiotic partner is collected from the environment upon establishment of a new colony (horizontal transmission). The requirement that partners are able to find and recognize each other af this hypothesis, we have recently shown that a single colonisation of Madagascar by fungus-growter independent reproduction is likely to severely constrain long distance dispersal. In support ofing termites has occurred. The successful colonizers belong to the genus Microtermes, known to inherit their symbiont from the parental colony (vertical transmission). However, the fungal symbionts of Madagascar were not monophyletic, as expected under strict vertical transmission. Here we further discuss these findings, and we suggest further bottlenecks to dispersion and propose a transient window for horizontal transmission for the otherwise vertically transmitted Termitomyces strains.

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