• How the Chagas pathogen changes the inte

    From ScienceDaily@1:317/3 to All on Mon Mar 21 22:30:46 2022
    How the Chagas pathogen changes the intestinal microbiota of predatory
    bugs
    Fundamental research for novel approaches for the control of Trypanosoma parasites

    Date:
    March 21, 2022
    Source:
    Goethe University Frankfurt
    Summary:
    In Central and South America, predatory blood-sucking bugs transmit
    the causative agent of the widely prevalent Chagas disease. As
    the disease can induce severe symptoms and to date there is no
    vaccine against the Trypanosoma parasites, the main approach
    at present is to control the bug using insecticides. A research
    team has now studied how trypanosomes change the bug's intestinal
    microbiota. The long-term goal: to change the bacterial community
    in the predatory bug's intestine in such a way that it can defend
    itself against the trypanosomes.



    FULL STORY ========================================================================== According to estimates by the World Health Organization (WHO),
    between six and seven million people worldwide, predominantly in
    Central and South America, are infected with the Trypanosoma cruzi
    species of trypanosome. This single-celled (protozoan) parasite causes
    Chagas disease (American trypanosomiasis), which in the acute phase is inconspicuous: only in every third case does the infected person develop
    any symptoms at all, which can then be unspecific, such as fever, hives
    and swollen lymph nodes. However, the parasites remain in the body,
    and many years later chronic Chagas disease can become life-threatening,
    with pathological enlargement of the heart and progressive paralysis of
    the gastrointestinal tract.


    ========================================================================== There is no vaccine against the pathogen and treating the disease in the advanced stage is difficult. That is why the focus in Latin America is
    rather on controlling the bug that transmits Chagas trypanosomes: the
    predatory blood- sucking bug of the insect subfamily Triatominae. It
    ingests the trypanosomes during the sting, which then colonize its
    intestine. Through its faeces that it mostly deposited next to the bite,
    the bug excretes the pathogen, which is often rubbed into the wound when scratching the extremely itchy bite.

    Although the number of new infections has dropped in various regions where insecticides are sprayed on a wide scale, problems are emerging: over
    the last decade, resistance to common insecticides by several species
    of predatory bugs has been increasingly observed. These insecticides
    also have a negative impact on the environment and the local population.

    Researchers worldwide are making intense efforts to find alternative
    methods to help control Trypanosoma cruzi. One possibility might be to
    modify bacteria in the predatory bug's intestine in such a way that they eliminate the Chagas trypanosomes or inhibit their development.

    In collaboration with scientists at the Instituto Rene' Rachou in Belo Horizonte, Brazil, parasitologists and infection biologists Fanny Eberhard
    and Professor Sven Klimpel from Goethe University, the Senckenberg --
    Leibniz Institution for Biodiversity and Earth System Research (SGN)
    and the LOEWE Centre for Translational Biodiversity Genomics have now investigated how Chagas trypanosomes change the bacterial community in
    the predatory bug's intestine.

    To do so, they used genome analysis, which allowed them to compare
    the composition of the bacterial community in the bug's intestine, the microbiome, before and after infection with the pathogen (metagenomic
    shotgun sequencing).

    The result: after the infection, the range of bacterial strains in the
    bug's intestine significantly decreased. Certain strains, including the potentially pathogenic bacterium Enterococcus faecalis, profited from the parasites' presence. Moreover, the researchers succeeded in identifying
    four bacterial species that probably take on functions important for
    the bug, such as the synthesis of B vitamins.

    Fanny Eberhard explains: "Vitamin B is one of the nutrients that
    blood-sucking insects do not obtain through their blood meals. Bacteria
    that produce vitamin B are therefore very important for the bug, are
    found in practically all individuals and stay in the predatory bug's
    intestine even across generations.

    Hence, such bacteria are potentially suitable recipients for genes that
    produce defensive substances against Chagas trypanosomes." Professor Sven Klimpel elaborates: "Ultimately, our goal is for the predatory bug to
    defend itself against Chagas trypanosomes and, in this way, to prevent infection in humans. However, before we can produce bacteria with such properties and then release predatory bugs containing them, we need to understand better how the ecology of the bug's intestine is structured
    and how the extensive interactions between host, pathogen and microbiome function. Our work is delivering an essential contribution to this."

    ========================================================================== Story Source: Materials provided by Goethe_University_Frankfurt. Note:
    Content may be edited for style and length.


    ========================================================================== Journal Reference:
    1. Fanny E. Eberhard, Sven Klimpel, Alessandra A. Guarneri, Nicholas J.

    Tobias. Exposure to Trypanosoma parasites induces changes
    in the microbiome of the Chagas disease vector Rhodnius
    prolixus. Microbiome, 2022; 10 (1) DOI: 10.1186/s40168-022-01240-z ==========================================================================

    Link to news story: https://www.sciencedaily.com/releases/2022/03/220321132131.htm

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