Pathogens as potential hitchhikers on intercontinental dust

Article Article scientifique Article Pathogens as potential hitchhikers on intercontinental dust eng 2012 author Toepfer Ilka author Favet Jocelyne Louise 24703 author Schulte Anette author Schmölling Maria author Butte Werner author Triplett Eric W. author Broughton William John 22724 author Gorbushina Anna 669621 221-231 10.1007/s10453-011-9230-2 0393-5965 Desert dust seeds distant lands and waters with minerals as well as micro-organisms raising the question of whether this ancient phenomenon also spreads pathogens across the globe. Severe dust storms require strong winds blowing over land-masses that are largely devoid of vegetation, effectively limiting the scope for winds to raise pathogens into the air. Nevertheless, changing patterns of land-use, often driven by belligerency, result in refugees spreading to areas that were previously deemed barely habitable. With the help of the International Committee of the Red Cross, a number of sand/dust samples were collected from the Republic of Chad, some near refugee camps, others further removed from human influence. In parallel studies, we documented the micro-organisms present in these samples and used a number of the isolates here to test the effect of environmental constraints on their ability to survive intercontinental flight. We also added traditional pathogens to the palette of microbes and tested the effects of UV irradiation, desiccation and temperature on survival of both bacteria and fungi. A clear trend was obvious—those microbes that are coloured or able to form conidia or spores (in other words, those that are native to deserts) were well able to resist the imposed stresses. On the other hand, most pathogens were more sensitive to stresses than the environmental isolates. Toxin production in two species of Aspergillus was also investigated. Short-term desiccation (simulating environmental conditions during intercontinental travel) of sand amended with fungal spores containing sterigmatocystin leads to increased mycotoxin contents, but significant mycotoxin production was only possible under growth-permissive conditions, e.g. at higher humidity. It thus seems likely that an ever-decreasing fraction of the initial pathogen load survives as the dust recedes from its desert source and that those organisms that land on other continents are highly enriched in desert dwellers. Dewey 580 Open Access - Licence nationale Springer 45 Département des sciences végétales 163 false Aerobiologia 28 2 ce5287c0-d51d-46eb-aacf-454c66e656c9 Article (Published version) Public Toepfer2012_Article_PathogensAsPotentialHitchhiker.pdf 890088 application/pdf openAccess Faculté des sciences / Section de biologie / Département des sciences végétales

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Pathogens as potential hitchhikers on intercontinental dust	Aerobiologia			2012	458	437

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Gorbushina, Anna