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Bacterial and fungal agents in house dust and wheeze in children: the PARSIFAL study


  • PARSIFAL (Prevention of allergy – Risk factors for sensitization in children related to farming and anthroposophic lifestyle) study group: Göran Pershagen, Tobias Alfvén, Johan Alm, Anna Bergström, Lars Engstrand, Helen Flöistrup, Marianne van Hage, Niclas Håkansson, Gunnar Lilja, Fredrik Nyberg, Annika Scheynius, Helena Svensson, Jackie Swartz, Magnus Wickman (Sweden); Charlotte Braun-Fahrländer, Marco Waser, Felix Sennhauser, Roger Lauener, Johannes Wildhaber, Alex Möller (Switzerland); Bert Brunekreef, Dieneke Schram-Bijkerk, Gert Doekes, Mirian Boeve, Jeroen Douwes, Machteld Huber, Mirjam Matze (the Netherlands); Erika von Mutius, Marcus Benz, Jörg Budde, Markus Ege (Germany); and Josef Riedler, Waltraud Eder, Ellen Üblagger, Gertraud Weiss, Mynda Schreuer (Austria), Karin Michels (USA).

Dieneke Schram-Bijkerk, Institute for Risk Assessment Sciences, University of Utrecht, PO Box 80176, 3508 TD Utrecht, The Netherlands.


Background Growing up on a farm and an anthroposophic lifestyle are associated with a lower prevalence of allergic diseases in childhood. This might be related to increased inhalatory exposure to microbial agents.

Objective To assess the association between microbial agents in house dust and atopic wheeze in farm children, Steiner school children and reference children.

Methods Levels of bacterial endotoxin, fungal β(1,3)-glucans and fungal extracellular polysaccharides (EPS) in mattress and living room floor dust were measured in a population of 270 atopic (=Phadiatop-positive) children with self-reported wheezing, including 168 current atopic wheezers, and 441 non-atopic, non-symptomatic controls. These children were selected from a cross-sectional study in five European countries.

Results In the study population as a whole, average levels of mattress dust endotoxin, EPS and glucans were slightly (1.1–1.2-fold; P<0.10) higher in control children than in atopic wheezers. Atopic wheeze was related to mattress levels of endotoxin, EPS and glucans in farm and farm-reference children. However, when adjusting for group (farm vs. farm-reference children), the associations became non-significant whereas the group effect remained. No associations between atopic wheeze and microbial agents were observed in Steiner and Steiner-reference children. For current atopic wheeze, the farm effect became non-significant after adjustment for microbial agent levels.

Conclusion Not only bacterial endotoxin but also mould components might offer some protection against atopic wheeze in children. However, the protective effect of being raised on a farm was largely unexplained by the mattress microbial agent levels measured in this study.

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