D2.540 - Nationwide Analysis of Domestic Mites in Germany

House dust mites (HDM) and storage mites (SM) are among the most important triggers of IgE-mediated indoor allergies. For a long time, it was assumed that SM only occurred in rural areas, but their presence in urban households is now also recognized. Since SM rarely cross-react with HDM or with each other, separate diagnostics and therapy are necessary. Until now, there has been no overview of the occurrence of different mite species in German federal states. The aim of this study was, on the one hand, to record the domestic mite fauna in Germany. On the other hand, through the analysis of dust samples from various altitudes, the influence of abiotic factors on mite populations was to be investigated.

Between 2006 and 2009, 2,554 dust samples were collected from mattresses of volunteers from all German federal states. Additionally, between July 2008 and June 2009, samples were taken from mattresses and upholstered furniture in accommodations located at various altitudes in the Alpine foothills. The samples were examined microscopically for various species of HDM and SM to provide an overview of the distribution of allergologically significant species.

The HDM species Dermatophagoides pteronyssinus and Dermatophagoides farinae were identified nationwide in about 50% of the dust samples. The HDM Euroglyphus maynei was scarcely represented in the north. In contrast to HDM, SM showed significant regional differences: While Glycyphagus domesticus was found in dust samples from all federal states, Acarus siro was detected exclusively in Thuringia and Rhineland-Palatinate. Tyrophagus putrescentiae was found in all federal states except Thuringia, and Lepidoglyphus destructor in all except Berlin-Brandenburg. The proportion of positive dust samples decreased with increasing altitude; nevertheless, Dermatophagoides species could still be detected on the Zugspitze at 2,964 meters.

In addition to the ubiquitous HDM, several allergologically relevant SM were also detected in house dust from all federal states. To our knowledge, this is the first investigation of analyzing house dust samples across the entire federal territory regarding mite populations. The assumption that mites cannot survive at 2,000 meters altitude was not confirmed by this analysis. The results help to refine the diagnosis and treatment of mite allergy and can serve as a reference for future studies.