Domestic mites and their whereabouts in Germany

Background: Domestic mites, i.e. house dust mites (HDM) and storage mites (SM), which cause an IgE-mediated reaction, are a major cause of indoor allergies. For a long time, SM were thought to be restricted to rural areas; however, they can also be found in urban dwellings. Given that SM exhibit minimal cross-reactivity with HDM and among different SM species, these mite species should be diagnosed and treated separately. To date, there is no overview of which mite species occur in which areas of Germany. The aim of this study was therefore to investigate the indoor acarofauna in Germany, especially allergologically relevant HDM and SM. Methods: Between 2006 and 2009, 2554 dust samples were collected from volunteers in all German federal states at different times of the year. Samples from mattresses were microscopically analysed for various species of HDM and SM to provide an overview of the prevalence of allergologically relevant species for each federal state. Results: The HDM species Dermatophagoides pteronyssinus and Dermatophagoides farinae were most common throughout Germany, whereas the abundance of SM species such as Lepidoglyphus destructor and Tyrophagus putrescentiae varied regionally. Little or no seasonal variation in mite populations was observed. Conclusion: In addition to the ubiquitous HDM, some allergologically relevant SM were found in house dust from all federal states. To our knowledge, this is the first study to analyse house dust samples for mite populations throughout Germany. The results help to specify the diagnosis of mite allergy and can be used as a reference for future analyses.