One of the more important etiological factors of allergies are mites occuring in the closest vicinity of humans, i.e. in the house dust and in the stored foodstuffs. The most important are the species representing the families: Pyroglyphidae (mainly Dermatophagoides pteronyssinus, D. farinae, and Euroglyphus maynei), Glycyphagidae (e.g. Lepidoglyphus destructor, Blomia sp.), and Acaridae (e.g. Tyrophagus putrescentiae, Acarus siro). Mites shed an abundance of allergenic proteins. Particularly abundant in allergens are the extracts of mite faeces as well as the extracts of their purified bodies or culture substrate. In humans the may inflict atopic allergies (respiratory and dermal), such as bronchial asthma, rhinitis, or atopic eczema. It has been estimated that some 5% of the human population is sensitive to dust mites allergens.