Dermatophagoides pteronyssinus (Trouessart, 1897) in mattress and floor dust in a temperate climate (Acari : Pyroglyphidae)

The arthropod fauna of mattress dust, bedroom dust and living-room dust was sampled during a 1-year period in a center for asthmatic children (near Nijmegen, The Netherlands) with the aid of a vacuum cleaner, Berlese funnels and a flotation method. Dermatophagoides pteronyssinus was most abundant; Psychodinae, Cheyletidae and Gamasina were present in numbers high enough to allow ecological consideration. Separate counts were made for living and dead specimens. Populations of D. pteronyssinus were detected throughout the year only in mattresses. In June-July the infestation spread to the bedroom floors where the mieroclimate was then suitable for development; this population died out in October. Livingroom floors were not infested due to the unsuitable microclimate, the absence of food and the distance from the bedrooms. There was a strong correlation between the weather (outdoors and indoors) and the numbers and distribution of D. pteronyssinus within the home. Microorganisms and fibers of plant origin (most likely from the cotton bed sheets) were found frequently in the alimentary canal of these mites. As a site for control of pyroglyphidinfestations in the environment of house dust atopies, mattresses are much more important than living-room floors which have been sampled most frequently in other studies.