title: Distribution of house dust mite allergen: comparing house dust mite allergen levels in dust samples collected from different sites on living room floors with smooth coverings.
abstract: BACKGROUND
  The distribution of house dust mite allergen (Der p1) in living rooms with smooth floor coverings, as measured in the middle compared with the border of the floor was investigated. It was hypothesized that activity causes displacement of Der p1, from the middle towards the border.
  
  
  METHODS
  Dust samples from the middle and border of 50 floors with smooth coverings were collected and analysed on Der p1 content in a standardized way.
  
  
  RESULTS
  The Der p1 exposure expressed as per unit area (ng/m2) showed that border samples contained significantly more Der p1 compared with middle samples (median: 2.57 vs 0.27, respectively, P = 0.023). Presence of pets and presence of more than two inhabitants increased the difference. When expressed as per unit weight of dust (ng/g), significant differences were only detected when comparing Der p1 content of samples collected in households with three or more inhabitants [median: 2 (border) vs 53 (middle), respectively; P = 0.035].
  
  
  CONCLUSIONS
  The Der p1 is unequally distributed on living room floors with smooth coverings, most likely because of displacement of dust from the middle towards the border due to activity. Expression as ng/g of dust and ng/m2 could not obviously be interchangeable.
authors.affiliation: Department of General Practice, Maastricht University, The Netherlands.
authors.forename: T
authors.initials: T
authors.lastname: Maas
authors.forename: J J M
authors.initials: JJ
authors.lastname: Rovers
authors.forename: H J A M
authors.initials: HJ
authors.lastname: Schönberger
authors.forename: C P
authors.initials: CP
authors.lastname: Schayck
mesh_terms: D000818:Animals; D039741:Antigens, Dermatophagoides / Q000032:analysis*; D060829:Arthropod Proteins; D003546:Cysteine Endopeptidases; D004391:Dust / Q000032:analysis*; D005430:Floors and Floorcoverings; D008925:Mites / Q000276:immunology*
chemical_list: D039741:Antigens, Dermatophagoides; D060829:Arthropod Proteins; D004391:Dust; D003546:Cysteine Endopeptidases; C451162:Dermatophagoides pteronyssinus antigen p 1