title: School as a risk environment for children allergic to cats and a site for transfer of cat allergen to homes.
abstract: BACKGROUND
  Many children are allergic to furred pets and avoid direct pet contact. The school may be a site of indirect exposure to pet allergens, which may induce or maintain symptoms of allergic diseases.
  
  
  OBJECTIVE
  We sought to investigate airborne levels of cat allergen (Fel d 1) at schools and in homes with or without cats and to study clothes as a route for dissemination of allergens between homes and school.
  
  
  METHODS
  Airborne cat allergen was collected with personal samplers from (1) children attending classes with many (>25%) or few (<10%) cat owners and (2) homes with or without cats. A recently developed amplified ELISA assay, which detects low levels of airborne cat allergen in pet-free environments, was used. Dust samples were collected from clothes and mattresses.
  
  
  RESULTS
  There was a 5-fold difference in the median levels of airborne cat allergen between classes with many and few cat owners (2.94 vs 0.59 ng/m3; P <.001). The median airborne cat allergen concentration in classes with many cat owners was significantly higher than that found in the homes of non-cat owners (P <.001) but lower than that found in homes with cats (P <.001). Allergen levels in non-cat owners' clothes increased after a school day (P <.001). Non-cat owners in classes with many cat owners had higher levels of mattress-bound cat allergen (P =.01).
  
  
  CONCLUSIONS
  The results indicate significant exposure to cat allergen at school. Allergen is spread through clothing from homes with cats to classrooms. There the allergen is dispersed in air and contaminates the clothes of children without cats. The allergen levels in non-cat owners' homes correlate with exposure to cat allergen at school.
authors.affiliation: Department of Environmental Health, Karolinska Hospital, Stockholm, Sweden.
authors.forename: C
authors.initials: C
authors.lastname: Almqvist
authors.forename: P H
authors.initials: PH
authors.lastname: Larsson
authors.forename: A C
authors.initials: AC
authors.lastname: Egmar
authors.forename: M
authors.initials: M
authors.lastname: Hedrén
authors.forename: P
authors.initials: P
authors.lastname: Malmberg
authors.forename: M
authors.initials: M
authors.lastname: Wickman
mesh_terms: D000393:Air Pollutants / Q000276:immunology; D016902:Air Pollution, Indoor / Q000032:analysis*; D000485:Allergens / Q000032:analysis; D000818:Animals; D001513:Beds; D002415:Cats / Q000276:immunology*; D002648:Child; D003020:Clothing; D004391:Dust / Q000032:analysis; D004777:Environment; D006023:Glycoproteins / Q000032:analysis*; D006801:Humans; D012307:Risk Factors; D012574:Schools; D011795:Surveys and Questionnaires
chemical_list: D000393:Air Pollutants; D000485:Allergens; D004391:Dust; D006023:Glycoproteins; C059296:Fel d 1 protein, Felis domesticus