School as a risk environment for children allergic to cats and a site for transfer of cat allergen to homes,☆☆,

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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). Conclusion: 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. (J Allergy Clin Immunol 1999;103:1012-7.)

Section snippets

Questionnaires

All secondary schools in 2 suburban districts of Stockholm, consisting of both rural and urban areas, were identified. Headmasters and teachers in grades 4 and 5 (age of students, 10 to 12 years) were informed about the study. A questionnaire regarding possession of domestic animals and furred pets was distributed to all 2042 pupils and their teachers. The answers were confirmed and signed by one of the pupil’s parents. The teachers compiled and mailed all questionnaires from their classes. If

RESULTS

The questionnaires were sent to 2042 pupils and teachers, and complete questionnaires were obtained from 1931 pupils (52% boys and 48% girls) and 83 teachers in the 85 school classes identified (response rate, 95%). One class had 2 teachers. Three classes did not respond despite reminders, and a few pupils in other classes declined participation or did not respond. Eighty-three percent of the children were between 10 and 11 years old, and 11% of the children were 12 years old. Fifty-eight

DISCUSSION

This study provides new data partly based on methods not previously available. There are 2 main findings. There is an association between the levels of airborne cat allergen and the number of cat owners in classes, with higher levels of Fel d 1 in classes with greater than 25% cat owners and lower levels in classes with less than 10% cat owners. The levels could be sufficient to influence the allergic inflammation in children with cat allergy.13, 20 Airborne cat allergen levels were not

Acknowledgements

We thank André Lauber for expert computer assistance and Inger Kull and Siw Siljerud for sample collection. We also thank the children and teachers in the schools, without whose assistance this study would not have been possible.

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    Supported by The Swedish Council for Work Life Research grant no 950150 and the Vårdal Foundation.

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    Reprint requests: Catarina Almqvist, MD, Department of Environmental Health, Norrbacka building, level 3, Karolinska Hospital, S-171 76 Stockholm, Sweden.

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