Cat allergen (Fel d 1) levels on school children's clothing and in primary school classrooms in Wellington, New Zealand

Background: New Zealand has a high prevalence of the major allergic diseases including asthma, rhinitis, and eczema, and cat ownership is common, with more than 50% of homes containing a cat. Objective: The study was designed to examine the levels of cat allergen (Fel d 1) in the primary school environment, both on floors and on children's clothing. Methods: We collected and analyzed dust samples from 11 school classrooms and from 202 children's garments using vacuum sampling and two-site monoclonal antibody ELISA, respectively. Environmental variables were identified by questionnaire. Results: The geometric mean level of Fel d 1 in classrooms was 2.61 mu/gm (95% confidence interval, 1.28 to 3.84); however, seven classrooms had a floor sample with Fel d 1 greater than 8 mu g/m(2). Carpeted floor levels at 2.21 mu g/gm (1.28 to 3.84) were considerably higher than those on uncarpeted floors, at 0.33 mu g/gm (0.1 to 1.14). Floor levels and pupil cat ownership rates were positively correlated (r(2) = 0.93, p = 0.0003). Children from homes with cats carried allergen on their clothes (mean Fel d 1, 6.10 mu g per garment compared with non-cat owners (0.72 mu g per garment). Wool and polyester garments contained more Fel d 1 than cotton clothing. Girls' clothing had significantly higher levels of allergen than did that of boys, even after controlling for cat status and fabric differences. Conclusions: Carpeting should be discouraged in environments such as schools and child care centers, where children spend considerable time. Transport of Fel d 1 on clothing from the domestic to the school environment is a major source of classroom cat allergen.