Fel d 1 and Can f 1 in settled dust and airborne Fel d 1 in allergen avoidance day-care centres for atopic children in relation to number of pet-owners, ventilation and general cleaning

Background Special day-care centres fur atopic children have been establish ed in Sweden. Objective To study concentrations of cat (Fel d 1) and dog (C an f 1) allergens in settled dust and airborne cat allergen in day-care cen tres in relation to pet ownership among children and staff, ventilation and general cleaning. Methods Twelve allergen avoidance day-care centres and 23 conventional day- care centres were included in the study. Settled dust was collected and ana lysed with ELISA. Airborne cat allergen levels were measured in eight aller gen avoidance and seven conventional centres with a personal air sampler an d analysed with an amplified ELISA. Air change rate per hour (ACH) was meas ured. A questionnaire which focused on keeping of cat and dog among staff a nd children and frequency of general cleaning was used. Results In the allergen avoidance day-care centres neither children nor sta ff reported ownership of cats or dogs, compared with 21/22 of the conventio nal centres in which children and staff kept furred animals. Fel d 1 and Ca n f 1 were found in settled dust in all day-care centres. In the allergen a voidance compared with the conventional centres the concentrations of Fel d 1 and Can f 1 were lower, Fel d 1: median 0.64 mu g/g vs 5.45 mu g/g and C an f 1: 0.39 mu g/g vs 2.51, both P < 0.001, and airborne Fel d I was also lower in the allergen avoidance centres compared with the control centres, 1.51 ng/m(3) vs 15.8 n,/m(3), P = 0.002. A correlation was found between ai rborne and settled Fel d I, r(s)=0.75, P<0.001. Furthermore, a correlation was found between increased ACH and decreased levels of Fel d 1 in the air in the day-care centres with no cat-owners, r(s) = - 0.86, P = 0.007, No re lation was found between levels of cat or dog allergen and amount of genera l cleaning. Conclusion Not keeping pets seems to reduce children's exposure to pet-alle rgen in their working environment. Additionally, appropriate ventilation se ems to reduce Fel d 1 in the air in day-care centres.