DOMESTIC ALLERGENS IN PUBLIC PLACES .2. DOG (CAN-F-1) AND COCKROACH (BLA-G-2) ALLERGENS IN DUST AND MITE, CAT, DOG AND COCKROACH ALLERGENS IN THE AIR IN PUBLIC BUILDINGS

Background Sensitization and exposure to indoor allergens are the majo r risk factors for asthma. It is possible that significant exposure to domestic allergens occurs outside the home. Objectives To investigate the levels of Can f 1 and Bla g 2 in the dust from carpeted floors an d upholstered seats in public buildings and public transport and the a irborne concentrations of Der p 1, Fel d 1, Can f 1 and Bla g 2 in sch ools and offices. Methods Can f 1 and Bla g 2 were measured in the dus t collected by vacuuming a 1 m(2) area of carpet, as well as upholster ed seats in five schools, six hotels, four cinemas, six pubs, three bu ses and two trains. Dust was also collected from the bedroom carpet, l iving room carpet, mattress and sofa in 20 homes with and 20 homes wit hout a dog in the same area. Personal airborne sampling (2 L/min) was conducted for 8 h in offices (n = 16) and classrooms (n = 9). In addit ion, airborne samples in schools were collected using a high volume pu mp (60 L/min) for 1 h in three classrooms immediately after the childr en vacated the school. Can f 1, Bla g 2, Der p 1 and Fel d 1 were assa yed using a two-site monoclonal antibody-based ELISA. Results Can f 1 was detected in all dust samples from public places, ranging from 0.2 to 52.5 mu g/g. Significantly higher levels were found in upholstered seats (geometric mean - GM 9.4 mu g/g) than in carpets (GM 1.5 mu g/g; P<0.001), and levels of Can f 1> 10 mu g/g were found in 40% of uphol stered seats in public places. Can f 1 was significantly higher in uph olstered seats in public places than in sofas in homes without a dog ( GM 1.8 mu g/g; P < 0.001). Detectable levels of Bla g 2 were found in all of the schools (GM 2.4 U/g, range 0.8-4.4 U/g). Bla g 2 concentrat ion greater than 2U/g (provisional threshold level representing risk o f sensitization) was measured in 65% of the classrooms sampled. Der p 1 and Bla g 2 were below the detection limit in all airborne samples. However, airborne Fel d 1 and Can f 1 were detected in schools and off ices, albeit in low concentrations. Conclusions Upholstered seats from public places constitute a reservoir for the accumulation of dog alle rgen, and a source of exposure to Can f 1 inside public buildings or o n public transport. Exposure to cockroach allergens in schools may be important for cockroach sensitized asthmatic children.