Background: We investigated the levels of Fel d I and Can f I in dust from tables, chairs, and floors in 29 classrooms in four Swedish schools.
Methods: School authorities were questioned about building characteristics, students were interviewed about their health and exposure to animals, and cleaning personnel were asked about methods and frequency of cleaning. Dust samples were taken from floors and horizontal surfaces of chairs and tables in all classrooms during a 6-week period.
Results: Higher amounts of Fel d I were found on chairs (geometric mean, 953 ng per gram of dust) than on tables (525 ng/gm) and floors (134 ng/gm). The concentration of Can f I (5.3 ng/gm) on chairs was 2 to 20 times higher than Fel d I. The concentration of Can f I (200 ng/gm) in dust from floors was twice as high as that of Fel d I. The concentration of Can f I on chairs was within the range previously found by other investigators in houses with dogs.
Conclusions: Since the levels of both Fel d I and Can f I were much higher on chairs than on floors, we hypothesize that allergen is brought to schools on the clothes of students and teachers. We conclude that the levels of the two major allergens from furred pets (i.e., Fel d I and Can f I) in Swedish schools are probably high enough to sensitize children and to induce asthma in most children who are allergic to cats or dogs.