COCKROACH ALLERGEN (BLA-G-1) IN SCHOOL DUST

Background: Cockroach allergen, Bla g 1, is an important indoor allerg en. Although household exposure has been documented, little is known a bout the potential for exposure outside the home. Objective: We invest igated the settled dust concentration of Bla g 1 in 147 samples collec ted from classrooms, kitchens, cafeterias, and other sites in four pri mary schools in the city of Baltimore. Methods: School authorities wer e questioned about characteristics of schools, teachers, and students, as well as cockroach control and cleaning procedures, Settled dust sa mples were collected with a hand-held vacuum cleaner from the floors o f all classrooms, food-related areas, and other sites of the schools o ver a 3-week period. A sample collection in each school took 1 to 2 da ys. Dust samples from each room were pooled and analyzed as a single s ample for Bla g 1 by using a two-site monoclonal ELISA. Results: One h undred two (69%) of the 147 samples had detectable Bla g 1 and were wi thin the range reported by other investigators in inner city homes. Th ere was no difference between the median levels of Bla g 1 in three sc hools: school 1 (5.2 U/gm), school 2 (3.0 U/gm), and school 4 (2.7 U/g m); but school 3 had a significantly lower level (<0.8 U/gm, p < 0.001 ), The median level from the food-related areas was significantly high er than the median classroom level (p = 0.048). School 3 had fewer stu dents on subsidized lunch, fewer African-American students, and fewer students per teacher. Bla g 1 levels were compared in the different sc hools while controlling for potential confounding variables by a stepw ise multiple regression analysis with a logit model for ordinal respon ses. On the basis of this analysis. Bla g 1 levels in schools 1, 2, an d 4 differed significantly from levels in schools 3 (p < 0.001 in each case). Food-related areas had significantly higher levels than classr ooms (p = 0.048). Floor level, the presence of a sink and the presence of carpeting did not have significant effects. Conclusions: We conclu de that Bla g 1 is detectable at potentially significant concentration s in some inner city schools. Furthermore, the level of exposure is di fferent between different schools and between sites within individual schools.