Animal house exposure to endotoxin and rodent allergens

Abstract

Rationale A consistent method for measuring airborne allergens and endotoxin in animal houses is essential for evaluating the risk of sensitization and the impact of measures taken to reduce exposure. Methods Levels of airborne mouse and rat allergens in animal rooms were measured using a recently described method for collecting airborne allergens employing an ion charging device with a flow rate of 1.7m 3/min for 24 hours (Clin Exp All 33:986). The allergens were measured using a two-site monoclonal assay for rat and a monoclonal primary/polyclonal secondary assay for mouse (Indoor Biotechnologies). Endotoxin was assayed in parallel using the Limulus Amoebocyte Lysate test QCL 1000 (Bio-Whittaker). Results Airborne mouse and rat was present in relevant animal rooms, however there was a very wide range of results for both allergens (<.004ng/m 3 to >6ng/m 3) and endotoxin (<2.4pg/m 3 to >1000pg/m 3). The primary factor influencing airborne allergen and endotoxin was the presence of filter tops on individual animal cages for mouse (allergen p=.003, endotoxin p=.01) and rat (allergen p=.013, endotoxin p=.001). Filter tops reduced the airborne allergen and endotoxin levels by >98%. Conclusions Though previous studies have attributed reduced allergen levels to filter tops, this study shows the same effect on endotoxin levels. The reduced levels are similar to levels of airborne allergens found in domestic studies and thus filter tops may provide sufficient protection from exposure for animal technicians.