Determinants of airborne rat and mouse urinary allergen exposure

A Hollander, Dick Heederik, G Doekes, Hans Kromhout
1998 Scandinavian Journal of Work, Environment and Health  
Hollander A, Heederik D, Doekes G, Kromhout H. Determinants of airborne rat and mouse urinary allergen exposure. Scand J Work Environ Health 1998;24(3):228-235. Objectives The purpose of this study was to determine the factors affecting exposure to rat and mouse urinary allergens. Methods Ambient and personal air sampling was performed on a large scale in 7 laboratoly animal facilities. Results Allergens were mainly present as large particles (25.8 pm). The higher the number of animals in a
more » ... of animals in a room, the higher the allergen concentrations. Allergen levels were twice as high on Mondays as on other days due to the tasks performed on Mondays. Filter tops on animal cages were associated with 6-17 times lower ambient allergen levels. An inverse day-night rhythm for rats produced 210 times higher rat urinay allergen levels. Personal exposure to rat and mouse urinary allergens differed between job titles but especially between facilities, probably because of differences in task performance and technology. Task-specific sampling revealed that the highest personal exposure levels occurred when contaminated bedding and high numbers of conscious animals were handled. The proportion of time spent on these tasks determined the degree of allergen exposure to a large extent. C O~C~U S~O~S This study showed that the number of animals present in the room, use of filter top cages, and an inverse day-night rhythm were important determinants of rat and mouse urinary allergens in ambient air. Personal exposure to rat and mouse urinary allergens was predominantly determined by the task and site and, to a limited extent, by ambient exposure levels. The presented determinants can be used to develop exposure reduction strategies and also to aid epidemiologic studies of laboratory animal allergy. Laboratory animal workers are at high risk of developing occupational allergy (1-8). Several studies (5,6,9) have shown that the risk of developing laboratory animal allergy is related to the allergen exposure level. Exposure control can potentially decrease the risk of developing the disease. Effective exposure control, however, requires detailed knowledge of the most important determinants of exposure (10, 11). When available, this kind of knowledge can be used to estimate exposure levels in epidemiologic studies as well (12) (13) (14) . Rat and mouse urinary proteins are highly allergenic (15) (16) (17) (18) (19) and are the most important allergens in airborne dust in laboratory animal facilities (16, 19) . In previous studies associations have been found between ambient air levels of urinary allergens and the number of animals in the room (20-22), the bedding material used (20, 23), the relative humidity in rooms (24), the use of filter top cages (20), and the rate of ventilation (25). Little is known, however, about the determinants of personal allergen exposure levels of laboratory animal workers. A large epidemiologic study among approximately 600 laboratory animal workers started in 1992 (8,9). As part of this epidemiologic study on laboratory animal all e y , ambient air sampling in animal rooms, and shift-and task-based personal air sampling was performed. This paper describes an analysis of potential determinants of rat (RUA) and mouse (MUA) urinary aeroallergen exposure. Linear regression models were used to determine the factors affecting RUA and MUA concentrations. In contrast to the findings of other studies (20, 22, 26) , air samples were taken at more than 1 laboratory animal facility. Furthermore, this study had no experimental
doi:10.5271/sjweh.303 fatcat:tlw6nanhmzan7dabnkm4evm6qi