Evaluation of individually ventilated cage systems for laboratory rodents:occupational health aspects

New ventilated caging systems for laboratory animals were compared with con ventional caging regarding allergen distribution, ergonomic suitability, ca ge environment and animal welfare. This paper presents occupational health evaluations. Mice were placed in individually ventilated cage (IVC) systems, a ventilate d cabinet, and in cages on open shelves (conventional husbandry). The IVC s ystems were studied at negative and positive airflow. Aeroallergens were sa mpled on filters (n = 204, including controls) in undisturbed rooms and dur ing cage changing. Concentrations of mouse urinary allergen (Mus m 1) in fi lter eluates were measured using sandwich ELISA. An ergonomic evaluation wa s performed with measurement of traction forces. Staff exposure during cage changing was high in all systems, range 116-4430 ng Mus m 1/m(3). In undisturbed animal rooms, allergen levels were orders of magnitude higher when using conventional caging compared with ventilated systems; P < 0.001. At positive pressure, both IVCs leaked allergen (media n Mus m 1 concentration was < 0.08 ng/m(3) at negative, but 6.5 ng/m(3) (IV C 1) and 0.8 ng/m(3) (IVC2S) at positive pressure). The IVC systems had erg onomic disadvantages compared with the conventional husbandry and the venti lated cabinet, for instance with cages in unsuitable working heights. Ventilated husbandry solutions reduce levels of airborne allergen substanti ally at negative pressure, but are ergonomically less suitable. To prevent allergen exposure during cage changing, we propose that this procedure shou ld be performed under ventilated conditions. Producers and users must coope rate in optimizing animal caging systems for both animals and staff.