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"Aeroallergens in animal holding facility : An Occupational Health Hazard" The continuous exposure of laboratory animals users to mice and rats skin/fur/urine allergens is today a matter of concern within the scientific community. For many years we focused our attention on protection of staff from zoonotic diseases. Today, we know that realistically the risk to staff of developing such a disease is almost negligible. This result is mainly due to the development of large colonies of SPF animals thanks re-derivation and embryo transfer techniques.If removal of pathogens from our units is primarily an animal-related issue, allergens exposure reduction is very much an equipment-related matter. Incidence of allergy among laboratory animal carers and scientists is quite variable: 15 to 40%, (Hunskaar & Fosse 1990, Renstrom 1997), and approximately 35% in UK and the greatest incidence occurs in the first two years of exposure. Manufacturers of equipment for laboratory animals have developed specific solutions to the above problem improving dramatically at once the degree of protection for both workers and technicians from reciprocal contamination. The most famous answer to the allergens problem is the Individually Ventilated Cage capable to work possibly at a significant level of positive or negative pressure. During a recent course on Laboratory Animals allergy at Imperial College of Science, Technology and Medicine (London UK, 9 October 2000) most of the speakers agreed on a suggested limit for the max. reasonable concentration of mice allergens in the animal rooms: below 3 ng/m3 . It is quite evident that working with an IVC system under negative pressure the goal of less than 3 ng/m3 should be achieved easily whereas under positive pressure the failure in achieving the goal is much related to severe problems connected with the cages sealing quality and other technical details responsible of leaks not acceptable for a purpose designed and expensive equipment like this. A recent paper (Evaluation of IVC systems for laboratory rodents: occupational health aspect, Laboratory Animals, 2001, 35, 42-50, A.Renstrom,G.Bjoring &A.U.Hoglund) investigates the issue demonstrating the need for an accurate evaluation of the product to be selected once allergen protection of users is in the list of priorities. |