Use of nasal filters for allergen exposure measurements in veterinary practices

Objectives: In this study, we applied novel nasal filters to assess animal allergen exposure of veterinary staff during their normal daily routine. Methods: Rhinix nasal filters were worn during work by 94 employees at different veterinary practices and 18 employees at a research institute, who acted as controls representing an animal-free environment. Contact with animals and the activities performed were documented by the study participants using a short questionnaire. Major allergens of cats (Fel d 1), dogs (Can f 1), and domestic mites (DM) were measured using fluorescence enzyme immunoassays. Results: At the practices, Can f 1 was detected in 98%, Fel d 1 in 82%, and DM allergens in 39% of the samples. Allergens were also detected in some control samples (6% for Can f 1, 39% for Fel d 1, and 17% for DM) but in very low concentrations. There was a highly significant difference between allergen levels in veterinary workers who treated at least one cat or dog during the sampling period and those who did not (2.66 vs. 0.70 ng/filter for Can f 1 and 1.01 vs. 0.20 ng/filter for Fel d 1). The amount of sampled Fel d 1 increased significantly with increasing duration of contact with cats. This effect was not observed for Can f 1. Conclusions: The majority of veterinary workers are exposed to dog and cat allergens, even without direct contact with these animals. Rhinix nasal filters may be considered a simple and easily applicable method for monitoring personal allergen exposure.