Measurement of Horse Allergen (Equ cx) in Schools.

Background. The presence of horse allergen in public places is not well-known, unlike for instance cat and dog allergens, which have been studied extensively. The aim was to investigate the presence of horse allergen in schools and to what extent the influence of number of children with regular horse contact have on indoor allergen levels. Methods. Petri dishes were used to collect airborne dust samples during one week in classrooms. In some cases, vacuumed dust samples were also collected. All samples were extracted, frozen and analysed for Equ cx content shortly after sampling, and some were re-analysed six years later with a more sensitive ELISA assay. Results. Horse allergen levels were significantly higher in classrooms, in which many children had horse contact, regardless of sampling method. Allergen levels in extracts from Petri dish samples, which had been kept frozen, dropped about 53% over a six-year period. Conclusion. Horse allergen was present in classrooms and levels were higher in classrooms where many children had regular horse contact in their leisure time. This suggests that transfer of allergens takes place via contaminated clothing. Measures should be taken to minimize possible transfer and deposition of allergens in pet-free environments, such as schools.