Background The occurrence and accumulation over time in public environments of cat, dog, and horse allergens was evaluated.

Methods Concentrations of animal danders were analyzed by ELISA and countercurrent immunoelectrophoresis (CCIE).

Results Among factory-new mattresses, 15/17 contained detectable levels of cat and/or dog allergen, whereas no horse allergen was found although six of the mattresses were stuffed with horschair, Dust from 15 used mattresses contained significantly higher concentrations of Fcl d 1 and Can f1 than the factory-new ones (P<0.001).

Allergen concentrations and titers correlated to the period of time that the mattresses had been tried by customers ; rs=0.52-0.77, P=0.04-0.001 (cat), rs=0.38-0.48, P=0.15-0.08 (dog), and rs=0.64-0.74, P=0.008-0.003 (horse).

The increase over time occurred rapidly in highly frequented stores and after 3 weeks reached concentrations that have been found in homes where furred pets had formerly been kept or even the lower allergen scale of homes where pets were currently kept.

Conclusions The dispersion of allergens from furred animals to pet-free public places is likely to occur by deposition from people who have been in direct or indirect contact with pets, and high levels of such allergens seem to accumulate in a short period of time.