Evaluation of different techniques for washing cats: quantitation of allergen removed from the cat and the effect on airborne Fel d 1.
OBJECTIVE
The purpose of this study was to examine the quantity and distribution of the major cat allergen, Fel d 1, on cats and to evaluate the efficacy of washing, both in removing allergen from the cat and reducing airborne allergen levels.


METHODS
Airborne samples were collected on four glass fiber filters in a 30 m3 room, before and 3 hours after serial washing of eight cats (45-minute sampling at 18 L/min for each filter). Aliquots of hair and bath water were also collected and assayed for Fel d 1 content.


RESULTS
Extracting cat hair with tap water or pet shampoo for 3 minutes removed mean levels of 191 and 245 microg of Fel d 1 per gram of hair, respectively; the quantity of allergen on samples of cat hair ranged from 1 microg/gm to more than 1770 microg/gm. The highest concentration of allergen was found on hair from the neck. Estimates of the total Fel d 1 on the cat, based on shaving the whole cat, ranged from 3 to 142 mg (mean = 67 mg). Washing cats reduced airborne allergen 3 hours later. Washing three cats at weekly intervals for 5 weeks in a veterinarian's office produced a mean decrease of 44% in airborne Fel d 1 (n = 15, p < 0.02). Washing three cats by immersion for 3 minutes at weekly intervals for a 1-month period produced a mean decrease in airborne allergen of 79% (n = 12, p < 0.001). However, after repeated washing, the airborne levels before the next wash were not consistently decreased. The quantity of Fel d 1 removed by immersion varied from 1 to 35 mg.


CONCLUSIONS
Cats carry large quantities of Fel d 1, only a small proportion of which (approximately 0.002%/hr) becomes airborne. Washing cats by immersion will remove significant allergen from the cat and can reduce the quantity of Fel d 1 becoming airborne. However, the decrease is not maintained at 1 week.
Avner
D B
DB
University of Virginia Asthma and Allergic Diseases Center, Charlottesville 22908, USA.
Perzanowski
M S
MS
Platts-Mills
T A
TA
Woodfolk
J A
JA
D000393:Air Pollutants / Q000032:analysis*; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D002415:Cats / Q000276:immunology*; D004781:Environmental Exposure; D004784:Environmental Monitoring; D006023:Glycoproteins / Q000032:analysis*; D006204:Hair Removal; D006799:Housing, Animal; D008297:Male; D012130:Respiratory Hypersensitivity / Q000517:prevention & control*
D000393:Air Pollutants; D000911:Antibodies, Monoclonal; D006023:Glycoproteins; C059296:Fel d 1 protein, Felis domesticus