House dust mite allergy in Florida. Mite survey in households of mite-sensitive individuals in Tampa, Florida.

This study evaluated the prevalence of positive house dust mite skin tests in a population of atopic individuals and identified the mite species present in mattress and house dust samples in homes of the Tampa Bay area. Four hundred consecutive individuals were evaluated for respiratory complaints and skin tested with standardized extracts of Dermatophagoides pteronyssinus (Dp) and Dermatophagoides farinae (Df). Two hundred forty individuals (60%) had a positive skin test to the mite extracts. Dust samples were collected in 40 homes of mite-allergic individuals and analyzed by light microscopy. Mite species were found in 53 of the 60 dust samples (20 mattresses and 40 carpets). Mite numbers ranged from 110-6200 mites/g of mattress dust and from 120-5500 mites/g of carpet dust. Eleven different mite species were identified and Blomia tropicalis (Bt), not previously identified in the United States, was found in 30% of the samples. Dp and Df wee the predominant species. These observations suggest that house dust mite allergy is common in the Tampa Bay area and that the house dust mite fauna comprises several mite species besides Dp and Df. Prospective studies in progress are designed to confirm the role of different mite species in house dust mite allergy.