Abstract

We studied the efficacy of a special cloth encasing (Microguard) in protecting against house dust mite exposure. We vaccumed dust from right or left half surface of a shiki-futon (Japanese style mattress). Then we encased the shiki-futon by a new special encasing, vaccumed dust from the other part of the shiki-futon and got a pair of dust samples. We had done the same of the same shiki-futon by a used special encasing (used for one and half years) for about 2 weeks later. We prepared 7 shiki-futons and collected 14 pair dust samples. We weighed the dust and measured the mite allergens with a monoclonal antibody to Dermatophagoides pteronissynius and Dermatophagoides farinae. The dust level was 1.0% of the control (no encasing) in the new encasing group and 2.0% of the control in the used encasing group. The Der I concentration was 2.5 micrograms/(g dust) in the new encasing group and 3.2 micrograms/(g dust) in the used encasing group. The Der II concentration was 1.6 micrograms/(g dust). The total amount of Der I was 0.1% of the control in the new encasing group and 0.5% of the control in the used encasing group. The total amount of Der II was 0.2% of the control in the new encasing group and 0.7% of the control in the used encasing group. We compared Der p and Der f levels in the dust samples which we assayed and found no significant differences either in Der I or in Der II allergen. We concluded that Microguard was a useful tool to avoid mite allergen exposure by reducing not only the concentration of mite allergens but also the amount of dust.