Anti-mite Covers: Potential Criteria for Materials Used Against Dust Mites

Abstract

There are many types of material used to construct bedding encasing for dust mite and allergen protection, but relatively few have been evaluated for their anti-mite properties. This study surveyed the anti-mite/allergen properties and physical characteristics of covers with a view towards establishing potential parameters for evaluating the efficacy of such encasings. Fifty-three covers advertised as mite-proof were randomly purchased from local markets found in ten different countries. All fabrics were evaluated for their ability to block the movement of allergens and live mites. Air permeability, dust leakage, and thread count, where applicable, were also measured. The major finding was that plastic and the tightly woven covers completely prevented mite penetration while exhibiting > 99 % allergen impenetrability. The film-coated fabrics, the mixed type, and the acaricidal-coated non-woven were successful in blocking allergens, but were commonly observed to allow some mite penetration. For the tightly woven fabrics, dust leakage and air permeability were minimal, while thread count was uniformly high. Cotton bed sheets were completely penetrable by mites and allergens. Overall, allergen impenetrability was negatively associated with dust leakage, thread count, and air permeability. Thread count also exhibited inverse relationships between dust leakage and air permeability. Dust leakage and air permeability were positively associated. The optimal characteristics for effective encasings include tightly woven covers with allergen impenetrability > 99 %, resistance to live mite penetration, dust leakage of < 4 %, air permeability between 2 and 6 cm3/sec/cm2, a thread count ≥ 246/in2, and a pore size of 2—10 µm. © 2009, SAGE Publications. All rights reserved.