Optimisation of a screening procedure for house dust mite numbers in carpets and preliminary application to buildings

Abstract

The relative performances of the mobility and heat escape methods for measuring house dust mite numbers in carpet has been evaluated. The optimum method was found to be the mobility method for 24 hours at ambient temperatures which exhibited a mite collection efficiency of approximately 30%. Measurements in three dwellings showed that the method should be applied to carpet at several locations in the living room and/or bedrooms as a general sampling procedure, or adjacent to loungeroom seating to determine the worst case scenario. Carpets using different types of fibre within the same dwelling should be assessed separately. For the limited number of dwellings investigated, wool carpets were found to exhibit higher mite numbers than nylon carpets, even when the former had been insect-resist treated. No house dust mites were found in the wool carpets of an office building which was mechanically ventilated and heated and achieved low indoor humidities in winter.

A lack of influence of permethrin treatments of wool carpet on habitation by house dust mites

“…The samples were placed in the building at the start of autumn 1994 and remained undisturbed, except for monthly rotation and normal cleaning activities, until late autumn 1995 (a period of 14 months) when the live house dust mite levels were measured. These were measured in the carpets using a mite mobility-adhesive tape method with which Brown (1994) found that approximately 30% of live house dust mites were captured in 24 h.…”

Air Toxics in a New Australian Dwelling over an 8-Month Period

“…House dust mite numbers using the adhesive tape and mobility method [2] and mite allergen (Der pl) were measured at several locations in the house, and from new materials (rugs, couch) or old materials (mattress), as presented in table 6.…”

Penetration of light into carpet, and responses of the European house-dust mite (Dermatophagoides pteronyssinus) to varying light intensity and diurnal cycle

“…under adverse conditions. Whatever their response to light, it appears that house-dust mites do spend some portion of time in the upper strata of carpet, as evidenced by appreciable recovery rates from 'mobility' tests involving the placement of adhesive films on the surface of the test material, and their later removal (Bischoff and Fischer 1990;Brown 1994). The number of mites adhering to the film may then be determined by scanning under a stereobinocular microscope (Bischoff et al 1992).…”