The use of domestic steam cleaning for the control of house dust mites.

Background: Control of dust mites using extremes of temperature is an alternative to the use of acaricides. In the past we have attempted control by freezing with liquid nitrogen. The present paper deals with the opposite extreme, the use of steam. Objective: To assess the feasability and effectiveness of a domestic steam cleaner for the control of dust mites, its effect on mite populations and concentrations of the allergen Der p I. Methods: A domestic stream cleaner was used to treat carpet squares that had been seeded in the laboratory with known numbers of dust mites (Dermatophagoides pteronysinnus). The number of live mites was monitored for a period of 4 months in eight treated carpet squares and eight controls. Dust samples were taken from 12 standardized areas of carpet in a tenement flat in Glasgow, UK, before and after steam cleaning treatment, and the concentration of allergen Der p I was compared with 12 adjacent, control areas. Results: No live mites were found at any time in the treated carpet squares, whereas in the control squares geometric mean mite population density rose from 11 after 3 days to 39 after 1 month, 66 after 2, 122 after 3 and 185 after 4 months. There was a mean reduction of 86.7% in Der p 1 concentration (3.3–.0.44 &mu/g) compared with a reduction of 4.7% (2.22–2.116 μg/g) in control areas, a difference that was statistically significant at the 5% level. Conclusion: These data indicate that steam cleaning has considerable potential as an highly effective and efficient method of killing dust miles and reducing concentrations of Der p 1 in domestic premises. [ABSTRACT FROM AUTHOR]