Background Control of dust mites using extremes of temperature is un alternative to the use of acaricides. In ihe past we have attempted control by freezing with liquiid nitrogen. The present paper deals with the opposite exlrcnic, the use of steam.
Objective To assess the feasibility inid 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 steam cleaner was used to treat earpet squares that had been seeded in the laboratory with known numbers of dust mites (Dermatophagoides pterpmussomis). The number of live mites was monitored for a period of 4 months in eight treated earpet 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 treatmet. and the concentration of allergen Der p 1 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 frotn 11 after 3 days to 39 after 1 month, 66 after 2.122 after 3 and 185 after 4 months. There was a mean reduetion of 8.7% in Der p I concentration (3.3-0.44 μg/g) compared with a reduction of 4.7% (2.22-2.l16μg/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 mites and reducing concentrations of Der p 1 in domestic premises.