Disodium octaborate tetrahydrate (DOT) application and vacuum cleaning, a combined strategy to control house dust mites.

BACKGROUND: The effectiveness of acaricides in homes is controversial.

OBJECTIVE: To determine whether disodium octaborate tetrahydrate (DOT) combined with vacuuming lowers dust mite numbers and their allergens in carpets and sofas.

METHODS: A 6-month study was carried out with 93 homes, which were randomized into three groups: (i). active, received DOT; (ii). placebo, received water; and (iii). control, received no application. Active and placebo homes were vacuumed weekly. Dust was collected from carpets and sofas at the start of the study and every 2 months thereafter and quantified for live, total mites, and mite allergen levels.

RESULTS: At 2 months, live mite numbers in active carpets were 3 +/- 1, in placebo carpets 129 +/- 48, and in control carpets 177 +/- 39 mites/g. The corresponding numbers in sofas were 3 +/- 2, 81 +/- 31, and 134 +/- 45 mites/g, respectively (P < 0.001 active vs placebo and vs. control). Live mites in carpets and sofas remained lower in the active group at 6 months (P < 0.001). Total mites in active carpets decreased from 555 +/- 69 at baseline to 223 +/- 32 mites/g at 6 months (P < 0.001) and mite allergen levels from 1.36 +/- 0.13 to 0.85 +/- 0.16 microg/g (P < 0.001). Total mites in active sofas remained unchanged, but mite allergen levels decreased from 1.48 +/- 0.25 at baseline to 0.7 +/- 0.15 microg/g at month 6 (P < 0.05).

CONCLUSION: DOT kills mites in carpets and sofas, and, combined with vacuuming, effectively reduces total mites in carpets and mite allergen levels in carpets and sofas.