Pj. Vojta et al., Effects of physical interventions on house dust mite allergen levels in carpet, bed, and upholstery dust in low-income, urban homes, ENVIR H PER, 109(8), 2001, pp. 815-819
House dust mite allergen exposure is a postulated risk factor for allergic
sensitization, asthma development, and asthma morbidity; however, practical
and effective methods to mitigate these allergens from low-income, urban h
ome environments remain elusive. The purpose of this study was to assess th
e feasibility and effectiveness of physical interventions to mitigate house
dust mite allergens in this setting. Homes with high levels of house dust
mite allergen (Der f1 + Der p 1 greater than or equal to 10 mug/g dust by e
nzyme-linked immunosorbent assay) in the bed, bedroom carpet, and/or uphols
tered furniture were enrolled in the study. Carpets and upholstered furnitu
re were subjected to a single treatment of either dry steam cleaning plus v
acuuming (carpet only) or intensive vacuuming alone. Bed interventions cons
isted of complete encasement of the mattress, box spring, and pillows plus
either weekly professional or in-home laundering of nonencased bedding. Dus
t samples were collected at baseline and again at 3 days (carpet and uphols
tery only) and 2, 4, and 8 weeks posttreatment. We compared pretreatment me
an allergen concentrations and loads to posttreatment values and performed
between-group analyses after adjusting for differences in the pretreatment
means. Both dry steam cleaning plus vacuuming and vacuuming alone resulted
in a significant reduction in carpet house dust mite allergen concentration
and load (p < 0.05). Levels approached pretreatment values by 4 weeks post
treatment in the intensive vacuuming group, whereas steam cleaning plus vac
uuming effected a decrease that persisted for up to 8 weeks. Significant de
creases in bed house dust mite allergen concentration and load were obtaine
d in response to encasement and either professional or in-home laundering (
p < 0.001). Between-group analysis revealed significantly less postinterven
tion house dust mite allergen load in professionally laundered compared to
home-laundered beds (P < 0.05). Intensive vacuuming and dry steam cleaning
both caused a significant reduction in allergen concentration and load in u
pholstered furniture samples (p < 0.005). Based on these data, we conclude
that physical interventions offer practical, effective means of reducing ho
use dust mite allergen levels in low-income, urban home environments.