The acarine fauna in dust samples from domestic pantries in southern Brazil

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Comparison of house dust mites found on different mattress surfaces

Background: House dust mites have been considered the most important source of allergens for humans. These allergens have been encountered at different indoor sites, mainly on mattresses and pillows. Objective: To evaluate the number and different specimens of mites on Brazilian bunk-bed mattresses. Methods: Dust samples were collected once using a standardized method on the upper mattress surface (US) and lower mattress surface (LS) (bed frame also included in the latter) of 58 mattresses. Results: The total number of mite bodies on the LS was 3.5-fold higher than on the US, with a mean concentration of 932 mites per gram of fine dust (mites/g) on the US (range, 0-3,375 mites/g) and 3,254 mites/g on the LS (range, 125-14,500 mites/g) (P < .001). Additionally, the number of house dust mite bodies on the LS was 2.4 higher than on the US (P < .001); the mean concentration was 750 mites/g on the US (range, 0-2,875 mites/g) and 1,816 mites/g on the LS (range, 0-10,875 mites/g). Approximately 91% (n = 52) of the US and all LS dust samples had more than the limit of 100 mites/g. The most frequent family was Pyroglyphidae in both mattress surfaces, with Dermatophagoides pteronyssinus the most important species found. Storage mites, including Glycyphagidae (P < .001), Acaridae (P < .001), and other families (P < .001), also showed significant differences in the number of mites between both sample counts. Conclusions: This study shows a significant difference in US and LS mite counts, with higher counts on the LS. Mite allergen avoidance should include the LS and bed frame as potential targets.91655956

Mites in dust samples from mattress surfaces from single beds or cribs in the south Brazilian city of Londrina

The aim of this study was to investigate the mite fauna in mattresses dust samples from cribs or beds in the south Brazilian city of Londrina, State of Parana. A total of 133 dust samples from upper and lower mattress surfaces, and bed frames were aspirated once from 38 dwellings (18 cribs and 21 beds), and one day nursery (six cribs). A total of 758 mite bodies were counted in slides: 233 (30.7%) from cribs and 525 (69.3%) from beds (p < 0.001). House dust mites - mainly Dermatophagoides pteronyssinus, represented 72% and 84% of total mite count in crib and bed dust samples, respectively. The mean HDM body concentration in crib or bed slides were, respectively, 289.9 +/- 136.7 and 875.0 +/- 183.6 mites/g. Statistical analysis showed a significantly higher mite bodies count on lower mattress surface compared with upper surface in bed samples only (p = 0.025). Data herein show that cribs like mattress have sufficient mite bodies to cause sensitization to humans. The use of mattress covers for cribs and beds should be encouraged in order to avoid allergens exposure.16213213