Mites in mattress dust and relevant environmental factors in student dormitories in Shenzhen

Three hundred and eight mattress dust samples were collected from college dormitories in Shenzhen with a mite prevalence of 88%(271/308).From the samples,6 163 mites were isolated and identified.Dermatophagoides farinae,D.pteronyssinus and Blomia tropicalis were three most abundant species,occupying 29.7%,21.7% and 17.9%,respectively.It was found that sex of the students,mattress cover(bamboo mat or bed sheet),with or without air conditioner installation,and daily using of air conditioner(2 h,2-8 h and 8 h) had no significant influence on the mite prevalence(P0.05).However,logistic regression analysis revealed that the risk of mite sensitization in male student dormitory was significantly lower than that in female dormitory(OR=0.55,P=0.038),and the risk of using bed sheets was significantly higher than using bamboo mats(OR=2.13,P=0.040).Both mite prevalence and the risk of mite sensitization significantly decreased with higher floor of the dormitory building.