Presence and density of domestic mites in the microenvironment of mite-sensitive dogs with atopic dermatitis.
ABSTRACT This study was designed to investigate the presence and density of domestic mites (DMs) in households with atopic dogs sensitive to these mites (group A; n=20), in households with clinically healthy, nonatopic dogs (group B; n=20) and in households without pets (group C; n=25). Dust samples were vacuum-collected from the owner mattress (all groups) and dog sleeping area (groups A and B) or living room couch (group C) on four consecutive occasions, reflecting the four seasons of the year. DMs were found, at least once, in 19 of 20 (95%) group A, 13 of 20 (65%) group B and 21 of 25 (84%) group C households. DM numbers per gram of dust were 0-159 (median, 8.8), 0-302 (median, 3) and 0-1473 (median, 6.9) for group A, B and C, respectively. Dermatophagoides farinae predominated in all groups, since it was identified in 60% of group A, 40% of group B and 64% of group C households. Dermatophagoides pteronyssinus was found in 45%, 35% and 48% of households, in group A, B and C, respectively. No differences were found between households with (groups A and B) or without dogs (group C). When considering both sampling sites together, frequency of DM recovery was higher in group A than in group B (P=0.044). Also, both mite frequency (P=0.011) and density (P=0.015) in dog sleeping area were higher in group A than in group B. In conclusion, presence and density of DMs is higher in the microenvironment of mite-sensitive dogs with atopic dermatitis than in that of clinically healthy nonatopic dogs.