Prevalence of house dust mites in the homes of atopic dogs in Finland.

Abstract

BACKGROUND: The house dust mites (HDM) Dermatophagoides farinae and D. pteronyssinus are important environmental allergens implicated in the pathogenesis of human and canine atopic dermatitis. Sensitization to HDM measured by allergen-specific IgE is common in Finnish atopic dogs. Studies on HDM prevalence in Finland are few but suggest that HDM are scarce. OBJECTIVE: The aim of the present study was to evaluate the prevalence of HDM in the home environments of atopic dogs in Finland. METHODS: Dust samples were obtained from the homes of 50 atopic dogs. Samples were collected by vacuuming the owners' mattresses and each dog's bed. In each case, an area of 21 × 30 cm was vacuumed for 2 min. Samples weighing 100 mg or more were considered sufficient for determination of HDM allergen concentrations (Der f 1 and Der p 1) using standardized ELISA. Samples sufficient for further analysis were also examined by direct microscopy for the presence of mites and by multiplex PCR for HDM DNA. RESULTS: Eighty one samples were sufficient for analysis by ELISA, 59 by PCR and 29 by direct microscopy. A single sample was analysed from four homes in which the dog shared the owner's bed. Der f 1 was detected in three samples (3.7%). Der p 1 was not detected in any sample. No mites were identified on microscopy. Five samples were positive for HDM on multiplex PCR (8.4%). CONCLUSION: House dust mites seem to be uncommon in the home environment of atopic dogs in Finland despite reported frequent allergen-specific IgE antibodies.