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

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.