Dog sensitization and allergy to mites: do they respond the same way to poultry red mite as to house-dust and storage mites?

Abstract

Background Dermanyssus gallinae, the European poultry red mite (PRM), is a common ectoparasite of laying chickens and pigeons but can also feed on other birds, humans and domestic animals, causing from mild discomfort to severe dermatitis, with possible transmission of several infectious agents. In affected dogs clinical signs resembling flea allergy were reported, but very little is known about either a possible type I hypersensitivity to PRM in dogs or an eventual cross-sensitization with house-dust or storage mites. Investigating on IgE-mediated allergy to PRM in dogs is important from both veterinary and human health perspectives as knowledge about an IgE-mediated allergy in humans and their dogs, and possible cross-sensitization with dust and storage mites will favor a better clinical approach. Our aim was to clarify i) whether there is evidence of type I hypersensitivity to PRM in dogs, by testing for specific IgE to PRM and ii) the possible occurrence of cross-sensitization with dust and storage mites. Method Sixteen dogs with long-lasting close contact with chickens from traditional bird houses and 5 control dogs from an allergy outpatient consultation, with no direct contact with birds, were subjected to commercial intradermal tests for the most common dust and storage mites (Diater, Spain) and with D. gallinae extract (LETI, Spain) in four concentrations (1, 0.5, 0.1 and 0.01 mg/mL). Serum specific IgE (sIgE) to PRM was determined by ELISA at LETI Animal Health Laboratories (Spain). Results Three control dogs presented positive IDT to PRM and 2 were negative, each of them to every concentration. IDT were found positive in 10 chicken-contacting dogs with 0.1 mg and in only 6 with 0.01 mg/mL. IDT response to PRM was found gradual between 0.1 and 0.01 mg/mL of extract concentration. Serum sIgE to PRM was detected in 1 control (20%) and in 7 (44%) chicken-contacting dogs. No significant correlation was found between PRM and dust and storage mites IDT and between IDT and sIgE to PRM. Conclusion The adequate PRM IDT extract concentration could be in the 0.1-0.01 mg/mL range. Close contact with infested chickens, hence with PRM may conduce to a possible state of sensitization with detectable sIgE without allergy, necessarily. Sensitization and allergy to PRM may be independent from their equivalent to dust and storage mites.