Molecular Detection of Avian Pathogens in Poultry Red Mite (Dermanyssus gallinae) Collected in Chicken Farms

Poultry red mite (PRM,Dermanyssus gallinae) is a blood-sucking ectoparasite as well as apossible vector of several avian pathogens. In this study, to define the role of PRM inthe prevalence of avian infectious agents, we used polymerase chain reaction (PCR) tocheck for the presence of seven pathogens: Avipox virus (APV), Fowl Adenovirus (FAdV),Marek’s disease virus (MDV), Erysipelothrix rhusiopathiae (ER),Salmonella enterica (SE), Mycoplasma synoviae (MS) andMycoplasma gallisepticum (MG). A total of 159 PRM samples collectedbetween 2004 and 2012 from 142 chicken farms in 38 prefectures in Japan were examined. APVDNA was detected in 22 samples (13.8%), 19 of which were wild-type APV. 16S ribosomal RNA(16S rRNA) of MS was detected in 15 samples (9.4%), and the mgc2 gene ofMG was detected in 2 samples (1.3%). Eight of 15 MS 16S rRNA sequences differed from thevaccine sequence, indicating they were wild-type strains, while both of the MGmgc2 gene sequences detected were identical to the vaccine sequences.Of these avian pathogen-positive mite samples, three were positive for both wild-types ofAPV and MS. On the other hand, the DNAs of ER, SE, FAdV and MDV were not detected in anysamples. These findings indicated that PRM can harbor the wild-type pathogens and mightplay a role as a vector in spreading these diseases in farms.