title: PCR amplification and DNA sequencing of Demodex injai from otic secretions of a dog.
abstract: BACKGROUND
  The identification of Demodex mites from dogs is usually based on morphology and location. Mites with uncharacteristic features or from unusual locations, hosts or disease manifestations could represent new species not previously described; however, this is difficult to determine based on morphology alone.
  
  
  OBJECTIVE
  The goal of this study was to identify and confirm Demodex injai in association with otitis externa in a dog using PCR amplification and DNA sequencing.
  
  
  METHODS
  Otic samples were obtained from a beagle in which a long-bodied Demodex mite was identified. For comparison, Demodex mite samples were collected from a swab and scraping of the dorsal skin of a wire-haired fox terrier and an otic sample from a dog with generalized and otic demodicosis. To identify the Demodex mite, DNA was extracted, and 16S rRNA was amplified by PCR, sequenced and compared with Demodex sequences available in public databases and from separate samples morphologically diagnosed as D. injai and Demodex canis.
  
  
  RESULTS
  PCR amplification of the long-bodied mite rRNA DNA obtained from otic samples was approximately 330 bp and was identical to that from the mite morphologically identified as D. injai obtained from the dorsal skin of a dog. Furthermore, the examined mite did not have any significant homology to any of the reported genes from Demodex spp.
  
  
  CONCLUSIONS
  These results confirmed that the demodex mites in this case were D. injai.
authors.affiliation: Department of Small Animal Clinical Sciences, University of Tennessee, Knoxville, TN 37996-4544, USA.
authors.forename: Milivoj A
authors.initials: MA
authors.lastname: Milosevic
authors.forename: Linda A
authors.initials: LA
authors.lastname: Frank
authors.forename: Rupal A
authors.initials: RA
authors.lastname: Brahmbhatt
authors.forename: Stephen A
authors.initials: SA
authors.lastname: Kania
mesh_terms: D000818:Animals; D004247:DNA / Q000235:genetics* / Q000302:isolation & purification; D004283:Dog Diseases / Q000469:parasitology* / Q000473:pathology; D004285:Dogs; D004423:Ear / Q000469:parasitology*; D005260:Female; D008925:Mites / Q000235:genetics*; D010032:Otitis Externa / Q000469:parasitology / Q000662:veterinary*; D010802:Phylogeny; D016133:Polymerase Chain Reaction / Q000379:methods*; D017422:Sequence Analysis, DNA / Q000662:veterinary
chemical_list: D004247:DNA