title: RT-qPCR for the diagnosis of dermatophilosis in horses.
abstract: BACKGROUND
  Dermatophilus congolensis causes a crusting dermatitis that affects horses. Diagnosis requires the identification of the organism with cytological evaluation of crust samples. This method can lack sensitivity in chronic cases.
  
  
  OBJECTIVE
  To develop a probe-based real time quantitative polymerase chain reaction (RT-qPCR) test to assist with the diagnosis of dermatophilosis in horses.
  
  
  METHODS
  Twenty six privately owned horses and seven horses from a research colony were used.
  
  
  METHODS
  Crust samples, collected from 14 horses with suspected dermatophilosis and 12 horses with crusting skin disease not characteristic of dermatophilosis, were evaluated by cytological evaluation and RT-qPCR; the latter was also performed on hair samples collected from seven healthy horses.
  
  
  RESULTS
  Cytological evaluation revealed organisms consistent with Dermatophilus congolensis from nine horses with suspected dermatophilosis, with only a few organisms seen from five samples. Cytological evaluation of all other crusts was negative for Dermatophilus. Other bacterial organisms were detected on cytological evaluation from 15 samples. RT-qPCR for Dermatophilus was positive from 11 crusts, whereas all other samples were negative. Two samples were cytologically negative but RT-qPCR positive for Dermatophilus. No samples were cytologically positive but RT-qPCR negative for Dermatophilus.
  
  
  CONCLUSIONS
  Results of this study show that RT-qPCR may be a more sensitive and easier method than cytological evaluation for the diagnosis of dermatophilosis in horses.
authors.affiliation: Department of Small Animal Clinical Sciences, University of Tennessee, 2407 River Drive, Knoxville, TN, 37996, USA. lfrank@utk.edu.
authors.forename: Linda A
authors.initials: LA
authors.lastname: Frank
authors.affiliation: Department of Biomedical and Diagnostic Sciences, University of Tennessee, 2407 River Drive, Knoxville, TN, 37996, USA.
authors.forename: Stephen A
authors.initials: SA
authors.lastname: Kania
authors.affiliation: Department of Biomedical and Diagnostic Sciences, University of Tennessee, 2407 River Drive, Knoxville, TN, 37996, USA.
authors.forename: Ellie
authors.initials: E
authors.lastname: Weyant
mesh_terms: D039903:Actinobacteria / Q000302:isolation & purification*; D000818:Animals; D016908:Gram-Positive Bacterial Infections / Q000175:diagnosis / Q000382:microbiology / Q000662:veterinary*; D006734:Horse Diseases / Q000382:microbiology*; D006736:Horses; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods / Q000662:veterinary*; D017192:Skin Diseases, Bacterial / Q000382:microbiology / Q000473:pathology / Q000662:veterinary*