Comparative Study of Colorimetric In Situ Hybridization and Quantitative Real-Time Polymerase Chain Reaction for Diagnosis of Infection by in Dogs in Formalin-Fixed and Paraffin-Embedded Skin.

The zoonotic visceral leishmaniasis is caused by the protozoan and dogs are reservoirs for this parasite. For the diagnosis of at the species level in dogs in formalin-fixed, paraffin-embedded skin (FFPES) samples, colorimetric in situ hybridization (CISH) and quantitative real-time polymerase chain reaction (qPCR) are options, but their sensitivities are not well established. Therefore, the aim of this study was to determine the sensitivity of these two techniques in FFPES for the diagnosis of the infection in dogs using culture as the reference standard. The FFPES of 48 dogs with cutaneous infection by confirmed by culture and by multilocus enzyme electrophoresis were examined by CISH and qPCR using specific probes for . The sensitivities of qPCR, CISH and their combination were, respectively, 77.0%, 58.0% and 83.3%. The sensitivities of qPCR in dogs with and without clinical signs were, respectively, 74.2% and 82.4%. The sensitivities of CISH in dogs with and without clinical signs were, respectively, 61.3% and 52.9%. The CISH and qPCR showed satisfactory sensitivities for the diagnosis of in the FFPES of dogs, even in dogs without clinical signs, and their combination increases the sensitivity for this diagnosis.