Molecular diagnosis of Canine Leproid Granuloma out of paraffin-embedded histological cuts using polymerase chain reaction (PCR) – a retrospective study (2002-2009)

Abstract

Canine leproid granuloma or “canine leprosy” is a mycobacteriosis that has a dermatopathic framework, which includes aspects that are still unclear, especially regarding its mode of transmission and etiological agent. In order to verify the genetic characterization of the mycobacteria that is involved in the condition, the present study analyzed histological cuts from animals with an established diagnosis of such disorder. The study samples were taken from of 13 dogs that were assisted at the HOVET / USP Dermatology Service. This material was subsequently subjected to “nested” and real-time polymerase chain reaction (PCR). The nested PCR confirmed the presence of the agent in 18.7% of the animals, whereas the real-time PCR detected 69.2% of samples with DNA of the mycobacterium, thus proving that such method presents higher sensitivity. Furthermore, it was observed that the species of mycobacterium that causes Canine Leproid Granulnoma in dogs from Brazil presents a 100% genetic homology when compared to samples obtained from animals in studies abroad.