The development of a real-time PCR assay for the quantification of Leishmania infantum DNA in canine blood.

Recent research has demonstrated the high sensitivity of real time PCR (qPCR) in the diagnosis of Leishmania infantum infection. The goal of this study was to develop and evaluate a qPCR detection system for the diagnosis of visceral leishmaniosis (VL) in dogs. Specific primer sets were developed for the Leishmania donovani complex, in which a fragment of 132 bp of kDNA from L. infantum was amplified. The reaction was performed using the ABI PRISM 7000 system with ABI PRISM software used to carry out the analysis. When canine blood samples were assessed using this system the detection limit of the method was found to be 0.07 parasites per reaction, the efficiency was 94.17% (R(2)=0.93, slope=-3.47) and the sensitivity and specificity were 100% and 83.33% respectively. The use of such a sensitive, reproducible and rapid qPCR-based assay will be useful in the diagnosis and control of L. infantum infection in endemic areas, where serological surveys often underestimate true disease prevalence.