QJVMS (2018) Vol. 17 No. (2) 6 th (1 st international) Scientific Conference 27-28 Sep. 2017 Al-Qadisiyah Journal of Veterinary Medicine Sciences (P-ISSN 1818-5746/ E-ISSN 2313-4429) www.qu.edu.iq/journalvm 99 Research article Identification of Leishmania donovani in blood of experimentally infected rats by quantitative real-time PCR Noor Idan Jarad Ghaidaa Abbas Jasim Department of Microbiology and Parasitology, College of Veterinary Medicine, University of Al-Qadisiyah, Iraq Corresponding Author Email: Ghaidaa.Abass@qu.edu.iq (Received 17/8/2017, Accepted 23/12/2017) Abstract The present study has been carried out at the Department of Microbiology and Parasitology, College of Veterinary Medicine/Al-Qadisiyah University to diagnose the visceral leishmaniasis molecular technique (Quantitative real time polymerase chain reaction). Experimental study include fourth Wistar female rats (weighted 250 ± 2 g.) were injected by blood from infected patient in the peritoneal cavity, after 8-10 days of experimental infection , blood samples had been collected directly from the heart in order to diagnose the infection by using quantitative real time polymerase chain reaction. Quantitative Real Time PCR qPCR technique was used for amplification of conserved region in GAPDH gene that was used for detection of Leishmania donovani in blood samples of rats. It show the Amplification of genomic DNA template concentrations of Leishmania donovani during reaction with syber dye inside the apparatus under threshold cycle, also shows the melt peak of Leishmania donovani genomic DNA template concentrations is demonstrate the specialization of Leishmania donovani genomic DNA amplification in single peak for all samples. Keywords: Leishmania donovani, Rats, Experimental infection, Diagnosis, RT-PCR. Introduction Leishmania donovani is protozoan parasite belongs to Eukaryota, was discovered in parallel by Sir William Leishman in 1900 and by Charles Donovan in 1903 (1).The life cycle of Leishmania species are complex (2). These parasites remain in nature by transmission between mammalian hosts via the bite of infected female sand fly. Human becomes infected if he intrudes into this cycle (3). parasite Leishmania exist in two morphological stage, the promastigote (long flagellated form exist in the insect vector or in vitro culture at 25 C°) and amastigote (round, intracellular parasite, without free flagellum exist in mammalian host cell (4).Some studies found that the molecular basis for amastigote survival in the mammalian host, previously identified an amastigote stage-specific gene family termed ‘‘A2’’ whose corresponding mRNA and protein are abundant in amastigotes but are largely absent in promastigotes (5). Several lines of evidence have indicated that the A2 gene/protein family could be one of the most eligible factors of virulence in VL infections (6).There are at least seven members of the A2 gene family that encode a family of proteins ranging from 45 to 100 kDa and that are specific to the amastigote stage (7). A2 proteins are mainly comprised of a repetitive amino acid sequence; each repeat encodes a stretch of 10 amino acids (8). Diagnosis of Leishmaniasis is performed by direct visualization of amastigotes using microscopic examination of stained material