A simple and innovative quantitative PCR analysis for diagnosis and therapy management of human cutaneous leishmaniasis

Leishmania infection manifests across various clinical syndromes, predominantly affecting humans in less developed regions globally. Cutaneous leishmaniasis (CL), caused by Leishmania major and transmitted by infected female sand flies, is a crucial neglected disease prevalent in tropical and subtropical areas. Diagnosis of leishmaniasis is performed mostly through staining of blood or skin samples, which can accompany some problems such as appropriate slide preparation avoiding artifacts, low amount of parasites, and expertise of the technicians. Therefore, it is important to develop an easy, sensitive, and specific method that harbors a quantitative aspect like a semi-quantitative method. We present a new, easy-to-handle, innovative, and specific quantitative method to detect L. major in skin lesions of suspicious leishmaniasis patients. For this aim, DNA was extracted from the promastigote form of L. major, human cells, and the slide smears prepared from the skin lesion. The quantitative PCR was performed with the primer pair derived from 18S rRNA genes of L. major and human gene, which can amplify the DNA of both origins simultaneously. As expected, the PCR product originating from human cells had a PCR product of 255 bp in length, whereas the PCR product originating from the parasite had a PCR product of 360 bp in length, which can be used for quantitative analysis. Since this method is innovative, sensitive, specific, and convenient, we believe that it can also be used for the management of successful therapy.