DNA-based detection of Leishmania and Crithidia species isolated from humans in cutaneous and post-kala-azar dermal leishmaniasis from Shiraz and Kharameh, southern Iran.

Abstract

Leishmania major and L. tropica are the main pathogens of cutaneous leishmaniasis (CL) in several rural and some urban regions of Iran, respectively. The aim of this study was to detect Leishmania species, and update the distribution data of these species in humans suspected to CL in two endemic foci in southern Iran. From March 2016 to March 2017, 276 positive samples from of 350 suspected cases were diagnosed and compared by different diagnostic methods, viz. microscopy, culture, and PCR. In PCR assay, four different gene identifications were performed including minicircle kDNA, and cysteine protease B genes for Leishmania detection, and glyceraldehyde-3-phosphate dehydrogenase, and internal transcribed spacer 1 genes for Crithidia detection. In total, 68% (235/350) and 65.3% (177/271) of patients suspected of leishmaniasis were positive by microscopy and cultivation methods. In PCR assay, L. major, and L. tropica were detected in 86.2% (238/276), and 13.1% (36/276) of CL cases, respectively. Also, dermal L. infantum strain was isolated from 0.7% (2/276) of post-kala-azar dermal leishmaniasis patients. In addition, Crithidia fasciculata was detected in two CL patients chronically infected with L. major. It appears that the epidemiology of CL has changed during the last decades and can complicate the control strategy aspects of CL in southern Iran. Therefore, more epidemiological, ecological, and gene polymorphism studies are needed to understand the pathogenic role of these species in human, as a main host of leishmaniasis in Iran.