Tehran University of Medical Sciences Journal of Arthropod-Borne Diseases 2322-1984 13 2 2018 10 12 198 205 Afshin Barazesh Department of Microbiology and Parasitology, Faculty of Medicine, Bushehr University of Medical Sciences, Bushehr, Iran Mohammad Hossein Motazedian Department of Parasitology and Mycology, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran Moradali Fouladvand The Persian Gulf Marine Biotechnology Research Center, Bushehr University of Medical Sciences, Bushehr, Iran Gholamreza Hatam Department of Parasitology and Mycology, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran Saeed Tajbakhsh The Persian Gulf Marine Biotechnology Research Center, Bushehr University of Medical Sciences, Bushehr, Iran Sepideh Ebrahimi Department of Parasitology and Mycology, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran Danial Purkamal Diagnostic Lab of Leishmaniasis, Valfajr Health Center, Shiraz University of Medical Sciences, Shiraz, Iran 2019 06 15 Background: Leishmania major and Leishmania tropica are two main species causing cutaneous leishmaniasis (CL) in Iran. Recently, Crithidia spp. has also been reported in the wound of patients with CL. In this study, we determined the species causing CL in the southern of Iran and the role of Crithidia spp. in creating skin ulcers. Methods: In this cross-sectional study from Apr to Sep 2016, 66 patients with CL referred to Diagnostic Lab of Leishmaniasis, Valfajr Health Center, Shiraz, Iran, were selected. After DNA extraction from the Giemsa stained smears, all samples were amplified in two separate steps using specific primers, firstly, to differentiate Leishmania species and then to identify Crithidia spp. Results: Two species L. major and L. tropica were responsible for 60 and 6 cases, respectively. Moreover, in two patients, mixed infection with Crithidia was confirmed. In mix infection cases, the morphology of the cutaneous ul­cers was not different from the wounds of other patients. Conclusion: Leishmania major is responsible for the most common CL in southern Iran. In addition, in two patients with L. major and L. tropica, mix infection with Crithidia was confirmed. The potential role of Crithidia as the main factor for CL and the probability of this parasite to have synergistic effects on Leishmania, as a hypothesis, requires more comprehensive researches on the ambiguity of this protozoon. https://jad.tums.ac.ir/index.php/jad/article/view/1141 https://jad.tums.ac.ir/index.php/jad/article/download/1141/456