Ilam province has been identified as a major center for zoonotic cutaneous Leishmaniasis (ZCL) in western Iran. The present study was conducted with the objective of investigating the infectivity of Phlebotomus spp. with Leishmania major in Mehran city of Ilam province, Iran. The present study was conducted during the two seasons of the peak mosquito activity, i.e. summer and autumn of 2019. The sticky papers method was utilised for the collection of sandflies. The installation of 400 sticky paper traps resulted in the collection of 2,860 sandflies (950 females and 1,910 males) over the course of two seasons. The female Phlebotomus genus and species were identified using the Iranian standard identification key. Subsequently, Leishmania DNA was extracted from the female Phlebotomus specimen using the phenol-chloroform method, and the ITS1 gene was amplified by PCR. Subsequently, a comparison was made between the genome sequence and the sequence of other samples in the GenBank database, utilizing bioinformatics software. In conclusion, the species of the samples under investigation were determined according to the results of the phylogenetic tree. Furthermore, the parasite species was determined by utilizing the HaeIII restriction enzyme. Of the 617 Phlebotomus female samples collected, 34 were found to be infected with the Leishmania parasite. Of these, 32 (5.18%) of Ph. papatasi and 2 (0.32%) of Ph. sergenti were found to be infected. The results of the RFLP method and sequencing indicated that these mosquitoes were infected with only L. major. It is evident, based on the findings of this study, that ZCL type of Leishmaniasis is prevalent in Mehran city. It is imperative that the findings of this study be given greater consideration by the health officials of the province.
Keywords: ITS1 Gene; Iran; Mehran; sandflies; L. major.