Tehran University of Medical Sciences Iranian Journal of Parasitology 1735-7020 9 3 2014 09 15 329 335 EN Mohammad Matini Dept. of Medical Parasitology and Mycology, School of Medicine, Hamadan University of Medical Sciences, Hamadan, Iran AND Dept. of Medical Parasitology and Mycology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran. Sassan Rezaie Dept. of Medical Parasitology and Mycology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran. Mahdi Mohebali Dept. of Medical Parasitology and Mycology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran AND Center for Research of Endemic Parasites of Iran (CREPI), Tehran University of Medical Sciences, Tehran, Iran. Amir-Hossein Maghsood Dept. of Medical Parasitology and Mycology, School of Medicine, Hamadan University of Medical Sciences, Hamadan, Iran. Soghra Rabiee Dept. of Obstetrics and Gynecology, Fatemieh Women Hospital, School of Medicine, Hamadan University of Medical Sciences, Hamadan, Iran. Mohammad Fallah Dept. of Medical Parasitology and Mycology, School of Medicine, Hamadan University of Medical Sciences, Hamadan, Iran. Mostafa Rezaeian Dept. of Medical Parasitology and Mycology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran AND Center for Research of Endemic Parasites of Iran (CREPI), Tehran University of Medical Sciences, Tehran, Iran. 2015 10 14 Background: Trichomonas vaginalis is the agent of urogenital tract infection that causes human trichomoniasis with some serious health complications. More understanding about genetic features of the parasite can be helpful in the study of the pathogenesis, drug susceptibility and epidemiology of the infection. For this end,we conducted analysis of the actin gene of T. vaginalis by applying the PCR-SSCP(PCR-Single Stranded Conformational Polymorphism) and nucleotide sequencingmethod. Methods: Fifty T. vaginalis samples were collected from 950 women attending gynecology clinics in two cities of Iran, Hamadan and Tehran, from November 2010 to July 2011. After axenisation of isolates, all samples subjected to PCR-SSCP and nucleotide sequencing. Results: According to the SSCP banding patterns and nucleotide sequencing, seven sequence types were detected among the isolates. Alignment of the nucleotide sequences showed five polymorphic sites in the different strain types. Amino acid substitution was not observed in the nucleotide sequence translation of the all sequences. Conclusion: The actin gene analysis represents genetic diversity of T. vaginalis and it suggests that various strains can be responsible for clinically different trichomoniasis in infected individuals. It is expected that further studies will be conductedto increase our knowledge about relationship between the actin gene polymorphism and different biological behavior of the parasite. https://ijpa.tums.ac.ir/index.php/ijpa/article/view/395 https://ijpa.tums.ac.ir/index.php/ijpa/article/download/395/349