Tehran University of Medical Sciences Iranian Journal of Parasitology 1735-7020 14 1 2019 03 10 52 58 EN Fariba BERENJI Department of Parasitology and Mycology, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran Seyed Aliakbar SHAMSIAN Department of Parasitology and Mycology, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran Marziyeh NOURI DALOEE Department of Thoracic Surgery, Cardiothoracic Surgery and Transplant Research Center, Mashhad University of Medical Sciences, Mashhad, Iran Seyed Hossein FATTAHI MASOOM Department of Thoracic Surgery, Cardiothoracic Surgery and Transplant Research Center, Mashhad University of Medical Sciences, Mashhad, Iran Elham MOGHADDAS Department of Parasitology and Mycology, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran 2017 10 08 2019 03 10 Background: Human hydatidosis is endemic in northeastern Iran. The present study aimed to investigate molecular diversity of Echinococcus granulosus isolates collected from human surgically. Methods: Sixty human hydatid cysts (58 lung cysts and 2 liver cysts) were collected through surgery from Ghaem and Emam Reza hospitals in Mashhad University of Medical Sciences during 2015-2016. Cysts were characterized using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis of the internal transcribed spacer 1 (ITS1) gene and sequencing fragments of the genes coding for mitochondrial cytochrome c oxidase subunit 1 (cox1) and NADH dehydrogenase subunit I (nad1). Results: Overall, 55 out of 60 Echinococcus granulosus cysts (91.6%) were determined as the G1 strain, 4 cases (6.6%) were determined as the G6 strain and 1 sample was not identified. Conclusion: Although sheep strain (G1) is dominated in human patients in Great Khorasan, the prevention of camel-dog cycle should pay attention in this region. https://ijpa.tums.ac.ir/index.php/ijpa/article/view/1813 https://ijpa.tums.ac.ir/index.php/ijpa/article/download/1813/912