Tehran University of Medical Sciences Iranian Journal of Parasitology 1735-7020 15 1 2020 03 09 31 39 Shahrokh IZADI Department of Medical Parasitology and Mycology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran Mohammad Ali MOHAGHEGH Department of Laboratory Sciences, School of Paramedical Sciences, Torbat Heydariyeh University of Medical Sciences, Torbat Heydariyeh, Iran AND Health Sciences Research Center, Torbat Heydariyeh University of Medical Sciences, Torbat Heydariyeh, Iran Zahra GHAYOUR-NAJAFABADI Department of Medical Parasitology and Mycology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran Mehdi AZAMI Skin Diseases and Leishmaniasis Research Center, Isfahan University of Medical Sciences, Isfahan, Iran Farzaneh MIRZAEI Department of Medical Parasitology and Mycology, School of Medicine, Shahid Sadoughi University of Medical Sciences, Yazd, Iran AND Department of Laboratory Sciences, School of Para-Medicine, Shahid Sadoughi University of Medical Sciences, Yazd, Iran Fatemeh NAMDAR Department of Medical Parasitology and Mycology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran Mehdi MOHEBALI Department of Medical Parasitology, 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 Dhammika LESHAN WANNIGAMA Department of Microbiology, Faculty of Medicine, Chulalongkorn University, King Chulalongkorn Memorial Hospital, Bangkok, Thailand AND Davison of Pediatrics, School of Medicine, Faculty of Health and Medical Sciences, The University of Western Australia, Nedlands, Western Australia, Australia Seyed Hossein HEJAZI Department of Medical Parasitology and Mycology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran AND Skin Diseases and Leishmaniasis Research Center, Isfahan University of Medical Sciences, Isfahan, Iran 2020 03 09 Background: The purpose of this study was to determine the prevalence and genotype of Cryptosporidium spp. in different groups of immunocompromised patients admitted to the referral hospitals in center of Iran during 2015–2016. Methods: This cross-sectional study was conducted on 346 immunocompromised patients (HIV+/AIDS, Lymphoma, Leukemia and organ transplants) in referred hospitals from central parts of Iran including Isfahan, Markazi, Yazd and Chaharmahale Bakhtiari provinces. Stool samples were analyzed for Cryptosporidium species, modified Ziehl–Neelsen staining techniques followed by the semi-nested PCR and DNA sequencing methods. Results: The total rate of Cryptosporidium spp. was 3.46% (12/346) in the patients, however, the prevalence of the parasite, was 4.6% (4/87) in HIV+/AIDS patients, 3.6% (6/168) in patients with blood malignancy and 2.1% (2/91) in organ transplant recipients. The SSU rRNA gene of Cryptosporidium spp. in all microscopic-positive samples was effectively amplified by the semi-nested PCR and DNA sequences, exposed the existence of two Cryptosporidium species, including C. hominis 91.6% (11/12) and C. parvum 8.3% (1/12). Conclusion: The predominance of C. hominis in the present study may be certifies the importance of anthroponotic transmission of cryptosporidiosis in center of Iran. https://ijpa.tums.ac.ir/index.php/ijpa/article/view/2830 https://ijpa.tums.ac.ir/index.php/ijpa/article/download/2830/1009