en Infectious diseases and public health Infectious diseases and public health Original article Original article <p dir="ltr"><strong><span style="font-family: garamond,serif;"><span style="font-size: 10pt;">Introduction:</span></span></strong> <span style="font-family: garamond,serif;"><span style="font-size: 10pt;">Livestock is a known source of Crimean-Congo Hemorrhagic Fever (CCHF) virus infection in humans. Although CCHF is endemic in Iran, limited human cases of CCHF are reported from northwest of Iran. Considering the lack of complete and updated information on the status and distribution of CCHF infection among domestic animals in Ardabil province, this study was conducted to investigate the CCHF status among sheep in this area. <strong>Methods: </strong>In this study, 256 sera from sheep were collected from various geographical regions of Ardabil in 2011, and tested for specific CCHF IgG antibodies by ELISA. <strong>Results: </strong>The Seroprevalence of CCHF in this area was 27.34%. The seropositivity rate of CCHF in northern regions (36.36%) was higher than in central (26.27%) and southern (20%) regions. The highest and lowest seropositivity of CCHF were seen in Parsabad (45.57%) and Khalkhal counties (17.78%), respectively. <strong>Conclusions:</strong> In this study, a relatively high seroprevalence of CCHF was seen among livestock in the province. Therefore, health care system should increase its surveillance for the detection of CCHF patients. Molecular studies to compare the virus strains circulating in this province and those in the eastern regions of the country can shed more light on the epidemiology of the disease.</span></span></p> CCHF, Seropositivity, Epidemiology, Zoonosis, Iran 16 19 http://jommid.pasteur.ac.ir/browse.php?a_code=A-10-134-1&slc_lang=en&sid=1 Ehsan Mostafavi mostafavi@pasteur.ac.ir Yes Department of Epidemiology and Biostatistics, Research Centre for Emerging and Reemerging Infectious Diseases, Pasteur Institute of Iran, Tehran, Iran Fahimeh Bagheri Amiri drop.dr.bagheri@gmail.com No Urology and Nephrology Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran Sahar Khakifirouz sahar_khakifirouz@yahoo.com No Department of Arboviruses and Viral Hemorrhagic Fevers (National Reference Laboratory), Pasteur Institute of Iran, Tehran, Iran Saber Esmaeili dr.saberesmaeili@gmail.com No Department of Bacteriology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran Fatemeh Kazemi-Lomedasht fatemeh1044@yahoo.com No Department of Epidemiology and Biostatistics, Research Centre for Emerging and Reemerging Infectious Diseases, Pasteur Institute of Iran, Tehran, Iran