en Parasitologiy Parasitologiy پژوهشي Research <div><strong>Introduction:</strong> Sheep farming is one of the most important economic aspects of the livestock industry in Gilan province, Iran. Toxoplasmosis is a prevalent zoonotic disease and a major cause of abortion, congenital infection, and stillbirth in animals and humans. Previously, it was assumed that sheep are mostly infected with <em>Toxoplasma gondii</em> (<em>T. gondii</em>) after birth. Nevertheless, recent studies have shown that <em>T. gondii </em>congenital transmission is more prevalent than previously speculated. Therefore, determining the genotypes of this parasite in the intermediate host plays an important role in human infections and prevention programs. This cross-sectional study aimed to determine the <em>T. gondii</em> genetic diversity in aborted ovine fetuses during the lambing season (2018-2019) in Gilan province, Iran.<br> <strong>Materials and Methods:</strong> Molecular detection of <em>T. gondii </em>was performed in 44 brain tissue samples, collected from aborted ovine fetuses, using a nested polymerase chain reaction (nested-PCR) assay, to target the <em>GRA6</em> gene. Also, the nested-PCR products belonging to the <em>GRA6</em>-positive samples underwent genotyping with the help of <em>Tru1I </em>(<em>MseI</em>) restriction enzyme using the PCR-restriction fragment length polymorphism (PCR-RFLP) method to classify strains into one of the three major lineages of <em>T. gondii</em><em>.</em><br> <strong>Results:</strong> The results revealed infection in 30 (68.18%) out of 44 brain samples of aborted ovine fetuses, based on the nested-PCR assay with <em>GRA6 </em>gene<em>. </em>Also, the PCR-RFLP results demonstrated the predominance of type II <em>T. gondii</em> in all of the isolates.<br> <strong>Conclusion: </strong>Overall, the present results revealed the high incidence of <em>T. gondii</em> infection through congenital transmission.This is the first molecular detection and genotyping of&nbsp;<em>T. gondii</em>&nbsp;in ovine aborted fetuses in Gilan Province, Iran.</div> Toxoplasmosis, Sheep, Abortion, Genotyping, Iran 53 62 http://jbrms.medilam.ac.ir/browse.php?a_code=A-10-518-1&slc_lang=en&sid=1 Mohammad Reza Chaechi Nosrati mohammadchaichi1@gmail.com 10031947532846004143 10031947532846004143 No Department of Pathobiology, Faculty of Veterinary Medicine, Science and Research Branch, Islamic Azad University, Tehran, Iran Bahar Shemshadi bshemshadi@yahoo.com 10031947532846004144 10031947532846004144 Yes Department of Pathobiology, Faculty of Veterinary Medicine, Science and Research Branch, Islamic Azad University, Tehran, Iran Parviz Shayan pshayan@ut.ac.ir 10031947532846004145 10031947532846004145 No Department of Parasitology, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran Shahrokh Ranjbar Bahadori bahadory_2000@yahoo.com 10031947532846004146 10031947532846004146 No Department of Parasitology, Faculty of Veterinary Medicine, Garmsar Branch, Islamic Azad University,Gamsar, Iran Ali Eslami alieslami1936@gmail.com 10031947532846004147 10031947532846004147 No Department of Parasitology, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran