Tehran University of Medical Sciences Iranian Journal of Parasitology 1735-7020 17 1 2022 03 14 79 89 Lida Khaleghi Rostamkolaie Department of Parasitology, Faculty of Veterinary Medicine, Shahid Chamran University of Ahvaz, Ahvaz, Iran Hossein Hamidinejat Department of Parasitology, Faculty of Veterinary Medicine, Shahid Chamran University of Ahvaz, Ahvaz, Iran Mohammad Hossein Razi Jalali Department of Parasitology, Faculty of Veterinary Medicine, Shahid Chamran University of Ahvaz, Ahvaz, Iran Hossein Najafzadeh Varzi Department of Pharmacology, Cellular and Molecular Biology Research Center, Babol University of Medical Sciences, Babol, Iran Massoud Reza Seifi Abadshapouri Department of Parasitology, Faculty of Veterinary Medicine, Shahid Chamran University of Ahvaz, Ahvaz, Iran Hedieh Jafari Department of Venomous Animal and Biological Product, Razi Vaccines and Serum Research Institute, Agricultural Re-search Education and Extension Organization, Ahvaz, Iran 2020 10 31 2021 06 15 Background: The present study determined the effect of the fractions obtained from Hemiscorpius lepturus scorpion venom on the tachyzoite of Toxoplasma gondii. Methods: The fractions of dried venom of He. lepturus scorpion of Khuzestan Province, southern Iran in 2019 were isolated through gel filtration chromatography, and then tachyzoites were exposed to fractions of venom at different concentrations. Trypan blue counting and MTT were applied to assay tachyzoite viability, and the inhibition of the cellular growth of fractions in Vero cells was evaluated. Results: The maximum effect on tachyzoite was observed in fraction 5 of venom. To further separate the protein, fraction 5 was used in high-performance liquid chromatography assay to purify its proteins. Based on the results of HPLC of fraction 5, among which the second peak, a peptide with <10 KDa representing a more potent effect in eliminating the tachyzoite of T. gondii. Conclusion: The scorpion venom-purified fractions possess anti-parasitic activity against the tachyzoite of T. gondii and can be used in parasite-controlling studies. https://ijpa.tums.ac.ir/index.php/ijpa/article/view/3139 https://ijpa.tums.ac.ir/index.php/ijpa/article/download/3139/1198