Tehran University of Medical Sciences Iranian Journal of Parasitology 1735-7020 16 2 2021 05 28 279 288 EN Parisa Shahbazi 1. Department of Pathobiology, Faculty of Veterinary Medicine, University of Tabriz, Tabriz, Iran Ahmad Nematollahi Department of Pathobiology, Faculty of Veterinary Medicine, University of Tabriz, Tabriz, Iran Sanaz Arshadi Department of Pathobiology, Faculty of Veterinary Medicine, University of Tabriz, Tabriz, Iran Hosein Hashemzadeh Farhang 1. Department of Pathobiology, Faculty of Veterinary Medicine, Islamic Azad University Tabriz branch, Tabriz, Iran Amir Ali Shahbazfar Department of Pathobiology, Faculty of Veterinary Medicine, University of Tabriz, Tabriz, Iran 2019 12 08 2021 05 28 Background: A specific treatment has not yet developed for cryptosporidiosis, and some of the used drugs had side effects in immunodeficient patients. The goal of an appropriate remedy is to remove symptoms and improve immune responses in hosts. The current study was designed to evaluate the therapeutic efficacy of Artemisia spicigera ethanolic extract in experimentally infected immunosuppressed mice. Methods: Thirty six NMRI mice, 4-6 wk old, were randomly divided into six equal groups. C1: uninfected, treated control; C2: infected, untreated control; T1, T2, T3, and P: infected, treated with 0.2, 2, and 20 mg/ml extract, and 5mg/ml paromomycin, respectively. Mice were experimentally infected by oral administration of 104 oocysts/animal of Cryptosporidium parvum and treated orally for eight days per 12h, starting 12h before experimental infection. The presence of oocyst shedding, weight gain/loss, and the histopathology of ileum sections were examined. Results: Results revealed that oocyst shedding was significantly (P<0.05) reduced in treatment groups. There was no significant difference between the mean of weight gain/loss in the infected control and treated groups. Histopathological analysis of ileum sections further supported the parasitological findings. Conclusion: Artemisia spicigera had acceptable efficacy as a therapeutic agent for cryptosporidiosis. https://ijpa.tums.ac.ir/index.php/ijpa/article/view/2738 https://ijpa.tums.ac.ir/index.php/ijpa/article/download/2738/1133