en Other Other Letter to the Editor Letter to the Editor <p dir="ltr"><span style="font-family:times new roman;"><span style="color: black;">[No Abstract] Crimean-Congo hemorrhagic fever (CCHF) is considered as the most important arboviral infection in Iran. Early diagnosis of CCHF is essential for preventing the spread of the infection and providing appropriate treatment to patients. Given that clinical symptoms of CCHF may overlap with other common infectious disease; differential diagnosis is a matter of great importance. In this report, we describe a case of rheumatoid arthritis intoxicated with methotrexate mimicking CCHF. This observation suggests that non-infectious medical conditions such as drug toxicity should be considered</span> as a possible differential diagnosis of CCHF.</span></p> [No keywords] Crimean-Congo Hemorrhagic Fever, Differential Diagnosis, Methotrexate 37 38 http://jommid.pasteur.ac.ir/browse.php?a_code=A-10-132-1&slc_lang=en&sid=1 Mehdi Fazlalipour mfp.virology@gmail.com No Department of Arboviruses and Viral Hemorrhagic Fevers (National Reference Laboratory), Pasteur Institute of Iran, Tehran, Iran Vahid Baniasadi baniasadivahid@gmail.com No Department of Arboviruses and Viral Hemorrhagic Fevers (National Reference Laboratory), Pasteur Institute of Iran, Tehran, Iran Mohammad Hassan Pouriayevali Mhpouriayevali@yahoo.com No Department of Arboviruses and Viral Hemorrhagic Fevers (National Reference Laboratory), Pasteur Institute of Iran, Tehran, Iran Tahmineh Jalali jalalitahmineh@gmail.com No Department of Arboviruses and Viral Hemorrhagic Fevers (National Reference Laboratory), Pasteur Institute of Iran, Tehran, Iran Tahereh Mohammadi tahereh.mohammadi12@gmail.com No Department of Arboviruses and Viral Hemorrhagic Fevers (National Reference Laboratory), Pasteur Institute of Iran, Tehran, Iran Sanam Azad-Manjiri s.a_92@yahoo.com No Department of Arboviruses and Viral Hemorrhagic Fevers (National Reference Laboratory), Pasteur Institute of Iran, Tehran, Iran Yasaman Jamshidi YASAMAN.JAMSHIDIII@gmail.com No Department of Arboviruses and Viral Hemorrhagic Fevers (National Reference Laboratory), Pasteur Institute of Iran, Tehran, Iran Sara Azizizadeh saraazizi15@yahoo.com No Department of Arboviruses and Viral Hemorrhagic Fevers (National Reference Laboratory), Pasteur Institute of Iran, Tehran, Iran Motahareh Hosseini mt.hosseini1991@gmail.com No Department of Arboviruses and Viral Hemorrhagic Fevers (National Reference Laboratory), Pasteur Institute of Iran, 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 Mostafa Salehi-Vaziri mostafavaziri1985@gmail.com Yes Department of Arboviruses and Viral Hemorrhagic Fevers (National Reference Laboratory), Pasteur Institute of Iran, Tehran, Iran