en Infectious diseases and public health Infectious diseases and public health Case Report Case Report <div style="text-align: justify;"><span style="font-size:11pt"><span style="background:white"><span style="line-height:normal"><span style="tab-stops:45.8pt 91.6pt 137.4pt 183.2pt 229.0pt 274.8pt 320.6pt 366.4pt 412.2pt 458.0pt 503.8pt 549.6pt 595.4pt 641.2pt 687.0pt 732.8pt"><span calibri="" style="font-family:"><span style="font-size:10.0pt"><span new="" roman="" style="font-family:" times=""><span style="color:#221f1f">A 53-year-old male farmer presented with clinical manifestations consistent with Crimean-Congo Hemorrhagic Fever (CCHF) virus infection, reporting a recent history of tick bite. To confirm the diagnosis, molecular and serological assays were performed on four specimens collected following the onset of illness. Reverse transcription-polymerase chain reaction (RT-PCR) detected CCHF virus RNA in the initial sample, while serum immunoglobulin M (IgM) antibodies were undetectable in all specimens. Notably, a robust immunoglobulin G (IgG) antibody response was observed across all samples.</span></span></span><span style="font-size:10.0pt"><span new="" roman="" style="font-family:" times=""><span style="color:#221f1f"> The concurrence of detectable viral RNA with the presence of IgG antibodies, but the absence of IgM, in the acute phase sample suggests a potential case of CCHF virus re-infection. These findings hold significant implications for public health, particularly regarding our understanding of CCHF virus infection dynamics, diagnostics, and vaccine development strategies.</span></span></span></span></span></span></span></span></div> Crimean-Congo Hemorrhagic Fever, Re-infection, Iran, Case report, RT-PCR 156 162 http://jommid.pasteur.ac.ir/browse.php?a_code=A-10-441-9&slc_lang=en&sid=1 Mostafa Salehi-Vaziri mostafavaziri1985@gmail.com 0000-0001-8892-8505 No Department of Arboviruses and Viral Hemorrhagic Fevers (National Reference Laboratory), Pasteur Institute of Iran, Tehran, Iran Tahmineh Jalali jalalitahmineh@gmail.com 0000-0002-1183-4356 No Department of Arboviruses and Viral Hemorrhagic Fevers (National Reference Laboratory), Pasteur Institute of Iran, Tehran, Iran Ali Asghar Bolandakhtar kargar.mh@gmail.com No Educational and Treatment Centre, Valiasr Hospital, Kerman University of Medical Sciences, Shahrebabak, Iran Mehdi Fazlalipour mfp.virology@gmail.com 0000-0001-9367-6955 No WHO Collaborating Center for Reference and Research on Rabies, Pasteur Institute of Iran, Tehran, Iran Ehsan Mostafavi mostafaviehsan@gmail.com 0000-0002-1997-517X No Department of Epidemiology and Biostatistics, Research Centre for Emerging and Reemerging Infectious Diseases Sana Eybpoosh 0000-0002-2304-8352 No Department of Epidemiology and Biostatistics, Research Centre for Emerging and Reemerging Infectious Diseases Vahid Baniasadi 0000-0002-8479-0593 No Department of Arboviruses and Viral Hemorrhagic Fevers (National Reference Laboratory), Pasteur Institute of Iran, Tehran, Iran Mahsa Tavakoli 0000-0001-8474-5381 No Department of Arboviruses and Viral Hemorrhagic Fevers (National Reference Laboratory), Pasteur Institute of Iran, Tehran, Iran Tahereh Mohammadi 0000-0002-5555-1075 No Department of Arboviruses and Viral Hemorrhagic Fevers (National Reference Laboratory), Pasteur Institute of Iran, Tehran, Iran Sanam Azad-Manjiri 0009-0008-0546-6703 No Department of Arboviruses and Viral Hemorrhagic Fevers (National Reference Laboratory), Pasteur Institute of Iran, Tehran, Iran Motahareh Hosseini 0009-0008-0546-6703 No Department of Arboviruses and Viral Hemorrhagic Fevers (National Reference Laboratory), Pasteur Institute of Iran, Tehran, Iran Zahra Fereydouni 0009-0008-0546-6703 No Department of Arboviruses and Viral Hemorrhagic Fevers (National Reference Laboratory), Pasteur Institute of Iran, Tehran, Iran Mohammad Mehdi Gouya 0000-0002-0288-8790 No Centre of Disease Control (CDC), Ministry of Health, Tehran, Iran Gary P Kobinger 0009-0008-0546-6703 No Département de microbiologie-infectiologie et d’immunologie, Université Laval, Quebec City, Quebec, Canada Mohammad Hassan Pouriayevali M.H.Pouria@gmail.com 0000-0003-0133-1517 Yes Department of Arboviruses and Viral Hemorrhagic Fevers (National Reference Laboratory), Pasteur Institute of Iran, Tehran, Iran; Research Center for Emerging and Reemerging Infectious Disease, Pasteur Institute of Iran, Tehran, Iran