Tehran University of Medical Sciences Iranian Journal of Microbiology 2008-3289 17 6 2025 12 13 1023 1032 Parvaneh Bahrami Department of Environmental Health Engineering, Environmental Technologies Research Center, School of Public Health, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran Afshin Takdastan Department of Environmental Health Engineering, Environmental Technologies Research Center, Medical Basic Sciences Research Institute, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran Manoochehr Makvandi Department Virology, School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran Sahand Jorfi Department of Environmental Health Engineering, Environmental Technologies Research Center, Medical Basic Sciences Research Institute, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran Mohammad Karimi Baba Ahmadi Department of Medical Biotechnology, School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran Abdolkazem Neisi Department of Environmental Health Engineering, Environmental Technologies Research Center, Medical Basic Sciences Research Institute, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran 2025 02 09 2025 12 02 Background and Objectives: The presence of the BK virus in wastewater indicates pollution, as it is shed in the urine of infected individuals. Over fifty percent of the human population remains asymptomatic for the BK virus. Reactivation of the BK virus in immunosuppressed individuals can lead to serious health issues, including cystic hemorrhagic, nephritis, and kidney graft rejection. The BK virus is associated with various cancers, such as head and neck, prostate, bladder, and colorectal cancers. The urban wastewater inlets into the Karun River cause the river contamination. This study focused on detecting the BK virus in wastewater inlet in Karun River, Ahvaz city, Iran. Materials and Methods: Sixty raw wastewater samples were collected from diverse urban sources and concentrated using polyethylene glycol 6000 to isolate BK virus. The BK virus isolates were analyzed for genotypes and the non-coding control region (NCCR). Results: The Nested PCR results indicated that thirty-two out of sixty samples (53.33%) were positive for the BK virus. The phylogenetic analysis revealed the dominance of BK virus genotype Ib2, followed by genotype 4. The BK virus non-coding control region (NCCR) analysis identified an archetype strain. Conclusion: The sewage plant treatment should be implemented to remove pathogenic viruses specially BK virus and to curb the circulating of BK virus in human and environment. https://ijm.tums.ac.ir/index.php/ijm/article/view/5292 https://ijm.tums.ac.ir/index.php/ijm/article/download/5292/1850