Trends of adenovirus occurrence in drinking and wastewater treatment plants of the city of Hamadan, Iran

Despite significant advancements in water treatment, waterborne disease outbreaks are being reported from across the globe. A total of 29 source and treated water samples from the two drinking water treatment plants (DWTPs), and 32 influent and effluent water samples from the municipal wastewater treatment plant (WWTP) were collected in the city of Hamadan, Iran. In addition, eight municipal sewage samples were collected. The samples were concentrated by polyethylene glycol precipitation, and nucleic acids were extracted and assayed for Adv using standard PCR, nested PCR and real-time PCR targeting the hexon gene. More than half (55.1%) of the samples tested positive for AdV by at least one of the detection methods. In the WWTP, 63.6% of influent and 80% of effluent samples tested positive, indicating ineffective viral removal during the treatment process. Whereas, in the DWTPs, 50% of source and 28.6% of treated water samples tested positive, indicating a more effective viral removal by the DWTP. Among the molecular techniques employed, nested PCR demonstrated superior sensitivity. The study identifies the trend of adenovirus occurrence and the effective methods for determining their prevalence and the potential risk of viral exposure from the municipal water systems in the city of Hamadan, Iran.