Frequent and abundant Merkel cell polyomavirus detection in urban wastewaters in Italy

Viruses strongly associated with human cancer have recently been detected in urban sewages and other water environments worldwide. The aim of the present study was to assess the presence of Merkel cell polyomavirus (MCPyV), a newly discovered, potentially oncogenic human virus, in urban sewage samples collected at wastewater treatment plants (WTPs) in Italy. A total of 131 raw sewage samples were collected from 21 WTPs in nine Italian regions and analyzed by both qualitative (PCR/nested) and quantitative (Real-Time qRT-PCR) methods. Of these, 66 samples (50.3 %) were positive for MCPyV by the qualitative assay. Quantitative data showed high viral loads in wastewaters (mean, 1.5E + 05 genome copies/liter). High concentrations of MCPyV were found in all WTPs under study, suggesting a wide circulation of the virus and thus the need for further studies to assess possible waterborne MCPyV transmission.