Adenovirus is the most prevalent enteric virus in waters worldwide due to its environmental stability, leading to a public health concern. Mitigation strategies are therefore required.The aim of this study was to assess the inactivation of human adenovirus type 5 (HAdV-5) by gamma radiation in aqueous environments. Various substrates with different organic load, including domestic wastewater, were inoculated with HAdV-5 either individually or in a viral pool (with MNV-1), and irradiated in a Co-60 irradiator at several gamma radiation doses (0.9 – 10.8 kGy). The infectivity of viral particles, before and after irradiation, was tested by plaque assay using A549 cells. D10 values were estimated for each substrate based on virus infectivity inactivation exponential kinetics. The capability of two detection methods, nested-PCR and ELISA, to track inactivated viral particles was also assessed.After irradiation at 3.5 kGy it was obtained a reduction on HAdV-5 titer of 4 log PFU/ml on subtracts with lower organic load, but in highly organic matrixes the virus titer reduction was only 1 log PFU/ml. The D10 values of HAdV-5 in high organic substrates were significantly higher than in water suspensions. The obtained results point out some discrepancies between nested-PCR, ELISA and plaque assay on the assessments of HAdV-5 inactivation.These results suggest that the inactivation of HAdV-5 by gamma radiation, in aqueous environments, is significantly affected by the substrate composition. This study highlights the virucidal potential of gamma radiation that might be used as disinfection treatment for sustainable water supplies.
Adenovirus (HAdV) is the most prevalent of enteric viruses in environmental waters worldwide. The intended outputs of this study are to open new insights on the inactivation of enteric virus by gamma irradiation and to introduce new concepts and re-inforce the benefits and utility of radiation technologies as a disinfection process. It may be an effective tool to guarantee the reduction of viral pathogens and to contribute for public health and sustainable water supplies.