Low pressure ultraviolet inactivation of pathogenic enteric viruses and bacteriophages

To elucidate the roles of physical and chemical properties of viruses and their sensitivity to UV radiation, the kinetics and extent of inactivation of several waterborne pathogenic viruses and bacteriophages with different virion sizes and genomic composition by monochromatic, low-pressure (LP) UV was determined in phosphate buffered saline or a filtered drinking water. The inactivation rates of the small RNA viruses, poliovirus 1 and Coxsackievirus B4, by LP UV were very rapid and reached similar to 4 log(10) and >5 log(10), respectively, within a UV dose of 30 MJ/cm(2). In contrast, the inactivation of the small RNA bacteriophage, MS2, was much slower and only 2 log(10) inactivation was achieved at a UV dose of 30 mJ/cm(2). The inactivation of the large DNA virus, adenovirus 2, was relatively slow and only 2 log(10) inactivation was achieved with a UV dose of 60 mJ/cm(2). In contrast, the inactivation rates of the three large DNA bacteriophages were very rapid and reached >5 log(10) with a UV dose of 10 mJ/cm(2). Therefore, the results of this study indicate that inactivation of human enteric viruses and bacteriophages by UV irradiation is not simply predictable by the type and size of the virus or its nucleic acid genome and there is no strong correlation between virion size and genetic composition of enteric viruses and their response to LP UV irradiation.