Evaluation of Human Norovirus Genogroup-II (HNoV-II) Inactivation by Ozonated Water Using Quantitative PCR Combined with PMA Pretreatment

ABSTRACT

The disinfection efficiency of ozonation by ozonated water on human norovirus genogroup-II (HNoV-II) and MS2 as a surrogate was investigated using plaque assay and/or quantitative PCR (qPCR). The qPCR combining propidium monoazide (PMA) pretreatment was used to evaluate the damage to the viral capsids, which showed that the PMA pretreatment could be applied to HNoV-II but not to MS2 because PMA inhibited qPCR even in undamaged MS2. The ozonation reduced the viability of MS2 by more than 99.9999% (= 6 log; CT = 0.036 mgXmin/L) and the qPCR detection of HNoV-II by approximately 90–95%. However, it is assumed that significant damage to the HNoV-II capsid did not occur in all inactivated viruses.

KEYWORDS:

• HNoV-II
• MS2
• Ozonation
• PMA
• qPCR

Acknowledgments

The authors would like to express their gratitude to DG TAKANO Ltd. for the support of research funds and the provision of the equipment for this study.