Simulated sunlight inactivation of norovirus and FRNA bacteriophage in seawater
Article first published online: 2 JUL 2013
© 2013 The Society for Applied Microbiology
Journal of Applied Microbiology
Volume 115, Issue 3, pages 915–922, September 2013
How to Cite
Flannery, J., Rajko-Nenow, P., Keaveney, S., O'Flaherty, V. and Doré, W. (2013), Simulated sunlight inactivation of norovirus and FRNA bacteriophage in seawater. Journal of Applied Microbiology, 115: 915–922. doi: 10.1111/jam.12279
- Issue published online: 14 AUG 2013
- Article first published online: 2 JUL 2013
- Accepted manuscript online: 13 JUN 2013 01:11AM EST
- Manuscript Accepted: 5 JUN 2013
- Manuscript Revised: 4 JUN 2013
- Manuscript Received: 22 MAR 2013
- Environmental Protection Agency. Grant Number: 2008-EH-MS-7-53
- FRNA bacteriophage;
- plaque assay;
- solar disinfection;
- virus inactivation
To investigate norovirus (NoV) and F-specific RNA (FRNA) bacteriophage inactivation in seawater under simulated sunlight and temperature conditions representative of summer (235 W m−2; 17°C) and winter (56 W m−2; 10°C) conditions in Ireland.
Methods and Results
Inactivation experiments were carried out using a collimated beam of simulated sunlight and 100 ml of filtered seawater seeded with virus under controlled temperature conditions. NoV concentrations were determined using RT-qPCR, and FRNA bacteriophage concentrations were determined using RT-qPCR and by plaque assay. For all virus types, the fluence required to achieve a 90% reduction in detectable viruses (S90 value) using RT-qPCR was not significantly different between summer and winter conditions. S90 values for FRNA bacteriophage determined by plaque assay were significantly less than those determined by RT-qPCR. Unlike S90 values determined by RT-qPCR, a significant difference existed between summer and winter S90 values for infectious FRNA bacteriophage.
This study demonstrated that RT-qPCR significantly overestimates the survival of infectious virus and is therefore unsuitable for determining the inactivation rates of viruses in seawater.
Significance and Impact of the Study
Results from this study provide initial data on the inactivation of NoV and FRNA bacteriophage in seawater under representative summer and winter conditions and will be of interest to shellfish and water management agencies alike.