title: Simulated sunlight inactivation of norovirus and FRNA bacteriophage in seawater.
abstract: OBJECTIVE
  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.
  
  
  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.
  
  
  CONCLUSIONS
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Marine Institute, Rinville, Oranmore, Co. Galway, Ireland. john.flannery@marine.ie
authors.forename: J
authors.initials: J
authors.lastname: Flannery
authors.forename: P
authors.initials: P
authors.lastname: Rajko-Nenow
authors.forename: S
authors.initials: S
authors.lastname: Keaveney
authors.forename: V
authors.initials: V
authors.lastname: O'Flaherty
authors.forename: W
authors.initials: W
authors.lastname: Doré
mesh_terms: D004203:Disinfection; D007494:Ireland; D029322:Norovirus / Q000528:radiation effects*; D012317:RNA Phages / Q000302:isolation & purification / Q000528:radiation effects*; D012621:Seasons; D012623:Seawater / Q000821:virology*; D013472:Sunlight; D013696:Temperature; D038301:Virus Inactivation / Q000528:radiation effects*; D014780:Viruses / Q000235:genetics / Q000302:isolation & purification; D014871:Water Microbiology
keywords: FRNA bacteriophage; RT-qPCR; norovirus; plaque assay; solar disinfection; virus inactivation