Presence, infectivity, and stability of enteric viruses in seawater: relationship to marine water quality in the Florida Keys

Concerns about the presence of enteric viruses in the surface waters of the Florida Keys prompted analyses of virus stability and persistence in these waters. In an in vitro study we evaluated the survival of poliovirus and stability of viral RNA in filtered natural seawater (FSW), unfiltered natural seawater (USW), artificial seawater (ASW) and DI water. This study compared cell culture infectivity with direct reverse transcription–polymerase chain reaction analysis. Attenuated poliovirus was seeded in the above water types and incubated in the dark at 22 and 30 °C for 60 days. At 22 °C, enhanced poliovirus survival and enhanced detection of viral RNA was observed in the seeded DI water control, artificial seawater and FSW samples. Detection of viruses in unfiltered seawater decreased rapidly at both temperatures by both methods of detection, suggesting that in the natural environment detection of enteroviral RNA may indicate a recent contamination event. In addition, in situ sampling in the Florida Keys during the late winter of 2000 revealed the presence of infectious enteroviruses at two sites and no sites exceeded recommended levels of microbial water quality indicators (enterococci or fecal coliform bacteria).