Quantitative study of persistence of human norovirus genome in water using TaqMan real-time RT-PCR

Abstract

To evaluate the persistence of human norovirus (NoV) in different types of water at various temperatures using conventional and TaqMan real-time reverse transcription-PCR (RT-PCR). Water from different sources was spiked with NoV and incubated at different temperatures over a 3-month period. NoV viral RNA was amplified by one-step TaqMan real-time RT-PCR and by conventional two-step RT-PCR. NoV persisted in mineral and tap water for over 2 months at all tested temperatures but disappeared after 100 days. At 4 and -20 degrees C, viral degradation was slower than that at 25 degrees C. In river water and effluent from primary sewage treatment, a slight reduction in viral load was observed after 1 month at 4 degrees C. This is the first demonstration of medium-to-long-term survival of human NoVs in different types of water using TaqMan real-time detection. NoV genome may persist for long periods of time in different types of water. Quantitative TaqMan real-time RT-PCR is a sensitive system that allows accurate evaluation of the persistence of human NoVs in different water samples. Our study is one of the few to demonstrate the ability of NoV to survive for a long time in water.