RESUMO
AIMS: To provide a rapid and sensitive method for detecting NoV GI and NoV GII in water and to evaluate the use of the murine norovirus (MNV-1) as a process control. METHODS AND RESULTS: The method is based on viral concentration by filtration on electropositive filters and direct lysis of adsorbed viruses from filters before RNA extraction and RT-qPCR amplification. An one-step multiplex RT-qPCR assay was developed for the simultaneous detection of NoV GI, NoV GII and MNV-1. Then, water samples were artificially contaminated to determine mean virus recoveries and method sensitivity. The method showed a higher sensitivity for detecting NoV GII (10(3) genome copies per 0·5 l) than for NoV GI (10(4) genome copies per 0·5 l) in the presence of MNV-1 regardless of the type of water. The data also showed that MNV-1 is a robust option as process control. CONCLUSIONS: The method described provides a valuable tool for the monitoring of potential public health risks associated with NoV contamination in drinkable water. SIGNIFICANCE AND IMPACT OF STUDY: Given the increasing evidence for NoV involvement in food outbreaks, the one-step multiplex RT-qPCR assay we used in this study would be a very useful tool to investigate NoV contamination in other food products.
