Persistence of human astrovirus in fresh and marine water

Large gastroenteritis outbreaks associated with astroviruses are being reported with increasing frequency suggesting that astrovirus may be an important agent of epidemic acute non-bacterial gastroenteritis in children and adults. In this study, a procedure, based on infection of CaCo-2 cell monolayers followed by reverse-transcription polymerase chain reaction, was developed to ascertain the persistence of infectious human astroviruses in tap and marine water at 4±1°C and 20±1°C. The adequacy of this methodology for monitoring the decay of infectious fastidious viruses was assessed by determining the survival of a cytocidal virus (poliovirus 1) concomitantly by MPNCU and cell infection plus RT-PCR. After 60d in dechlorinated tap water, the decay of astrovirus infectivity was lower than 2 logs at 4±1°C and around 3.6 logs at 20±1°C, while after 90d the titre reduction was around 3.3 and 4.3 logs at 4±1°C and 20±1°C respectively. In natural non-autoclaved seawater at 20°C, astrovirus showed a lower level of persistence. The possibility to acquire data on the survival of fastidious viruses in the environment opens new perspectives on the epidemiology of some health significant infections transmitted by the faecal-oral route.