Infectivity and genome persistence of rotavirus and astrovirus in groundwater and surface water

In this work, we have characterized the survival of Rhesus rotavirus (RRV) and human astrovirus Yuc8 in clean groundwater and contaminated surface water, as well as in phosphate-buffered solutions maintained in the same conditions as the environmental waters, and have compared the dynamics of virus inactivation with the persistence of the viral genomes, as determined by quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR). In addition, we also studied the tolerance of these viruses to chlorine disinfection. The reduction of infectivity of astrovirus was higher than for rotavirus, and also higher for both viruses in surface water as compared to groundwater. The enterobacterial content of the water as well as extrinsic factors, such as temperature and light, correlated with the stability of virus infectivity, and with the persistence of the virus genetic material, suggesting that molecular techniques to detect and quantify viral genomes would be suitable for the detection of viruses in water. The virus infectivity persisted in both types of water as well as in chlorine for times longer than previously reported. No decrease of infectivity was observed after 15 days of incubation in either type of water and the viruses remained infectious for months in groundwater. After 120 min in groundwater containing 2 mg/L of free chlorine, the infectivity of rotavirus and astrovirus was reduced by 0.78 and 1.3 logs, respectively. The longer persistence of viruses in this study could result from a combination of factors, including aggregation of the virus.