Evaluation of Murine Norovirus, Feline Calicivirus, Poliovirus, and MS2 as Surrogates for Human Norovirus in a Model of Viral Persistence in Surface Water and Groundwater

Abstract

ABSTRACT Human noroviruses (NoVs) are a significant cause of nonbacterial gastroenteritis worldwide, with contaminated drinking water a potential transmission route. The absence of a cell culture infectivity model for NoV necessitates the use of molecular methods and/or viral surrogate models amenable to cell culture to predict NoV inactivation. The NoV surrogates murine NoV (MNV), feline calicivirus (FCV), poliovirus (PV), and male-specific coliphage MS2, in conjunction with Norwalk virus (NV), were spiked into surface water samples ( n = 9) and groundwater samples ( n = 6). Viral persistence was monitored at 25°C and 4°C by periodically analyzing virus infectivity (for all surrogate viruses) and nucleic acid (NA) for all tested viruses. FCV infectivity reduction rates were significantly higher than those of the other surrogate viruses. Infectivity reduction rates were significantly higher than NA reduction rates at 25°C (0.18 and 0.09 log 10 /day for FCV, 0.13 and 0.10 log 10 /day for PV, 0.12 and 0.06 log 10 /day for MS2, and 0.09 and 0.05 log 10 /day for MNV) but not significant at 4°C. According to a multiple linear regression model, the NV NA reduction rates (0.04 ± 0.01 log 10 /day) were not significantly different from the NA reduction rates of MS2 (0.05 ± 0.03 log 10 /day) and MNV (0.04 ± 0.03 log 10 /day) and were significantly different from those of FCV (0.08 ± 0.03 log 10 /day) and PV (0.09 ± 0.03 log 10 /day) at 25°C. In conclusion, MNV shows great promise as a human NoV surrogate due to its genetic similarity and environmental stability. FCV was much less stable and thus questionable as an adequate surrogate for human NoVs in surface water and groundwater.