Efficiency of Reovirus Concentration from Water with Positively Charged Filters

Comparison of four concentration methods of adenovirus, norovirus and rotavirus in tap water

Human enteric viruses, as adenovirus (HAdV), norovirus (HuNoV) and rotavirus (RVA) are significant causes of gastroenteritis associated with consumption of contaminated water worldwide. Various methods have been described for their detection and monitoring in water. The aim of this study was to compare the performance of four conditions for concentrating HAdV, HuNoV and RVA from water matrices, in order to develop a single protocol that could simultaneously concentrate all target viruses from tap water. The tested conditions were based on the adsorption-elution using electronegative filters, in which we evaluated cation-coated filtration by MgCl2 with or without acid rinse by H2SO4 and two elution buffers, namely NaOH and tris-glycine-beef extract. Genomic material was extracted and amplified by real-time PCR and real-time RT-PCR using commercial kits. Based on the statistical analysis of amplification results (cycles of quantification), the condition involving cation-coated filtration by MgCl2 using electronegative filters with acid rinse by H2SO4 combined with NaOH elution allowed efficient recovery of both HAdV, HuNoV and RVA from tap water compared to the other conditions. These findings confirm the effectiveness of the approach used to monitor three major enteric viruses in tap water.

Assessing the Occurrence of Waterborne Viruses in Reuse Systems: Analytical Limits and Needs

Detection of waterborne enteric viruses is an essential tool in assessing the risk of waterborne transmission. Cell culture is considered a gold standard for detection of these viruses. However, it is important to recognize the uncertainty and limitations of enteric virus detection in cell culture. Cell culture cannot support replication of all virus types and strains, and numerous factors control the efficacy of specific virus detection assays, including chemical additives, cell culture passage number, and sequential passage of a sample in cell culture. These factors can result in a 2- to 100-fold underestimation of virus infectivity. Molecular methods reduce the time for detection of viruses and are useful for detection of those that do not produce cytopathogenic effects. The usefulness of polymerase chain reaction (PCR) to access virus infectivity has been demonstrated for only a limited number of enteric viruses and is limited by an understanding of the mechanism of virus inactivation. All of these issues are important to consider when assessing waterborne infectious viruses and expected goals on virus reductions needed for recycled water. The use of safety factors to account for this may be useful to ensure that the risks in drinking water and recycled water for potable reuse are minimized.