Two-step concentration of complex water samples for the detection of viruses

The accurate detection and quantification of pathogenic viruses in water is essential to understand and reduce the risk of human infection. This paper describes a two-step method suitable for the concentration of viruses in water and wastewater samples. The method involves a tangential flow ultrafiltration step that reduces the sample volume of 1-10 l to approx. 50 ml, followed by secondary precipitation using polyethylene glycol 6000 that reduces the volume to 1-4 ml. For method validation, water samples were spiked with different concentrations of enteric viruses and viral recoveries in the concentrates exceeded 10% in all experiments. The method is suitable for water samples with high and low salinity and turbidity, allowing the accurate comparison of viral titers in a diverse range of water types. Furthermore, the method has the potential to concentrate other pathogens, e.g. bacteria or protozoa. Hence, the use of this method can improve the holistic assessment of risks associated with wastewater-contaminated environments.