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Abstract
The goal of this study was to survey the concentrations of rotaviruses (RVs) and enteroviruses (EVs) in raw sewage using reverse transcription droplet digital PCR (RT-ddPCR) and to compare the use of ViroCap filters, polyethylene glycol/sodium chloride (PEG/NaCl) precipitation and mixed cellulose ester (HA) filter methods for virus recovery. Sewage samples were collected from lagoons in Kenya (KE) (5 L, n = 10) and Michigan (MI), United States (USA) (10 L, n = 10). From four wastewater treatment plants (WWTPs) in Virginia (VA), USA (0.05 L, n = 42) and one WWTP in California (CA) (2 L, n = 18). Samples were concentrated either using ViroCap, PEG/NaCl or HA filter method. Nucleic acid was extracted using either the QIAamp Viral RNA Mini Kit or the bioMerieux NucliSens easyMag. Detection and quantification of RV and EV was done using RT-ddPCR. Rotavirus was detected at a geometric mean concentration of 1.31E + 05 genome copies/L (gc/L) (CA), 2.71E + 04 gc/L (KE) and 1.48E + 05 gc/L (VA). Enterovirus at 1.39E + 06 gc/L (CA), 3.72E + 06 gc/L (KE) and 6.18E + 03 gc/L (VA). The mean RV concentrations using PEG and ViroCap methods in MI lagoon was statistically significant (p < 0.01). The bag-mediated filtration system (BMFS) using ViroCap filters was an inexpensive method when concentrating large volumes. Therefore, we recommend the use of BMFS with ViroCap for routine monitoring of viruses in polluted water sources in low resource countries while PEG and HA filters can be used across all environmental virology laboratories where resources are available.
