Ferrihydrite treatment to mitigate inhibition of RT-qPCR virus detection from large-volume environmental water samples.

Highlights • Ferrihydrite (Fh) treatment was developed and optimized. • Fh treatment was able to effectively mitigate inhibition of RT-qPCR virus detection in humic acids and seawater concentrates. • Its recovery of viruses in heavily inhibited water samples ranged from 2% to 12%. • Fh treatment improved RT-qPCR detection of indigenous virus in seawater samples. Abstract Molecular assays are currently the most widely used method to quantify pathogenic viruses in water; however, their performance is often disrupted by matrices present in environmental samples. The present study used ferrihydrite (Fh) treatment to mitigate inhibition of RT-qPCR virus detection from environmental water concentrates. Fh treatment was performed to improve the detection of spiked Aichi virus 1 (AiV) and Qβ bacteriophage (Qβ) in commercial humic acids and seawater concentrates. The optimal Fh doses were found to be 200, 500, and 1000 mgFe/L for humic acid concentrates at UV 254 of 1.5, 3.0, and 6.0 cm−1 respectively, whereas this value was 1000 mgFe/L for the seawater concentrates at UV 254 of 1.5 cm−1. At these optimal doses, the recoveries of spiked AiV and Qβ ranged from 2% to 12% in the humic acid and seawater concentrates, respectively. In addition, high levels of indigenous viruses (including AiV ≥ 2.81 log 10 copies/mL and pepper mild mottle virus ≥ 2.77 log 10 copies/mL) were detected from seawater concentrates after Fh treatment, while none were detected without Fh treatment. Fh treatment effectively mitigated the inhibitive effects from environmental water samples. [ABSTRACT FROM AUTHOR]