Evaluation and molecular characterization of human adenovirus in drinking water supplies: viral integrity and viability assays

Fongaro, Gislaine; Nascimento, Mariana A do; Rigotto, Caroline; Ritterbusch, Giseli; da Silva, Alessandra D’ A; Esteves, Paulo A; Barardi, Célia R M

The efficiency of the viral recovery using the concentration method described by Katayama et al. (2002) [13] was measured. When analyzing the samples from all sites (1, 2, and 3), the recovery rate was approximately 10%, as evaluated with both PFU and GC units. The PA value (PFU/mL) equivalence, when compared to ICC-RT-qPCR values (GC/mL) immediately after the concentration of water samples and after a series of decimal dilutions (10 0 to 10 -8 ), is shown in Figure 1 . The average equivalence of a PFU unit for GC was 3.4 logs, which means that 10 2 PFU is equivalent to 10 5 GC. This proportionality was confirmed via statistical testing (Linear Regression test) conducted with GraphPad Prism version 5.0 (USA). The ICC-RT-qPCR assay was more sensitive than the PA in the detection of HAdV, demonstrating a detection limit of 1×10 2 GC/mL (decimal dilution 10 -7 ), while the PA had a detection limit of 1×10 1 PFU/mL (decimal dilution 10 -3 ) (Figure 1 ).