Pepper mild mottle virus in wastewater in Egypt: a potential indicator of wastewater pollution and the efficiency of the treatment process

There is increasing evidence that the fecal indicator bacteria that are routinely used for testing water quality are inadequate for ensuring protection of the public health. Pepper mild mottle virus (PMMoV) has recently been suggested as an alternative indicator of human fecal contamination in water; however, in Egypt there are no data available about its occurrence and concentration in aquatic environment. The concentration of PMMoV in the influent and effluent of three wastewater treatment plants was measured using qRT-PCR over a period of one year and compared to that of human adenovirus (HAdV), which is considered an indicator for human fecal contamination. PMMoV was detected in similar to 94% of the influent samples and 78% of the effluent samples, with concentrations ranging from 3.9 x 10(4) to 3.3 x 10(8) genome copies/l (GC/l) in the influent and 3.9 x 10(4) to 1.2 x 10(7) GC/l in the effluent. Similarly, HAdV was identified in 88% and 78% of the influent and effluent samples, respectively. The HAdV concentration ranged between 1.5 x 10(4) and 1.5 x 10(7) GC/l for the influent and 2.6 x 10(4) and 4.4 x 10(6) GC/l for the effluent. No significant difference was found between the removal ratio of PMMoV and HAdV. Viral reduction of 0.2-1.9 log(10) and 0.2- 2.3 log(10) by the treatment process was observed for PMMoV and HAdV, respectively. Both viruses showed no clear seasonality. Our data support the use of PMMoV as a fecal indicator of wastewater contamination and a process indicator for the performance of the treatment process.