Abundance and possibilities of crAssphage and PMMoV as a viral indicator in raw sewage in wastewater treatment plants

Given their abundance in human fecal samples, crAssphage and Pepper Mild Mottle Virus (PMMoV) are proposed as indicators for human enteric viruses. This study measured crAssphage and PMMoV in raw sewage samples (n = 24) between June 2014 and May 2015 from two wastewater treatment facilities in southern Arizona, USA. Both crAssphage and PMMoV were detected in nearly 100% of samples. The greatest incidence of crAssphage typically occurred during late-winter to spring seasons, as concentrations reached 8.63 and 8.38 log₁₀ copies/L in May and February. Meanwhile, PMMoV was significantly (p < 0.05) higher during the fall season, with concentrations at 8.69 and 9.12 log₁₀ copies/L in September and October. Among the two tested indicators, a positive correlation (p < 0.05) was observed between PMMoV and tested human enteric viruses (norovirus genogroups I, II, adenovirus, and Aichi virus). Due to abundance, presence, and correlation with other viruses, PMMoV may be used as an appropriate indicator for human enteric viruses.