High prevalence of tomato brown rugose fruit virus in domestic wastewater as a potential viral indicator for treatment systems

Waterborne pathogenic viruses present a critical public health challenge, particularly in potable water reuse systems where stringent safety standards must be met. Achieving the necessary Log Reduction Values (LRVs) for viruses in water treatment remains difficult due to their low prevalence and high detection limits. This study investigated tomato brown rugose fruit virus (ToBRFV) as a novel viral indicator to assess advanced treatment efficacy of advanced treatment systems in achieving target Log10 Reduction Values (LRVs) for pathogenic viruses. Over 13 months, wastewater samples from the Reno-Sparks Metropolitan Region (Nevada, USA) were analyzed using metagenomics and RT-qPCR to compare ToBRFV, pepper mild mottle virus (PMMoV), and MS2 bacteriophage. Results demonstrated that ToBRFV was consistently detected at high concentrations across all samples, exhibiting minimal seasonal variability. In contrast, PMMoV showed moderate fluctuations, while MS2 was detected at lower levels. The robustness and stability of ToBRFV suggest it could serve as a reliable indicator for verifying LRVs in potable reuse systems, complementing existing methods. Additionally, its plant-based origin reduces human health risks during handling. These findings support ToBRFV’s potential to enhance treatment monitoring and public health safeguards. Further research should validate its applicability across diverse geographic and climatic conditions, as well as its correlation with enteric virus removal, to optimize water reuse frameworks.