From plant pathogen to public health tool: A review of tobamoviruses and their role in wastewater & environmental surveillance.

Since the pandemic, interest in Wastewater and environmental surveillance (WES) has expanded rapidly, alongside advances in PCR-based detection and the need for reliable normalization strategies. One widely adopted approach to quantification in WES involves normalizing pathogen measurements using human-associated fecal biomarkers such as tobamoviruses. While pepper mild mottle virus and tomato brown rugose fruit virus have been extensively studied and utilized in hundreds of WES studies, the broader tobamovirus genus remains relatively underexplored. We reviewed over 270 published studies, assessed the suitability of 43 tobamoviruses for application as indicators of human fecal contamination or for normalization biomarkers for WES applications. Tobamoviruses were systematically evaluated based on host range, likelihood of human dietary exposure and gastrointestinal passage, environmental persistence, and evidence of detection in wastewater. This analysis identifies 11 tobamoviruses with significant potential as current or emerging biomarkers across diverse geographic and dietary contexts. Our analyses identify 11 tobamoviruses with significant potential as biomarkers across global wastewater contexts. Tobamoviruses have proven suitable for wastewater and environmental surveillance normalization due to their frequent and high-volume introduction into the human food chain through staple crops, in which they induce only mild or asymptomatic infections. This results in reliable, high-abundance measurements in municipal wastewater.