indicator bacteria

Water Research

• Typical crAssphage concentration reported 4.8-9.1 log 10 gc/L in untreated wastewater. • CrAssphage showed 93% specificity and 92% sensitivity to human fecal pollution. • Typical LRV of crAssphage in WWTP is 1.0–2.9 log 10 and depends on treatment process. • CrAssphage is an effective human fecal indicator for microbial source tracking in water. • Crassphage has good potential as a performance indicator of virus reduction in WWTP. Viral indicators of human-fecal contamination in wastewaters and environmental waters have been getting much attention in the past decade. Cross-assembly phage (crAssphage) is the most abundant DNA virus in human feces. Recently, the usefulness of crAssphage as a microbial source tracking and water quality monitoring tool for human-fecal contamination has been highlighted. Here, we conducted a comprehensive review on crAssphage in water, focusing on detection methodology, concentration range in various waters and wastewaters, specificity to human-fecal contamination, and reduction in wastewater treatment systems. This review highlights that crAssphage is globally distributed in wastewaters and various fecal-contaminated water bodies at high concentrations without seasonal fluctuations. CrAssphage is highly specific to human-fecal contamination and is rarely found in animal feces. It also has a good potential as a performance indicator to ensure virus reduction in wastewater treatment systems. Accordingly, crAssphage could be an effective tool for monitoring of human-fecal contamination and potential presence of fecal pathogenic microbes in environmental waters. Bridging the research gaps highlighted in this review would make crAssphage a powerful tool to support the control of water-related health risks.

CrAssphage as an indicator of human-fecal contamination in water environment and virus reduction in wastewater treatment