Occurrence and reduction of gastrointestinal pathogens at wastewater treatment facilities in West Java, Indonesia

• Wastewater was analyzed for six gastrointestinal pathogens in West Java, Indonesia • Clostridium perfringens was detected in high frequency , followed by noroviruses • The detection ratio of bacteria and viruses in effluent samples was up to 75% • LRVs of the pathogens in centralized WWTF were lower than those of E. coli • C. perfringens was prevalent in decentralized WWTF throughout the year Indonesia has experienced a persistently high prevalence of gastrointestinal disease, yet lacking surveillance data. On the other hand, wastewater-based epidemiology is a promising tool which has gained attention to enhance public health surveillance. In this study, we assessed the presence of bacteria and viruses associated with gastrointestinal infectious diseases in wastewater samples collected from West Java. A total of 140 wastewater samples (70 influent and 70 effluent) were collected between March 2022 and February 2023 from two wastewater treatment facilities (WWTFs) employing stabilization pond and anaerobic upflow filter process, respectively. Among the six pathogens tested by quantitative polymerase chain reaction (three bacteria and three viruses), Clostridium perfringens was identified as the most prevalent in influent samples (71%; 50/70), followed by noroviruses of genogroups I (64%, 45/70) and II (51%, 36/70). The concentration of these pathogens in influent samples fluctuated between the dry and wet seasons, and detected in effluent samples, showing low log 10 reduction values (LRVs). The LRVs of pathogens were lower than those of Escherichia coli (3.1 ± 2.0) in the centralized WWTF. In the decentralized WWTF, the LRVs of pathogens and Escherichia coli were <1.0. Correlation analysis among the concentrations of bacteria and viruses, as well as principal component analysis, was conducted to evaluate the microbial profiles within the two WWTFs. The centralized WWTF exhibited a more pronounced separation between the influent and effluent samples, indicating a more effective treatment process compared to the decentralized system. In regions with limited clinical data availability, wastewater-based epidemiology can be applied to monitor the temporal dynamics of gastrointestinal pathogens circulating within the community, making it a potential tool for waterborne disease surveillance.