Climate and Land Use Effects on Pathogenic Bacteria in Fluvial Systems: Trends, Risks, and Mitigation Strategies

Much of the world’s population lives along the banks of rivers, depending on them as a water source for multiple purposes. As such, the presence of human bacterial pathogens in fluvial systems poses a major threat to public health. Efforts have been made to strengthen predictions of how future changes to climate and land use will affect pathogen concentration and bacterial community composition to minimize health and environmental risk. However, current models often overlook the interdependence between climate change and land use. This interdependence creates nonlinear, potentially synergistic effects that challenge traditional modelling approaches. Beyond the historical reliance on fecal indicator bacteria as proxies, recent advances in genomics, in-situ sensing, and artificial intelligence-based modelling now enable more pathogen-specific assessments and scenario analyses of future microbial water quality. Process-based catchment models coupled with socioeconomic pathways can identify spatial pathogen hotspots, quantify seasonal contamination shifts, and evaluate management interventions under different climate and land use scenarios. Interventions range in scale from local solutions such as wastewater infrastructure upgrades to broad management strategies including policy change. By employing next-generation models that account for dynamic feedbacks between climate change and land use, and by incorporating pathogen-specific data, researchers and decision-makers can develop more accurate water quality predictions. This integrated approach enables the implementation of targeted strategies to safeguard river water quality in both urban and rural contexts worldwide.