Human fecal markers in environmental waters and association with indicators of human and rodent infections in urban Salvador, Bahia, Brazil

This study explores the use of human mitochondrial DNA (mtDNA) markers, specifically hCYTB484, as fecal source tracking (FST) tools for environmental surveillance in a high-density, low-income community in Salvador, Bahia, Brazil. Here, we hypothesized that hCYTB484 concentrations in wastewater would correlate with indicators of human pathogen exposure, such as viral antibody prevalence and helminth infections in rodents, both of which are potential zoonotic threats. Our study found that higher concentrations of mtDNA in wastewater were associated with increased viral exposure in humans and the presence of helminths in rodents. This suggests that fecal mtDNA could serve as a promising tool for environmental surveillance of pathogens in vulnerable communities. Our findings underscore the potential of mtDNA markers to be integrated into disease monitoring systems, particularly in resource-limited urban areas with inadequate sanitation. Implementing mtDNA-based tracking in environmental waters could strengthen early-warning systems for public health, allowing for a more proactive response to emerging health threats. Further research is needed to deepen our understanding of pathogen circulation and inform more effective public health interventions.