Environmental pathogen surveillance in cities without universal conventional wastewater infrastructure

Area of Science:

• Environmental microbiology
• Public health surveillance
• Wastewater epidemiology

Background:

• Wastewater surveillance is crucial for community health but limited in low- and middle-income countries due to lack of conventional services.
• Environmental surveillance beyond wastewater treatment plants (WWTPs) offers potential for public health insights in resource-limited settings.
• Understanding pathogen distribution in various environmental matrices is key to assessing exposure risks and informing interventions.

Purpose of the Study:

• To explore the utility of environmental surveillance for public health in Maputo, Mozambique, a city with limited conventional wastewater infrastructure.
• To measure pathogen, source-tracking marker, and fecal indicator bacteria concentrations across diverse environmental samples.
• To assess the potential for environmental pathogen surveillance to inform public health responses and intervention strategies.

Main Methods:

• Collected samples from WWTP influent/effluent, surface discharges, river water, soils, open drains, stormwater, and fecal sludges.
• Utilized multi-parallel RT-qPCR to detect a wide range of pathogens across all environmental matrices.
• Developed a pooled regression model to analyze pathogen concentrations and their association with environmental factors like precipitation.

Main Results:

• A broad spectrum of pathogens was detected in all sampled matrices, revealing complex pathogen flow dynamics.
• Pathogen concentrations were lower in treated effluent, surface discharges, drains, river water, and stormwater compared to WWTP influent.
• Increased 7-day cumulative precipitation was significantly associated with higher pooled pathogen concentrations across all matrices.

Conclusions:

• Environmental pathogen surveillance is a viable strategy for informing public health responses in urban areas lacking comprehensive wastewater systems.
• The frequent detection of pathogens in various environmental compartments highlights potential exposure routes and the need for targeted interventions.
• Findings support the expansion of environmental surveillance approaches to enhance public health monitoring and disease prevention in resource-limited settings.