Context
- Pathogens (bacteria, viruses, parasites) that cause diseases in humans and animals can be detected in environmental samples like sewage, wastewater, or effluents.
- This method, called environmental surveillance (wastewater-based epidemiology), acts as an early-warning system for outbreaks.
How it Works
- Sample Sources: sewage treatment plants, hospital effluents, public toilets, even airplanes.
- Detection: Pathogens shed in stools/urine are tracked.
- Diseases covered: viral (COVID-19, polio, influenza), bacterial, parasitic (roundworm, hookworm).
- Protocols: Rigorous collection, storage, sequencing ensure pathogen identification and variant tracking.
Why it Matters
- Early-Warning Signals
- Pathogens appear in wastewater days/weeks before clinical cases rise.
- Example: COVID-19 viral load in sewage predicted surges ahead of testing data.
- Better Public Health Planning
- Captures asymptomatic and undiagnosed infections.
- Allows more accurate infection prevalence estimates.
- Complements clinical surveillance.
- Wastewater-Based Epidemiology
- Used globally since 2001 for polio eradication.
- Applied during COVID-19 pandemic.
- Potential for avian influenza, respiratory diseases.
- Cost-Effective & Scalable
- One wastewater sample = represents an entire community.
- Reduces cost of mass individual testing.
What is India Doing?
- ICMR initiative: launching wastewater surveillance for 10 viruses across 50 Indian cities.
- Scope: hospital + community sampling, standardized data-sharing protocols.
- Future prospects:
- Sampling cough/spit droplets in public places.
- AI/ML modelling for predictive epidemiology.