Context
- Why in News: India’s expansion of environmental pathogen monitoring (wastewater, soil, audio signals) for early detection of infectious diseases and variants.
- Definition: Monitoring pathogens (viruses, bacteria, parasites) in environmental samples like sewage, soil, hospital effluents, or even audio signatures (cough recordings).
- Purpose: Detect hidden circulation of infectious agents in a community before clinical cases surge.
- Approach: Complements traditional clinical surveillance by capturing infections from both symptomatic and asymptomatic individuals.
Relevance
- GS Paper 2 (Health, Governance): Public health systems, disease surveillance, pandemic preparedness.
- GS Paper 3 (Science & Tech, Environment): Environmental sampling technologies, data science, epidemiology.
Why Environmental Surveillance is Important
- Early Warning System: Pathogen levels in wastewater rise days to weeks before clinical cases peak.
- Captures Asymptomatic Carriers: Traditional surveillance misses those not tested or with mild symptoms.
- Real-time Tracking: Enables daily/weekly updates of community infection burden.
- Variant Detection: Genome sequencing of pathogens in wastewater reveals emerging mutations or new variants (COVID-19 example).
- Cost-Effective: One sewage sample can represent thousands of people — far cheaper than mass clinical testing.
- Programmatic Integration: Helps allocate hospital beds, medicines, vaccines, and public health resources in advance.
How Wastewater Sampling Works
- Sources of Samples:
- Sewage treatment plants
- Hospital effluents
- Public toilets, railway stations, airplanes
- Process:
- Rigorous collection protocols → lab analysis → PCR tests or sequencing → pathogen load quantified.
- Pathogens Monitored: Viruses (COVID-19, Polio, Influenza, Hepatitis A/E, Rotavirus), bacteria (Cholera, Typhoid), parasites (hookworm, roundworm).
Indian Experience & ICMR’s Initiative
- Polio Surveillance: First wastewater program in Mumbai, 2001, crucial in polio eradication.
- COVID-19: Environmental monitoring was initiated in five Indian cities; continued post-pandemic for variant tracking.
- ICMR 2025 Plan:
- Surveillance for 10 viruses (includes avian influenza, polio, COVID-19, hepatitis, etc.)
- Across 50 cities, with standardised protocols.
- Current Gaps:
- Limited data sharing across institutions.
- Lack of national template/framework for surveillance.
- Mostly project-driven, not integrated into national health surveillance systems.
Global Practices & Lessons
- 40+ years of use: Wastewater-based epidemiology used worldwide for measles, cholera, and polio.
- COVID-19: Countries like Netherlands, USA, and Australia ran nationwide wastewater monitoring networks to anticipate case surges.
- Global Health Security: Helps detect imported pathogens (airplane wastewater sampling for SARS-CoV-2).
Emerging Frontiers in Environmental Surveillance
- Audio Surveillance: Using cough recordings in public spaces + AI/ML to predict prevalence of respiratory diseases.
- Soil & River Sampling: For parasitic infections, AMR (antimicrobial resistance), and zoonotic spillovers.
- Metagenomics: Identifies novel pathogens from environmental samples before outbreaks occur.
Challenges for India
- Technical: Standardised protocols for collection, storage, sequencing.
- Institutional: Need a national wastewater surveillance framework, not scattered projects.
- Data Integration: Must link environmental data with Integrated Disease Surveillance Programme (IDSP).
- Funding & Capacity: Sustained investments needed; avoid short-lived project cycles.
- Privacy & Ethics: Must ensure aggregate data use; no targeting of specific communities.
Way Forward
- Develop National Wastewater Surveillance System (NWSS): On the lines of US CDC’s program.
- Integrate into IDSP & Health Grid: Combine environmental and clinical surveillance.
- Open Data Protocols: Standard templates across states/institutions.
- Expand to Antimicrobial Resistance (AMR) Tracking: Major emerging health threat.
- International Collaboration: Share methods and results with WHO’s Global Environmental Surveillance Network.
