Unlocking the Potential of Wastewater Surveillance
As the world grappled with the COVID-19 pandemic, a unique collaboration emerged in the city of Prayagraj, Uttar Pradesh, showcasing the power of wastewater-based epidemiology (WBE) in public health monitoring. Partnering with the esteemed Centre for Cellular and Molecular Biology (CCMB) in Hyderabad, the Prayagraj district administration embarked on a groundbreaking initiative to harness the insights hidden within the city’s wastewater.
Wastewater surveillance is a powerful tool that can provide an early warning system for disease outbreaks, allowing public health authorities to stay one step ahead of the curve. By analyzing the presence and concentration of disease-causing pathogens in wastewater samples, officials can detect the circulation of viruses, bacteria, and parasites within a community, even before clinical cases are reported.
This approach has proven particularly valuable during the COVID-19 pandemic, when many individuals remained asymptomatic for several days after contracting the SARS-CoV-2 virus. Wastewater surveillance filled this critical gap, enabling authorities to monitor trends and identify hotspots in disease concentration across different sewage treatment plants (STPs) and open drains within the city.
In Prayagraj, the collaboration between local administrators and CCMB scientists has been running smoothly since late 2022, setting a precedent for effective public-private partnerships in the realm of public health monitoring. This initiative serves as a shining example of how wastewater surveillance can be leveraged to tackle not only COVID-19 but also a wide range of infectious diseases, including antimicrobial resistance (AMR) – a growing threat that demands a comprehensive, “One Health” approach.
Tracking COVID-19 and Beyond: The Prayagraj Model
The Prayagraj district, home to a population of over 1.2 million, has six STPs with a combined treatment capacity of around 270 million liters per day, processing nearly 60% of the city’s sewage. Each month, samples from these six STPs are meticulously collected during periods of higher sewage flow, typically between 7 am and 11 am, following a standard operating procedure (SOP) established by the CCMB scientists.
These wastewater samples are then securely packaged in a 1% sodium hypochlorite solution and transported to the CCMB laboratory in Hyderabad, where they typically arrive within 7 to 10 days. At the CCMB, researchers apply a molecular technique called RT-PCR to quantitatively detect the presence of SARS-CoV-2 in the wastewater samples.
The findings from this ongoing surveillance effort have been remarkably consistent with the daily COVID-19 caseloads gathered from laboratory test results, showcasing a striking correlation between the wastewater surveillance results and the clinical data, with a lead time of around 15 days.
“These findings mirror those obtained in other cities and countries, suggesting that wastewater surveillance can provide a 15-day advance warning for COVID-19,” explains the team behind the Prayagraj initiative.
The insights garnered from this collaboration have been actively shared within the public health community in the district, as well as with the state surveillance authorities in Lucknow, the capital of Uttar Pradesh. This exchange of information is crucial, as it paves the way for integrating wastewater surveillance into the decision-making processes of public health officials, enabling them to take proactive measures to contain the spread of infectious diseases.
Expanding the Scope: Tackling Antimicrobial Resistance and Beyond
While the Prayagraj initiative has primarily focused on tracking SARS-CoV-2, the team has also explored the potential of wastewater surveillance in detecting other pathogens and addressing the growing challenge of antimicrobial resistance (AMR).
Through genomic sequencing of the sewage samples, the researchers have identified a high concentration of certain microbes, such as Pseudomonas aeruginosa, a germ that can cause infections like pneumonia in humans. By taking a focused approach, they aim to trace the pathogens most likely to cause disease outbreaks in the local geography.
The efforts in Prayagraj also delve into the critical issue of AMR, a global health threat that arises when pathogens evolve to evade antimicrobial drugs, including antibiotics, antivirals, antifungals, and antiparasitics. Wastewater surveillance for AMR can provide invaluable insights, aiding in the understanding of the AMR profile within the community and the role of wastewater components, such as antibiotic residues from industries and mobile genetic elements, in fostering the emergence of antibiotic-resistant bacteria (ARBs).
“Wastewater plays a crucial role in the development and dissemination of AMR, as it serves as a habitat for ARBs and antimicrobial resistance genes (ARGs),” the team explains. “Sewage-based surveillance is widely employed to comprehend the occurrence and distribution of antimicrobial resistance in communities, which can help develop an early warning system for emerging diseases and antimicrobial resistance.”
The insights gleaned from the Prayagraj initiative have the potential to inform risk assessment, source tracking, and AMR management in urban environments, ultimately contributing to the broader “One Health” mission of the Indian government, which recognizes the interconnectedness of human, animal, and environmental health.
Navigating Challenges and Scaling Up Wastewater Surveillance
Despite the promising results from the Prayagraj model, the implementation of wastewater surveillance is not without its challenges, particularly in the context of low- and middle-income countries (LMICs) like India, where centralized wastewater management systems are often of low quality or even non-existent.
One of the key parameters for accurate COVID-19 prevalence estimation using WBE is the population size contributing to the fecal input in the wastewater. This is easier to determine in areas with centralized wastewater systems, as the size of the contributing population can be more accurately estimated.
However, the lack of robust wastewater infrastructure in many LMICs poses a significant hurdle, requiring creative solutions to mobilize the WBE approach effectively. One potential strategy is to divide large areas into smaller sub-areas, each corresponding to the existing wastewater management systems, and then coordinate with various stakeholders to estimate the population size for each sub-area.
Furthermore, the time lag between sample collection and the availability of results needs to be reduced to enhance the responsiveness of wastewater surveillance. Efforts are underway to develop digital systems capable of analyzing the data and assisting public health officials in interpreting the findings, including accounting for population and demographic differences across various catchment areas.
Despite these challenges, the potential of wastewater surveillance to transform public health monitoring remains immense. As the Prayagraj initiative has demonstrated, this approach can serve as an invaluable complement to traditional disease surveillance methods, providing early warnings, identifying hotspots, and informing decision-making processes.
Embracing the Future of Public Health Monitoring
The success of the Prayagraj model lies in its ability to transition from laboratory and research seminars to review meetings and discussions among administrators and public health officials. This seamless integration of wastewater surveillance into the decision-making framework is a crucial step in realizing its full potential.
Moreover, the applications of wastewater-based epidemiology extend far beyond infectious disease monitoring. Some countries are already utilizing this approach to track illicit drug use within their populations, while researchers have explored its potential in estimating socio-demographic characteristics and consumption patterns within specific catchment areas.
As the world grapples with emerging health challenges, the lessons learned from the Prayagraj initiative and other successful wastewater surveillance programs can serve as a blueprint for scaling up this innovative approach across India and beyond. By leveraging wastewater data to identify disease hotspots, monitor antimicrobial resistance, and inform public health interventions, we can enhance community resilience and pave the way for a healthier, more sustainable future.
The Joint Action for Water blog is proud to showcase the pioneering work of the Prayagraj-CCMB collaboration, demonstrating how wastewater surveillance can be a powerful tool in the arsenal of public health authorities. As we continue to navigate the complexities of global health challenges, the insights and lessons from this initiative will undoubtedly inspire and empower communities worldwide to embrace the transformative potential of wastewater-based epidemiology.
